No start
Thread Starter
Advanced
Joined: May 2005
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No start
First, my L98 had a rough hunting idle between 400 and 700rpm. The timing is 10 BTDC, fuel pressure is 34psi, TPS is .54 volts, IAC and oxygen sensor are about a year old, injectors all read 16.4 ohms, there is spark, and there aren't any trouble codes. After disconnecting the battery to reset the ECM the car cranks but will not start. What could be the problem?
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Spray some starting fluid in the throttle body while cranking. If it starts and runs with the starting fluid, then you have a fuel delivery problem or the injectors are not recieving the ref pulses from the ECM.
The hunting idle sounds like a vacuum leak. Did you hear any hissing when the idle goes down? What year vette?
The hunting idle sounds like a vacuum leak. Did you hear any hissing when the idle goes down? What year vette?
Team Owner
Joined: Jan 2003
Posts: 20,293
Likes: 240
From: Summerland B.C. Canada
I see you have a 90, this info is from my 86, but may help. As RRT stated, try some starting fluid.
http://members.shaw.ca/corvette86/En...ButWontRun.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
Thread Starter
Advanced
Joined: May 2005
Posts: 59
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Thanks for the help guys. It is a '90 vette. I got it started after putting the wires in the TPS weatherpak in their proper positions, don't ask. The rough hunting idle is still there, and when making a hard stop it drops to about 400rpm and feels like it is going to stall the way a carburated car would. I checked for vacuum leaks using propane and did not find any.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
Just make sure that you have checked and double checked for vac leaks. There are vac lines all over the engine bay. If the runner gaskets are bad, it can cause a vac leak also.
Does it run rich or lean? pulled the plugs lately?
Have you checked your injectors out? Leak down? ohms?
How about the O2 sensor?
Does it run rich or lean? pulled the plugs lately?
Have you checked your injectors out? Leak down? ohms?
How about the O2 sensor?
Thread Starter
Advanced
Joined: May 2005
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The o2 sensor only has about 3000 miles on it, the plugs looked good (light tan), and the injectors all have 16.4 ohms. I will check again for a vacuum leak, but I will most likely have to bring the car in to have a scanner hooked up.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
As Rick (how are you doing BTW Rick?) suggested, propane is good to use and is how I found my leak. You can also use starting fluid, WD-40, Seafoam in the brake booster, and some have introduced a good bit of smoke into the thottle body to find leaks with good results.
A scan tool will not tell you that you have a vac leak, only show you that a leak is potential depending on the readings. A hunting idle is usually a vacuum leak causing the ECM to contol the IAC motor in and out.
A scan tool will not tell you that you have a vac leak, only show you that a leak is potential depending on the readings. A hunting idle is usually a vacuum leak causing the ECM to contol the IAC motor in and out.
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Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
old thread, same issue, no start
I see you have a 90, this info is from my 86, but may help. As RRT stated, try some starting fluid.
http://members.shaw.ca/corvette86/En...ButWontRun.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
joe
Racer
Joined: Feb 2009
Posts: 486
Likes: 3
From: el cajon ca
