starting problem
Thread Starter
2nd Gear
Joined: Jul 2010
Posts: 2
Likes: 0
starting problem
I just got a 1989 corvette. One day It was running fine...the next it would not run past 3000 RPM. Now it wont even start. I have replaced the fuel pressure regulator and fuel pump but no change. Is this a simple fix that im just overlooking?
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
As stated elsewhere on the forum, you need fuel, spark, compression and proper timing for the engine to run. Are there any codes? If so, start there. If not, check for the basics, above (compression probably ok, it doesn't go away arbitrarily.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
When it won't start, thats when you do some measurements to find out why. First see what error codes are stored and then follow the diagnosis steps in the GM manual. If no codes, then use a timing light while someone cranks to see if you have spark and spark at the right time. Pull a plug wire and bring a grounded wire near the plug boot while someone cranks. You should see a snappy at least 1/2" spark. Use a fuel pressure gauge on the shraeder valve at the end of the right fuel rail and turn the ign sw to run for longer than 2 seconds. You should see 35-42 psi and it should hold up for at least 1/2 hr with ign off or you have a leaky injector/s or a defective check valve in the fuel pressure regulator. Unplug an injector on each bank and use a noid light while someone cranks to see if you have pulsing. You can make your own noid light with an LED (light emitting diode) and a series 680 ohm resistor. You have to get the polarity correct on the homemade noid light. Spray starting fluid into the MAF and see if it will start. If so, you have a fuel delivery problem.
Thread Starter
2nd Gear
Joined: Jul 2010
Posts: 2
Likes: 0
i have checked fuel pressure, it was weak. the fuel pump did the trick but it still (more often then not) will not start on its own. When it does it it idles ok but will not rev. past 2500 rpm. As far as testing to see if it will hold pressure.....well i will have to try. thanks. also I think I can rule out the mas. while it was running i unpluged it and it stalled.
