New Member Needs Help

[Kats246]

Hi All,
I own a 1990 L98 Corvette which I have owned for 11 yrs and am having a problem that seems to be a real stumper. The mechanic that has done all the work on this car can't figure out the problem. The car runs fine at a constent speed however once the car is warm and I punch the throttle it bogs out and will take little to no throttle. Spent hundreds trying to fix I was wondering could this be the ignition coil? Mechanic said there is spark but I am wondering if maybe not hot enough exhust smells very very rich like in the old days and you flooded a car. I just limped home and pulled the dip stick and I smell gas. Just bought a MSD coil rotor and cap which cost me $120.00 but wanted some input before installing I've thrown so much money at this car now that I can't just keep throwing $ at it without some advice.

[ctwright]

Here are some things you need to check into. Check your spark plugs to make sure they aren't fouled, might as well just go ahead and buy new ones if they haven't been changed in awhile. Check for vacuum leaks, gasket leaks around your intake, and check your ignition timing. Hopefully that will get you headed in the right direction.

[Kats246]

Thanks for the info unfortunately all that's been done already. This is where all my money has been spent new plugs, wires, cap, rotor, egr valve, ignition modular, computer brain, fuel system analyzed press remains stable , vacuum system analyzed no leaks found, no computer codes for this problem, most recently replaced a slightly pinched fuel line mechanic was so sure that was the problem that he never test drove it before I picked it up and I got about 10 miles from his shop & it was the same old same old problem. After smelling gas on the dip stick I kind of new that new plugs and an oil change were a must. I just have never had to replace a coil on any vehicle. repair manuel trouble shooting suggests several things all of which have been already addressed except the coil. What I'm thinking is that maybe there is spark from coil but it's not hot enough to burn all the fuel and the engine is flooding. wondered if someone out there has had a similar problem?

[ctwright]

Originally Posted by Kats246

Thanks for the info unfortunately all that's been done already. This is where all my money has been spent new plugs, wires, cap, rotor, egr valve, ignition modular, computer brain, fuel system analyzed press remains stable , vacuum system analyzed no leaks found, no computer codes for this problem, most recently replaced a slightly pinched fuel line mechanic was so sure that was the problem that he never test drove it before I picked it up and I got about 10 miles from his shop & it was the same old same old problem. After smelling gas on the dip stick I kind of new that new plugs and an oil change were a must. I just have never had to replace a coil on any vehicle. repair manuel trouble shooting suggests several things all of which have been already addressed except the coil. What I'm thinking is that maybe there is spark from coil but it's not hot enough to burn all the fuel and the engine is flooding. wondered if someone out there has had a similar problem?

You just mentioned everything except for your timing. Not sure if it's because you forgot to mention it or not.

[Kats246]

I have assumed that my mechanic would have started with the basic like timing but I think i'll ask him to check it out again. Thanks for your help.

[rhandwor]

I would pull the vacuum hose on the pressure regulator if it has gas in it replace it with a new one.
If no fuel check the fuel pressure.

[ctwright]

I agree with the last post too. I know you said your mechanic has checked the fuel system over and all of this other stuff over. So far he doesn't know the problem so it doesn't hurt to second guess your mechanic sometimes. If you need help in trying to do some checks on these things write back and I'm sure someone can walk you through the processes.

[Kats246]

A driving fuel pressure test was done and pressure remained constant. Wouldn't the fuel pressure be all over the place or are you saying not necessarially?

[Kats246]

Originally Posted by ctwright

I agree with the last post too. I know you said your mechanic has checked the fuel system over and all of this other stuff over. So far he doesn't know the problem so it doesn't hurt to second guess your mechanic sometimes. If you need help in trying to do some checks on these things write back and I'm sure someone can walk you through the processes.

I don't doubt my mechanics ability he's made a good living at this for 25 yrs and I do trust him he hasn't charged for all the parts and as much work as he has done he has yet to charge me for labor because he hasn't resolved the problem he is a certified mechanic he owns and operates a state of the art high tech garage and I'm not foolish enough to think I should continue to do business with him because he's a friend and is one of the good guys. I confess that I had a moment that I felt like he may be relaying too heavily on all his high tech devices and missing the obvious so I did take the car to a 2nd garage another longtime friend that has been in the business for 30+ yrs but it's a low tech mom & pop place with 2 old school mechanics. I took the owner for a ride about ten miles punched it and bogged then stalled that day it wouldn't start back up and he towed it. He doesn't have an answer either.
I'll pull the vacuum hose on the pressure regulator and check it. One other detail that I remember was this is an automatic and my last ride the other day I started & stalled 4 X in 1/2 mile on the 5th start I dropped it accidentally into drive and not over drive car ran fine for the next 1/2 mile until I crested a hill 100 ft from home idle got rough it bogged and stalled I immediately restarted drove it into the garage and it was still idling had kind of an up down surging type idle. I just have to get this car running bad winters here in the northeast so my alternate vehicle for winter is a 1997 jeep grand cherokee and three weeks ago I blew the trany. You can drive a corvette like you stole it. A Jeep not so much! I know it's going to be something so obvious but over looked. Thanks any help is welcomed and appreciated!

[rhandwor]

I suggested checking the regulator because if its leaking the vacuum pulls it gas into the intake.
Coils do go bad but not often I have a meter which reads voltage. The Haynes manual tells you how to ohm them. Some people use a spray bottle and mist water trying find electrical leaks.
I would ask your friend to use his Mitchell manual and check all ground points for corrosion or if their loose.
I have also had pickups in the distributor go bad. Use a analog ohm meter across the plug lead. The gage should sweep as somebody is cranking the engine.
I think this failed and is the problem it won't start/

[Kats246]

On the suggestion and great detailed discription from vette079@hotmail.com I performed the Ohms test this morning and found that cylinder 3=1.9 and 7=8.3 I can't believe that this was not checked before now! I am speachless!

Thank You all for your help and patience with me, I know I got a little wordy.
Will replace all 8 injectors
Can anyone recommend a good affordable brand? As we all know I can't trust anyone around here.

Thanks Again and Again!!!

[denisond3]

For the two cars on which I have replaced injectors, I got them from an ebay seller of remanufactured injectors. For a Toyota Avalon tow of them cost me about $30 each, instead of about $120 each at the local discount auto parts place. And they have been working fine for 20k miles now.