The $500 500SL Offroadster

[gsxr]

Here's the FSM link for 124 prop shaft angles to give you an idea what the specs are:

https://www.500eboard.co/forums/misc/Manuals/Servicev3.2/W124/w124CD2/Program/Chassis/41-085.pdf

I have a similar issue with one of my cars, low RPM / high load (shortly after launch at the dragstrip). There's also a freeway-speed vibration. I have not yet diagnosed nor solved this. I would like to get a driveshaft balanced and see if that makes any difference...

 

[Beater400E]

Got some measurements. Looks like it's in spec.
-0°24', +0°36', -0°36'

I won't rule out those angles, but it looks good at this point.

 

[Beater400E]

Well, the soft top issue has gotten interesting.

The issue is the roll bar retracted switch. The switch itself is good, and just for sanity I swapped it out with a good used one I had on the shelf and the issue remains. The switch is simple. Ground on one side. When the roll bar is fully retracted it closes the circuit and sends a ground signal to the soft top control module. I have ground in and out, but at the module I no longer have ground. With the module and the switch both disconnected I have no continuity across the wire.

So I have an open circuit somewhere in the harness. Joy.

This harness runs through bowels of the car. Not even sure what to do now.

I could run a new wire. That would take care of it, I'm sure. I hate that though. I'd lose sleep over it. Even in a beater like this.

I have to ask myself what changed between the last time the top was used, and today.

I removed the hard top a couple weeks ago. I'm not certain, but I think that does require a roll bar down signal. So presumably it worked then. I didn't try the actual soft top then, so can't be totally sure.

Between then and now the main thing that would be suspect would have been the strobe light installation. To install those lights I did run wires through from the trunk into the passenger compartment along the right side of the car, and then under the right side floor sill.

I don't know exactly where the wires for this circuit go, but I'm guessing they went through there. I can't imagine what I could have done to damage the wires, but that had to be it.

What a nightmare. I really don't want to have to gut the whole car to find this.

 

[R129 UK]

I could run a new wire.

What a nightmare. I really don't want to have to gut the whole car to find this.

At least run a temp wire to 100% confirm the issue is resolved, then you can decide if you want to appease your inner demons or not.

 

[Beater400E]

At least run a temp wire to 100% confirm the issue is resolved, then you can decide if you want to appease your inner demons or not.

Are you suggesting my diagnostic skills aren't entirely infallible?

I probably should do that, but that would require some reassembly at this point to test, so I'm going to chase some outer demons for a bit before I try that.

 

[Beater400E]

In this case I wish I had been wrong, but I ran a jumper wire to test and the top works fine. So it's definitely an open circuit. I fear that the damaged wire might be inside of the silly molded foam wiring looms. I don't know.

All I can tell is the wire disappears into the abyss, and reemerges from a different abyss. I don't know what the route is that it takes. That's the big challenge here. If I could determine the routing, I could give it a visual inspection, but so far I can't figure out where it goes.

 

[Beater400E]

It's almost time for the first Gambler event of the season. I gave up on trying to find the open circuit in my soft top control. I just ran a new wire. It is a beater car after all. I hate doing that kind of thing, but I made solid connections and ran the new wire through a loom and secured it all properly. It's a top-quality hack job. The top now works perfectly.

The plastic windows in the soft top cracked last year. I'd like to replace them at some point, but for now I just got some heavy duty clear vinyl tape to hold it together and keep the rain out. The top will be down whenever the car is out anyway. The tape is mostly just to keep rain from flooding the interior when the car is parked outside.
 
I ended up replacing the driveshaft center support bushing and bearing, but the replacement I got had a different mounting height for some reason. No problem. That gave me a chance to make new drop brackets for mounting it.

This time I got the driveshaft perfectly aligned without the center support in place, and then measured the exact dimensions necessary to lock it in that position. Took a couple hours to whittle the new mounts out of billet steel, but in the end it worked great. The driveshaft vibration is pretty much gone. I honestly don't know if it was angles or the bushing since I changed both simultaneously. I suspect it was the angles. Although it measured right on spec when I'd inspected it previously, I felt like reducing the angle across the u-joint would be an improvement, so the new mount is set up to give me basically zero degrees at the joint. That should eliminate vibrations and pulsing, although experts would likely say it'll eventually cause the u joint to seize since the bearings will basically never turn. I'll cross that bridge when I come to it. I'm happy with it for now.

