Can the MAF fail only when hot? (SL500)

[powerofgreen]

Guys, a very important input here!
I replaced the coil next to the engine; since it's the easiest to access and can be replaced in 10 min.
Well, it didn't change Anything absolutely in the idle.
But... I thought I would better test the voltage to see if there is any drop near the coil........
Guess what??
I measured 3 to 4 volts ONLY; at the primary, with the engine running!
I almost fainted... lol!
Directly I went to the trunk to test the battery voltage. Here are the results:
With engine off: 12.9 V
With engine running: 14.2 V
That rules out the possibility of a deffective alternator/battery.
I then measured the voltage at the second coil; same: 3 to 4 volts maximum!!!
I'm not an expert, but I think it should be around 12V to trigger the coils, right??
Even at the fuse box, the voltage was too low at the fuses.
That may explain why these days I have some troubles activating the outside auto folding mirrors...
Something in between the battery and the coils is shorting out or simply not conducting the current...

 

[Klink]

Attached picture of my rotor bracket.

That is a late version rotor bracket. Could you also post photos of the back of the rotor bracket, and, maybe even better, could you post a photo of the “side“ of the cylindrical portion of the rotor bracket showing the slot for the locating lug. Please also post photos of the front and rear of the rotors. Also, are you sure that your other rotor bracket is the same as the one in the picture? You mentioned “washers” earlier? Could you post a photo of the washers, state their quantity, and post a photo of where you found these washers?

 

[Klink]

Guys, a very important input here!
I replaced the coil next to the engine; since it's the easiest to access and can be replaced in 10 min.
Well, it didn't change Anything absolutely in the idle.
But... I thought I would better test the voltage to see if there is any drop near the coil........
Guess what??
I measured 3 to 4 volts ONLY; at the primary, with the engine running!
I almost fainted... lol!
Directly I went to the trunk to test the battery voltage. Here are the results:
With engine off: 12.9 V
With engine running: 14.2 V
That rules out the possibility of a deffective alternator/battery.
I then measured the voltage at the second coil; same: 3 to 4 volts maximum!!!
I'm not an expert, but I think it should be around 12V to trigger the coils, right??
Even at the fuse box, the voltage was too low at the fuses.
That may explain why these days I have some troubles activating the outside auto folding mirrors...
Something in between the battery and the coils is shorting out or simply not conducting the current...

If you measured the voltage ACROSS the primary terminals of the coil with the engine running, that reading is probably correct, or at least closer to “correct“ then you might imagine. These are low impedance coils and they are subject to significant charge current limiting by the EZL, especially at low engine speed. If these coils were only simply switched at conventional the dwell times without any current limiting they would burn up in short order. You must also bear in mind if you measured across the coil primary that just the nature of this voltage being cyclically switched would result in a reading significantly below 12V. Also bear in mind that you may be seeing the effects of induced voltage from the secondary spark discharge. Measure the voltage between the coil positive and chassis ground and see what you get. That will be more representative of your source voltage.

 

[Klink]

Now, to your point about possible low source voltage, this being a 129SL, it should be noted that there is a single output terminal of the ignition switch, that terminal being labeled “15Z” That terminal has one job, and that is to supply the ignition system with source voltage. I have seen a number of these switches fail by offering low or no voltage at 15Z.
In every case that I have seen this so far though, the engine would not start. That being said, if you do in fact have low source voltage at this or possibly some other systems in the car, the electrical portion of the ignition switch could be the culprit. This “barrel style” switch is used in slightly different electrical configurations on the 129, 140, and 210. I have seen them fail as I have described on all three of these models.

 

[powerofgreen]

That is a late version rotor bracket. Could you also post photos of the back of the rotor bracket, and, maybe even better, could you post a photo of the “side“ of the cylindrical portion of the rotor bracket showing the slot for the locating lug. Please also post photos of the front and rear of the rotors. Also, are you sure that your other rotor bracket is the same as the one in the picture? You mentioned “washers” earlier? Could you post a photo of the washers, state their quantity, and post a photo of where you found these washers?

