Engine idle erratic on 1989 300TE?
Thread Starter
Member
Joined: Jun 2004
Posts: 159
Likes: 6
From: BC, Canada
2007 ML350 (M272) 30-509034 & 2008 ML320 CDI
Engine idle erratic on 1989 300TE?
My car, since ownership 2 months ago has been idling rough in drive while stopped at lights etc. I used fuel injector cleaner in the gas and cleaned out my throttle body/air intake and that seemed to help a little with my hesitation off the line I was experiencing. Now however, the car is running quite poor. In drive while at a light, it cycles high then low and back again. When I put it into neutral, it does it now as well (didn't before) but worse than in drive as it idles from about 900 to 1500 RPM every second...idling high then low etc. It is running quite rough. Any ideas? You think a new O2 sensor will make a huge diff as it may possibly be the culprit or? I will be driving from Victoria to Edmonton on Sunday (14 hour drive). Please, if possible, could someone give me some knowledgable feedback. Thanks everyone as always for the input and help!!
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Joined: May 2003
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From: USA
18 G550, 24 EQB3504M
I would do the following myself:
Plugs, wires, rotors and caps
and replace the OVP Relay (actually, I'd do this first).
The OVP relay is behind the battery I believe. It's black in color and has a fuse in it. Take it out clean it and put a new fuse in .. but replace the part anyhow. They updated it.
Plugs, wires, rotors and caps
and replace the OVP Relay (actually, I'd do this first).
The OVP relay is behind the battery I believe. It's black in color and has a fuse in it. Take it out clean it and put a new fuse in .. but replace the part anyhow. They updated it.
Thread Starter
Member
Joined: Jun 2004
Posts: 159
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From: BC, Canada
2007 ML350 (M272) 30-509034 & 2008 ML320 CDI
I assume this is the OVP in the pic I took? THe fuse looks ok but bloody hell is it ever difficult to get your hand or even fingers in there. How the hell does one pull it out?
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Joined: Mar 2003
Posts: 232
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From: Seattle
2005 E320 CDI
Ahh the infamous irratic idle....I finally fixed mine.
In my case it was a loose vacuum. But I've read about many other causes.
1. OVP - even if the fuse is good, the OVP itself might be bad
2. MAS
3. Actuator
4. ICV
5. fuel pump relay
6. plugs/wires/distributer cap/rotor
7. fuel pump
6. fuel filter
I would start with the cheap DIY stuff...ie clean out the ICV, check your vaccum lines, install a new OVP (if it's still the original), then do the cheap DIY stuff change the MAS, fuel filter/pump/relay, plugs wires/distributor.
If that doesn't do it, then your last resort is the actuator (you're talking a couple thousand dollars).
Good luck.
In my case it was a loose vacuum. But I've read about many other causes.
1. OVP - even if the fuse is good, the OVP itself might be bad
2. MAS
3. Actuator
4. ICV
5. fuel pump relay
6. plugs/wires/distributer cap/rotor
7. fuel pump
6. fuel filter
I would start with the cheap DIY stuff...ie clean out the ICV, check your vaccum lines, install a new OVP (if it's still the original), then do the cheap DIY stuff change the MAS, fuel filter/pump/relay, plugs wires/distributor.
If that doesn't do it, then your last resort is the actuator (you're talking a couple thousand dollars).
Good luck.
Thread Starter
Member
Joined: Jun 2004
Posts: 159
Likes: 6
From: BC, Canada
2007 ML350 (M272) 30-509034 & 2008 ML320 CDI
Where is the ICV located on this car? Any ideas? The OVP is an absolute biznatch to get out!!! Is the fuel filter underneath the car, at the fuel tank, or near the engine? The wires, dist cap, rotor, and plugs are new.
It was running rough while in "D" but only when stopped. Now after adding fuel injector cleaner and cleaning the air intake, it idles all over the place in "N" and "P." I sort of think it has to do with one of those but so hard to say? =(
THanks for the advice, if ya know when those few items are located, that would be a great help sir! I would have to do as much as I can tomorrow as I leave Sunday =(
It was running rough while in "D" but only when stopped. Now after adding fuel injector cleaner and cleaning the air intake, it idles all over the place in "N" and "P." I sort of think it has to do with one of those but so hard to say? =(
THanks for the advice, if ya know when those few items are located, that would be a great help sir! I would have to do as much as I can tomorrow as I leave Sunday =(
Super Member
Joined: Jun 2003
Posts: 595
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From: Middlefield, CT
1994 E320
The fuel filter is under the car towards the back, covered by a black plastic shield.
The MY89 3.0L engines still used the M103 engine, and there is no actuator (drive-by-wire).
If you know how, hook up a duty cycle meter to the X11 diagnostic connector to read the on/off ratio. That will give you a good indication as to where to start looking for failing components.
The MY89 3.0L engines still used the M103 engine, and there is no actuator (drive-by-wire).
If you know how, hook up a duty cycle meter to the X11 diagnostic connector to read the on/off ratio. That will give you a good indication as to where to start looking for failing components.
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Thread Starter
Member
Joined: Jun 2004
Posts: 159
Likes: 6
From: BC, Canada
2007 ML350 (M272) 30-509034 & 2008 ML320 CDI
If you know how, hook up a duty cycle meter to the X11 diagnostic connector to read the on/off ratio. That will give you a good indication as to where to start looking for failing components.
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Super Member
Joined: Jun 2003
Posts: 595
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From: Middlefield, CT
1994 E320
X11 is in the engine compartment on the driver-side wheel well. It is round. Pin 3 is data and pin 2 is earth, although you might be better off just using the chassis for earth.
My previous post might have been confusing. There is NO actuator and NO drive-by-wire. The accelerator cable is connected to the throttle body by a steel cable. Very simple and old-school.
Visit http://www.landiss.com/mixture.htm for more info.
My previous post might have been confusing. There is NO actuator and NO drive-by-wire. The accelerator cable is connected to the throttle body by a steel cable. Very simple and old-school.
Visit http://www.landiss.com/mixture.htm for more info.
