throttle actuator? - PeachParts Mercedes-Benz Forum

anziani · #1 04-09-2009, 03:49 PM

The car is a '93 300CE, Federal version with ASR, 170K, with the following problem: Occasionally in the first block when the car is cold, I lose pedal and have to go almost to the floor to get power back. I then stop, shut off and restart and it goes away. There is NO ASR light lit. I can drive the rest of the day and evening with multiple starts and stops and it never reoccurs until the next morning. I called Beckmann Technologies about sending in the actuator but they thought it was a throttle position switch. (Reading the codes I get Idle Speed Control at upper or lower control stop or CC or EA indicates "limp Home" on Pin 8. On Pin 14 I get :"closed throttle position contact")
I spent time with the Benz parts guy with my VIN but could find no exterior throttle position switch. My mechanic concurs. Is it the Throttle actuator?
Any ideas?
Anziani
'93 300CE 170K
'95 E420 116K

mbdoc · #2 04-09-2009, 04:39 PM

Possibly an over/under voltage issue at that point & time.

Try connecting a voltmeter & watch voltage as the problem happens.

anziani · #3 04-10-2009, 12:43 PM

Thanks. I'll see where I can pick up voltage gracefully in the cabin and take a look.
Anziani

anziani · #4 04-10-2009, 01:59 PM

M.B. Doc,
Do you think I might have an "overload relay" problem?
Anziani

mbdoc · #5 04-10-2009, 03:54 PM

Always a possibility...but under the conditions of the problem, sounds like a battery/charging system problem.

anziani · #6 04-10-2009, 04:39 PM

M.B. Doc,
The car has a new battery and alternator, all installed by others a few months ago. You said to measure voltage. Do you mean at the battery terminals?
Thanks,
Anziani

mbdoc · #7 04-10-2009, 05:03 PM

Either get a voltmeter from radio shack & plug it into the cigarette lighter OR run wires from a voltmeter to the battery.

anziani · #8 04-10-2009, 05:33 PM

M.B. Doc,
Thanks for your help. I have a VOM. I'll get wired up. Have a nice weekend.
Anziani

anziani · #9 04-13-2009, 08:21 PM

M.B. Doc,
I took voltage from Pins 1 and 16 on the 16 pin readout. I assume this is OK. And of course, there wasn't the "problem" today but I will keep monitoring the voltage.
What I do have is a steady 13.40 to 13.80 output while driving the car.
Anziani

anziani · #10 04-14-2009, 03:19 PM

OK, this AM the "problem" returned. I was watching the VOM. Nothing unusual. I then restarted the car and the voltage went to 14.3 and stayed in this area. I have a feeling that it is the voltage regulator even though it is supposedly new. Anybody?
Anziani

EricSilver · #11 04-14-2009, 03:29 PM

There are currently three or four 95/94 E320’s in this forum experiencing the same problem under the same conditions.

I keep hearing the voice of a tech a few years back, when the ignition lock failed on my 260E. He said, “The 89’s are starting to go,” in reference to a sudden increase in 89 E-Class ignition tumblers he had to replace. I wonder if there is some component on 94/95 E320’s that is also “starting to go” and causing these ASR faults….

FYI: In every single post I have read on MercedesShop, in which the throttle actuator was replaced, it did not solve the problem, so you can probably put away your checkbook.

My ASR issue is also temperature related and for a long time I suspected it was the coolant temperature sensor, but that never made sense – and still does not. But on a bitterly cold day this past January I drove from VA to DE (low 20’s outside) and the effect of 20-degree air being rammed into the radiator at 80+ MPH apparently affected the CTS enough to keep the car in so-called limp mode for the entire trip. (So-called because at 80+ I was hardly limping.) Only when I exited in DE, and my speed dropped to about 60 on a local road, did the sensor apparently send a “good” signal that released the ASR fault condition.

I have researched this a lot, reading all the opinions of the causes, but the bottom line is my ASR fault occurs when the coolant temp sensor is cold, and goes away after it warms up. The fact that my fuel economy is down a bit and I can often smell harsh fumes when hot idling lends further credence to a faulty coolant sensor. That sensor is perhaps the most weather-exposed electrical component under the hood, sitting right up front, just behind the grille, where cold breezes and moisture can easily find it. Indeed, my ASR faults most frequently occur(ed) on cold & windy and, especially, cold/\windy & wet days either after the car was sitting overnight, or, when bone-chilling cold, after sitting for a few hours. The behavior is always the same:

Strong crank and normal initial idle speed. Touch accelerator and there is an RPM surge for a few seconds (or longer), then a relay in the back seat area pings, ASR light illuminates, and rpm drops to about 500. Interestingly, tapping the brake pedal can stop the surge and immediately trigger the relay ping/ASR/low idle. However, if I do not touch the accelerate after startup, and simply use the car’s traction to back out, and move forward, applying the brake will not trigger the ASR fault. Only after I travel a bit and then use the accelerator will that occur. (This points to Accelerator switch.)

