1996 4.3 to 1997 5.7 engine swap

jeff1953 · Apr 18, 2017

Ok so we got the bright idea one day to swap the engine in my 96 Chevy 4x4 a 4.3 v6 and go with the 97 Yukon 5.7 v8 I had everything computer, wiring harness, steering column, everything now we got it all in I have no fire to the plugs, I have it coming through the coil wire just not through the distributor and I have changed it, the crank sensor, cam sensor, traced the wires down, still no fire does anyone have any ideas. THANKS for your time.

east302 · Apr 18, 2017

So you disconnected the coil wire from the cap and get spark there but not at any of the plugs?

Is the rotor turning? Is it a good spark at the coil wire

Could be a bad distributor cap/rotor, weak coil or the distributor could be a tooth or two off.

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jeff1953 · Apr 18, 2017

Yes good spark from coil, rotor is turning, yes no spark at any plugs, new cap, rotor, wires and distributor. what I cant figure out is I pulled it all from a running vehicle

east302 · Apr 18, 2017

Thinking out loud here...

Do you still have the old ignition coil and module? You might try swapping them out to see if the coil spark is too weak.

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Dirty98 · Apr 18, 2017

Did the 97 have any sort of VATS system?

df2x4 · Apr 18, 2017

Dirty98 said:
Did the 97 have any sort of VATS system?

To the best of my knowledge that was only '98 and up.

east302 · Apr 19, 2017

Here are the ignition system diagnostics for a 1998 350, giving some voltage and resistance values. Maybe it will help.

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Ignition coil module connector...

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jeff1953 · Apr 19, 2017

thank you all, I will do more testing and get back with you.

jeff1953 · Apr 21, 2017

Well I have 12v to the crank sensor and 5.5v going to the computer don't know if that is correct or not, power to the computer but don't know if the right wires, pulled the harness off the 4.3 they all look the same, so I am puzzled.

olduglyforeman · Apr 28, 2017

BUrnt rotor can arc to the distributor shaft. Bad grounds for pcm on the back of head and intake cause issues too.

1996 4.3 to 1997 5.7 engine swap

jeff1953

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df2x4

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