Hey All,

I recently got my car back after having major A/C work done on it (extended warranty covered it, thankfully), but now my car doesn't idle correctly. I'm going to make an appointment to take my car in, but in the mean time (while I wait for my service advisor to call me back) I was curious to know if anybody has experienced this before.

When I first start the car and it's in the warmup cycle, everything is fine. However, as soon as I make my next move (tap the gas, put it in gear, turn on the climate contro, turn OFF the climate control,or etc.), the idle starts to get funny. The idle cycles between 400 and 800 RPMs in a pattern like fasion. The idle will rev up to about 800 RPM, then rev down to about 400 RPM, then repeat. When the idle is on the low side, the engine gets rough and if I apply the accelerator it bogs down for a second before revving up. If I play with it, I can actually get it to stall. Sometimes, it idles fine! However, this problem is more often than it is not.

I know that when the dealer worked on my A/C they disconnected the battery. From past experiences with other vehicles (so I could be wrong when it comes to the TSX), when the ECU loses power it needs time (aka drive cycles) to complete all the "readiness" tests or basically re-learn the condition of the system and the various sensors. One of these things is the idle.

Anywho, my question is, could this "issue" be part of the idle relearn? I carpool to work so I don't drive the car every day, but I have driven it to and from work and around town a few days since this problem has started.

Any insight/input/feedback would be appreciated. Thanks!

 

Is the bogging in sync with the AC compressor switching on? That'd be the first thing I'd investigate.

If it's not that it almost has to be a sensor issue.

 

wow that has to be a problem.

 

At first I thought it was related to the compressor engaging, but the problem happens regardless of if the climate control is on or off. The problem seems to most noticably start when the A/C clutch engages, but will come and go even when the climate control is off. So, I'm not sure if it's A/C related or not. I'm able to recreate the problem by doing the following:

1) Start the car
2) Do one of the following: tap the gas, turn the climate control on (if it was off) or off (if it was on).
3) Watch the idle fluctuate and attempt to rev the engine when the idle is on the low side (near 400 RPM).
4) Not always, but 1/3 of the time it'll stall. If it doesn't stall, it bogs down then revs. During the bog (1/2 a second or so), all interior lights and dash lights dim.

Also, I failed to mention that once the car stalls, when I start it again cranks for 3-4 seconds, starts to sputter for a second, then starts. I'm assuming this is becase the engine is flooded due to the stall.

I recorded several videos of the problem using my digital camera, but the files are too large to post on YouTube. I tried reencoding a video to make it smaller, but I can't get any of them small enough without losing quality.

lol...I think so, too. I'm dropping the car off at the dealer after work today. Unfortunately they won't be able to look at it until tomorrow so it'll sit there over night.

 

There's a circuit called the ELD (electrical load detection) which is supposed to signal the ECU to increase the engine rpm should certain electrical load is detected (including the items you mentioned). Any CEL?

 

No CEL yet. There could be a pending code(s), but I haven't gotten around to checking. Hopefully the dealer will figure it out...we'll see.

 

My 2002 RSX did that exact thing with the RPM's changing like that, however i traded it in for my TSX before i tried getting it fixed. I heard it is somthing to do with your computer compensating for different fuel and O2 mixture, or something along those lines, or i can be totally off.

 

According to the RO...

The dealer cleared the memory in the PCM and ECM (are they separate units in the TSX?) and reset them. The drive back from the dealership (about 6 miles) seemed to be much better than before. We'll truly see when I drive it tomorrow.

Was this something I could've done just by disconnecting the battery, or does the ECM/PCM have non-volatile memory?

 

Erm, my mistake. The RO states word for word...

"Erased memory in PCM & ECU reinitialized. Roadtested operating to factory specifications."

So, my same question still applies. Is this something I could've done by disconnecting the battery, or does the TSX's computer(s) have non-volatile memory?

Thanks!

 

reproduce the problem and then disc ur negative terminal to test :P

 

I hope I'm unable to reproduce the problem because so far it's gone!