Not Running! - ZR-1 Net Registry Forums

ZR-1Mike · 04-03-2012

I'm needing a little help. I've not been driving my '91 much in the last year and a half and last October on a trip we stopped for lunch and when we came out the engine started fine but idled and maintained cruise power poorly. I replaced the coils over the winter and now under WOT it runs like a beast but still has major problems with smoothness at idle and cruise. There is a tech in town trained 20 years ago and he found a bad vacuum line but won't take it any further. I live in SE Oklahoma and am looking for someone competent on LT5's. Anyone out there have any ideas about a fix or someone that might be able to help it? Now that she's not running I really miss her!!

Kevin · 04-03-2012

I wonder how far jerry is from you. he's in edmond i think

1990 quasar blue · 04-03-2012

Quote:

Originally Posted by ZR-1Mike

I'm needing a little help. I've not been driving my '91 much in the last year and a half and last October on a trip we stopped for lunch and when we came out the engine started fine but idled and maintained cruise power poorly.

Any chance you popped the hose off the map sensor?

ZR-1Mike · 04-03-2012

The first thing I checked was the map sensor, but wasn't that lucky for it to be that simple! I've met Jerry a couple of times, do you think he knows someone near by to look at it? I'll leave him a message... Thanks

1990 quasar blue · 04-03-2012

Stock injectors still? Any check engine light?

VetteMed · 04-03-2012

If you were able to change coils yourself, then you already can do everything necessary to rule out vacuum leaks under the plenum. A mityvac or similar tool can be used to pull a vacuum on the various lines and fittings under the plenum, unless of course there's something obviously disconnected when you get in there.

If the cruise and/or HVAC aren't working 100% properly, then that would increase the likelihood of a vacuum leak being present.

I recently found a vacuum leak where the brake booster hose meets the plenum. It seemed snug, but after I put a hose clamp on it to snug it up, the idle smoothed out considerably.

Also, a failing throttle position sensor could do funny things at part throttle (not usually at idle, though).

04-03-2012	#1
ZR-1Mike Join Date: Jan 2006 Location: SE Oklahoma Posts: 69	Not Running! I'm needing a little help. I've not been driving my '91 much in the last year and a half and last October on a trip we stopped for lunch and when we came out the engine started fine but idled and maintained cruise power poorly. I replaced the coils over the winter and now under WOT it runs like a beast but still has major problems with smoothness at idle and cruise. There is a tech in town trained 20 years ago and he found a bad vacuum line but won't take it any further. I live in SE Oklahoma and am looking for someone competent on LT5's. Anyone out there have any ideas about a fix or someone that might be able to help it? Now that she's not running I really miss her!! __________________ [COLOR=black]'91 #1101 Red/Saddle, Corsa exhaust [/COLOR] [COLOR=black] :saluting: [/COLOR]

04-03-2012	#2
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,632	Re: Not Running! I wonder how far jerry is from you. he's in edmond i think __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

04-03-2012	#4
ZR-1Mike Join Date: Jan 2006 Location: SE Oklahoma Posts: 69	Re: Not Running! The first thing I checked was the map sensor, but wasn't that lucky for it to be that simple! I've met Jerry a couple of times, do you think he knows someone near by to look at it? I'll leave him a message... Thanks __________________ [COLOR=black]'91 #1101 Red/Saddle, Corsa exhaust [/COLOR] [COLOR=black] :saluting: [/COLOR]

04-03-2012	#5
1990 quasar blue Join Date: Feb 2004 Location: Ma Posts: 404	Re: Not Running! Stock injectors still? Any check engine light? __________________ 1990 ZR1 #2574 Medium Quasar Blue Metallic 1 of 19

04-03-2012	#6
VetteMed Join Date: Mar 2009 Location: Orlando, FL Posts: 1,828	Re: Not Running! If you were able to change coils yourself, then you already can do everything necessary to rule out vacuum leaks under the plenum. A mityvac or similar tool can be used to pull a vacuum on the various lines and fittings under the plenum, unless of course there's something obviously disconnected when you get in there. If the cruise and/or HVAC aren't working 100% properly, then that would increase the likelihood of a vacuum leak being present. I recently found a vacuum leak where the brake booster hose meets the plenum. It seemed snug, but after I put a hose clamp on it to snug it up, the idle smoothed out considerably. Also, a failing throttle position sensor could do funny things at part throttle (not usually at idle, though). __________________ 2004 Z06/Z16 LeMans Commemorative Edition 1991 ZR-1 #302 White/Gray (sold) 1991 ZR-1 #1147 Red/Saddle (sold)