Hmmm. I see and smell eco junk being a common fault between all those issues

 

Done...replaced a couple of years ago.
Actually replaced before all this stalling nonsense started.
But thanks for the input.

 

I agree it sounds like the wiring harness is the fault. My old 93 400E had the exact same symptoms and after I replaced the harness it was perfect.

 

And don't forget the throttle body. If vehicle still has the original throttle body, it too has eco junk.

 

This is a non-ASR car so the TB is not as much of an issue....but I did split the harness and it is perfect. Apparently TB's with the round plug are not as prone to wire degradation as those with the cannon plug. Although, I have not removed the TB itself ......that's about the only thing I haven't removed.Thanks for the reply.

 

 

Tip: Here are a couple of places where you can check if your harness is deteriorating without disturbing your existing harness

 

And throttle body was replaced as well???

 

I'd put throttle body on the top of the suspect list, followed by removing all the modules, cleaning the connections with deoxit and replacing the 4 mini fuses on the base module and reinstall.

ALL of the throttle bodies had eco junk at no extra cost (ASR or not)

 

The TB was next...and I'll do the same to the computer box.
My point is, this is a recurring complaint from many owners over the months.
There has to be some common fault that once found isn't updated to the forum.

 

you replaced both fuel pumps with Bosch?

 

Yes...both. But fuel pressure was never an issue...always about 50PSI

 

I wouldn't rule out ignition coils

 

Or worn out voltage regulator

 

Never considered that.....but how would a bad voltage regulator affect driveability?

 

To-day, as usual it started perfectly. We went 3 miles to the mall. Came out 15 min. later and it wouldn't start...of course.
I had my DMM and tested the coils. I had 4 ohms between the wire connectors, same as when cold...but 11.5 ohm between the center coil wire to the small connectors. When cold this value is 10 ohms. Is that difference (10 ohm to 11.5 ohms) enough to create the problem? Or does the resistance go up when they get hot normally?
The other question I have is...which one of the computer modules fire the coils?

 

EZL = ignition

Resistance is temp dependent.

When you tested batt voltage, make sure engine is idling at operating temp with EVERYTHING (max A/C, heated seats, fogs, high beams, etc, etc, etc,) turned on

 

Also be aware that with the M119 on occassion the EZL on the driver side fender is known to go out. No random pattern to it.

 

Also be aware that with the M119 on occasion the EZL on the driver side fender is known to go out. No random pattern to it.

If the ignition module fires the coils....what controls the ignition module?
I've put three different EZL (ignition modules) in this car with basically the same result.

It seems that if I start the car cold it will run fine until I turn it off.....allow it to heat soak.....then it won't start.
I have a feeling, (although I'm not game to try it) the car will drive without issue, at highway speed, for ever.
But that is just a guess because it doesn't miss or spit at lights any more...at least not since I changed the coil.
Then pattern of failure has changed....but it still fails
Start cold and drive >no problem.
Turn the car off when hot and let stand for 5-10 minutes > it will not start. It tries to but just back fires.
Let it sit for 1/2 an hour or so> starts right up and idles as if it was a new car.

I ordered the dust covers / insulators for the distributors to-day as suggested by Dave M on another forum. Mine are fine (at least they look fine) but he was pretty adamant so why not.

 

Until your car is completely free of eco junk, i.e. throttle body, it cannot really be troubleshot.

If you're going to replace the throttle body, make sure you install a new gasket everytime the unit is R&R'd

 

The EZL gets input from the crank sensor and sends the info to the EZL module in the module bay.

As I said a few times before, throttle body is top suspect in my book followed by voltage regulator. Especially based on the amount of parts, sometimes repeatedly, you have thrown at this issue.

No W124 can be reliably fixed when eco junk is still at play.

 

No news yet on codes. Have you checked fault codes? This may give a clue.

Also we have not mentioned the fuel pump relay. Cheap and easy to replace.

 

The relay was swapped out and the pumps are working. I can hear them plus my fuel pressure gauge shows good pressure even when the car is acting up. \the issue here, I think, is ignition. The car is getting fuel. So much so that when it is acting up the smell out of the exhaust would make your eyes water...rotten eggs. Unburnt fuel. Not good for the cat.

 

Until the car has been remedied and verified to be eco junk free, I wouldn't put much faith in the codes it spits out.

 

The upper harness has been replaced with an updated one some times ago.
The lower harness is original and has had "repairs" done to it.
I split the harness on the ETA to check the wires and they are all good. The only thing I can think of with the ETA is the solder joints on the ETA itself maybe bad. That's what I am going to look at next.

I am going to pull codes right now after yesterdays issue. I'll let you know. Last code reading only showed #6 on pin 7. Starter lockout backup switch.

Re: the voltage regulator...I'm getting 14.5V output at the battery with everything ON.

 

Are you able to pull codes from the modules? That might give you a clue. Also, it wouldn't hurt to ensure the connections at the modules to the motherboard are clean. Contact cleaner would be good for this.

 

OK, I think it's time to regroup here. OP needs to list EVERYTHING that has been done so far, instead of someone recommending something only to have the OP come back with "already done"

Second, list in sequence what and when was performed

Thirdly, list exactly which parts were replaced and how often and brand (new/used/recon, etc.)