Hi Klink! Thanks for the info, it's very helpful for me...
Unfortunately, I couldn't get to remove the 3rd allen head screw for both rotors! I'm away from home right now and I don't have enough good tools in my trunk.
Yet I have 1 or 2 more pictures taken when I installed the caps & rotors 4 days ago.
I will attach them straight away.
To clarify about the washers; I was a little bit confused... There was only 1 washer per bracket(the same as the pictures posted by Dave). No difference at all. Besides, the rotors only had 3 washers per screw(what came inside the package).
To tell you, when I removed the caps last night and tried to remove the rotors too, even if I couldn't get to remove the rotors, everything looked perfectly fine and well seated...
I also remember when I first removed the bracket a week ago to check the insulators, they were bone dry and clean(no cracks,no oil, no moisture whatsoever!) And when I refitted the brackets, I made sure they were well seated where they had to(the groove on the ball type mount, so they were steady).
Really, I'm convinced they are nicely mounted with the rotors and the caps.

 

[powerofgreen]

That is a late version rotor bracket. Could you also post photos of the back of the rotor bracket, and, maybe even better, could you post a photo of the “side“ of the cylindrical portion of the rotor bracket showing the slot for the locating lug. Please also post photos of the front and rear of the rotors. Also, are you sure that your other rotor bracket is the same as the one in the picture? You mentioned “washers” earlier? Could you post a photo of the washers, state their quantity, and post a photo of where you found these washers?

Here is the back of the bracket...

 

[Stevester 500E]

There are several threads on how to remove the rotor bolts.
They can be a pita, but I think it's worth a try to check that everything is seated properly.

 

[powerofgreen]

There are several threads on how to remove the rotor bolts.
They can be a pita, but I think it's worth a try to check that everything is seated properly.

I'm sure they are well seated. I can tell by the way the 2 other bolts have moved out and in when I removed them. I paid attention first when I installed them.

Thanks anyway...

 

[powerofgreen]

Btw, the resistance of the primary section of the coils were: 0.9 ohm.
the secondary: 11000 ohm.
Is it within specs or no??

 

[powerofgreen]

Hi!
Another input: I tried to swapp my EZL with a known good unit but no change in the ride...
The same annoying poor knocking idle; the same hesitations in acceleration whether at take off or when climbing a hill...

 

[powerofgreen]

Well guys, I was finally able to sort the issue!
You will laugh, but I have to report back the solution to all of you who helped and advised me through the whole thread.
I didn't pay enough attention when I plugged the plug wires back into the dissy caps! Whereas I was very careful in the process... I re-checked the sequence this morning and realized that cylinder#6 and #7 had there plug wires inverted!
Put back correctly, now my engine timing is back to normal again.
I hope I won't see the misfires and rough idle again this time with the new caps&rotors...
Anyway, I will order a new set of caps&rotors from Bosch/Beru as Dave told me...
Thanks again to all of you and I apologize if the thread was long or annoying...
Best regards,

 

[powerofgreen]

Btw, I would like to know the answer regarding the resistance values for the ignition coils... If my coils are ok or if they need to be changed.
The primary resistance for the bosch after market coils is:
0.9 ohm
Whereas the old original OE coils resistance is: 0.8 ohm
The secondary resistance is approximately: 11000 ohm for all of them.
The primary resistance value makes me doubt if they are still fine...
Can someone shed some light please??

 

[gsxr]

Glad to hear you got it figured out! Now see if it keeps running properly.

The difference in primary resistance, 0.8 vs 0.9 ohms, is nothing to be concerned about. Most ohm meters are not accurate enough to have a meaningful measurement below 1 ohm anyway (unless you are using a high-end Fluke, or similar). I've replaced coils proactively just based on age / miles, but I've never had a defective one that I could measure with an ohm meter to see the difference between good and bad.

 

[195910]

This is one of the most annoying mistakes on a M119 ever! could happen to anyone.

Glad you spotted mixup, it is surprising how well these cars run with 1 injector/spark off

 

[powerofgreen]

Update guys...

