Surging on Accel. and Decel.
 

Help please!

Car is acting very strange. It's a '92 500e.

On acceleration, car pulses very subtly. On deceleration it does the same thing. Occasionally, when going from D to P, idle will surge up above 10k, then gradually come down. Sometimes when this happens, ASR light goes on. Also, more troubling, when driving, the ASR and ABS light come on and acclerator peddle offers no response. In this instance, I shift to N, turn off ignition and turn on and we're back in business. No fault codes to give us a clue.

Just replaced brake light switch, with no effect.

I'm at a complete loss.

Thanks for any help/ideas you might have.

Forgot to mention, wiring harness replaced in the last 10k miles. Mechanic says MAF checks out fine.

Check the Throttle Body Actuator (TBA) - it’s the most common fault for what you are experiencing. The TBA is not cheap though, around $900-$1100 new.

Thanks,

That's what we've suspected, but are trying to rule everything else out first, including idle sensors as much of the troubling activity is occuring under 10mph.

Here's what we (and by we, I mean my trusted Mechanic) found:

One of two return springs on ASR Actuator was disconnected; large amounts of build-up between butterfly and housing, causing throttle to stay slightly; rubber boot between throttle body and ASR unit was cracked, causing cacuume leaks. Cleaned throttle body and butterfly, increased tension on springs and replaced boot.

Accelerator feels decidely different under foot. No surging on a brief hiway run bringing car home from shop.....If you hear nothing further, problem solved...though wallet is a bit lighter for the effort.

Sounds like you got to the bottom of the issue, great to hear. The throttle linkage can get too loose as well beyond tightening, I had mine replaced and the pedal response is perfect now.

Dittos. Look around, you can find them at boneyards or rebuilt for MUCH less.

Well, ASR and Brake light symptoms appear to have been eliminated, as has been the pulsing acceleration. Accelerator is firm and responsive.

But it still pulses on deceleration at highway speeds. Seems like a constant frequency, not so subtle.

Ideas?

Pulsing with breaks applied or not applied?

Do you have an aftermarket alarm?

No brakes...occurs when I lift my foot completely off the accelerator, particularly noticeable going downhill. Seems to go away if I depress the accelerator ever so slightly.

No after market alarm

rjfjr1, try these two sites and post your scenarios. These sites are the best places to run your 500E by the group - http://www.500ecstasy.com/forums and/or http://www.500espot.com/forums I wish I could help more, but this is outside of my knowledge.

Problem solved (ouch $$).

Replaced the Throttle actuator, everything is back to normal.

Well at least now all is ok. Btw, how much was the job was the TBA a new one?