Engine dies at the stop light...?

[Duh_Vinci]

Cheers all!

This never happened since my ownership of this car. Come to the stop light or traffic light, engine cuts off. Re-starts fine, has full power. But when you get the the light, RPMs tend to dip lower then usual for a moment, and just cuts off. I can feel a little occasional miss now at idle, but drives fine otherwise.

I pulled the car in the garage, letting the engine cool for few hours.

Other than the usual: Caps, rotors, insulators, wires, anything else I need to be on the look out for (all of these replaced with in the last 5k miles or so, along with coils)?

Regards,
D

 

[gsxr]

Is idle RPM normal (500-550 in gear, 650 in Park)? I'd check for vacuum leaks to start with. Stock airbox, right?

 

[Duh_Vinci]

Is idle RPM normal (500-550 in gear, 650 in Park)? I'd check for vacuum leaks to start with. Stock airbox, right?

Thanks, will definitely check!

Idle just a bit lower, 450-500 in gear, 650 in park... Stock airbox, clean fresh filters 2k miles or so, all new "small" diameter vacuum lines with associated connectors and elbows few years back...

Regards,
D

 

[Duh_Vinci]

Well, I did find one of the larger “T” above the driver side valve cover was weak, not broke, but very loose. Fixed that.

Replaced the air filters, God knows I have enough of them stashed (blowout from rockauto).

Pulled the caps, refreshed the contacts, and very happy to report there is zero evidence of moisture build up!!!

Ran the car up to the temperature, the issue seem to be resolved, RPM in gear 500+ish now. Cold was was absolutely beautiful! Hot - well, I can feel occasional miss, very little, and not all the time, but I can feel it.

The only thing I can think of, sometime back, when I was trying to trace the huge misfire ( ended up being a coil, replaced both) I did replace all the spark plugs without giving them to 1mm (left at stock 0.8).

Perhaps I need to install new MB plugs and gap them to 1mm as recommended here on multiple occasions?

Regards,
D

Edit: not sure about .036 passenger side access for the cap bolts, but on R129 it’s kinda tight there, this is my new favorite combo to access and unscrew the bolts… ratcheting 1/4”

 

[gsxr]

I wonder if the loose vac pipe was the cause. Air filters wouldn't do it, and the plug gap wouldn't cause the engine to stall. Weird! Hope it's fixed though.

 

[Duh_Vinci]

Drove it again, so far so good, has not stalled once (other than the faint occasional tiny tiny miss at idle, very faint). Maybe that line was a culprit! I have another set of rotors/caps/plugs, will swap next when I have some extra time. Thanks for the tip Dave, appreciate it!

Regards,
D

 

[Duh_Vinci]

Unfortunately it's back... back with "plus some"... Stalled few times again, when you get to to a stop light. Restarts fine, but here is what it's doing in addition:

Slow acceleration - fine, but if you give it a quick gas, RPMs drop, like it "chokes" and nearly dies, so basically no quick take offs...

I'm going to build a "smoke machine" as outlined by @TX Benz Driver here HOW-TO: Make a Smoke Machine (intake vacuum leak testing) | Tools and Shop Equipment Where exactly does one connect this tube under the hood please (my first time)?

Regards,
D

P.S. I will do the blink test to see if there are any codes, and I also noticed that passenger side is in need of a new cam seal, will replace those and will clean up and re-fresh the contacts on caps/rotors

 

[gsxr]

D, how old are the fuel pumps? Do you have a fuel pressure gauge that you can connect to the rail and observe pressures while you blip the throttle?

BTW, I'm assuming there is no misfire or backfire, just a smooth loss (or lack of) power - correct?

 

[Duh_Vinci]

D, how old are the fuel pumps? Do you have a fuel pressure gauge that you can connect to the rail and observe pressures while you blip the throttle?

Dave, no clue, since I bought the car as a basket case, and while it had thousand of dollars spent by prior owner, no records were available from his son. If I buy the gauge, where exactly do you connect it at the rail?

EDIT: Found it HOW-TO: Checking M119 & M104 fuel pressure | "HOW-TO" Tutorial Articles and

BTW, I'm assuming there is no misfire or backfire, just a smooth loss (or lack of) power - correct?

No back fire. There really is no loss of power to note, it seem to have full power once you get to above 1000rpms or if feather the pedal first then mash it - no problem at all. That RPM drop only if I press the gas pedal quickly from dead stop or occasionally when coming to a stop light, RPMs may dip down for a split second as here 0:02 second of the video above

 

[gsxr]

OK... if power is 100% normal once RPM's come up, it's probably not fuel pressure or pump related.

Carry on!

 

[Duh_Vinci]

Carry on!