I took the SL on a trip this morning(150 miles). I drove at various speeds/loads. The car ran/shifted perfectly well... until I finally reached my destination.
So just when I stopped, parked the car and put into "P", that the idle jumped at about 1000 rpm and the engine seemed to
miss and shake badly again!
Not exactly as before, now it's like the power is down; but the computer is compensating the loss by revving the engine higher to increase the power... I see it like that.
First the rpm goes high; then it hunts just a little snd stays at 1000 rpm approximately; after that the engine shakes badly almost every second. But the car never stalls!
I don't know what to think this time; yet 2 things came to mind:
1/- I won't buy any new part without being 100% sure that it's the real culprit.
2/- I don't have any issue swapping out some parts with used ones from my E500 or from my buddy's wrecked SL500(same year/model) to seek for any improvement... as long as these parts would be free of charge.
Of course the last option would be to take it to the dealer and let him perform a scan with Star diagnosis.. but I would keep it as last resort due to their exorbitant cost...
Until then, any suggestion would be greatly appreciated...
P.S: could the rough idle in my case be caused by the FPR?
I changed it 2 years ago btw; but perhaps...

 

[195910]

Update guys...

I took the SL on a trip this morning(150 miles). I drove at various speeds/loads. The car ran/shifted perfectly well... until I finally reached my destination.
So just when I stopped, parcked the car and put into "P", that the idle jumped at about 1000 rpm and the engine seemed to
miss and shake badly again!
Not exactly as before, now it's like the power is down; but the computer is compensating the loss by revving the engine higher to increase the power... I see it like that.
First the rpm goes high; then it hunts just a little snd stays at 1000 rpm approximately; after that thd engine shakes badly every second almost. But the car never stalls!
I don't know what to think this time; yet 2 things came to mind:
1/- I won't buy any new part without being 100% sure that it's the real culprit.
2/- I don't have any issue swapping some parts with used ones from my E500 or from my buddy's wrecked SL500(same year/model) to seek for any improvement... as long as tgese parts would be free of charge.
Of course the last option would be to take it to a dealer and let him scan it with Star diagnosis.. but I would keep it as last resort durle to their exhorbitant cost...
Until then, any suggestion would be greatly appreciated...
P.S: could the rough idle in my case be caused by the FPR?
I changed it 2 years ago btw; but perhaps...

I might have an answer to your original question about the MAF this week. What distributor caps are you running now?

 

[powerofgreen]

I might have an answer to your original question about the MAF this week. What distributor caps are you running now?

I'm running brand new Bremi caps&rotors since 2 weeks only.
Regarding the MAF, I don't know if it could be the culprit. I tried disconnecting it and driving without it for 3 days and finally the problem reappeared...

 

[195910]

Have a look at the caps and insulation first, Bremi caps don't have painted (sealed) inner side, so they might already have some moisture.

As for MAF, I might have a surprise for everyone later this week.

 

[powerofgreen]

I may have a clue: when I release the gas pedal; once I would like to slow down, 3 or 4 times the rpm wouldn't go down gradually as it should be. It sticks just a little and then goes down if I don't accelerate again. Vice versa, if I'm climbing a hill for eg, the throttle wouldn't respond as quick as it should be when I accelerate.
Now, don't think that I am blaming the throttle body. It doesn't go into limp home mode or blocks the acceleration; but today I noticed this small lack of power while climbing a hill 2 or 3 times. Then, when I reached my destination in town, 3 or 4 times at a traffic light or roundabout when I take off, I feel a very small hesitation(lack of power?!) When I press on the gas pedal. It takes just about a second; but enough for me to feel it...
That's why I was asking about a possible drop of fuel pressure may be caused by the fpr..??

 

[powerofgreen]

Quick update:
Took it for a ride since my previous post and 30 min later I stooped for 10 min and I restarted again... well, unstable idle; in "P" it climbs to 800 rpm or so; then hunting a little.
In reverse, the engine shakes, the power seems not appropriate; the engine definetly struggles if I just lift my foot from the brake pedal without accelerating; but it's not like in the past when the idle was so poor. Now it seems better but the shaking and missing is still there... I'm not so convinced that the ignition is the culprit right now. I've replaced almost every ignition item to no avail!
I wish I could explain it to you better than this; if I could I would make a video but I don't know if one would feel the miss and shaking as I do...

 

[powerofgreen]

Have a look at the caps and insulation first, Bremi caps don't have painted (sealed) inner side, so they might already have some moisture.

