First of all, sorry if my english is not perfect and thank you in advance for your help. I have a 1988 C4 Coupé Corvette. I had it written off (in spanish "dado de baja", means out of circulation) during about three years. I started it sometimes, but not so often.

Recently, I have registered the car again for circulation and restored all the interior. Now the car looks amazing. I have also replaced the fuel injectors, the iddle air control valve and the gas recirculation valve. Before the car was written off, I changed also the spark-plugs and the ignition coil.

In few words, the car seems fully operational and it is supposed to start with no problems, in fact it does and now RMP on iddle sound perfect like a kitten. BUT I have a strange problem that were not present before registering the car again: sometimes the engine does not start... It is not something usual, but still happens. When the engine does not start, no matter how many attempts you try, it does not start at all and you only drain battery; then, after about 10 minutes, the car start again with no problems. This has happened to me both after days without driving the car and, more strangely, even few minutes after put off the contact.

I must say that I have also replaced the oil, that was black and at minimum level (just the "add" line). Since then, the car starts well, but the mechanic says that oil can not be the cause, so I am affraid that I am missing something.

The only thing that I have not replaced is the fuel pump, but I have already checked that it sounds when I put the contact, so at least it activates; I do not know if it can work sometimes perfectly and few times bad... Also, another mechanic has told me that it should be something like a "no return" valve, that prevents the fuel from exit from the engine, and that this could be the cause. But I do not know anything about this valve... exist it?

Any suggestion will be very much appreciated, since it is anxious to take the car with this problem (imagine the car stalling and not starting again in the middle of the road...). Thank you again for your time and support!

 

Does the car crank over, or is there just nothing when you turn the key?

 

You're missing either spark or fuel for the no start events if the freshly charged battery spins the motor and normal starting speed.

Check spark with a test tool or the shade tree method.

Check fuel by using starting spray.

Also, did you remove all of the old gasoline from when it was parked?

 

Dear Mr. ******, if you mean if the car "sounds" when I turn the key, the answer is of course, it sounds perfectly with full battery and usually it starts perfecly. Only some times, it continues to sound, trying to start, but the cylinders fail to blow.

Dear 94z07fx3 (wow), the mechanic already checked the spark and he said that it is not so much powerful, but there it is. In any case, if this were the cause, how it is possible that, when the car does not start, no matter how many attemps you do until about 10 minutes later? Then it starts normally... By the other way, I do not know what is a starting spray, do you mean the liquid to clean the injectors? Finally, I have added fuel three times since the car was parked, but I never removed the old fuel... O_OU

 

If the engine is cranking, and you have spark it may be a VATS issue. The chip in the key is worn, or the key switch, and it's unable to read the proper resistance value to authorize the injectors to pulse. It would make sense that it starts intermittent. Either get a VATS bypass kit, or have someone program it out.

 

Dear Mr. ******, do you mean the black chip on the key??? I had not even thought about it! If this happens again, I will try to remove the key and insert it again to check if it works. If then the car starts, this broblem could be due to the VATS as you say.

 

You must wait 4 minutes if it sets a fault. It's actually the pellet in the black plastic.

 

Mmmm, that have a lot of sense! When the car does not start, efectively it is mandatory to wait some minutes to start it again.

In any case, if the car has recognized the key and it stalls, meanwhile I do not turn off the contact, it should always start again, right?

And one last thing: where can I get a copy of my old key? I suppose that here in Spain, in GM, but I am sure that I will pay x5 the price in the USA...

Thanks for all your help!

 

http://www.joestradingpost.com/vats/

You would measure the resistance value in your key, and order another like it. Read the site I linked, and you should find your answers.

 

I have read all the info and it seems very interesting. For the moment, I will order another key and see if that fix the issue. If not, I will replace the other VATS parts, because I do not want to bypass the security, only to start the engine usually! Thanks again!