I also decided to see if I could figure out why my belt was slipping on full throttle 1-2 shifts. I popped the belt off and inspected the tensioner. It seems to be basically brand new. The belt was also in great shape. The fan pulley was glazed so I decided to scuff it with a 36 grit disc on a rotary tool. That gave it some teeth. Then I spotted what I suspect was the true cause. My alternator pulley was tiny.

I pulled several other alternators out of storage and noticed they all had larger pulleys. I decided to swap one of the larger ones over.



The larger pulley was about 5mm larger in diameter, which would provide more surface area for the belt to grip, and should spin the alternator faster. With the larger pulley in place and a brand new belt installed, the belt slip is gone.

With all that done I took the car out for a rip along with my buddy in his Gambler Subaru Brat. I really beat on the car this time. My home-made rear control arm sensors work. Every time the car left the ground the roll bar would automatically deploy. I just love that. It's a stupid fun game. The Subaru has zero chance of keeping up. Even in 4wd, it couldn't climb hills like the Offroaster.



With the 3.69 gears and the diff locker this thing just wants to blaze the rear tires at all times. It'll do donuts all day.

For now, I declare the car done. I'm heading to Oregon on Friday for an event. Should be a good time.

 

[TerryA]

@Beater400E,
Try and get us a little video of your bomb in action.

 

[Beater400E]

Been a little bit since my last update. I took the car to a couple events and had a ton of fun with it. On the last run the car developed a couple problems.

First, the rear subframe front right mounting bolt ripped out of the body. This already happened on the left side. In that case I rewelded the bung into the body. That seems to be holding up, so I did the same on the right side to fix it this time. Hopefully that takes care of it.

The second issue is engine related. At high speeds, above maybe 80 MPH, when I put my foot down the car will kind of surge. I had a very similar issue with my 400E a couple years ago. In that case I did a bunch of testing with the overload protection switch and EZL and eventually ended up swapping in a 5 liter EZL, which eliminated the issue. I suspect it was a failing EZL, and that the 5 liter just happened to be the only good spare I had.

I'm guessing this high speed surging issue is a semi-common failure mode for the EZL.

I'll try swapping the EZL from my 400E into the SL to see if the issue goes away. I'm guessing it will. I do have another EZL on my 95 SL500 parts car, but I've never had it on the highway to confirm if it's good or not. If the 400E EZL fixes it I guess I'll swap the parts car EZL into one of the cars to test.

I might be in the market for an EZL. Or maybe it's not the EZL at all. We'll see.

 

[Beater400E]

Ok, it's not the EZL. I swapped the EZLs between the offroadster and the 400E and both cars are unchanged.

 

[Beater400E]

I replaced the overload switch with a new one I had on the shelf. It might be a tiny bit better, but the symptom is still there. No relevant codes stored. Not sure where to go from here.

 

[Beater400E]

When I pulled the switch the reaction valve remained in the trans. I didn't worry about pulling it. I wonder if I should pull it, clean it, and reseal it. I don't know if the valve itself could cause this issue, but that is one variable i have not touched.

 

[R129 UK]

The second issue is engine related. At high speeds, above maybe 80 MPH, when I put my foot down the car will kind of surge.

Do you mean surge as in starts to rev higher and then dies off and then recovers again?

 

[Beater400E]

Do you mean surge as in starts to rev higher and then dies off and then recovers again?

Yeah, so I generally only notice it in highway passing situations. Wide open throttle, usually a downshift and then high rpms.

