idle problem 1998 e300 td please help
 

hello everyone, I am the new kid on the block with the 1998 e300 td, great car except this idle problem that I had since I've got it. In the morning it starts easy but it shakes for about 30-50 seconds and it smokes a little bit (white smoke). It is fine after that until it warms up all the way to the normal temperature. After that if I put it in Park or Neutral it starts shaking again. Now the interesting part is that the shaking stops if I turn on the head-lights or the A/C. I have changed the filters, I ran two cans of Diesel Purge and I even replaced the lowest clear plastic fuel line with O-rings and everything because I saw air bubbles running through it under acceleration. Still the same. I took it to the mechanic, he hooked it up to the diagnostic machine and there is no codes ,he is suspecting that the EGR valve may be stuck or the timming. I have search the forum regarding this but no luck. If anyone can help me with this I would appreciate it. I am down in Atlanta ,GA and my name is Joe. Tanx again.

'98 e300 turbodiesel 118k

I was just about to post a similar question when I saw your post.

My car starts quickly and without smoke. When in Neutral or Park it has either a regular rhythmic miss or sometimes an irregular miss which makes the whole car shake. This can happen, but infrequently, when the car is in Drive while waiting for a traffic light to change. It also seems to be triggered if the vent system is on and I press the EC button (economy mode fan: is on but not the AC compressor). I haven't checked to see if it correlates with the headlights. It also seems to get worse with deceleration.

Yesterday the "check engine light check electronics" message came on. Mechchanic checked the code and said it needed a mass air sensor. That was repalced but the problem persists.

PO had the new fuel lines (not sure if all of them) and O rings installed. I have tried to look for air bubbles but I am not sure where to look and haven't seen any even with the laser pointer.

I did the lubro moly diesel purge (thanks again crmont) x2 with no improvement.

Prefuel and fuel filter changed 4k miles ago.

Any suggestions?

we may want to check if the EGR is stuck, I'll probably do it this weekend , I'll let you know if that is it the problem. Joe

I am sure that it will be fouled and cleaning could result in improvement. It does require the manifold removal which is detailed in other posts.

I get the feeling from the intermittant nature of it and the way that it changes with putting the car into Park or Neutral makes me think it is a vacuum line or something. But then I really don't know anything about cars.

Let me know how it goes removing the manifold, what you find, and how it affects the rough idle.

by the way after I turn the engine off I can hear a hissing sound from somewere. I dont know if its normal, I'll check into that.

I hear a similar sound as well, but I figured out that it was my wife who wants a new car.

In my case, I think it was some cooling fans for the ECM box behind the pass shock tower area. That was where the electronic controllers are and I believe the fans were to keep them cool for a while after shutdown

I hear it somewere from the turbo area, not sure exactly and I don't know if it's normal or not.

It sounds like that and that it is coming from the EGR area too but i finally traced it down to the ECM area where all the controllers are.

I am getting close to the problem
 

today I have checked one of my friends 1999 e300 td and there was no air bubbles at all in his fuel lines, so IT'S NOT NORMAL to have it. Now I will have to check all the lines with O-rings and everything. I will post the results.

no luck yet
 

I finally took off the intake manifold and the EGR, everything very clean , also checked the O-rings at the fuel lines everything is fine, I am thinking it maybe something to do with the electric part....

I do not know if your cars have a klima and over voltage protection relay. The climate control, idle and transmission circuits are connected there. Mine are located behind the shock tower near the electronics where you are talking about hearing the fan after shut down. I have an 87 300D. I just thought it was worth a mention in case you guys have this or something similiar to it.

THAT's a tough one....Best to take care of that Hiss lest it develop into a bite!

white smoke
 

White smoke indacates unburnt fuel. With an ohm meter disconect the wires on the glow plugs Check each one for resistance. About 1 ohm. They should all read the same. If not you may have found the problem.
Additionaly my VW TDI the glow plugs all were within spec but it still through a code. Along with rough idle and white smoke. Replacing the glow plugs solved the problem.
As I understand it. The glow plugs remain on after starting for a time.
Emissions no doubt.
-A
1999 E300 TD

glow plugs should be fine, I have no codes and the car starts excellent except for the shacking(half a minute). On my tdi the car ran fine even without the glow plug harnes on, anyway I think the GP-s are helping under 38- 40 degres F.