M103 Stalling issue, fuel mixture or cat? - PeachParts Mercedes-Benz Forum

John5788 · #1 12-03-2008, 12:16 AM

[edit 12/9/08 update]

I just went out and decided to check the X92 port for trouble codes and found these two:

#7 - TNA (Engine RPM) Signal

#27 - Data Exchange Fault Between CIS-E Control Unit and EZL ignition Control Unit

both are obviously related. What do you suggest i replace first? maybe the OVP relay?

[/edit]

my 93 2.6 decided to take a dump on me today. funny story: (skip these paragraphs if you dont care)

on my way to a final exam, but wanted to stop for dinner first before the exam. left work and managed to hit every single traffic light on the way so I was already running a bit late. come to a busy intersection in the middle of Irvine, CA and there was a huge traffic accident right in the middle, forcing everyone to take a detour. along the detour, bad drivers almost nail my car twice, and end up spending about 10-15 minutes in slow idling traffic.

eventually I made it to an intersection and missed 3 cycles because people were gridlocking the T intersection and couldnt turn. finally I make it to the front of the line and my engine shuts off and I start smelling sulphur from inside the cabin. I tried starting the car up again because I knew people would be pissed because i am preventing them from moving, but the car wouldn't start. the starter just keeps going but engine wouldnt start.

a police officer helps me direct traffic so I could move my car into a parking lot and get a ride to my final. at this point the car started up again, but I didn't trust it so I left it in the parking lot. ( made it about 5 mins late, had to skip my meal. wanted to eat my scantron during the exam

).

PROBLEM:

M103 2.6 stalled while idling in heavy traffic today and wouldn't start back up until after about 5 tries and 10 minutes of waiting. also there were smells of sulphur when I was sitting inside the car. does this mean the fuel mixture is too rich or the catalytic converter is on its way out?

I wouldn't think that a bad exhaust would cause a car to stall while idling though. my idle is very smooth and wasn't jerky when it stalled, it just turned off.

edit:

i forgot to mention that my car has been feeling sluggish as of a month ago and that my exhaust rattles at 2400rpm and 1100rpm.

any thoughts?

mbdoc · #2 12-03-2008, 04:01 PM

The other possibility is lack of spark. If you don't have good secondary ignition, the results are just as described.

John5788 · #3 12-03-2008, 04:33 PM

is there a reliable way to check if the secondary ignition is causing problems before I rule it out? I was thinking of just pulling all the plugs out and examining them along with the distributor cap and rotor.

duxthe1 · #4 12-04-2008, 12:25 AM

I've seen seized air pumps stall an enigne accompanied by the burning belt smell. That rattle may not have been the exhaust. Would be a good idea to look at the belt drive to make sure everything is turning.

Mike Murrell · #5 12-04-2008, 12:52 AM

Replace the ignition coil. No more weak ignition secondary.

John5788 · #6 12-09-2008, 08:49 PM

alright, I did some work this weekend on the car. i replaced all the old vacuum hoses and connectors, took out all the spark plugs and regapped them to 0.034'' (some were way out of spec at 0.040''), replaced all the spark plug wires with brand new ones, replaced the distributor rotor with a known good old one because the current one looked bad.

the car seems to run better and I thought i fixed the problem but the damn thing stalled on me again! this time while I was in drive and moving, not idling! it was embarassing to be stuck in the middle of the road trying to get the car to start.

the issue feels like an electrical one, but I'm not positive. maybe like Mike Murrell mentioned, the ignition coil? is there a way to test to see if mine is going bad?

John5788 · #7 12-09-2008, 09:41 PM

update: I just went out and decided to check the X92 port for trouble codes and found these two:

#7 - TNA (Engine RPM) Signal

#27 - Data Exchange Fault Between CIS-E Control Unit and EZL ignition Control Unit

both are obviously related. What do you suggest i replace first? maybe the OVP relay?

mbdoc · #8 12-10-2008, 08:10 AM

Both are related to a problem with the ignition module!