This fault cycle will happen repeatedly until the coolant temperature reaches, and remains, at 82C. (There is a false-positive interval when temp reaches 82, then drops back to 80 as the thermostat opens. After a few more minutes, temp reaches 82 and stays there.)

My current planned course of action is to replace the coolant sensor, since I need to do that regardless. Then the brake switch, and the accelerator micro-switch (if I can actually find it).

Below are links to possible solutions per the experiences of the members and expert techs here. As you will see, none of them say anything about coolant temp, obviously because it makes no sense. But it appears to be involved nonetheless. Hope everything works out for you.

ignition switch
http://www.peachparts.com/shopforum/showthread.php?t=28514&highlight=e320+ASR

Tire Inflation
http://www.peachparts.com/shopforum/showthread.php?t=61476&highlight=e320+ASR

fuel system control unit
http://www.peachparts.com/shopforum/showthread.php?t=61476&highlight=e320+ASR

base module
http://www.peachparts.com/shopforum/showthread.php?t=61476&highlight=e320+ASR

The Elusive Throttle Safety/Micro Switch.
http://www.peachparts.com/shopforum/showthread.php?t=61476&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=114906&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=84223&highlight=voltage+regulator

Brake/Stop Light Switch
http://www.peachparts.com/shopforum/showthread.php?t=84265&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=133918&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=204365&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=188665&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=164241&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=164241&highlight=e320+ASR&page=2

Wheel Speed Sensor
http://www.peachparts.com/shopforum/showthread.php?t=108466&highlight=e320+ASR

Voltage Regulator -- (I Still Need to Check This)
(MSG # 20) http://www.peachparts.com/shopforum/showthread.php?t=105682&highlight=e320+ASR&page=2

Water In Electronics/Control Units
http://www.peachparts.com/shopforum/showthread.php?t=209356&highlight=e320+ASR
(MSG # 21) http://www.peachparts.com/shopforum/showthread.php?t=105682&highlight=e320+ASR&page=2

OVP
(MSG #58) http://www.peachparts.com/shopforum/showthread.php?t=188665&highlight=e320+ASR&page=4
(Oh, and MSG# 59 is, um, amusing.)

Related Threads/Comments Worth Noting
http://www.peachparts.com/shopforum/showthread.php?t=108761&highlight=e320+ASR

The below thread is very interesting since that area my car had become exposed to rainwater around the same time my ASR issues began:
(MSG #15) http://www.peachparts.com/shopforum/showthread.php?t=164083&highlight=e320+ASR
“..ea/cc/isc has own computer in pass side floor …”

Finally, in these threads ETA’s were successfully replaced “just because,” and with no mention of ASR problems.
http://www.peachparts.com/shopforum/showthread.php?t=204530&highlight=e320+ASR
http://www.peachparts.com/shopforum/showthread.php?t=147929&highlight=e320+ASR

anziani · #12 04-14-2009, 03:52 PM

Eric,
You have done a wonderful job of gathering all of the ASR problems in one page. My '93CE doesn't have a throttle position switch that anyone can find but it does have mis-matched tires. Also, I never get the "ASR" light but this could be indicative of the '93's.
I also live in the desert but will take a look at the temperature switch. The car started off in Florida but spent the last 4-5 years in San Diego. I've contacted the previous owner to see if she ever had this "problem". If "no", then it has to be the new alternator that was replaced right before I picked up the car.
Anziani
'93 300CE
'95 E420

mbdoc · #13 04-14-2009, 05:42 PM

On at least 6 cars like yours...1993-95 E-class with a M104 engine with above symptoms

The voltage regulator WAS the problem............

Connecting a volt meter while driving & watching for a HIGH voltage spike is good idea.

I use an old radar detector plug connected to my Fluke that has a min/max recording feature.

EricSilver · #14 04-14-2009, 06:01 PM

Quote:

Originally Posted by M.B.DOC

On at least 6 cars like yours...1993-95 E-class with a M104 engine with above symptoms

The voltage regulator WAS the problem............

Connecting a volt meter while driving & watching for a HIGH voltage spike is good idea.

I use an old radar detector plug connected to my Fluke that has a min/max recording feature.

That's the one major thing I have not checked, and will definitely do. Arthur Dalton also suggested it several months ago. (I'm obviously a procrastinator.) I'll open the alternator and have a look tomorrow.

It's interesting that you suggest looking for a voltage spike. I was wondering if a erratic/fluctuating/oscillating current from some component could throw the computers into a tizzy and trigger the fault.

anziani · #15 04-14-2009, 06:27 PM

Hopefully, mystery is solved! Just got a reply from the P.O. She NEVER had any problems with ASR or loss of power. The alternator was replaced AFTER I bought the car and before I brought it home. I've ordered a new regulator and will install on Thursday. I'll let you know.
Anziani