As for MAF, I might have a surprise for everyone later this week.

Ok.
Will do tomorrow morning.
Wait for your surprise...
Thnxxx

 

[Klink]

Is your engine fitted with exhaust gas recirculation (EGR) for emission control? If it is, have you tried disconnecting the vacuum hose from it when the engine is acting poorly? You could have vacuum applied to the valve when it shouldn't be, and/or the EGR valve itself could be leaking. There should be no flow through the EGR valve at idle. The solenoid valve that switches the vacuum to the EGR valve could be sticking, and/or you could have vacuum lines misrouted causing a misapplication of vacuum to the valve. Does your vehicle have fuel vapor purging managed by an electric solenoid valve? If it does, it will likely be mounted in an area near the air conditioner refrigerant dryer tank (behind theleft side headlamp). Is it leaking vacuum? Is it sticking open? That's very common.
Is the alternator possibly defective thereby putting electrical "noise" or rapid voltage fluctuations into the system?
Some combination of these "smaller" issues could be adding up to your problem...

 

[powerofgreen]

Is your engine fitted with exhaust gas recirculation (EGR) for emission control? If it is, have you tried disconnecting the vacuum hose from it when the engine is acting poorly? You could have vacuum applied to the valve when it shouldn't be, and/or the EGR valve itself could be leaking. There should be no flow through the EGR valve at idle. The solenoid valve that switches the vacuum to the EGR valve could be sticking, and/or you could have vacuum lines misrouted causing a misapplication of vacuum to the valve. Does your vehicle have fuel vapor purging managed by an electric solenoid valve? If it does, it will likely be mounted in an area near the air conditioner refrigerant dryer tank (behind theleft side headlamp). Is it leaking vacuum? Is it sticking open? That's very common.
Is the alternator possibly defective thereby putting electrical "noise" or rapid voltage fluctuations into the system?
Some combination of these "smaller" issues could be adding up to your problem...

Hi Klink!

Thanks so much for the info...
Yes I have an EGR valve. Yet I didn't try to unplug it when the idle was bad. What should it do?? I guess if at that time there is no change it means that there's a problem with the EGR valve itself or its solenoid valve?? Please clarify...
Regarding the alternator I've already changed it. The previous one was OK too. I replaced it because I wanted to upgrade from 115A to 150A. Meanwhile I replaced the voltage regulator too.
2 months ago I replaced the vapor canistor solenoid valve because the old one was leaking vacuum.
I hope I will be able to sort the issue; I really love this car and I paid too much fixing all kind of issues in the past 3 years I've owned it. I don't want to get rid of it because of an annoying mysterious problem like this one...

 

[powerofgreen]

Hi.
One of my friends lend me a MAF he had as spare. Not a reman unit; a good used one.
I cleaned it with Liqui Moly MAF cleaner and installed it in the car.
I must say that I had a surprise once again... a nice one this time.
The engine runs better and is more responsive upon acceleration. Shifting is better too.
No idea if it will have an effect on the idle the next days; but 3 or 4 times when I put in "P" the rpm went high(800/900 rpm). If I accelerate in park it will go down to 500. I thought may be some vacuum leak so I sprayed some brake cleaner around the engine and on the EGR changeover valve but besides a very small surge when I sprayed over a breather hose(unnoticeable), nothing seamed weird.
I also disconnected the rubber elbow of the vacuum pipe that goes to the EGR, at idle, and nothing happened: no surge in the rpm; no vacuum when I blocked the rubber elbow with my finger...
I'm open to any suggestion..
Thanks folks...

 

[195910]

Well, that was my suggestion. MAF turned out to be more complicated than thought, now that these units are old its not a question of a fault code and cleaning the filament.
Must be checked with live data!

RPM at idle should be 630-700. 500RPM at P is too low, whats the RPM in D?

 

[powerofgreen]

Well, that was my suggestion. MAF turned out to be more complicated than thought, now that these units are old its not a question of a fault code and cleaning the filament.
Must be checked with live data!

RPM at idle should be 630-700. 500RPM at P is too low, whats the RPM in D?

