High idle after driving

[XfireZ51]

Originally Posted by S.hafsmo

Thanks. Now I've just got to figure out whether to go for the Haibeck chip, or a revised stock chip?

I'm pretty certain Marc would use the AYBK cal as the basis for any revised chip he would provide.

[rkreigh]

Originally Posted by A26B

The problem may be in the ECM PROM. There are 3 different versions for the 1990 ZR-1, the original & 2 upgrade versions by GM to resolve issues, one of which was high idle.

Here are the 3 different calibration versions in the order of release. The number is on the PROM.

1990 ; 16129717, 16148554 & 16163905

Thx Jerry~!

the LT5 sometimes does an "idle step down" strategy where the car hovers above idle, once the car is at TPS zero for a bit it FINALLY goes back to idle

doesn't do this when cold, and the IAC isn't the issue, it's the code.

so what to do! see if you can borrow a prom with the latest stuff in it and chances are you will see what I mean.

my LSV has that strategy due to the big cams to prevent stalling, and it drives me NUTS. car is mild enough it really doesn't need it.

The right tuner can see this and program it out so the idle snaps back when you get off the throttle.

great posts about the dog gone dag My throttle body is a bit long in the tooth from many miles and smiles, and I also suspect my ASR mechanism is grouchy as my car hangs at 2k rpms until I blip the throttle, and then it goes through the whole mickey mouse drop to 1500 until I sit there at a light, and then after about no joke 20 seconds of idle time at zero TPS, it finally goes to a nice silky 1k idle.

Demps and I will be looking at this more in depth and report back. The LSV runs great but I'm getting a code 61 due to the secondary vacuum system (the air pump in the nose) crapping out. well I don't have secondaries so I don't need the pump but the dumb chip and pooter don't know it.

remember computers and light bulbs have equal intelligence, we still need actual not artificial intelligence, and the ZR-1 is just another challenge.

The old computer and memcals are a pain to work with, but it returns me to my mainframe roots when hex and binary were king.

kids now don't know what that means.

[XfireZ51]

Ron,

There shouldn't be anything in the calibration that would cause u to have a Code 61 unless the cal is not set to essentially ignore the secondary map readings.

[S.hafsmo]

Originally Posted by S.hafsmo

I'm sure I checked the charge voltage just after I bought the car, but I obviously have to re-check. To completely fill an acid battery approx. 14.4V is necessary from the charger/alternator. The battery should then read 12,7V when the battery is fully charged.
Unless it has some sort of "float charge" that occurs when the battery is full. I'll try to double check later today.

I re-checked the voltage the other day, and at least when cold it does make 14 Volts. Can I measure at the ALDL connector to check what the Tech 1 is reading?`

Originally Posted by XfireZ51

I'm pretty certain Marc would use the AYBK cal as the basis for any revised chip he would provide.

I would assume as much, the question was more in term of actually wanting the additions of the Mark chip. I can't seem to find any downside to it though.

[TealZR1]

S.hafsmo-

Been following this - any resolve? Mine idle does the same thing

[S.hafsmo]

Unfortunately, not yet. I'm currently at work in Africa, and won't be back until the beginning of June. I've ordered Mark's chip, and I've got a bottle of Molykote D321R ready for DAG-replacement testing.

[Andreas]

Hi, did you replace the DAG, i'm curious for the result?

[S.hafsmo]

I didn't get around to it this trip either. Due to our short summers, other projects got priority (leaky roofs and such). I did however install the chip from Mark, and it certainly made great impact on coast-down idle, as well as idle when engine is hot. The issue is now only a minor one, and I assume it's due to worn throttle body. If mine is anywhere near as worn as Roadster's, the DAG would be just a band-aid, and a TB overhaul is due. Come autumn I will make an attempt on the DAG, but will probably end up sending the TB over to Haibeck this winter for an overhaul.

[lfalzarano]

I had to send my throttle body to Marc and the car has been fantastic after that!


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[Roadster]

Just to clarify, I never mentioned that my TB was worn.....besides doing the dag and the other items on my thread, my idle is perfect and the engine runs great. I don't co rider doing the dag a band aid fix, time consuming, yes..... band aid, no
JMO.....😁😁😁

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