Startup issues
Thread Starter
Instructor
Joined: Sep 2007
Posts: 145
Likes: 0
From: Morristown TN
Startup issues
I recently purchased a 19884+3 with only 39,000 miles. The previous driver only put 12,000 miles on it since 1999. It is a L98 and runs great. The problem I am having is when I start the car it does not want to start. I have to pump the accelerator for it to start, or it will start after 4-5 seconds.
The battery is fine. It acts like it is not setting enough gas. I have put some Techron in it on the last 2 fillups and it sometimes starts fine and at other times it is slow. On cold starts it starts like it should 25% of the tome. It was 0% before Techron. Warm starts are now at 50% up from 0%.
The car runs perfect after startup. The check engine light has come on a couple of times and it has died while idling.
Could this be something the Techron will cleanup or do you think it could be something else like a fuel pump? Your suggestions are appreciated. I triedsearch and could not find what I was looking for.
Keith
The battery is fine. It acts like it is not setting enough gas. I have put some Techron in it on the last 2 fillups and it sometimes starts fine and at other times it is slow. On cold starts it starts like it should 25% of the tome. It was 0% before Techron. Warm starts are now at 50% up from 0%.
The car runs perfect after startup. The check engine light has come on a couple of times and it has died while idling.
Could this be something the Techron will cleanup or do you think it could be something else like a fuel pump? Your suggestions are appreciated. I triedsearch and could not find what I was looking for.
Keith
Last edited by oaklands; Dec 11, 2007 at 11:27 PM. Reason: Left out some info
Le Mans Master
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Couple of things:
1. Bad/dirty injectors: ohm them out and/or test flow (use search function for info and directions.
2. fuel pump or fuel pump relay
3. fuel regulator
All testing and info can be found in the FSM - if you don't have one, you should
1. Bad/dirty injectors: ohm them out and/or test flow (use search function for info and directions.
2. fuel pump or fuel pump relay
3. fuel regulator
All testing and info can be found in the FSM - if you don't have one, you should
Team Owner
Joined: Jan 2003
Posts: 20,322
Likes: 248
From: Summerland B.C. Canada
Start with finding out what trouble codes have been set, since you have seen the check engine light come on. A paper clip and the ability to count, is all you need to get the stored codes. 
Long cranking could be a fuel delivery problem.
Here is some good reading from my FSM.
http://members.shaw.ca/corvette86/No...it%20Check.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
http://members.shaw.ca/corvette86/Co...rt%20Valve.pdf
http://members.shaw.ca/corvette86/Co...0View%2086.pdf
Long cranking could be a fuel delivery problem.
Here is some good reading from my FSM.
http://members.shaw.ca/corvette86/No...it%20Check.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
http://members.shaw.ca/corvette86/Co...rt%20Valve.pdf
http://members.shaw.ca/corvette86/Co...0View%2086.pdf
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
The good fellows above pointed you in a good direction. Another thing to check is the cold start valve. The conditions you are describing are what would happen if the cold start valve was inop. The cold start valve is only active when the engine temp is below 95*. If it starts hard when warm, don't worry about the CSV. You can do a advanced search in C4 Tech under my user name for lots of info. If your not sure how to do an advanced search, let me know.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Your C4 is fuel injected and pumping the accelerator doesn't do a thing for starting. The computer takes care of starting, keep off the accelerator. Find out what error codes are stored and then follow the field service manual diagnostic instructions.
Car engines need spark, spark at the right time, fuel and air and in the correct ratio in order to start and run. Use your timing light to check for spark and timing while cranking. Measure the fuel pressure on the shrader valve on the end of the fuel rail and see how long it holds up after you turn the ignition off. If it drops rapidly, you likely have leaky injectors which make it too rich to start easily. Use a noid light (from a car parts place) or use a low power 12v lamp like a side marker light across an unplugged injector socket and see if it pulses while cranking the engine proving the injectors are being pulsed. Post your test results for further help.
Car engines need spark, spark at the right time, fuel and air and in the correct ratio in order to start and run. Use your timing light to check for spark and timing while cranking. Measure the fuel pressure on the shrader valve on the end of the fuel rail and see how long it holds up after you turn the ignition off. If it drops rapidly, you likely have leaky injectors which make it too rich to start easily. Use a noid light (from a car parts place) or use a low power 12v lamp like a side marker light across an unplugged injector socket and see if it pulses while cranking the engine proving the injectors are being pulsed. Post your test results for further help.