Thanks 195910!
In D the idle is less; about 250 or so.
In P as I said it's around 800.
Now it fluctuates a little bit in P.
If I accelerate when in P, the idle comes back to 500.

 

[powerofgreen]

I will report back tonight with proper measurements. I'm not so sure about the rpm at drive...

 

[powerofgreen]

Hello guys!
Back again..
I couldn't get a proper measure regarding the rpm at P or D ; but one thing I noticed is that if I loosen the throttle cable just a little bit the idle won't go up that much... It will settle at 550 in P and at 250/300 in D.
May be is it low, but I used to get these measures almost all the time since I bought the car...
Now, if I tighten the cable a little bit more it will climb to 750/800 rpm and fluctuate just a few times in P; whereas in D it will settle at around 650/700. One more thing: if I suddenly slow down and completely stop after load, and put in P the rpm will go very high(eventually reach 1000) and 5 seconds later will drop just to hit 800(with small fluctuations too). Finally, in the case of thight throttle cable, once or twice only would the engine idle around 650 at P and 500 at D.
But mostly as high as described above.
I am tempted to think of a hidden vacuum leak; but couldn't find any!
Could it be this other MAF?? Talking about this MAF, it's way better than mine: much more power; way better shifting...
Any thoughts??

 

[gsxr]

The throttle cable is not something you tweak to personal preference. It needs to be in the correct position, and there is only one correct position. You can eliminate excess play in the cable (so there's not a "dead space" where the pedal moves a bunch before actually pulling on the linkage), but that's it. This must be done via the factory manual procedure. It's not complicated.

When at operating temperature, idle speed is normally ~650rpm in P/N, and ~500rpm in any gear. The tachometer may not be accurate enough to show a precise reading, but if you are using a digital scanner you'll generally see those numbers, ±10rpm.

 

[powerofgreen]

Guys, one thought.. does the Bosch fuel pump come with the check valve already installed on the pump itself or separate??
I must know... I forgot to check if the indy indeed installed the new pumps I bought last month with their check valves on the top or if he re-used the old check valves I previousely had on the old pumps!
The indy is on leave right now and I can't contact him to be sure of what he did at that time but I'm pretty sure if the check valves were installed from the Bosch factory on the pumps themselves, he must have fit them like they were; without removing them of course... lol!
I need your confirmation guys...
I must go to the bottom of my initial problem to find the culprit and repair it. For the moment I don't drive the SL that much; so the rough idle isn't coming back; but who knows??
I must check everything in the fuel system to eliminate any fuel starvation possible issue so I can narrow down my researches...
Thanks!

 

[gsxr]

New Bosch pumps include a new check valve.

You can rule out fuel starvation by temporarily connecting a fuel pressure gauge that can be viewed from the driver seat while driving, to see if pressure is normal when the stumble/misfire occurs. Based on what you've described previously, I think it's highly unlikely to be a fuel delivery issue, but you never know...

 

[powerofgreen]

New Bosch pumps include a new check valve.

You can rule out fuel starvation by temporarily connecting a fuel pressure gauge that can be viewed from the driver seat while driving, to see if pressure is normal when the stumble/misfire occurs. Based on what you've described previously, I think it's highly unlikely to be a fuel delivery issue, but you never know...

Alright.
I'm just trying to rule out a fuel possible issue. Honnestly I was suspecting the FPR even though I've replaced it 2 years ago.
I tested it by just diconnecting it's small vacuum line and no fuel were dripping out of it. But who knows??
I will buy a gauge and see...
Thanks again Dave, you're the man... lol!

 

[gsxr]

You'll need at least a 4-foot length of stainless braided hose with AN fittings, and a fuel gauge that will attach to it... not cheap or easy to do this test. Hopefully you'd have use for the setup in the future!

I used AutoMeter components:

ATM-4612 2-5/8" 0-100 PSI Ultra-Lite Fuel Pressure Gauge, Mechanical
ATM-3229 4-foot #4 Braided Steel Line

I wish I had gotten a slightly longer hose, it just barely reaches to the windshield wiper.

 

[195910]

Have you done a new Star diagnosis tests? Fault codes and live data?

Needs to know you on/off ratio, MAF readings and how the car is idling.