So, say I'm doing 80 mph, and I hammer the throttle. The car will downshift, begin to accelerate hard for just a moment, then it kind of stumbles, then it picks up again, then stumbles again. If I stay in it, it will continue that cycle of accelerate, then bog, then accelerate, then bog. Roughly half a second acceleration, followed by half a second bog per cycle. I've also noticed it in situations where it downshifts to 2nd gear, but only when the resulting 2nd gear rpms are above maybe 4500 or so. So, if I'm doing 35 mph and step on it, it won't do it. If I'm doing 50-55 and step on it, it will. From about 60-70 it generally won't, because it downshifts to 3rd, but the RPMs aren't high enough at that point. Above maybe 75 it will always do it when I floor it.

I'm at a bit of a loss. I took the car out this weekend for another Gambler run, and it seems to be slowly getting worse. The car basically refuses to go any faster that about 85-90 now. It just starts bucking.

I haven't scanned for codes following the trip. Hopefully I'll be able to do that in the next couple days.

My best guess right now is fuel pressure. I do have a fuel pressure tester. When I have time, I think I'll hook up the gauge and see if I can secure it in place so I can watch fuel pressure while I drive it.

 

[R129 UK]

I’m was thinking fuel starvation of some kind too but wanted to understand your symptoms better first.

I’d be surprised if you get a code for a fuel delivery issue

 

[gsxr]

If it is fuel delivery/pressure, there will be no codes. The system has no sensor on the fuel system, other than to detect a shorted or open injector.

Good idea to view fuel pressure while driving. I've had several cars with a similar issue and when it's a bad fuel pump, you can watch the fuel pressure drop on the gauge as you press on the accelerator (increase load). Pressure should increase with load (FPR does this based on lower vacuum), not decrease with load.

 

[Beater400E]

I’m was thinking fuel starvation of some kind too but wanted to understand your symptoms better first.

I’d be surprised if you get a code for a fuel delivery issue

Me too, but I cleared everything before my trip this weekend, so anything stored right now is new and worth a look before I go too deep on the fuel system.

At some point I really should replace the fuel pumps anyway. When I bought this car I tossed in a cheap set of Chinese pumps just to see if the car would run, and I'm still running on those pumps now, more than a year later.

 

[R129 UK]

Chinese fuel pumps are certainly a potential issue imo but definitely get some numbers while replicating the problem and of course checking for codes costs nothing.

 

[Beater400E]

It took a little doing, but I got a good test on the fuel pressure. It looks good. 50ish PSI at idle. Peaks around 65 at WOT. Stays steady at 60-65 even when the engine is doing its surging thing. Although those pumps really should be replaced with Bosch pumps just for peace of mind, they do not appear to be the cause of this problem.

I scanned codes and got the following:

6: 30
7: 2, 6
8: 5, 6
19: 4,6

I assume 6: 30, and 19: 6 are probably my ETA. It's original and will still go into limp mode once in a blue moon. BTW, does anyone know if there's a way to reset that without bringing the vehicle to a stop? I had it go into limp mode on a narrow, busy highway with no shoulder yesterday. Had to limp it several miles before I could find a spot to pull over safely and shut the car off to restart. Everything was fine after that, but I wish there was a way to reset that without stopping.

7: 2 and 7: 6 both sound like NSS? I don't think I've ever touched the NSS on this car. Might be time to crack it open and clean everything up. Could that cause what I'm seeing? It does seem to always follow a WOT downshift.

19: 4 is air injection. Whatever. 8: 5 is interesting. Maximum permissible temperature in module box exceeded. Not sure what I'm supposed to do with that information. Finally 8: 6, electromagnetic a/c compressor clutch blocked. My air conditioning seems to be working well, so I guess I'm not worried about that.

So, we have ETA faults, possible NSS faults, and a toasty module box.

I really don't want to mess with the ETA if I don't have to. This is a $500 car that only gets driven a few thousand miles a year to events that expect breakdowns. If I can avoid that expense, that would be my preference. I wonder if the ETA in my 95 SL500 would interchange and if it's any better.

NSS would be no big deal. I have like 5 of them sitting around, and I'm comfortable tearing mine apart to clean it up.

Anything else I should be looking at here? Obviously it's possible that my driveability issues are unrelated to any of these codes.

 

[R129 UK]

@Beater400E I think this is a cooling hose in the module box which might be blocked etc.



