I think I have pin pointed an issue with My car down to the Throttle accuator but wanted some input. The car has a rough and fluxuating idle and on cold engine has a very bad loss of power and what most would call a "misfire". As the car warms the issue starts to fade and after two hours or so of running at opperating temperature it is almost undetectable. I have changed OVP, O2 sensor and the Air flow unit. I ran the codes and it is giving me the code for the Throttle accuator but before I go on a wild goose chase to find one that doesn't cost half the value of the car, I want to see if I can verify that is actually the problem.

Has anyone out there had this issue and what resolved it?
How do you check the throttle accuator to see if it is failing?
Has anyone here ever rebuilt/rewired thier accuator?

Thanks for any input you have.

Gary

 

Common actuator symptoms don't exactly match yours.

It's basically a servo-motor controlled throttle plate moving to control intake air volume. It has a carbon resistive strip sending device. The strip acts like a throttle position sensor. A wiper contact sweeps the length of the strip reading resistance. This mysterious actuator effects idle through the throttle range. ASR (traction control) and cruise control are tied into it and can override your foot throttle position.

A common report is multiple codes and random ASR failure. Check engine and ASR dash indicator lamps often come on. The car can be miserable to drive. It collects certain codes and goes into limp-mode until the codes are cleared.

You can clean them on the car flushing down the intake neck with carb cleaner to free a sticky plate. The unit can be disassembled and sort of serviced. The famous bio-degradable wiring was used in these. Guys have resoldered a home-brew harness on it reusing the factory connectors with some success. You can inspect the wires and connectors without removing the actuator. The resistor strip is the killer. If it's grooved from wear, there are no replacement parts. You can find rebuilt units on the Internet but are still very expensive. You could chance luck and check with the wrecking yards.

Misfire is not a condition a failing actuator would create. The thing shouldn't heal itself from operation unless something was changing properties from heat. Normal bio-wire failure is drastic. Power loss could occur should the unit not respond to your foot position. The result would seem underpowered but other failures such as injector or ignition may create the same effect.

I had drifting idle, loss of power and misfire which turned out to be the MAF and crank position sensors failing at the same time. This symptom never cleared with operating time. Try to get a proper diagnosis before throwing parts at it, these babies are tricky.

 

Thanks for the info

 

On this same board I found this:

"My throttle actuator is bad and causing all kinds of issue with my idle and misfiring does yours have this part (000 141 5725 on mine) and have you checked it out? I had a tech tell me that it is right up there with the Wire harness for causing this issue. Just a thought".

I had never heard of "misfire" problems due to actuators - til now! Maybe the injectors continue firing and the plate positions too lean or rich - blam.

Hmmm, would be nice to have a known good one laying around. In a local wrecking yard there lives a '95, 78K mi. E320 (hit in the rear). I snagged the blower motor, regulator and climate control unit for $40. The engine was pretty complete. The two $$$ electronic control modules were gone. The actuator was on it. I asked back at the desk how much? The counter guy looks away and quotes - Oh, about $100 with the manifold. I reply - How about the airbox and plastics? (thinking MAF). He says - I'll throw them in, everything for $100.

I never went back. IDIOT!

 

Next time I find one rear ended I am going to strip it of everything I can get my hands on and tell the guy I'll give him $200.00 for a box full and see if it flies.

 

One thing to also consider is the wiring harness. I haven't followed all of your progress but have you replaced the wiring harness?

Also, if your car has the orignal throttle actuator, it was made with the same biodegradable wiring that's found on the wiring harness and the only solutions are to completely redo the wiring (if you're good at that) or to replace the entire unit.

Other than that the mechanicals of these throttle actuators don't have that much of a failure rate, unless you don't use premium or something.

 

I have confirmed that My Wiring Harness is a non-bio harness. I think it is the actuator as the symptoms have been pointing there. However I have other issues to deal with first so this is taking a bit of a back burner.

 

Got my second hand actuator today (ebay great price with a 7 day warranty if it is garbage). I will be popping the covers and checking the wiring before I put it on. I will post any relevant pics and what the result is.

 

Sweet... E-Pray comes through. Hope she's good and easy to bolt-on (within 7 days). Pics would be cool. Warm up the connectors with a hair-dryer if it's cold.

