Misfire/backfire help!
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Rookie
Joined: Jan 2011
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Misfire/backfire help!
Ok I have replaced my plugs wires cap rotor, and just replaced the plenum. But the truck still backfires/surges. From time to time. I doesnt dobit all the time. And it mainly happens 1/2-3/4 throttle. Any suggestions?
O and what is the fuel psi supposed to be? Mines 42-45. Good or bad?
O my truck is a 95 1500 4x4 5.2
O and what is the fuel psi supposed to be? Mines 42-45. Good or bad?
O my truck is a 95 1500 4x4 5.2
Amateur
Joined: Jan 2011
Posts: 26
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From: Zion, IL
mine used to do it under 3/4 to full throttle and mainly in the upper rpm range. changing my clogged cat helped a bit, then fixing the plenum helped slightly but changing my coil got rid of it. hasnt done it since i replaced my coil.
Amateur
Joined: Jan 2011
Posts: 26
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From: Zion, IL
did you do the new wiring routing? heres the TSB on it.
http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm
http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm
Registered User
Joined: Dec 2009
Posts: 9
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From: Cedar Park, TX
I had a similar situation with my 97 5.9. Misfires and backfires. I replaced the cap and rotor, cleaned and re-gapped the plugs. This helped but did not fix the problem. I replaced the coil today as it was out of spec. Seems to have resolved the issue.
If you have a multi meter, check the resistance accross the primary terminals and then across one primary terminal and the high voltage output terminal. Primary resistance should not be more than 1.2 ohms. Output resistance between 10k-15 or 18k depending on the brand. I'm not sure of the exact measurement on the output so please verify.
My primary resistance was 2.1 ohms. Doesn't seem like much but it is a significant percent out of spec.
Truck ran much better this morning.
Good luck.
If you have a multi meter, check the resistance accross the primary terminals and then across one primary terminal and the high voltage output terminal. Primary resistance should not be more than 1.2 ohms. Output resistance between 10k-15 or 18k depending on the brand. I'm not sure of the exact measurement on the output so please verify.
My primary resistance was 2.1 ohms. Doesn't seem like much but it is a significant percent out of spec.
Truck ran much better this morning.
Good luck.
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Registered User
Joined: Jun 2011
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dodge miss fire at high rpms
i,m a tech of 27 years and had a problem with my 97 4x4 .
it ran fine at idle but anything over 1/4 petal it backfired and just gave a fit .
1000 bucks later and 3 trips to the dodge dealer .
i finally found the problem .
the COIL .
it was to spec and everything looked fine but the spark was out of time with the eng .
37 bucks and all is well worth a try anyway.
Banks
hope this helps i searched the problem for a year and never found a answer.
it ran fine at idle but anything over 1/4 petal it backfired and just gave a fit .
1000 bucks later and 3 trips to the dodge dealer .
i finally found the problem .
the COIL .
it was to spec and everything looked fine but the spark was out of time with the eng .
37 bucks and all is well worth a try anyway.
Banks
hope this helps i searched the problem for a year and never found a answer.