Not my photo (might be GSXR’s) but I remembered having it saved for no apparent reason.

 

[gsxr]

It took a little doing, but I got a good test on the fuel pressure. It looks good. 50ish PSI at idle. Peaks around 65 at WOT. Stays steady at 60-65 even when the engine is doing its surging thing. Although those pumps really should be replaced with Bosch pumps just for peace of mind, they do not appear to be the cause of this problem.

Great - at least that is ruled out.

I assume 6: 30, and 19: 6 are probably my ETA. It's original and will still go into limp mode once in a blue moon.

Pin 6 code 30 is a phantom code generated every time limp mode is triggered.
Pin 19 code 6 is indeed the ETA.

BTW, does anyone know if there's a way to reset that without bringing the vehicle to a stop? I had it go into limp mode on a narrow, busy highway with no shoulder yesterday. Had to limp it several miles before I could find a spot to pull over safely and shut the car off to restart. Everything was fine after that, but I wish there was a way to reset that without stopping.

Put the car in neutral when rolling and quickly shut off / restart. Pray it restarts. Move the shifter back to D. Practice on an empty road before attempting in traffic.

7: 2 and 7: 6 both sound like NSS? I don't think I've ever touched the NSS on this car. Might be time to crack it open and clean everything up. Could that cause what I'm seeing? It does seem to always follow a WOT downshift.

Pin 7 code 6 is the NSS. Sounds like a good excuse to open, inspect, and clean it (assuming it's adjusted properly now). This can cause limp mode.

Pin 7 code 2 has a plethora of causes, mostly ETA related, but also the NSS, brake pedal switch, and various modules. You need SDS / HHT-Win with digital code readout to narrow down the specific code, and even then some digital codes have multiple meanings. This was a total fail by MB/Bosch engineers IMO.

19: 4 is air injection. Whatever. 8: 5 is interesting. Maximum permissible temperature in module box exceeded. Not sure what I'm supposed to do with that information.

Module box overtemp is a fairly common code which can usually be ignored, after you verify the blower is working. There's an HHT-Win activation to test this. Also make sure both hoses are connected as seen in R129's photo above. The blower circulates cabin air through the module box.

Finally 8: 6, electromagnetic a/c compressor clutch blocked. My air conditioning seems to be working well, so I guess I'm not worried about that.

Yep, that means the engine RPM and compressor RPM did not match at some point and the compressor was shut off until the next restart. Ignore this as long as it doesn't keep recurring.

So, we have ETA faults, possible NSS faults, and a toasty module box.

I really don't want to mess with the ETA if I don't have to. This is a $500 car that only gets driven a few thousand miles a year to events that expect breakdowns. If I can avoid that expense, that would be my preference. I wonder if the ETA in my 95 SL500 would interchange and if it's any better.

The ETA is highly suspect and could cause the surging you are experiencing. The ETA's are all interchangeable on M119 LH engines, the only difference is the cable length and connector type. You can use a 140 chassis or 400E420 ETA if the connector is the same, it will just have a bunch of extra cable length.

NSS would be no big deal. I have like 5 of them sitting around, and I'm comfortable tearing mine apart to clean it up.

Anything else I should be looking at here? Obviously it's possible that my driveability issues are unrelated to any of these codes.

Start with the NSS but that will only cure limp mode, not surging. The surging is very, very likely caused by worn ETA internal components.

 

[Beater400E]

New problems.

I got the car up on the lift just now. I was planning to pull the NSS and get it cleaned up. A quick inspection revealed some new issues though.








Both cv axles' bolts are loosening and backing out, and grease is spewing from the interface between the inner cv axle flange and the diff axle mounting flange. On both sides. Additionally, the shield under the fuel pumps is oozing fluid.

The fuel pump shield is either catching fuel leaking from the pumps or tank, or I suppose it could be related to grease spewing all over under there. I'm sure that will be easy enough to figure out.

