Different Idle relearn Procedure

[ursus]

I recently got the speed density update chip from GM for my 2.8l regal and the idle relearn procedure in the GM document that came with the update kit from GM is slightly different than the one described on this site.

 

1. Reset ECM by pulling ECM fuse (underhood) for 10 seconds.

2. Block the wheels and put on the Emergency brake then With A/C turned off, start car and immediately put it in Drive. ( difference here is they don't put foot on brake which I guess could make a slight difference as the power brakes will use vacumn)

3. If the car does not start initially, keep trying WITHOUT putting your foot on the accelerator.

4. Let the car idle in gear for 10 minutes or until the cooling fan cycles once whichever comes 1st, versus for at least 5 and no more than 7 minutes.

 

The rest is the same

 

5. Shut off the car for 10 seconds.

6. Start engine, place in drive and let idle for 5 minutes.

7. Shut off engine.

8. Idle is learned.

[White93z34]

i don't get the whole idle relearn thing, i never had to do it. the cars just bitchy to start the first time after the ECM looses power, thats all i've ever noticed

[RareGMFan]

i don't get the whole idle relearn thing, i never had to do it. the cars just bitchy to start the first time after the ECM looses power, thats all i've ever noticed

 

Some of my cars have given me problems after the battery has been disconnected/lost power. If I go out for a drive right after, sometimes when I come to a stop, the idle will spudder a bit, then die. It may do this a few times within the first day or two, then it's good to go no its own (I've never done an idle relearn on any of my cars).

[ursus]

I think eventually the ecm relearns the idle from regular use but the procedure is done by GM service so the car runs good right away rather than crappy and slowly getting better for the 1st few days/weeks after being serviced.

[Justin]

I've never had much of a problem with idle relearns. The car might die once, but then after it's restarted it purrs like a kitten.

 

One note with the procedure at the top, does anyones e-brake even work??

[THe_DeTAiL3R]

I've never needed to to a relearn on either of my w-bodies.

[Robby1870]

no working E-brake here!!

 

I do a short idle relearn, with me putting my foot on the brake and going through R N D a few times letting it stay in each gear for 30 secs or so, then drive it.

[GnatGoSplat]

The only W-body I've had that NEEDED the idle relearn was the '88 Cutlass. It had to be followed TO THE LETTER or it would stall at every stop sign. If the idle relearn had been followed to the letter, the car would run and drive perfectly! I had just figured it was just something different in the programming for that car that required it, but then one day I completely cleaned out the IAC on that car (very dirty). From then on, the battery could be disconnected anytime and it would run great without the relearn procedure. I guess the IAC before was so gunked up that a relearn had to be forced before the ECM could properly adjust to the IAC.

[1990lumina]

I had to do the relearn on my Lumina because every stop sign it would stall.

 

Yeah I'd say the brakes take a bit and the computer is probably to stupid to conpensate...but I've never had any problems doing it the w-body.com way lol

[Grand Moff Joseph]

so do they make these "density update chips" for the 3.1 as well? Better yet, what the hell are those things anyway?

[GnatGoSplat]

No, 3.1's are already using the speed density program as are 1989 2.8's.

 

The speed density update is for 1988 2.8's.

 

Speed Density is the method that the engine calculates the air/fuel ratio. A speed density system uses a MAP sensor.

 

The 1988 2.8L had a MAF that was used for its fuel calculations, but it was unreliable. Since it also had a MAP, the speed density update just makes use of the MAP sensor.

[rudefyet]

so is the MAF used at all on the 89-90 2.8/3.1?

[Lee]

It's been nearly 2 weks since getting a new computer and my mileage is still off a couple. Driven at least 400 miles.

 

But it ran pretty good right away. Now it is perfectly normal except for mileage.

[Robby1870]

so is the MAF used at all on the 89-90 2.8/3.1?

 

They got rid of the MAF

[patgizz]

The only W-body I've had that NEEDED the idle relearn was the '88 Cutlass. It had to be followed TO THE LETTER or it would stall at every stop sign. If the idle relearn had been followed to the letter, the car would run and drive perfectly!

 

my sisters old 91 lumina was the same way, wouldnt idle for crap and stalled without a relearn.

[rudefyet]

so is the MAF used at all on the 89-90 2.8/3.1?

 

They got rid of the MAF

 

Well i have a sensor in my air box...what is it then?

[Robby1870]

At teh back of the airbox? MAT/IAT

[rudefyet]

oh..."I see," said the blind man, as he picked up his hammer and saw

[mfewtrail]

I've had to do the idle relearn on my 93 a few times, it sounds mean before it relearns the idle(sounds like it has an aftermarket cam in it ) and will want to die with you at almost every stop.

[mhp]

I also have to do the relearn-process on both cars. If I don`t make it, the engines stall and a restart takes about 5 minutes. After the restart the idle goes up and down and so on.

So it`s very if you are standing at a heavy used crossing.

[ursus]

.... Better yet, what the hell are those things anyway?

 

Basically it is just the MEMCAL chip for the computer. The computer runs using only thr MAP sensor rather than a combination of the MAP/MAF to calculate the fuel map.

 

Basically I only updated because my MAF failed recently , new MAFs are ~ $400 from GM, ~$150 for a remanufactured aftermkt, ~$50 for a used one of unknown reliability while the update eprom from GM is only $80 bucks. The car also now idles better, more consistantly, than it ever has, since new but I would not get the update just because of this if the car was running ok before, its not really dramatic or anything.

[PeNZ]

On my 88 z24 2.8 it had a map. maybe its different on W's?