Dead on the side of the road- Help! - Page 2 - PeachParts Mercedes-Benz Forum

MrCjames · #16 05-24-2004, 01:51 PM

Hi Hassman

I would ask few questions, 1) does the car only stall after driving awhile, 2) have you let it run for a long time at home, and 3) was the hood up at the time you were watching for the stall to reoccur?

One thing I discovered about CKP (Crank Position Sensor) failures of that era is that they typically fail under high heat soak situations. Condition: engine at operating temperature usually while driving, but raise the hood and wait for a stall and it seldom dies. Close the hood and allow the under hood temperature to increase and poof, it dies. At the time it stalls you can test the CKP for an AC voltage signal, >.750mV (over 1V is best)

haasman · #17 05-24-2004, 03:45 PM

Wow! You guys are great! Thanks for all the suggestions and support!

I am installing the fuel pumps and filter now. Will know in a few if that/those are the culprits.

If they do not do it I will then also follow the crank position sensor wire and make sure it is good.

The problem most often happends when the engine is cool, has just started running and haven't covered a mile. The engine misses, stumbles and then dies. It won't restart. I let it sit all night and nothing this morning. It is now in the driveway getting the fuel pumps R&R'd.

I have a spare MAS relay but it hasn't seemed to make much difference.

Update in about an hour.

Thanks again for all the great support. What a group! What a site!

Haasman

haasman · #18 05-24-2004, 06:37 PM

The good news: The starts (yeah!)

The bad news: It stumbles upon sudden application of the throttle (like blipping the gas pedal).

Occassionally it wants to hold a 2,000 RPM idle. Turn it off and it will restart and go back to a normal idle.

This is a close to normal operating temperature.

What do you pros think?

Haasman

haasman · #19 05-26-2004, 10:54 AM

No start again! After I replaced the fuel pumps, the OVP relay, the throttle position sensor, MAS fuel pump relay, cap and rotor and the idle control valve it ran well and strong. I was very impressed. Then yesterday, no start when cold.

Suggestions at this point? Coil?

Haasman

EricSilver · #20 05-26-2004, 11:11 AM

Sounds like you still have not looked at the CPSU. The stall on gas pedal blipping is another characteristic of its failure.

haasman · #21 05-26-2004, 07:31 PM

You know, you are right. I will check this tonight.

Haasman

haasman · #22 05-29-2004, 12:18 PM

Is the CPSU wire similiar to the one on my 190E 2.3? I am trying to locate the proper wire. Gray and coaxial?

Haasman

stevebfl · #23 05-29-2004, 12:44 PM

Seems I remember it being green.

Find your ignition controller. It is a flat box attached to the left fender. It will have round electrical connectors plugged to it. The smallest one with what looks like only one wire is the crank position sensor. BTW I didn't answer this post earlier because I didn't know what a CPSU was.

haasman · #24 05-30-2004, 12:39 AM

Thanks for the replies-

Should I measure the resistance by disconnecting the wire at the ignition controller?

Haasman

etsa · #25 05-30-2004, 02:18 AM

Hey Haasman:

Steve is right about the color being green. It connects to the EZL attached to the drivers side fender.

Hope this helps.

Aloha,
Eric

haasman · #26 05-30-2004, 12:35 PM

I think I found it- it is a two conductor, almost like a RCA plug on a stereo.

The Ohms is .793 which is out of range according to the previous posts.

OK, determined here to get this pup back on the road ....

... where does it terminate on the back of the engine? I saw what looks like the crank position sensor in the front of the engine. Is this correct?

Thanks for all of the support!

Haasman

haasman · #27 06-02-2004, 03:18 PM

Bump

EricSilver · #28 06-02-2004, 03:23 PM

It's connected to the back of the engine -- the bell housing I recall. I was not watching when my mechanic replaced it. But it does indeed look somewhat like an RCA cable.

How is the conditition of the cable? Where mine connected to the engine, it looked like it had been chewed up.