The cv axles are a bit more of an unknown. I did secure the bolts with Loctite 243 (blue, oil resistant, medium strength) when I assembled. Maybe the combination of offroad abuse and the weird axle loads created by the locker was enough to break the bolts loose. Once the bolts are loose, I believe the inner steel cap could come loose and allow the grease to escape.

Another possibility is that the axle shafts are effectively too long for this setup, and that the axles actually pressed the inner caps out, and put enough load on the bolts that they eventually worked themselves free. I don't know why the axle length would be an issue though. I believe this combination of diff housing and cv axle length is the same as the 129.066 and the 124.036. Although this application is probably seeing more wheel travel and articulation than stock, none of that should cause the axle to be pressed further into the diff.

Really not sure. I'm going to have to remove the axles to clean everything and regrease and reinstall the inner caps. Hopefully things will become more clear at that point.

 

[Beater400E]

Fuel leak. Looks like the high pressure line coming out of the filter vibrated itself to death in its plastic clip. There's a hole in the hose right there.

 

[gsxr]

Yikes. How old is the high pressure fuel hose?

Axle length should not cause your bolt woes. The axles will move in/out due to the design of the CV joint. Should be no axial pressure unless something is overextended or overcompressed, which seems unlikely given the restraints of the 5 links.

 

[Beater400E]

Yikes. How old is the high pressure fuel hose?

Axle length should not cause your bolt woes. The axles will move in/out due to the design of the CV joint. Should be no axial pressure unless something is overextended or overcompressed, which seems unlikely given the restraints of the 5 links.

Let's see... 2025 - 1993 = 32 years old. I'm sure it's original. I really need to replace everything back there. The supply hose from the tank down to the pumps is still hacked together too from when I first got the car running.

Axle length is definitely not the issue. There's plenty of free axial movement. I'll yank the axles out, regrease and cap the joints, and then assemble with red Loctite.

 

[Beater400E]

I went ahead and ordered a bunch of fuel system parts. The strainer is NLA, but I'm pretty sure mine is in good shape. I ordered a new strainer o ring, strainer to pump hose, new pumps, filter, and pressure hose, as well as a set of pump hangers.

I really didn't want to spend that much on this car, but I had to remind myself that I only ever use this car in extremely remote and difficult situations, where a fuel system failure would be more than inconvenient.

Here's a perfect example from this past Saturday:



I was at about 9500 ft elevation, probably 50 miles from the nearest pavement. In the middle of July, the winter snow banks still weren't totally melted. We actually had to skid our cars down the hillside here to the next level of shelf road to get around this blockage.

So yeah, a breakdown would suck.

Anyway, I'll refurb the fuel system when the parts arrive. I don't expect that to solve any of my current issues, but it needs to be done.

I'll yank the cv axles and deal with them while I'm waiting for the parts. Is there a recommended grease for the cv joints?

I'll also go through the NSS and the reaction valve. After all that is done, and none of my driveability issues are resolved, I guess I'll have to look at the ETA. Victor's site (restoreyourmercedes.com) indicates that the 93 should not have biowire in the ETA, but of course internal components can still fail. My 95 parts car likely has a biowire ETA, so probably not a great candidate for a replacement. I also have a 94 S500 ETA sitting around, but I suspect the same is true with that one.

I wish I knew a bit more about the component failures and how best to test and repair them. I could send the ETA to Victor, but I don't know for sure that there's anything actually wrong with it and I don't want to waste the money if it isn't necessary.

I should probably just wait until I have all these other variables sorted before I go too far down that rabbit hole, but I'm trying to prepare myself for what comes next. I have an event in just over a month that will be especially grueling. 1500 miles in 4 days, with about 500 miles of serious offroading in the middle of that, so I'm trying to make sure I'm ready for that.

 

[gsxr]

Awesome photo!

The OE CV joint grease is $$$. This stuff is OEM and much more reasonably priced:

https://www.rmeuropean.com/Products/9004311-MFG60.aspx

 

[Beater400E]

The OE CV joint grease is $$$. This stuff is OEM and much more reasonably priced:

https://www.rmeuropean.com/Products/9004311-MFG60.aspx

View attachment 218656

Wow. Can't argue with the price. Shipping is fairly reasonable too, but I went ahead and ordered 10 pouches since the shipping price was the same regardless.

