have one that wont start

[C.R.]

1997 4.3 vortex won't start, getting fire to all plugs and getting gas. turns over, will start up then die. New fuel pump, wires, plugs, Cap and rotor button.
Floods out and gas going into oil. Any ideals?

[1990SSchevy65]

Have you checked any of the sensors? Is the air filter clogged? Your tbi might be an issue. Good Luck, sorry I cannot be any more help.

[C.R.]

New air filter, it has the CPI and its is a rebuilt one. Thanks for the reply.

[dfrank]

Originally Posted by C.R.

1997 4.3 vortex won't start, getting fire to all plugs and getting gas. turns over, will start up then die. New fuel pump, wires, plugs, Cap and rotor button.
Floods out and gas going into oil. Any ideals?

If gas is going into the oil then it sounds like your piston rings are shot.

[ChevyTech]

To me it sounds like a cracked fuel line under the plenum, or a ruptured fuel pressure regulator diaphram.

I would put a fuel pressure gauge on it and see if the pressure drops as soon as the pump gets done with the 2 second prime.

A leak under the plenum will dump fuel right into the valley which will drain into the crankcase.

[C.R.]

Thanks I will check it tonight and see.

[C.R.]

Checked the pressure on the pump on 2 second prime it stayed on 0.
Cranked engine over and it went to 58psi. Removed the plenum and no evidence of gas on the intake. Checked it again after turning the engine over still dry.

[ChevyTech]

Something is wrong!

If it did not build up any pressure during the fuel pump prime, then it it could be leaking all that fuel into the engine through the CPI unit.

Did you cycle the key and try running the pump a couple times in a row to see if it could build pressure?

[C.R.]

Yes cycled it several times same results.

[ChevyTech]

Pull the poppets out of the intake and set each one in a little cup leaving the CPI and supply lines intact, then cycle the key and see if fuel come out the poppets.

If fuel does come out the poppets, disconnect the wiring to the CPI and try it again. If fuel still leaks out the poppets, shop around for the upgrade unit that uses injectors instead of poppets, if your vehicle does not already have the upgrade.

If your vehicle already has the upgrade, let us know.

[hugger6933]

Spyder valve!! I consider those a tune up item on the 4.3 [vortec ]HO motors they make a ton of difference in the way they run. I had a hard time talking some of my customers into them because of price until they HAD to have them but once installed the thanked me. Their gas mileage went up and performance was like when they first bought them from me or better. Open up the manifold, just the top half and look for puddles and clean spots you will find the gas leak in there really easy. Jim

[ChevyTech]

Hugger, I agree.

It is hard to get people to do the upgrade, but once it is done they are very happy they did it.

C.R., I suggest having someone cycle the key for you as you watch the spider for leaks. It is very common for the regulator and supply lines to leak.

[C.R.]

I got the fuel problem figured out. On the 2 second prime the pressure will go up to the 58 psi and you can here the poppets spray. then it will slowly leak down to about 30 psi.