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Help: motor conversion


Nasty_Nate
06-28-2006, 01:38 AM
Ok i know i've hit on this before, but this time I'm gonna need all the resources i can get.

I got a '91 4.3 tbi i put into a '93 s-blazer. I have none of the origional cpi parts, otherwise i wouldn't be in the perdicament i'm in. Got the motor, engine harness, computer, and trans switched into the '93, but it won't start. It will fire if i pour gas into the thottle body. I know this motor runs, it ran fine one month ago when i pulled it outta my jimmy. Brand new motor mind you. So it's obviously a gas problem. More specifically the injectors are not opening. And i haven't got a clue. My brother has had the same problem with his, and that isn't running either. (his was an 88 2.5 efi into a '93 with a 2.8). His injector won't open up either. so this is really a post to solve 2 problems.

We're both stumped, and wondering if anyone has done this before or if they know what could be going on.

Thanks Guys,
Nasty

kahjdh
06-28-2006, 02:04 AM
Check all of the wiring into the injectors. Was the previous engine a 4.3? The fuel pumps are different between the two.

rlith
06-28-2006, 11:29 AM
Yes, make sure you have the correct fuel pump...Also hot wire the pump as well so you know it's coming on with the car properly. Also have you checked for clogged injectors?

Nasty_Nate
06-28-2006, 01:55 PM
ok yeah, i got the fuel pumped switched out. The previous motor was a vortec 4.3, but i didn't have any of the parts for that, which is why i pulled the tbi 4.3 outta my jimmy, and put in into the blazer. As for clogged injectors, I severely doubt that is the problem since it the motor ran fine 2 weeks ago in the jimmy before the motor swap.

I've got wiring diagrams out right now and am pouring over thise for a couple of answers,

so the quest continues.

rlith
06-30-2006, 08:47 AM
Well, since you can pour gas down the throttle body and get it to run, that leaves something in the pumping system. Meter the fuel pump at the tank, work your way up and make sure all grounds are good (especially the engine grounds) Meter the connectors at the injectors to make sure they are pulsing. Have you metered the fuel pressure?

Nasty_Nate
06-30-2006, 05:13 PM
fuel pressure is right at what it is susposed to be, the circuit for the injectors is the problem. I'm not finding anycontinuity for that cicuit. I'm thinkin I can trace it out to the power harness where it plugs into the body and concequently the fuse block. But i don't have pin diagrams for where it plugs into the body, and fuse block. Anyone know where i can find these, or if they know the pattern for a 91 and 93?

Thanks

Nasty_Nate
07-07-2006, 05:55 AM
I Did IT!!!!!
IT RUNS!!

that was very frustrating, it turned out that with the wire harness differences from 91 to 93, the body plug, where the harnesses' plug into the body to the fuse block, 3 wires were run differently. So instead of getting power, i was getting ground, and something else, but i got it.

i'll set up some pics if anyone will tell me how :)

thanks guys

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