backfireing
03-08-2011, 05:30 PM
#1
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Year: 1990
Model: Cherokee
Engine: 4.0 il 6
backfireing
1990 cherokee limited we replaced the motor with one from a larado and that was just the first problem. no we have it running and the thing keeps back fireing and hesitating when you give it just a little gas. we have replaced the dist,cap,plugs,wires,fuel filter,fuel pump,coil,water pump. checked the ground,wiring ect. anything else we could do.
03-08-2011, 05:40 PM
#2
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Year: 1998
Model: Cherokee
Engine: 4.0L HO
Were u able to hear the transplanted motor run before it was pulled? Re-check plug wires on the dist. cap going to the correct cylinder (firing order).
03-08-2011, 05:44 PM
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Year: 1990
Model: Cherokee
Engine: 4.0 il 6
no we were not able to hear it run. fireing order has been checked all good there. so when i checked the order the number 1 sitting pointing to the coil.
Last edited by tkrogh; 03-08-2011 at 05:53 PM.
03-08-2011, 05:48 PM
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is the distributor clocked 180* from where it's supposed to be?
03-08-2011, 05:54 PM
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Year: 1990
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Engine: 4.0 il 6
it points to the coil basically,the strange thing is that it idels so smooth.
Last edited by tkrogh; 03-08-2011 at 05:58 PM.
03-08-2011, 06:10 PM
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Year: 1999
Model: Cherokee
Engine: 4.0
Verify fuel delivery. With a gauge.
With a 1990, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator (still in play here as a possibility). The fuel pressure should then go up to approximately 39 psi.
Be sure that the vacuum line leading to the fuel pressure regulator is pulling good vacuum and is not wet with fuel. If that line has gas in it, you have a ruptured fuel pressure regulator.
With a 1990, you should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator (still in play here as a possibility). The fuel pressure should then go up to approximately 39 psi.
Be sure that the vacuum line leading to the fuel pressure regulator is pulling good vacuum and is not wet with fuel. If that line has gas in it, you have a ruptured fuel pressure regulator.
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03-10-2011, 09:32 AM
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Year: 1990
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update: we have now replaced the icm still not running right. the jeep is still backfireing and hesitation contuinues. is there anything else i could try. Please help before i buy dynomite!!!!
03-13-2011, 12:48 PM
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Year: 99
Model: Cherokee
Engine: 4.0
1990 cherokee limited we replaced the motor with one from a larado and that was just the first problem. no we have it running and the thing keeps back fireing and hesitating when you give it just a little gas. we have replaced the dist,cap,plugs,wires,fuel filter,fuel pump,coil,water pump. checked the ground,wiring ect. anything else we could do.
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