What’s the best place to connect the smoke machine? I’m I am going to have one ready made in an hour or 2…

 

[gsxr]

What’s the best place to connect the smoke machine? I’m I am going to have one ready made in an hour or 2…

I'd try the large PCV hose that goes into the back of the ETA. That should pump smoke directly into the intake manifold. Seal off the top of the MAF. (Edit: You MUST seal the MAF for this to work, as the port is above the throttle body plate.)

 

[Duh_Vinci]

I'd try the large PCV hose that goes into the back of the ETA. That should pump smoke directly into the intake manifold. Seal off the top of the MAF.

Thanks Dave! Will definitely do it! Unfortunately not today... some days one just need to look at the events, and put the tools away for another day:

Morning: Car is not running well, turned around, came back home, swapped cars.
Late morning: CT Equipment is down for today
Evening: Pressure regulator knob broke on the tank, so I can not dial the pressure back to use for the "smoke machine"
Now: Realized that my air pump is not charged, and the charger/adapter is nowhere to be found

So I'm done with the cars for today... on the upside,

Amazon has the charger/adapter, $10 will be here on Thurs.
Great lunch at Oishi, local Sushi place
The "smoke machine" is ready otherwise



Thursday will carry on...

 

[nocfn]

...and if you find that hose is petrified, you may have found the leak!

 

[Duh_Vinci]

...and if you find that hose is petrified, you may have found the leak!

I will be there tomorrow to explore for sure, and can't help but raise few questions,

What exactly is it called?
Part number?
Available still?

EDIT: I assume the first 4 parts in this post: How to replace main breather hose on ETA : VIDEO | "HOW-TO" Tutorial Articles

A1190947182 cam cover hose
A1190945582 cam cover centre hose
A1190944482 part of the hose that connects to the ETA
A1020940212 x2 connectors for the above hoses

?

 

[gsxr]

Full list for both sides is in the post below, including EPC diagrams & part numbers:

PCV breather hose replacement - Part numbers | M119 Engine

Hi, I noticed this weekend a hose on the driver's side next to the wires at the front is seeping (see pictures). Seems like a very easy replacement of an old, saturated breather hose. I checked epc for the part, but I can't find it anywhere - the closest thing was in the "Major Engine...

www.500eboard.co

 

[Duh_Vinci]

Cheers all!

So, thank you @gsxr for all the tips and PDF, thank you @TX Benz Driver for such easy smoke tool visual and everyone who contributed to the breath hose threads, much appreciated!!!

Smoke machine worked like a charm! Connected it to large large vacuum line of the brake booster



And after few minutes, started to see the smoke coming from somewhere under the intake center, just behind the MAF... Let us see

... here what I found



Not even connected to ETA



If I had to guess, whoever worked on the car before I purchased it, put that hose back onto ETA, never used the clamp, if forgot - probably just said "the hell with it, its on fairly tight, not doing the extra work removing ETA again" and "buttoned everything up". Eventually, it gotten loose, and finally worked it's way out of there?

Anyway, thanks to all, will make a list of hoses and connectors to replace and will order, all the small diameter hoses, elbows and connectors I have replaced already (all of them)!

Regards,
D

 

[gsxr]

YIKES! That ain't good. Glad you located the issue!

 

[Duh_Vinci]

Well, I removed the hose, once upon time it definitely had a clamp on (pressure imprint), no clamp in site though... It is in surprisingly good condition (other than grime), not sure if it's been replaced, but I'm replacing them all, made a list, will place the order on Mon.

For the time being, and while under the hood, decided to clean things up, and reconnected that breather hose. Ran the smoker again, no leaks to be detected, so that makes me happy, and will be glad to have all the new hoses that will last a while... On down side, the rpm drop/choking under quick gas pedal press remained

I decided to check if any codes are present (none were there after I replaced the LH module with WOT, cleared all and checked in few days... that was almost a year ago) Well well...

Socket 4 - 4 blinks: Voltage at air mass with hot wire circuit. Open or short circuit.

Actually, come to think of it, when I first bough this car, after few weeks of tinkering with it, I remember it did have similar behavior, RPMS would drop with quick gas pedal press. The car did come with new (remanufactured Bosch MAF), so I didn't really take MAF as consideration for the culprit, and replaced all the vacuum lines and bunch of other little things that the car needed anyway. And while it improved (dramatically), RPM drop remained)

Used $65 MAF via car-part.com arrived, and it solved the RPM issues and rich running smelly exhaust.

Well, this is that old used MAF that served me well for 3+ years



I'm not a hoarder, but I have accumulated few parts of the years here and there



And I've had a spare MAF from pick-a-part off W140 from last year, plugged it in, and voila

Exhaust has almost no smell to it (it was getting a little rich lately) and no more RPM drop!!! Semi-assembled everything back, drove the car for almost an hour at various paces, no drop, no stalling, no hick-ups

Came home, let it idle for 35-40 min while paps and I seat on the bench under the tree and enjoyed a beer. The car didn't die, RPMs didn't jump, no gasoline smell in the air at idle! So I'm assuming that culprit was the breather hose and MAF (this was my last spare), can't wait for all the new bling-black hoses/pipes to replace. Also noticed rub mark on the under side of the strut brace, that can mean only one thing: I need new motor mounts too! But that's another topic...

