sabrownco

I have a 94 E320 with about 150,000 miles. It ran fine until yesterday morning. At a light, it stalled. Then when I restarted it, the car acted like it was running out of gas; it would lurch under full power, and then all fuel would cutout, then lurch again. It was kind of like someone learning to drive a manual shift! At a stop, the idle would wander between 0 and about 1000rpm then eventually die.

I limped it home to my garage where it now sits. Could this be simply a fuel relay problem? Does it sound like something more?

Any help would be appreciated.

S A Brown
San Diego, CA

Jer

If the fuel pump relay failed the engine would not run at all, or even start. Could be something as simple as clogged fuel filters or more serious like the idle control valve. However, if the engine is losing power when attempting to accelerate, the EHA could be faulty. It is the final fuel trim servo in the injection system.

Arnie

Could it be the OVP relay?

bamberger_1

Could one (or more) of the injector seals have gone bad, and the engine is getting too much air? Try the following. Take off the air filter, let the engine idle and spray brake clean or alcohol (chemical, the good whiskey you better drink) on the injectors and the intake. This way you would find leaks in the intake and the injector seats.
Just a thought before you buy too much of expensive relays and controllers.

sabrownco

Thanks for the suggestions thus far. Here is an additional symptom; I am not sure if it will help the diagnosis.

Last night I drove the car around the block a few times. It sputtered and stalled several times. But as the engine warmed up, it seemed to fare a little better. At a stop, the idle would still pulsate, but only up or down 100 revs or so (but very quickly). It would not stall once warm, but simply sound like someone tapping the accelerator repeatedly.

I will try my best to do the air filter trick this afternoon.

As another aside, I do have a habit of putting fairly cheap fuel in the car including Baja Mexican fuel, as I drive down there pretty frequently.

Thanks again for the fantastic forum.

S A Brown
San Diego, CA

zac380SL

sounds like the overload protection relay, try Jonathan at
www.BuyMBparts.com they have a lot of oarts with really good prices and service

sabrownco

Thanks again for all the help. With several suggestions for the Overload Protection Relay, I bought one locally and repaced it yesterday. This had no luck; the car still ran the same miserable way.

I limped the car down the hill to a mechanic who has a Mercedes diagnostic computer. The computer picked up 3 error codes which all point to the air flow meter (the part right next to the air filter). Since the mechanic was so nice to do the diagnosing for free, I am going to have him replace the part on Monday for about $300. I can buy the part from a fellow at EEC parts for $250 and put it in myself for free, but thought it might be a good idea to have a rapport with a good MBZ mechanic.

It sounds like the air flow meter is not operating so the car is getting too much air, running too lean and stalling. Makes sense with the symptoms.

I will post on Monday the results.

Thanks again.

S A Brown
San Diego, CA

NDavies4

What was the outcome - all ok now? Have currently got a similar problem with my '93 300CE 24. Have been reading through all similar postings and this seems to be a common issue with the W124. Was advised to look at the cold start value to check for leaks as Plan A. Failing that the air flow meter is Plan B.

sabrownco

Sorry - I forgot to post the results. I had the air flow meter replaced and it solved the problem instantly.

As it turns out, slightly before this happened San Diego had severe fires that put tons of ash into the air. The mechanic who replaced the meter thought the ash was a contributor to its failure. He had replaced several that month.

He also recommended religious replacement of the air filter in order to protect the expensive air flow meter from any damage. I guess its metal tip is very fragile.

I hope this helps.

S A Brown
San Diego, CA

Jer

The air flow meter uses a titanium hot-wire which must be kept clean. It does this by heating the wire to over 1000 deg. C for a few seconds when the engine is stopped. However, it can not burn off ash, as you had on yours.

Stunnd

I have an 89 260E that's having a similar lurching problem. The dealership replaced the fuel distributor (very expensive) but that didn't solve the problem. They said their diagnostic system didn't pick up anything. Any suggestions other than just asking them if they noticed anything regarding this air flow meter?