Hi there, so I put a 2000 4.3 vortec out of an s10 blazer in my '84 jeep cj7. I've got the engine and transmission, which was mated together, all installed with a wire harness I ordered from street and performance.. Pretty close to everything is ready to go and it cranks, but it won't stay running! The only things not ready are the post cat sensor and fuel tank pressure sensor which are on the way, and the computer hasn't been flashed yet which takes out the VAT(vehicle anti-theft system). Do you think in doing the conversion that the VAT would have been tripped? Or is there something else I should try? Thanks!

 

first things first...........you say it "won't stay running"...but it does fire up for a brief moment? have you checked the fuel pressure?

i'm pretty sure the VAT system would prevent it from even firing up a little.

 

Well I never put a gauge to the shrader valve but I pushed the pin and fuel shot out with a pretty good force, so I didn't think that was an issue. As far as the "running" thing, it would crank and rumble for a second and return to cranking. It acted like it wanted to stay going but it just wouldn't. I sent the cpu off today to get it flashed so that'll be a couple weeks since I had to send it to Arkansas and I'm in California.. I'll try to find a gauge for the fuel pressure when it gets back if the VAT wasn't the problem. Troubleshooting this engine has been a real experience! Definitely excited for it to stay rumbling, had my heart pumpin! (A 2 year project winding down I hope) Thanks for the response! I'll keep the thread posted

 

If it runs for a few seconds and then cuts off, it likely is a passlock issue. Without the rest of the system, you really can't tell.

I would suggest an investment (or rental) of a fuel pressure gauge. One would be hard pressed to be able to discern the difference between 50psi and 60psi by watching the fuel spray from the schrader valve as it hits the hood.

 

That's a good point. I never thought of how important the fuel pressure was, I just figured the pressure would be good because it's a brand new fuel pump and I was getting pressure. I'll test that out when I get the cpu back. Thank you