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Old 12-08-04, 05:07 PM   #1 (permalink)
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1989 Z51 Coupe
Default auto v. manual starter, idle

Hi All-

I am gathering parts for a manual to auto conversion... and have arrived at the starter. Are the starters the same for both transmissions?

Also, is there a way to reduce the idle? I have set the TPS at .54, "base idle" at 400 rpms, but the idle is still at 850 or so. I'd like to cut it down to 600... but the computer just wants to bump it back up.

Thanks
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Old 12-08-04, 05:24 PM   #2 (permalink)
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04 Z06/Z16, 95 ZR1, 71 BB Cpe
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Quote:
Originally Posted by 89z51l98
Hi All-

I am gathering parts for a manual to auto conversion... and have arrived at the starter. Are the starters the same for both transmissions?

Also, is there a way to reduce the idle? I have set the TPS at .54, "base idle" at 400 rpms, but the idle is still at 850 or so. I'd like to cut it down to 600... but the computer just wants to bump it back up.

Thanks
Is the calibration in the ECM for auto or man?

Has the minimum air adjustment been changed?

Have you checked for vacuum leaks?

The idle speed is not adjustable and is controlled by the ECM calibration, so if it's 850 now, there's a problem somewhere. If it's to a vacuum leak, incorrect minimum air then I'd say there's a calibration problem.
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Old 12-08-04, 08:23 PM   #3 (permalink)
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1989 Z51 Coupe
Default

Good questions... By 'minimum air adjustment' i am thinking the throttle plate screw with the IAC valve disconnected... it was screwed way in when i got the car... so i set it at 450. It came from the factory as a manual.

I have a feeling the injectors might be leaking... idle exhaust smell, starts waaay too good cold for fuel injection, really bad mileage... but i haven't actually checked anything yet. i want to check fuel pressure with the engine running then turn it off and see how fast the pressure drops, check the spark plugs, and the resistance across the injectors (should be 16 ohms??)...

the starter though... is it the same for manual and auto?


Quote:
Originally Posted by Hib Halverson
Is the calibration in the ECM for auto or man?

Has the minimum air adjustment been changed?

Have you checked for vacuum leaks?

The idle speed is not adjustable and is controlled by the ECM calibration, so if it's 850 now, there's a problem somewhere. If it's to a vacuum leak, incorrect minimum air then I'd say there's a calibration problem.
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Old 12-09-04, 10:49 AM   #4 (permalink)
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Hib Halverson is offline
 
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04 Z06/Z16, 95 ZR1, 71 BB Cpe
Default

Quote:
Originally Posted by 89z51l98
Good questions... By 'minimum air adjustment' i am thinking the throttle plate screw with the IAC valve disconnected... it was screwed way in when i got the car... so i set it at 450. It came from the factory as a manual.
the starter though... is it the same for manual and auto?[/quote]
Did you make the minimum air adjustment per the Service Manual?

Did you check for vacuum leaks?

Are the throttle body's bores and throttle plates clean?

Quote:
I have a feeling the injectors might be leaking... idle exhaust smell, starts waaay too good cold for fuel injection, really bad mileage... but i haven't actually checked anything yet. i want to check fuel pressure with the engine running then turn it off and see how fast the pressure drops, check the spark plugs, and the resistance across the injectors (should be 16 ohms??)...
If you suspect leaking injectors, run the fuel pressure tests listed in the Service Manual. Do not use the procedure listed above because it is incorrect.
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Old 12-09-04, 11:36 AM   #5 (permalink)
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Default

Thanks for the help...

A FM is hopefully on its way... the Haynes book wasn't very valuable... in any area...

the minimum air adjustment info I got from the knowledgebase here... (http://www.corvetteactioncenter.com/....php?qstId=451)

For vacuum leak testing... this requires using a vacuum guage and checking for whatever value should be there?

Quote:
Originally Posted by Hib Halverson
the starter though... is it the same for manual and auto?
Did you make the minimum air adjustment per the Service Manual?

Did you check for vacuum leaks?

Are the throttle body's bores and throttle plates clean?


If you suspect leaking injectors, run the fuel pressure tests listed in the Service Manual. Do not use the procedure listed above because it is incorrect.[/quote]
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