8 cams are better than four! - Page 5 - ZR-1 Net Registry Forums

Kevin · 10-11-2013

Quote:

Originally Posted by Schrade

I'm bettin' his high idle is the chip problem (although could be both goin' on there)...

Doesn't vac leak cause loping in RPM's?

not always. I have a vac leak somewhere now and my idle is fine

We Gone · 10-11-2013

Sorry your having issues, but sometimes happens when a car sits for many years. here is a link to replacing it.

http://zr1.net/forum/showthread.php?t=14475

8cam · 10-11-2013

Got the window regulator out. Looking it over its clear water got in there at some point. I'm going to bite the bullet and order a new one rather than try to just replace the motor. At this point wife's eyes are just rolling.

Also had time to pull the air horn and get ready to pull the belt. Headed out of town now so the car will have to wait until Sunday.

8cam · 10-11-2013

And fwiw while I was listening to the pulleys and determining that it was indeed the water pump, the idle was perfect. Go figure. This was with the accordion removed but the air horn still in place.

We Gone · 10-11-2013

Mark,

Check the numbers on the prom, the 90's had a change to fix idle issues. Marc's site lists them.

" The performance calibration AYBKG is based on GM's latest release of the calibration for '90 LT5 engines. GM calibration AYBK was released as a service part via Product Service Bulletin 476503, dated February, 1994. It was released to address problems with idle fluctuation after a hot restart, increase in idle speed after a hot restart and excessive engine speed during coast down to a stop with the clutch disengaged."

http://zr1specialist.com/HAT%20Web/p...librations.pdf

8cam · 10-11-2013

Great info and considering how this car sat for so long, I'll bet its original. Come to think of it, the engine was warm when the idle was so high. This afternoon was a cold start and the idle was perfect. Maybe I'll buy more from Marc than I planned...

mike100 · 10-11-2013

When my evap purge line vac source had popped off the plenum, it would idle at 900 rpm cold, but creep up to 1400 or ?? whatever when it warmed up. These cars do tend to run on with a high idle until the car almost reaches a stop, but parked, it should be able to idle at 700 rpm.

I would still do the stiff binder book in front of the air horn to see if the engine stalls out or not. You will hear he leak if it can still manage 600 rpm with the intake blocked

Schrade · 10-11-2013

Quote:

Originally Posted by Kevin

not always. I have a vac leak somewhere now and my idle is fine

What are your symptoms? Have you ruled anything out?

Mine is killing me right now here - idling fine too, and I MIGHT have a vac leak, but can't figure it just yet here... It starts the 'lope' just ABOVE idle... (in the Hesitation diags thread, that GC changed for me there)

Sorry to boost your thread here 4cam...

Kevin · 10-12-2013

Quote:

Originally Posted by Schrade

What are your symptoms? Have you ruled anything out?

Mine is killing me right now here - idling fine too, and I MIGHT have a vac leak, but can't figure it just yet here... It starts the 'lope' just ABOVE idle... (in the Hesitation diags thread, that GC changed for me there)

Sorry to boost your thread here 4cam...

http://www.zr1.net/forum/showthread.php?t=21332

phrogs · 10-13-2013

Take that window motor apart and see if you can clean the magnito and the magnets, hookit up to a battery and see if it works.

Sometimes they get water in them I have fixed some in the past without replacing them.

The rust is just enough not to let it turn.

10-11-2013	#42
We Gone Join Date: Apr 2004 Location: Atlanta, GA Posts: 2,170	Re: 8 cams are better than four! Sorry your having issues, but sometimes happens when a car sits for many years. here is a link to replacing it. http://zr1.net/forum/showthread.php?t=14475 __________________ Steve 1990 Steel Blue/Black #2355 1990 Red/Red #1473 1991 Quasar /Black #118 Sold 1991 Turquoise/Black #766 Parted Out 1993 Yellow/White #179 Sold 1990 Black/Gray #1361 Headers/4:10s Sold

10-11-2013	#43
8cam Join Date: Jul 2013 Location: Atlanta Posts: 450	Re: 8 cams are better than four! Got the window regulator out. Looking it over its clear water got in there at some point. I'm going to bite the bullet and order a new one rather than try to just replace the motor. At this point wife's eyes are just rolling. Also had time to pull the air horn and get ready to pull the belt. Headed out of town now so the car will have to wait until Sunday.

10-11-2013	#44
8cam Join Date: Jul 2013 Location: Atlanta Posts: 450	Re: 8 cams are better than four! And fwiw while I was listening to the pulleys and determining that it was indeed the water pump, the idle was perfect. Go figure. This was with the accordion removed but the air horn still in place.

10-11-2013	#45
We Gone Join Date: Apr 2004 Location: Atlanta, GA Posts: 2,170	Re: 8 cams are better than four! Mark, Check the numbers on the prom, the 90's had a change to fix idle issues. Marc's site lists them. " The performance calibration AYBKG is based on GM's latest release of the calibration for '90 LT5 engines. GM calibration AYBK was released as a service part via Product Service Bulletin 476503, dated February, 1994. It was released to address problems with idle fluctuation after a hot restart, increase in idle speed after a hot restart and excessive engine speed during coast down to a stop with the clutch disengaged." http://zr1specialist.com/HAT%20Web/p...librations.pdf __________________ Steve 1990 Steel Blue/Black #2355 1990 Red/Red #1473 1991 Quasar /Black #118 Sold 1991 Turquoise/Black #766 Parted Out 1993 Yellow/White #179 Sold 1990 Black/Gray #1361 Headers/4:10s Sold Last edited by We Gone; 10-11-2013 at 07:35 PM.

10-11-2013	#46
8cam Join Date: Jul 2013 Location: Atlanta Posts: 450	Re: 8 cams are better than four! Great info and considering how this car sat for so long, I'll bet its original. Come to think of it, the engine was warm when the idle was so high. This afternoon was a cold start and the idle was perfect. Maybe I'll buy more from Marc than I planned...

10-11-2013	#47
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,786	Re: 8 cams are better than four! When my evap purge line vac source had popped off the plenum, it would idle at 900 rpm cold, but creep up to 1400 or ?? whatever when it warmed up. These cars do tend to run on with a high idle until the car almost reaches a stop, but parked, it should be able to idle at 700 rpm. I would still do the stiff binder book in front of the air horn to see if the engine stalls out or not. You will hear he leak if it can still manage 600 rpm with the intake blocked

10-13-2013	#50
phrogs Join Date: Jul 2004 Location: Kalamazoo MI Posts: 1,760	Re: 8 cams are better than four! Take that window motor apart and see if you can clean the magnito and the magnets, hookit up to a battery and see if it works. Sometimes they get water in them I have fixed some in the past without replacing them. The rust is just enough not to let it turn. __________________ JOHNNY P Currently own 90 ZR-1 #845 DRM 500 engine package 90 #226 Parts car Hit me up if you need anything.