Ever since my switch to OBDI, when I start my car it takes about 15 seconds for it to drop back to normal idle.... when I'm at a gas station and I see that the pump is broken I don't want to wait for the damn car to idle right again i want to just start and move. What tuning measures will rid me of this problem?

 

My 96 with OBDI conversion does the same thing. It also seems to keep the RPM up more when coming to a stop then slowly drops back down to around 800 after the car is fully stopped. I don't see this as a problem. Just something to get used to.

JeffA

 

All manuals keep the RPMs up during stopping to keep vacuum pressure up for the brakes.....Do a search, its been asked like 50 bizzilion kazillion million times

As far as the high rpms during start....I'm not really sure, sometimes my car does it real noticeably other times it really doesn't stand out. It more than likely is just the computer getting its bearing. I believe its OBD I specific, something to do with the programming I guess.

 

yes

 

scoobysnax83, how many zero's does 50 bizzilion kazillion million have?

 

I'd be interested in some start condition logs showing IAC counts and to take a look at how they move during the first 20 seconds or so (until the idle "normalizes").

Could be something doing with the IAC stepper motor not stepping correctly (gummed up), or something along those lines (out of range).

Mine did it I recall, can't remember what I did to fix it. I do recall pulling the IAC motor and cleaning it as well as I seem to recall adjusting the TB stop screw (actually screwing it in to open the blades a bit at full stop) in order to bring my IAC counts into the norm (obviously mine were maxing).

If you have the ability to log then take a log and post it or email it to me ( sotohe1@attbi.com not sure what is in my profile here). I can try to remember what I did to remedy that problem. I'll see if I can dredge up the logs and review what I did but dont know if I have them floating around at this location.

Good luck either way.

 

more than a little less than too much

 

My 95 Z M6 did the same exact thing. I bought it to the dealer about 10x under warranty. They changed the computer 2x's, TPS was changed or adjusted 3-4x's, after that they would tell me that they could not "Re-create the customer complaint". I just think they were tired of me complaining all the time! LOL It's just something that you have to get used to. Sometimes it's a real pain in the A** to sit and wait, but you just have to do it. Mine also didn't do it all the time......It's funny, when it started to do it a lot, I would get an oil change & it would stop for a few thousand miles! I don't think there is a relationship between the two, it's just seemed funny that would "cure" it for awhile.

 

If all the info below does not help go buy a $20.00 TPS from AutoZone and R&R yours. They do eventually wear out mechanically inside. It's a spring mounted into a two piece plastic housing and can get a wear spot (which can cause a high rpm backing off from idle like say coming to a redlight) from normal use. Mine did exactly what yours is doing and 20 bucks later it now backs off to 900 rpm normally which is almost instant. Good luck.

 

Again a data log will show this too. In the log you just look and see if you are still showing "open throttle" when you know you don't have your foot on the gas.

Hopefully 96 WS6 has a datalogger, so much more fun to "find" the problem than randomly hunt for it.

 

check to see if you have an exhause leak. Mine was doing same thing, except all the time, and the AIR fittings on my headers where "sucking" air in. You couldnt hear the leak but I noticed some black stuff around the plugs I used. I ultra-coppered the plugs and it hasnt done it since. Just a thought.

 

i drove my buddy's VR-4 the other day and it seemed to do the same thing exactly when coming to stop, the rpms would shoot up even when not downshifting..i didnt understand....

 

The TPS is fine because the voltage does not fluctuate on freescan... I was watching the IAC numbers when I start it and it jumps up to around 30 and starts dropping down slowly if I remember correctly. Is there any way to adjust the initial IAC value??

 

Hmmm mine on cold start is about 1500 or so RPM, and it slowly moves down toward the idle of 800 RPM, but that's in the programming to adjust idle based upon temperature.

Now if I go to a gas station and fill up, or start the car with a warm engine, I don't have the problem you mentioned with the idle going to 2000 and slowly coming down, unless for some reason the car did not start immediately (a half-assed crank or two at first).

 

Mine does that, but drops down in rpm much quicker. Definatly less than 5 seconds, and it probably has to do with the TPS/IAC and maybe throttle stop screw? Other than that, I have no clue.