 

The guy sent me an m119 actuator instead of the m104. Same actuator different connector. I am sending back the wrong one for the right one. I also found that there is a connector coming off the positives battery cable that has degraded wiring and is bare. The guy and the dealership couldn't tell me what it does. It cost $130 from the dealership and I am searching for it cheaper. It may or may not be the issue. I will post what happens.

 

Got the correct actuator and I lucked up. It is a benz replacement from 1999 so any original equipment wiring issues will be a non issue. I am going to try and get it on there tonight though I will be replacing the oil filter housing gasket also as I found it to be leaking.

 

Just finished putting the car back together and took her for a spin (in 2inches of snow) the sporadic Idle issue has been solved and the throttle is much more responsive and smooth. The cutting out issue is still there however so I still have some work to do. At this point I am still thinking fuel so I am going to replace the fuel filter and possibly the pump also. Any thoughts about what to look at please chime in.

Thanks

Gary

 

Have you replaced or cleaned your injectors? injector seals? Those are pretty easy things that I would check off the list. Good luck, glad you got some progress with the new throttle actuator.

 

I have not that is up there on the list. I had the fuel rail off and examined them and the jets were free and clear but I have not tested the electonic component on each one yet. Having 140k on the clock I will most likley just swap them out. Any good suppliers?

 

You really shouldn't replace injectors on a car like that, too expensive and they don't really ever wear out, better to just get them refurbished at a place like this:

http://www.cruzinperformance.com/

 

Cool on the dread actuator. Any pics to come? How's the "missing" issue since the swap?

Yeah the filter is suspicious. Hit that baby with a Seafoam dose and some Redline Injector treatment. Chemical Warfare as an opener.

 

Still missing very badly. I am going to get a filter today and slap it on there. I have done the Sefoam twice and it had no effect. There is something going on and I just gotta find it. I am going with cheapest most likely parts from this point on. If push comes to shove and it looks like I am going to be putting to much $$ into her I am just going to find a really nice 95 and use here as a donor car. Or at least that is what I am thinking now.

 

What fault code(s) is it giving you?

 

(copy of my post i put on tech talk that will explain everything)
have a 94 w124 e320. I believe the throttle actuator may be bad.
Here is what the car is doing.
At start up the car runs perfectly no problems. After almost exactly 3 minutes the car develops a rough engine and loss of power under acceleration. It almost feels like a car does when the Cat collapses and can't take any throttle without choking it out or you loose a cylinder on a four cyl engine. At first if I stayed on the throttle the engine would eventually clear up and accelerate as normal (typically 2 -3 seconds) at this point once the engine starts missing it will not clear up.

Additionally the car has engine surging at idle and in reverse at idle it is 200% worse
Here is what I have done.
Replaced 02 Sensor. (Ran the car for 2 weeks with the 02 unplugged before replacing and it made no difference)
Replaced MAF.
Checked and verified all coils are within specs for resistance.
Checked and verified Plug wires withing spec.
Verified the replacement of wiring harness.
Replaced OVP
I pulled the codes and got the following.

Pin 3

code 17 Data exchange malfunction between individual control module.

Pin 8

code 13 02S control system operating to rich for lean limit (replaced 02 Sens and it did nothing also drove it for a week completely unplugged and that had no effect either.)

Code 42 Can communication from ASR (I don't have ASR) EA/CC/ISC module

Pin 14

Code 9 CC/ISC Control Module

Code 5 Stoplamp switch

My question
Is there something I am missing. IS it possible that I have a sticking injector or valve sticking? What is the most likely thing to look at next? I don't want to just start replacing a bunch of $400 parts. Let me know anything you might think. Thanks

Gary

 

Just keep reading codes, deleting, reading again. Best clue there is ISC control module but that would be very rare. If you get another stop lamp switch code replace that only because it's cheap, wouldn't cause a engine missing.

 

Rockauto.com has rebuilt bosch injectors for $28.00 each. then I don't have to wait to send them out and wait for them to come back.

 

Cheap, sounds fishy, because these are $150 injectors, but RockAuto is usually OK. Let us know how it goes.

 

After driving home from work I am thinking I need to look at the coils a bit closer. I think there may be one going bad on the high voltage side after speaking with My Dad. I gotta try to find someone that tests them if that is possible because on the high voltage side they often seem fine on the Ohm test. I will let you guys know what I find.

 

Coil problems should show up on pin 8, then you can move them around to see if the code follows the coil. The connectors under the coil are a common problem.

http://www.autohausaz.com/search/pro...ug%20Connector

 

I will check it out. Thanks