To do a final test on MAF, see if its responding to the burn off control, as well as the voltage and KG/H readings as you increase RPM.

 

[powerofgreen]

Well, I don't know if I will be able to install such a gauge from the engine to my dashboard. But I will definetily at least buy the pressure gauge.
Another input: as I'm off today I went ahead and removed the air filter box off of the engine and started it. Then I sprayed some brake cleaner all around the intake manifold; breather hoses; vacuum lines; injectors; etc.
I even removed the plastic cover that protects the EZL and sprayed the same stuff all over the purge valve solenoid.
I was surprised there seems to be some vacuum leaks around the MAF! I thought may be the clamp that holds it around the rubber boot was loose, so I thightened it a little bit more; then I sprayed again. Yet it still sucks!
Then, seems the intake is leaking a little bit too! God! I did an intake job less than 4 months ago!!!
Does it have to be absolutely tight or could the brake cleaner be able to find its way under the intake gasket even though the gaskets are new and tightly fitted????? I can't imagine the intake gaskets already leaking 4 months later!!!
Beside that there seems to be a very small leak around what seems to be the head gasket(I think so; not sure) on the front left corner of the right cylinder bank. It's not leaking oil, but something like vapors; I can't explain it. When I sprayed there; the idle improved, and the weired stuff evaporated. As well as when I sprayed around the intake gasket on the upper side(around the injectors) and around the MAF. The idle seems to become more steady each time.
Guys, I can't think the indy did things wrong when he reassembled the intake. I was there with him the day he did the job. I saw him thouroughly cleaning the inside of the intake; the EGR; the ETA; reassembling every little piece and the mid seals. Then when he re-fitted the intake; how he installed the gaskets(Elring btw); re-tighttened the bolts...
To tell you, when we started the engine after that, I had the best idle ever on this car!
If I remember well, this rough idle started almost 1 month later.
Regarding the MAF, now I'm using the one my buddy lend me. He gave it to me completely for free.
As I said before, the car runs way better with this MAF: more power; better shifting.
What makes it leak vacuum; or again the brake cleaner is so powerful it could seep that far between the gaskets and the parts???
Also, could my rough idle/power loss be the result of various vacuum leaks?? I didn't have such problem before the intake job when I had an important vacuum leak around the intake!
But if so, why only intermittent and only when at hot temperatures..??
PS: I removed the vacuum line that attaches to the EZL when the engine was idling; just to see if any change would occur... well, the engine died! Is it normal?

Thanks folks, I really appreciate the help!

 

[powerofgreen]

Have you done a new Star diagnosis tests? Fault codes and live data?

Needs to know you on/off ratio, MAF readings and how the car is idling.

To do a final test on MAF, see if its responding to the burn off control, as well as the voltage and KG/H readings as you increase RPM.

No, unfortunately!

Until now I didn't find any indy with SDT!

Someone gave me the address of a Merc indy, he told me he thinks he saw him working with the SDT. Next week I will go to visit his garage and I hope he will be able to pull out some codes. Will keep you updated.
Last resort will be to head to the dealer, but with what they charge.........

 

[gsxr]

Well, I don't know if I will be able to install such a gauge from the engine to my dashboard. But I will definetily at least buy the pressure gauge.

Forgot to clarify: I meant this as a completely external setup. The stainless braided hose connects to the fuel rail at the front of the engine, routes over the top of the engine and out the rear of the hood, and the gauge sits under the windshield wiper... all outside the car. Nothing goes inside the car at all. It's a temporary setup for testing purposes only.

For safety reasons it's not recommended to ever have a pressurized fuel hose inside the car, there are kits which provide isolation that allows a gauge inside with no fuel line inside the car; although I'm not sure if those are available for high-pressure (i.e., fuel injected) systems.

 

[powerofgreen]

Ok Dave, noted!

Do you have any comment on what I wrote above??
Please dude, help me. I'm about to give up!

 

[gsxr]

I'm really at a loss here... not sure if you'll be able to diagnose further without driving it to obtain live data via SDS setup with 'driving' cable so you can see what's going on. Otherwise you're back to throwing parts at it. Seems odd that you may have some intake leaks, however make sure the spray mist isn't getting sucked in through the MAF, which could give false results.