Otherwise, this feels like chasing our own tail

I definitely concur on pulling all the modules, and cleaning the contacts in the box and the modules with deoxit or similar as I already states many posts ago

 

No, the harness is a Delphi 2006.
This car has always had problems running poorly on start but that was put down to the wet distributors.
So, when it started to miss while driving or at lights I initially thought it was those darn poorly designed caps..but a quick wipe usually solved that.
Now that didn't always work.
Then somehow it was good for a little while, couple of weeks, before the missing and stalling at lights started.
No codes.
I put in a known good used EZL and it seemed to work for a while but then it started to miss and stale when it got hot.
If you tried to apply accelerator it would bog right down with fowl smell from exhaust.
Thinking maybe the O2 sensor (NO CODE) I replaced that with a new OE Bosch with the correct plug. No difference.
Sometimes when that happened if you let off the gas it would idle and with a slow measured application of gas I could nurse it home.
Let cool off and it would start right up.
I then replaced the the caps and rotors with new but not the insulators....that'll be next week.
Didn't make any difference.
Good upper wiring harness and slit the ETA harness about 6 inches and those wires are perfect.
Now I'm think gas issue so I checked the pressure regulator, no leak and the vacuum was good, and the fuel pressure was good to the rail, even when it missed. Both pumps check out fine ( I could hear them) and the filter was only a few months old. I did bench test the pumps and they worked fine.
I replaced all the plugs with the correct new Bosch plugs and checked all the wires for continuity and resistance.
Still thinking it maybe a fuel issue I removed, cleaned and replaced all the injectors with all new "O" rings and pintel caps.
No difference....when it got hot and was allowed to sit it wouldn't re-start or it tried to start but was obviously running on 4 cylinders.
Sometimes it would backfire and fart like the timing was out.
Even though there was no code for the CPS I put a new OE one in because it was having trouble starting....no difference.
One night, after just making it home and the car was missing badly I pulled the coil wire off the left bank to see if it would start...it wouldn't!
Did the same to the right bank and it did start but ran as rough as when it starts to act up. Hurrray, it's the left bank coil.
I put in a good used one and it ran OK for a couple of local trips, but still had a slight miss...but it was better.
The last week it started all over again. So, I replaced the same coil again and it was even worse. That was a bad coil.
Put the one I had just removed back in, the one that had worked pretty good for a couple of trips and the car ran better...but still won't start when hot. |At least when I initially changed that coil things improved a lot.
So, the only parts I put in that are not new, but from a functioning accident car with no known issues, are the coils and the EZL.
I'm leaning towards new coils...but I am just getting sick of throwing money at this car.
And why aren't I getting codes for the coil(s).
Now to-day I let it get up to operating temp. in the drive way. Ran like a dream....no misses at all.
Foot on brake in gear increase load / RPM and nothing. No misses at all. Did that few times with the same result.
Let it sit for 10 minutes, hot, and it started right up with no misses at all even when I apply a load.
Did that several times...no problem.
The next test, tomorrow, will be to do the same static test but then drive it to the mall..go shopping and see if it starts when i come out.
If it doesn't (and it probably won't) how could adding a short drive to the mix affect it....but I'm jumping ahead of myself.
I was surprised it didn't act up to-day during the static / driveway test 'cause it has in the past.
That's pretty much it in a nut shell.

 

One more thing. This "new" upper harness wouldn't happen to be one of those DIY botch jobs by any chance, would it?

If so, that might explain everything.

 

Does this car have the alarm system/immobilizer? I think '93+ did, and the engine behavior you describe is exactly how my R129 behaves. I don't think you have any sort of key transponder on a W124, but on mine, I have an aftermarket key fob with the transponder chip in a little slot that allows it to move out of position. No start, I remove the key, tap the key end in my hand (moving the transponder chip), retry and it works, every time. (yes, I'm going to do surgery with double sided tape to fix that) On yours I think it's just tied to the alarm system somehow.

If you have it, there's a couple pins on a relay you can jumper to bypass it. Worth a try . . .

http://www.benzworld.org/forums/w12...orums/w124-e-ce-d-td-class/1539241-1992-300ce-original-anti-theft-features.html

http://www.benzworld.org/forums/w124-e-ce-d-td-class/1495824-how-disable-alarm-1993-w124.html

 

No significant codes - so we can rule out all sensors and modules and probably misfires on the ignition. A bad cat is possible but I'm not sure that would cause a no start condition.

Your last post does not mention new fuel pumps. Please see my post from some time ago about the fuel pumps.


http://www.benzworld.org/forums/w124-v8-400e-e420-500e-e500/2615665-new-fuel-pumps.html

 

Ok, thanks.....did the car try to start and backfire as if the timing was off. Or did it just quit?
Did the new pumps solve the issue with your car?

 

The new pumps fixed the problem I had. Car has run well ever since. It was frustrating to diagnose because it would start and run normal when cold but after driving around for a while it would start acting up.

I suggest you test fuel pressure. It's easy to do - there's a port right on the fuel rail. When I was testing mine the pressure was around 49 which was still in spec per the manual but the needle was shaky. I knew that wasn't right.

 

Does this car have a coolant temperature sensor? Not sure if this has CIS but it controls the EZL and Jetronic brain if so.

Also did you change the intank filter?

 

OP has a M119 V8 W124, thus no CIS and no Jetronic.

The intank filter is a long shot, but worth consideration.

 

Wasn't sure. My M119 is CIS on my R129.