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Author Topic: Up & down idle 88 Duke when warm  (Read 33084 times)

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Raydar

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Re: Up & down idle 88 Duke when warm
« Reply #165 on: April 02, 2019, 09:22:40 am »
It just occurred to me... I remember hearing that there were a number of PROM upgrades for the 87-88 Dukes, for various issues. (One of them was excessive pinging.)
I believe the Ogre even mentioned the upgrades on his page. I wouldn't be surprised if the hunting idle was one of those issues.
With that said, I don't know how one would go about researching TSBs for those upgrades, but I would suspect they're out there.
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Donster

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Re: Up & down idle 88 Duke when warm
« Reply #166 on: April 02, 2019, 01:02:14 pm »
Anyone know of a source where I can get an upgraded PROM?Seems like "Intermittent Higher Than Normal Idle" was one of the reasons for the upgrade.
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TopNotch

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Re: Up & down idle 88 Duke when warm
« Reply #167 on: April 02, 2019, 02:14:34 pm »
If I could find a blank, and one of those obsolete programmers that we used to use at work, I could copy my PROM. My duke idles perfectly.  But I don't remember if  your car is automatic or stick.
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Donster

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Re: Up & down idle 88 Duke when warm
« Reply #168 on: April 02, 2019, 03:31:53 pm »
If I could find a blank, and one of those obsolete programmers that we used to use at work, I could copy my PROM. My duke idles perfectly.  But I don't remember if  your car is automatic or stick.

Automatic
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Raydar

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Re: Up & down idle 88 Duke when warm
« Reply #169 on: April 02, 2019, 04:20:56 pm »
If I could find a blank, and one of those obsolete programmers that we used to use at work, I could copy my PROM. My duke idles perfectly.  But I don't remember if  your car is automatic or stick.

I have both a blank PROM and a programmer. And my car also idles perfectly. But mine is also a manual. Anybody have a line on the "newest" automatic 87-88 Duke BIN file?
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Fierofool

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Re: Up & down idle 88 Duke when warm
« Reply #170 on: April 02, 2019, 05:45:19 pm »
Might be a wild chance that Sinister may have a file in his ditty bag. 
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Raydar

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Re: Up & down idle 88 Duke when warm
« Reply #171 on: April 02, 2019, 08:47:26 pm »
Donster... When you have a free minute, grab the 4 character broadcast code off of your chip. 
You'll need to remove the two screws from the cover, and read the code from the label on the chip. (It may be different from the label on the outside of the ECM, if stuff has been swapped around.)
FWIW, the one that I have is "ACMH" (for a manual trans). 
I think there is a table of Fiero broadcast codes, here, on the forum.

Edit - Here it is. http://gafiero.org/ECMgood/fieroprom.html
Holy schnickies! There are 8 different revisions of just the 87-88 automatic Duke PROM.
« Last Edit: April 02, 2019, 08:52:40 pm by Raydar »
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Donster

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Re: Up & down idle 88 Duke when warm
« Reply #172 on: April 03, 2019, 12:56:28 am »
Raydar..... when I get home after work, I'll grab the ECM and get the codes off and from the inside of it.
I checked the Ogre's cave and compared it a few weeks ago, and I think this is the new/updated PROM I would need, if that helps:

Mine:
PROM ID: ALWN 6770
ECM: 1227748

Needed:
16143459
PROM ID:ATCA 3571
(as of 8/11) http://gafiero.org/ogre/promtsb.htm

This PROM was specifically for the "intermittent high idle" problem.
But I'll check to make sure.

Thanks.
« Last Edit: April 05, 2019, 08:53:29 am by Donster »
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Fierofool

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Re: Up & down idle 88 Duke when warm
« Reply #173 on: April 03, 2019, 09:22:22 am »
Do I read that chart correctly that it requires a new chip, a specific fuel sending unit, a specific fuel pump with a specific rubber bumper on the bottom of the pump and a specific pulsator on the fuel pump in order to overcome the issue? 
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GTRS Fiero

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Re: Up & down idle 88 Duke when warm
« Reply #174 on: April 03, 2019, 06:04:38 pm »
It sounds as if the issue could be addressed by replacing all those things.

Donster

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Re: Up & down idle 88 Duke when warm
« Reply #175 on: April 04, 2019, 12:33:48 am »
Do I read that chart correctly that it requires a new chip, a specific fuel sending unit, a specific fuel pump with a specific rubber bumper on the bottom of the pump and a specific pulsator on the fuel pump in order to overcome the issue? 

That is only if you need to repair Hard Hot Engine Restart, for the idle issue, it is only the PROM.
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Donster

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Re: Up & down idle 88 Duke when warm
« Reply #176 on: April 05, 2019, 08:42:00 am »
OK, here we go:
PROM: Delco ALWM 6770

ECM: 01227748 (Refurbished)
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Donster

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Re: Up & down idle 88 Duke when warm
« Reply #177 on: April 05, 2019, 04:19:01 pm »
Scanner / diagnostic kit has not arrived yet, but...........today I had the exhaust out to repair it (long story) and I noticed that from underneath, you can see a bracket from the alternator to the TBI. It was completely rusted and once I looked at it closer, I noticed the screw going into the TBI is torn off, hence, no real connection there. I remember the Ogre mentioning that the bracket itself functions as ground. Is it this one??
Could this be my issue??
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GTRS Fiero

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Re: Up & down idle 88 Duke when warm
« Reply #178 on: April 05, 2019, 04:48:06 pm »
Pic?

Donster

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Re: Up & down idle 88 Duke when warm
« Reply #179 on: April 07, 2019, 08:37:00 am »
Tore apart center console today, checked all cables from the ECM there, sanded down ground connector, used a stainless steel screw.
Went at the C500 connector again, replaced positive cable from battery to underneath C500 block, replaced negative cable to engine, replaced ground cable from engine to chassis, sanded all surfaces.
No change, idle still hunting. Scanner / diagnostic kit won't arrive until sometime next week. Had fun troubleshooting in the beginning, sort of a challenge.
Now frustration is setting in.  >:(
\D
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