Klink? Jono?

 

[195910]

We need live data.

 

[powerofgreen]

I appreciate Dave...

Regarding the intake, that's the most deceiving part of the story... How can it leak like that again??? The gaskets were brand new. The indy paid attention while performing the job. I can't understand...
The MAF looks like leaking anyway, even though I've replaced the rubber boot(OE new one); the ETA green gasket(OE too); tightened everything.
Again, could it be the brake cleaner seeps so well that it found its way in???
I mean comparing to normal air..?
The idle was good when I first fired the engine, then when I sprayed the brake cleaner the idle jumped high then stabilized again.
I'm sure I sprayed around the MAF but it almost died so it sucked the brake cleaner!
After I finished spraying everywhere I noticed that the idle went lower than expected: around 300 at "P". And it has what we can describe as a small misfire/fluctuation every 5 seconds or so. I could feel/hear it from the tail pipes.
I sprayed again and it didn't change a lot.
One thing for sure would kill me: An intake leak again! but how??
Any clue about the EZL vacuum that killed the engine??

 

[powerofgreen]

Dave, if ever it's confirmed that the intake is still leaking, can't we just remove it and add RTV or whatever you will indicate to properly seal the gaskets to the block?? Not that I'm not willing to buy new gaskets; but I didn't find something better than these Elring gaskets I bought last time!
In addition, I think the parts store did only have left side gaskets left in stock. The dealer didn't have any.
Even though I will search for new ones I may not find this time...
So could it be a good idea to put some sealant in between??

 

[powerofgreen]

Guys, I took 2 short videos of the car at idle. One showing the instrument cluster(car at idle); the second the exhaust sound at idle.
I think what's wrong with the rpm tacho reading is that it's showing less than the real measure. You can see with the white gauges that the inscription: *100/min is a little bit off-balance(about 1 mm to the left clockwise). What I conclude is that when the previous owner installed the white gauges stickers, he didn't installed them at the exact positions as the original ones. That's why the idle is showing 500 rpm at "P"; whereas it should show 650 rpm for example!
Both videos were taken at idle with engine hot. It wasn't exhibiting the bad idle behaviour but I wanted to post them to let you check if there were anything wrong with the idle(especially from the exhaust sound). Btw, the muffler is a genuine Brabus with double tail pipes.
Enjoy...

Links to the videos:


[video=youtube;cxj84Sv_-AA]https://www.youtube.com/watch?v=cxj84Sv_-AA[/video]
https://www.youtube.com/watch?v=cxj84Sv_-AA


[video=youtube;Cwp-hFUuYRU]https://www.youtube.com/watch?v=Cwp-hFUuYRU[/video]
https://youtu.be/Cwp-hFUuYRU

 

[195910]

Guys, I took 2 short videos of the car at idle. One showing the instrument cluster(car at idle); the second the exhaust sound at idle.
I think what's wrong with the rpm tacho reading is that it's showing less than the real measure. You can see with the white gauges that the inscription: *100/min is a little bit off-balance(about 1 mm to the left clockwise). What I conclude is that when the previous owner installed the white gauges stickers, he didn't installed them at the exact positions as the original ones. That's why the idle is showing 500 rpm at "P"; whereas it should show 650 rpm for example!

I think you are right, the replica white gauges look like crap, starts from 0 to 310 km/h !!
to be 100% sure you must check the live data.

why is it rumbling that high? does not sound right, these W124/R129 don't sound aggressive at idle, the Brabus exhaust just gives a slight deep sound at idle...roars above 3000

 

[powerofgreen]

I think you are right, the replica white gauges look like crap, starts from 0 to 310 km/h !!
to be 100% sure you must check the live data.

why is it rumbling that high? does not sound right, these W124/R129 don't sound aggressive at idle, the Brabus exhaust just gives a slight deep sound at idle...roars above 3000

thank bro...
the exhaust sounds pretty agressive indeed! I replaced the centre muffler with an X shaped one and I don't have cats at all(they were removed by the previous owner I guess).
It gives a little bit more power upon acceleration and an agressive sound too.
I didn't have time to go to the indy my buddy told me about, but will do in few days for sure...
will keep you updated guys...
thanks to all of you...

