Scared by my 400E today!! - PeachParts Mercedes-Benz Forum

carman850 · #1 02-13-2003, 07:11 PM

It was a cold day today, -22 Celsius, my 400E went mad!

I was driving on a busy highway, suddenly I found it continued to accelerate even after I lifted my foot from gas pedal. I was lucky that traffic was not bad at the time, it seemed like engine want to rev at 2500 rpm, to keep in the traffic at 110kmpH, for the whole half hour trip, I didn't even touch gas pedal once! I had to use brake to keep the speed down very often.

Exit the highway, the local made it even worse, engine wanted to rev at 2500 rpm even at low speed, it jerked if I used brake to force it down. Finally found a gas station to stop, put it into P, engine idled at 4000 rpm even after I turned ignition on/off twice, I then let it rest for 2 minutes, deeply stepped down gas petal several times, restarted the car, the problem went away.

Was this caused by sticky cable? I lubricated the throttle cable last year with Mobil-1 ATF, is ATF the correct lubricant for this?

#2 02-13-2003, 07:56 PM

hey sometimes with me its happens too but in my case its teh damn carpet which get stuck otherwise it has to be the cable my friend just lubricated his with wd40 and he says it works fine now
so if u want give it a try with wd40
mani

carman850 · #3 02-14-2003, 10:37 AM

I lubricated the cable, but it happened again this morning when I drive to work.

Today is -26 Celsius, even colder. It happened 5 minutes after I got on the highway. To slow down I used so much brake that at last that brake overheated and I was barely able to stop the car. I immediately opened the hood and checked the throttle cable, the cable was not stuck. As yesterday, I let it sit for 3 minutes, the problem went away. I then decided to take today off, on my way home, it didn't happen again.

To me, it's definitely temperature related, during the first 5 minutes after driving at highway speed, the temperature in the engine bay is the coldest. After I stop the car and wait for several minutes, the temperature raises and problem is gone.

If the cable from the throttle to the pedal is not stuck, could it be the throttle linkage itself or throttle actuator is stuck? I hope it's not the expensive throttle actuator, any idea?

MikeTangas · #4 02-14-2003, 12:55 PM

Try cleaning and lubricating all of the ball studs and sockets along the throttle linkage. Use AFT or light hydraulic oil to lube. Should be cleaned and lubed at every other service or so.

daddiojiggy · #5 02-15-2003, 08:30 AM

i'll be the first one to try and fix/figure out something myself in order to save $$,but this has gone too far.you say you think the problem is temp related yet it is still happening after you've gotten on the highway,right?you're putting everybody in danger now.take it or better yet tow it do a shop before someone gets hurt!

xp190 · #6 02-15-2003, 10:01 AM

Correct me if I'm wrong, but the repair manual for my 190 states that there is no need to lubricate the throttle cable because of the way it's made. On another note WD40 IS NOT A LUBRICANT! It works as a lubricant for 15 Minutes, it only displaces water to eliminate squeaks and loosen rusted parts, PLEASE DO NOT THINK THAT IT LUBRICATES! Get something decent for lubrication. So unless the throttle cables are different on your 400E there should be no need to lube it at all, and you mentioned it was fine anyway, temperature could be a part of this problem, my 190 had a problem starting in very low temperatures, but it did start on the second try every time.

xp

#7 02-15-2003, 10:28 AM

while i was getting my car oil change yesterday i asked a near by european mechanic about something like thsi he says there is an automatic CHOKE relay in ur car and some times it acts funny try to change that before u take it to the dealer i asked him about the location of it and he has no clue about 400e i tried myself to locate it but no luck again
hope it helps
mani

#8 02-15-2003, 03:40 PM

Carman850.

I had a similar problem with the throtle cable on my W124 300CE-24 after I had the engine bay steam cleaned. It would rev up when it shouldn't, the only way to bring it back down was to stick it in neutral and pump the accelerator. When I got home, I removed the air filter unit, which gave me access to the throttle linkages. I then used a degreasant and cleaned them up again. Then I put some clean grease on them, out of an aerosol can. This will keep it clean and to some extent protect it from the cold. Not sure if it will protect down to -26ºC

Haven't had any trouble since and that was 2 years ago.

Hope this helps.

carman850 · #9 02-15-2003, 11:10 PM

Thanks to everyone for the helps.

I studied the throttle control a little bit today, I am afraid that the problem is not the throttle linkage.

As you all know, M119 uses LH injection system, the throttle body and throttle actuator are in one piece, the throttle linkage between the throttle body and cable is a hard connection, preloaded with spring. If throttle linkage or cable is stuck, there should be noticeable difference in the gas pedal feel, in my case, when problem happened the gas pedal still had normal linear feel, so it's very likely that the problem is either throttle actuator or LH injection computer system. The throttle Linkage and cable was lubricated 6 months ago with Mobil-1 ATF, it moves freely.

The problem is basically very high idle, >4000 in P, approx. 2500 in D, twice it all happened approx. 5 minutes after extreme cold start, just after coolant temperature reached 80C, which is the nominal operating temperature, coincidentally, according to the service CD, LH injection system changes its mechanism after engine reaches 80C.

Tomorrow, I will do some test on my driveway, just simply warm up the car in "P", see if idle changes.

I was planning to keep this car for 5 more years, and had been enjoying the cheerful moment each times I drove it, even after all the troubles: brittle wiring harness, leaky Power steering pump, leaky camshaft seal, dead Becker stereo, malfunctioning alarm/power seat/sunroof, mysterious shake and other small things here and there, but after this scary experience, I don't know if I still have the times/money/courage to keep it running.

haasman · #10 02-16-2003, 03:24 AM

carman850

Try starting tomorrow morning as you said, but have the hood open and see if pull on the linkage makes any difference.

If it is just the cold, shut the engine off and have some very warm water ready to pour over the linkage. If this cures it, then go for a long, hot drive before shutting it down.

But I don't think this is the problem. I am not very familiar with your engine, but I am suspecting an air leak that is letting too much air in and fooling the fuel injection. Look carefully for disconnected lines, broken seals and/or cracked ones.

Haasman

pentoman · #11 02-16-2003, 05:13 PM

Quote:

Originally posted by xp190
Correct me if I'm wrong, but the repair manual for my 190 states that there is no need to lubricate the throttle cable because of the way it's made

Actually I think I remember reading in my service book that lubricating the 190's throttle cable/mechanism is a standard service item.