Cheers all, appreciate all the know-how and the resources!

Regards,
D

 

[gsxr]

Sweet! Glad it's fixed... but why didn't the CEL illuminate? LH code 4 should trigger the CEL (pin 19, code #10). Do you have SDS or other digital scanner that shows live data? This would confirm if both MAF's are definitely DOA. I'm assuming your upper engine harness has been replaced, btw, as this connects to the MAF.

 

[Duh_Vinci]

Unfortunately no, no digital scanner or SDS, keep postponing the purchase, but I will get it in few months, enough cars here to use it for sure. Upper harness is new, compliments of prior owner, updated DELPHI... Owner's son said they've had ETA, upper harness and MAF, among other things replaced.

Now, to the ETA, while there, I was looking for the build date, couldn't find it, so I did the search, guess who's post/image google pulls up (looks familiar?)




Now, I don't see these stamps on mine



But I did cut apart the insulation of the ETA and it looked new:



So I'm a little puzzled with this build date...

EDIT: This is what I saved for future purchase US$436.00 - Mb star c3 mercedes diagnostic tool with Dell D630 Laptop for Benz Trucks & Cars 2021.03 version I need to find some kind of online video so I can understand the basic of how all this bundle works

 

[gsxr]

Your ETA may have the triangle-inked date code somewhere else, not easily visible. If you remove it, inspect other areas. Bummer the label is damaged and you can't read the date on it. Good wiring is a good sign though, and the previous replacement might have been either new or late-datecode.

The C3 kit you linked to does not specifically mention that it supports HHT-Win. Contact the seller before buying! If they do not explicitly state it DOES have HHT-Win, do not buy it!! Some of the newer software setups don't have HHT-Win and you must, must, must have it for these early 90's cars. Also... some C3 multiplexers don't play nice with the EZL. Check the return policy, if it works with every module except EZL/DI, the mux is defective. I'm not sure if the C4 is more likely to work but so far I haven't heard of any confirmed problems with C4+EZL.

 

[JC220]

Unfortunately no, no digital scanner or SDS, keep postponing the purchase, but I will get it in few months, enough cars here to use it for sure. Upper harness is new, compliments of prior owner, updated DELPHI... Owner's son said they've had ETA, upper harness and MAF, among other things replaced.

Now, to the ETA, while there, I was looking for the build date, couldn't find it, so I did the search, guess who's post/image google pulls up (looks familiar?)

View attachment 138943


Now, I don't see these stamps on mine

View attachment 138944

But I did cut apart the insulation of the ETA and it looked new:

View attachment 138945

So I'm a little puzzled with this build date...

EDIT: This is what I saved for future purchase US$436.00 - Mb star c3 mercedes diagnostic tool with Dell D630 Laptop for Benz Trucks & Cars 2021.03 version I need to find some kind of online video so I can understand the basic of how all this bundle works

The original units date stamp ink wears off easily. And pancake plug ETASs do not suffer from wiring harness degradation. ETAs can of course have several other failures.

 

[Duh_Vinci]

The original units date stamp ink wears off easily. And pancake plug ETASs do not suffer from wiring harness degradation. ETAs can of course have several other failures.

Great information Joe, appreciate it! Learn something every day!

 

[Duh_Vinci]

The C3 kit you linked to does not specifically mention that it supports HHT-Win. Contact the seller before buying! If they do not explicitly state it DOES have HHT-Win, do not buy it!! Some of the newer software setups don't have HHT-Win and you must, must, must have it for these early 90's cars. Also... some C3 multiplexers don't play nice with the EZL. Check the return policy, if it works with every module except EZL/DI, the mux is defective. I'm not sure if the C4 is more likely to work but so far I haven't heard of any confirmed problems with C4+EZL.

Thanks for the info Dave, appreciate it! Mechanically I can try to tackle tings, computer wise - not sure how ell I will do with all that, I hope GUI is friendly enough lol

 

[Duh_Vinci]

With the new tubing in place, there are no more vacuum leaks that I could detect. Buttoned everything up and been driving to work and back last 2 days in mixed traffic, highway and back roads - the stalling is gone!!!

There is still occasional very light miss that fell, again, just every so often, but I know my pass side cam seal is leaking, new MB seals are here, will tackle that in the next week or two, will clean/check all connections, and hopefully that minor miss will go away completely.

Thank you all!
D

 

[TX Benz Driver]

Glad the smoke machine helped diagnose the issue. I resisted building mine at first, but once I did the problem became obvious...

Good job of fixing the problem.