 

[powerofgreen]

Guys, back again...

This time I FINALLY got the solution for my problem... Yes, FINALLY!

Could you believe it was indeed the ignition switch???

Yes, the IGNITION SWITCH!!!

That stupid tiny plastic cylinder!

I couldn't get any code whatsoever, but as I remembered what one of the electricians told me 3 months ago when he checked my car for an intermittent problem of windshield+flasher not working properly: "your ignition switch isn't giving enough power to some of the fuses"; I was decided to test any item that could have been the source of my dilemma...
So I went ahead and borrowed a complete ignition lock mechanism removed from my buddy wrecked 93 SL500 and did the test by plugging the electric connector into the switch(not a full install into the steering column).
Oh boy! When I started the engine it seemed to me it was coming out of a coma!!!
It started faster than before, the idle was good, steady, the rumble was stronger and more deep, the accleration and the shifting improved a lot, and finally after driving for 9 days now, and at differents loads, distances and temperatures; none of the bad symptoms I described in the past in this thread came back!
Thanks God the problem isn't serious and all is good right now... All the efforts; parts replaced with new; parts swapped for experience; money spent; time wasted; the solution was so simple yet so inexpected that I'm still in shock! lol!

Anyway, I wanted to describe the right solution and remedy for my problem here in this thread so that if ever somebody has the same symptoms as mine and especially if he finds out that the voltage at the main fuse box is low(test light proves that the light is dimming at the fuses) he could take a look at the ignition switch since it is the first part that provides electric power to the main computers and components... In my case it deteriorates to the point that the main electric parts like the EZL/COILS/MAF/SENSORS/etc, could barely function!

I would also like to express my grattitude as well as my sincere respects to all the members who helped me diagnose the issue, especially Dave; Gerry; Jono, 195910; Klink, etc.

Thank so much guys, I REALLY appreciated...

My best regards!

 

[Unavita]

Q: To be clear- you are speaking of the ignition key tumbler when you state "ignition" and "plastic" and not the ignition distributors located on the cylinder heads, correct?

This: Genuine Mercedes Benz R129 W140 W210 Ignition Lock Housing w/ Switch 2104601297 | eBay

Actually this? Genuine Mercedes Benz Ignition Starter Switch 14 Pin R129 SL W140 S W210 E | eBay

 

[gsxr]

So I went ahead and borrowed a complete ignition lock mechanism removed from my buddy wrecked 93 SL500 and did the test by plugging the electric connector into the switch (not a full install into the steering column).
Oh boy! When I started the engine it seemed to me it was coming out of a coma!!!

I believe he replaced the electrical switch behind the lock tumbler, similar to what's shown below.

@powerofgreen, can you confirm?

.

 

[Unavita]

Glad you responded Dave M! So he replaced the tumbler too but is that necessary? You and I were discussing some problems with my W140 and you'd suggested this part at the time.

Symptoms:
When resetting the batter the car runs fine. After a while though it will start cutting out at about 4K rpm. Above 80c temperature there is a noticeable power loss.
New symptoms as of yesterday: Zero oil pressure at idle. I replaced the modded ecu with the OEM one and it went back to 1bar for a while and then down to zero at times. I had to keep my foot on the pedal to keep pressure up. It made me think the sending unit is going bad. I don't think it's the 5w30 that I haven't changed just yet as it was changed in February and our temps have not hit 80 yet.
Also- suddenly the odometer stopped working.

 

[gsxr]

Unavita, yikes, you have some weird things going on! I'm not sure what the cause may be for all of it, but the low oil pressure is likely the sending unit if old/original. If so, order a new OE/OEM Hella/VDO sender. I've had to replace that on almost all of my engines. If it's recent OE/OEM, the next question would be the condition of the lower wiring harness. The LH module has no effect on oil pressure. The oil pressure is almost entirely a function of RPM and oil temperature.

The power loss at high RPM's could be a number of things, and is much harder to diagnose. The speedometer is electronic and that could be related, although see if the odometer is working or not. Check all fuses, etc etc. And make sure the alternator is putting out ~14 volts with the engine running. You may want to start a separate thread if the symptoms persist, after fixing the oil pressure gauge.