 

[Beater400E]

Completely unrelated to all my mechanical woes...

I was browsing Facebook Marketplace last week when I saw a listing for a cast iron crab sculpture. I can't explain why, but I immediately realized that the crab belongs on the hood of the offroadster.

So I coughed up $25, welded some bolts to the feet and mounted it up.



His name is Leonardo DaPinchi and he likes to party.

 

[Beater400E]

Another issue I noticed on this trip was my battery voltage. I usually drive around with a zillion lights on to make myself as visible as possible. We drive a lot of dusty trails, and sometimes it can be tough to see other cars through the dust. I noticed that if I let the car sit and idle with all the lights on, my voltage drops down sometimes as low as 12.0 volts.



Obviously all those lights are drawing some power, but I'm not sure whether I should be concerned or not. The car has a 150 amp alternator. I think it might be struggling to keep up.

Am I just asking too much from my charging system, or is there something wrong with it?

 

[Beater400E]

It looks like at idle with the lights off I'm only at 13.0 volts. I'm guessing my alternator is on its way out.

 

[gsxr]

Yeah - should be 14.2 cold, 13.8+ when hot. Could be the regulator is tired? The 150A can pump out 100-110A at idle RPM.

 

[Beater400E]

Yeah - should be 14.2 cold, 13.8+ when hot. Could be the regulator is tired? The 150A can pump out 100-110A at idle RPM.

That's my guess as well. I just ordered a new Bosch regulator. Hopefully that takes care of it.

 

[Beater400E]

I rummaged through my junk and found a W140 ETA with a 2003 date code. I believe this one came off my 94 S500 that had 202k miles on it. The extra wiring length is not a concern for me with this car. I can coil it up and zip tie it out of the way.

Is there any testing and/or cleanup I should do with it before I swap it over?

 

[Beater400E]

And it turns out the ETA already on my car has a 97 date code.

 

[gsxr]

I rummaged through my junk and found a W140 ETA with a 2003 date code. I believe this one came off my 94 S500 that had 202k miles on it. The extra wiring length is not a concern for me with this car. I can coil it up and zip tie it out of the way.

Is there any testing and/or cleanup I should do with it before I swap it over?

You can plug it in to the car, and with the throttle lever in the idle position, see if it makes all the usual noises.

I forget - do you have SDS / HHT-Win to view live data from the ETA between idle and WOT? That's another test you can do, to verify the switches and pots are mostly behaving correctly.

 

[Beater400E]

I forget - do you have SDS / HHT-Win to view live data from the ETA between idle and WOT? That's another test you can do, to verify the switches and pots are mostly behaving correctly.

I do not. I really need to just bite the bullet and get it. What's the best way to get into that these days?

 

[gsxr]

I do not. I really need to just bite the bullet and get it. What's the best way to get into that these days?

Ugh - there's no easy solution. Read the latest posts on the SDS threads. The "Seven" guy in China had some hardware changes (likely his suppliers) that caused problems. @dreaming.haze just days ago got his M6+ kit working after months of back & forth.

 

[Beater400E]

Ugh - there's no easy solution. Read the latest posts on the SDS threads. The "Seven" guy in China had some hardware changes (likely his suppliers) that caused problems. @dreaming.haze just days ago got his M6+ kit working after months of back & forth.

Well, between the expense and the hassle I probably won't bother at this point. I wonder if i could reasonably bench test the pots and switches and such.

 

[gsxr]

Well, between the expense and the hassle I probably won't bother at this point. I wonder if i could reasonably bench test the pots and switches and such.

I think so - but it would require comparing a few different ETA's to figure out "normal" values.

 

[Beater400E]

I think so - but it would require comparing a few different ETA's to figure out "normal" values.

The good news is I have several. Might be an interesting challenge.

 

[Beater400E]

Still waiting on fuel system parts. US Postal Service decided to spend a week bouncing my MB Laredo package around in Texas before finally sending it north.

