I decided to wash the car sunday because it was covered in dust. Have not driven it for at least six months. Car started and backed it onto driveway and washed it. After car wash, no start. I checked the fuses ,then the voltages at the ICM connector (koeo), got 11.4 vdc at two points and 0-2vac from the optical sensor wire while turning the motor over. I then checked the coil using Shoebox's method (8.5k ohms at the 4 test points) I bought a fuel pressure gage from Oreilly's. I'm getting 47 psi when the pump comes on. When the pump stops it goes to 0 psi in less than two seconds ! Is this normal ?? Guys, I did not raise the hood, I did not wash the engine. Is there a way to test the optispark output ?Is there something else I can check ? Thanks in advance !!

 

it should hold pressure for a few min....


but you most likely got the opti wet...it still should start but run like ***

 

Can't see how you could have gotten the opti wet. If it is not holding fuel pressure, cycle the key ON for a few seconds then OFF for 8-10 seconds a few times without cranking the engine to build up pressure in the fuel rails. Then try starting it.

 

I turned the pump on three times within 30 seconds , same result- I get 0 psi two seconds after the pump stops. By the way, I forgot to mention that it's a walbro 255lph unit and the fuel regulator is made by aeromotive if that makes a difference. Is this normal ? What 's the best way to check spark from the opti ? Thanks in advance.

 

If it is dumping all its pressure then the fuel pressure regulator is probably shot. Try a stock one from an auto parts store just to get you going for now.

 

This is not the most safe way to get it started but you can try jumping the fuel pump relay so the pump stays on all the time and you can at least build pressure to start the car. If the regulator is shot then it will let the fuel bypass by it and not build any pressure so there shouldn't be any worries about too much pressure.

 

not nessesarily. A weak or damaged regulator will allow pressure build but will "leak" pressure when the pump is shut off.

 

True.

 

Thanks fellas, I'll try a new regulator

 

Why not just take some carb cleaner and spray it into the TB while cranking? If car starts you are lacking fuel if car doesnt start check for spark?

 

Did you make sure your plug on the coil is pluged in. If have sometimes worked on my car and pulled that plug out just to bumb the motor when adjusting roller rockers and it will not start with out that plug in the coil.
Chris

 

Well, I found another problem, no spark. I pulled the #5 plug to examine it. It looks good (no fouling) smell like gas. Ground it to a exhaust manifold bolt and turned to key. nothing, nada no fire. Replaced the ICM and coil (brand new GM unit) Still no fire. now I'm thinking opti or pcm. any ideas fellas?

 

I would go staight to the Opti, I just had a simmilar experience myself. Even after 24hrs the Opti did not dry on its own despite reasonbly dry climate in my region (Australia) if you live in a cold or moist climate you would have far less chance of it drying on its own.
I found that I had to get a hairdryer pointed right at opti from underside of car for 45mins, this got opti dry enough to start and run a little rough at first. Another dose of Hairdryer for about 35mins got the car pretty much back to normal, but I found that after approx 40mins of driving it finally settled down to totaly normal behaviour. As strange as this seems it was certainly the problem in my case. I didnt realise how sensitive the Opti system is to moisture- god forbid if the water pump lets go on it!

 

My car is kida doing the same i got home thursday went to leave for work friday car just turns over cant hear the pump kicking on..tryed a little starter fluid still nothing just crankes over...what might be the probalem??

 

Start a new thread in this forum (if you have an LT1). I posted instructions on how to start a new thread in your other post.

Include the details of your car - year, model, engine, trans and any major modifications.

Have you checked for codes? Have you checked the fuel pressure? Have you checked for spark at the coil and at a few plugs?