Intermittent no start issue.
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
Likes: 0
From: Bulverde TX
Intermittent no start issue.
Ok here is the deal. I bought this car about 2 yrs ago. I have no past history. It ran fine for about 3 months then one morning it wouldn't start. So I replaced the module with a Holley module looking ahead knowing I was going to be making up grades. It started right up. Then a few months later again no start. So I replaced the cap,coil,rotor,plugs,wires and the wires leading into the distributor. Then is started right up. This no start issue has been happening ever since but without a pattern other then it's always in the morning almost NEVER after its warm (maybe 2 or 3 times tops). Its not a fuel issue as the pump,filter and regulator are all new. All parts are AC/Delco except for the module and adjustable regulator. I have cranked it with a fuel pressure gauge attached and have 60 psi. I feel like it's an electronic issue but just can't find it.
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From: So. Cal.
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Sounds like a VATS issue. It has to do with that little pellet on your key. It gives a signal to VATS. This tool below can be extreemly helpful. Tons of threads about this topic.
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From: So. Cal.
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From: So. Cal.
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Race Director
Joined: Jun 1999
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From: Merritt Ils Fl
Am I correct in assuming when you say no start the engine turns over but does not start? Or does the starter not engage and turn over? If it turns over Mike is on target. Additionally, you can have fuel pressure at the rail but the injectors not fire. Have you checked for codes?
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
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From: Bulverde TX
Am I correct in assuming when you say no start the engine turns over but does not start? Or does the starter not engage and turn over? If it turns over Mike is on target. Additionally, you can have fuel pressure at the rail but the injectors not fire. Have you checked for codes?
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Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
First, throwing parts at your engine is the dumbest, most expensive way to repair it! Second, 60 psi is excessive fuel pressure, your injectors and fuel system were designed for 35-42 psi. Lets start on page one of any auto engine repair book. When the engine will not start, that is when you start your diagnosis to find out why it won't start. Engines require hot spark, spark at the right time, fuel and air and in the correct ratio, and cylinder compression in order to start and continue running. Use a timing light while someone cranks to see if you have correct timing. Take a grounded wire and bring it near an unplugged spark plug boot, you should see a snappy at least 1/2 " spark. See if fuel pressure remains for at least 30 minutes after key is off, this tells you if the injectors are leaking or not, or if the check valve in the fuel pressure regulator is working. Connect a noid light (available at parts stores) and plug it into an injector on each bank and crank, you should see light pulses. Try spraying starter fluid into the intake and if the engine starts, you have a fuel delivery problem. Last, measure compression.
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
Likes: 0
From: Bulverde TX
First, throwing parts at your engine is the dumbest, most expensive way to repair it! Second, 60 psi is excessive fuel pressure, your injectors and fuel system were designed for 35-42 psi. Lets start on page one of any auto engine repair book. When the engine will not start, that is when you start your diagnosis to find out why it won't start. Engines require hot spark, spark at the right time, fuel and air and in the correct ratio, and cylinder compression in order to start and continue running. Use a timing light while someone cranks to see if you have correct timing. Take a grounded wire and bring it near an unplugged spark plug boot, you should see a snappy at least 1/2 " spark. See if fuel pressure remains for at least 30 minutes after key is off, this tells you if the injectors are leaking or not, or if the check valve in the fuel pressure regulator is working. Connect a noid light (available at parts stores) and plug it into an injector on each bank and crank, you should see light pulses. Try spraying starter fluid into the intake and if the engine starts, you have a fuel delivery problem. Last, measure compression.
I think you need to re-read my OP and then tell me where I threw parts at it? Then while you re-read it you should pick upon the reason I haven't had a chance to check spark! Heres a tip for you I know the fuel pressure is to high, but guess what it will cause no harm!
Now if you have any valuable info. please feel free to post it and I will greatly appreciate it.
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
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From: Bulverde TX
I have tried to check for spark but one of 2 things always happens either I don't have time right then and when I get back it starts or I pull the plug and it starts everytime to date this has happened to me. I haven't tried starting fluid yet and that is a great idea thanks.
Le Mans Master
Joined: Aug 2007
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From: WV
Thanks for your input however I'm no new comer to auto repair or rebuild however I am new to vettes and the electronics on them.
I think you need to re-read my OP and then tell me where I threw parts at it? Then while you re-read it you should pick upon the reason I haven't had a chance to check spark! Heres a tip for you I know the fuel pressure is to high, but guess what it will cause no harm!
Now if you have any valuable info. please feel free to post it and I will greatly appreciate it.
I think you need to re-read my OP and then tell me where I threw parts at it? Then while you re-read it you should pick upon the reason I haven't had a chance to check spark! Heres a tip for you I know the fuel pressure is to high, but guess what it will cause no harm!
Now if you have any valuable info. please feel free to post it and I will greatly appreciate it.
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
Likes: 0
From: Bulverde TX
I don't have a STOCK fuel system it's built for the future, but thanks for the tip from the FSM.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
Here's the link, second post down...WW
http://forums.corvetteforum.com/c4-t...-pressure.html
Last edited by WW7; Jul 12, 2010 at 08:57 AM.
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
Likes: 0
From: Bulverde TX
Here is something I just read and I didn't know. Its mentioned in this post that some fuel injectors will shut down if the fuel pressure gets to high..I just thought I would mention this since you say your fuel pressure is so high.Something for you to check anyway.Fuel pressure is always highest when the key is first turned on and this may be when the injectors would shut down sometimes..WW
Here's the link, second post down...WW
http://forums.corvetteforum.com/c4-t...-pressure.html
Here's the link, second post down...WW
http://forums.corvetteforum.com/c4-t...-pressure.html
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
ok here is the deal. I bought this car about 2 yrs ago. I have no past history. It ran fine for about 3 months then one morning it wouldn't start. So i replaced the module with a holley module looking ahead knowing i was going to be making up grades. It started right up. Then a few months later again no start. so i replaced the cap,coil,rotor,plugs,wires and the wires leading into the distributor. then is started right up. This no start issue has been happening ever since but without a pattern other then it's always in the morning almost never after its warm (maybe 2 or 3 times tops). Its not a fuel issue as the pump,filter and regulator are all new. All parts are ac/delco except for the module and adjustable regulator. I have cranked it with a fuel pressure gauge attached and have 60 psi. I feel like it's an electronic issue but just can't find it.
Last edited by jfb; Jul 12, 2010 at 07:40 PM.
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
Likes: 0
From: Bulverde TX
I would call that a tune up to eliminate any possible issue with a car I don't know.Then while changing the cap I found a splice in the wiring leading to the coil. Apparently you don't do your own tune ups!
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
Likes: 0
From: Bulverde TX
Thread Starter
Racer
Joined: Feb 2008
Posts: 435
Likes: 0
From: Bulverde TX