I've pulled my CV axles apart and regreased them. I also changed my diff fluid just to see its condition after ~1000 miles of driving with that locker in there. I'm happy to report the fluid looked pristine.

I've replaced the fuel pumps, filter, and high pressure hose. Just waiting on the tank supply hose and a couple other little things from Laredo.

I swapped out the voltage regulator. One of the brushes was kind of stuck with dirt and probably wasn't making great contact. I cleaned everything up and installed the new regulator. Unfortunately I can't test that until I get the fuel system back together.

I noticed that my cam position sensor was looking pretty oily, so I yanked it out to have a look. I was surprised to see a hole in the end of it, and some cracks in the housing.



My guess is that was the path the oil found out if the motor. I have some other sensors in my stash, so I'll definitely be replacing this one.

Is there any chance that sensor could have caused my surging issues? I doubt it, especially since there were no related codes, but it's something.

 

[Beater400E]

Ok, my fuel system parts came in. Got that all back together. I also modified my steering arms (again) and adjusted my tie rods to help with bump steer.

Took the car out and drove it. Honestly, it's pretty much the same as before. The bump steer is definitely better. The idle voltage is pretty much the same. I haven't bothered to let it sit for long to see how low it would go, but it seems like the regulator didnt do much.

The surge at high speed WOT is still there. I didn't expect the fuel system to actually make any difference on that, but I'd hoped. So next best guess is ETA. I have a bunch of OE crankcase breather hoses and MAF boots and such on order, but I can start testing before those arrive.

 

[Beater400E]

I've done a basic functionality test of the ETA on the car, as well as another one I have from a W140. They both seem to work as expected. That obviously doesn't rule out an intermittent issue, or the possibility that some internal components are out of spec.

I'm willing to try swapping this other ETA in, but I'm doubting this will be the issue.

Any other ideas what might be causing the car to intermittently cut power at high speed WOT?

 

[Beater400E]

I happened to pull a hose off my EGR purge valve and noticed it's full of a zillion little black pellets. I assume something has failed. Probably not the cause of my issue, but I'm not sure what to check.

 

[Beater400E]

That EGR purge valve should be normally closed, right? Mine is wide open at all times.

 

[Beater400E]

I replaced my EGR purge valve with one off my parts car. The pellets appear to have come from the charcoal canister. I blew out the hose back to the canister. With all that done, there is no change.

 

[Beater400E]

Well, I swapped in my W140 ETA and now I have no throttle at all. Just permanent limp mode. Not sure what's going on.

 

[gsxr]

Purge valve should be closed normally, and open with voltage. If stuck wide open it causes a vacuum leak. You can plug / block this tube at the intake side or at the purge valve. The carbon canister is also vented to atmosphere, the system just reduces emissions by burning the stored vapors. You canister internal screening has failed, causing carbon bits to get sucked into the valve & tubing. Since this is an offroad beater, I'd plug/disable the system.

Seems odd the spare 140 ETA would "bench test" ok but go into limp mode on the car. I assume you have the throttle cable & linkage rods set correctly, if the ETA lever is not on the idle stop (matching the pedal idle switch), you'll get automatic limp mode when the engine is started.

 

[Beater400E]

Seems odd the spare 140 ETA would "bench test" ok but go into limp mode on the car. I assume you have the throttle cable & linkage rods set correctly, if the ETA lever is not on the idle stop (matching the pedal idle switch), you'll get automatic limp mode when the engine is started.

I completely agree. I screwed something up. I did not adjust the cable or linkage. I just hooked the linkage up as it was before. I'll have to look into adjusting it.

Purge valve should be closed normally, and open with voltage. If stuck wide open it causes a vacuum leak. You can plug / block this tube at the intake side or at the purge valve. The carbon canister is also vented to atmosphere, the system just reduces emissions by burning the stored vapors. You canister internal screening has failed, causing carbon bits to get sucked into the valve & tubing. Since this is an offroad beater, I'd plug/disable the system.

I may do that. Sounds like I could just eliminate the lines and the valve and cap the ports at the intake manifold and at the carbon canister right? It won't cause any driveability problems to leave the valve wiring unplugged?