That also may be your stalling issue as well???

John5788 · #9 12-10-2008, 11:15 AM

after doing alot of digging and reading, it seems that the culprits could be the EZL, ECU, OVP or CPS. I guess ill start by replacing the cheaper stuff, OVP and CPS. if that doesnt fix it, ill try to pull parts at the junkyard.

John5788 · #10 12-10-2008, 10:07 PM

Wow this problem is getting really bad. I'm posting on the roadside with my cellphone while letting the engine cool down because I seriously cannot idle in traffic at all.

When I am driving on the freeway, it is fine, engine temp never runs above 80c. Once I hit traffic my engine temps go slightly above 80c, and car immediately stalls and I cannot get far.

Sometimes when I am cruising after I have stopped in traffic for a while, engine still slighly hot, car will stall while I am going 40mph or so, but after a few secs, launches a huge backfire, starts again for 2 secs, but dies immediately.

i tried replacing the OVP this morning, but that obviously didnt do anthing. I will have updates next week when I get to drive it after swapping the crankshaft position sensor.

mak · #11 12-10-2008, 10:23 PM

vapour lock is the problem due to low fuel pressure ,this can be caused by a partially clogged filter or a leaky fuel accumalator . to rectify replace the fuel filter and the fuel accumalator next to it.

Ocaasionally the fuel -pump relay does act up and cause idling shut down ,restarts immediately ; rectify by replacing fuel relay or by resoldering the cold solder joints carefully. Hopefully this will help

mak
300se W126
300SEL W109

John5788 · #12 12-14-2008, 03:31 AM

i think i fixed the problem, it was a bad crankshaft position sensor. here are pics:

old wire:

close ups:

new wire:

pawoSD · #13 01-17-2009, 11:15 PM

How did you tackle replacing this? From above or below? Where is it located back there?

I have to replace it on my 300E as its doing the same thing. (Stalled out at a light and wouldn't start up for 10 minutes or so)....threw code #7 immediately....Crank Sensor Signal. So I ordered one and it should be here Monday or Tuesday probably....

John5788 · #14 01-18-2009, 02:02 AM

i did the job from above and below. I jacked the car up a little bit so I wouldn't bend my band as far as usual to work in the engine bay and so I can lay under the car as well.

I removed the oil filter and looked around for the 5mm allen. I only saw one 5mm allen back there so I assumed it was for the crank sensor. Bolt was fairly dirty so i cleaned it out a bit before turning the wrench and stripping it entirely. I had to use a long 3/8''s extension to a u-joint in order to reach it in a W201 engine bay.

after undoing the bolt, I pulled the sensor out, undid the two clips under the intake manifold where the wire runs through and pulled it out from the front of the engine bay.

routing it under the intake was kinda tricky. I shoved it as far as I could under the intake manifold from above and then I laid on my back under the car to route it properly to the general area where the oil filter was at. then plugged it in from top and bolted it back in.

pawoSD · #15 01-18-2009, 05:40 PM

Quote:

Originally Posted by John5788

i did the job from above and below. I jacked the car up a little bit so I wouldn't bend my band as far as usual to work in the engine bay and so I can lay under the car as well.

I removed the oil filter and looked around for the 5mm allen. I only saw one 5mm allen back there so I assumed it was for the crank sensor. Bolt was fairly dirty so i cleaned it out a bit before turning the wrench and stripping it entirely. I had to use a long 3/8''s extension to a u-joint in order to reach it in a W201 engine bay.

after undoing the bolt, I pulled the sensor out, undid the two clips under the intake manifold where the wire runs through and pulled it out from the front of the engine bay.

routing it under the intake was kinda tricky. I shoved it as far as I could under the intake manifold from above and then I laid on my back under the car to route it properly to the general area where the oil filter was at. then plugged it in from top and bolted it back in.

Awesome, thanks! There's more room in the W124 compartment, I don't want to remove the oil filter....I'm going to go at it trying not to.

We'll see how it goes....my part should come tomorrow or Tuesday....