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View Full Version : Fuel pump/ check engine light delay. Electrical? Need help. 95 cherokee.


Intellect
November 20th, 2017, 11:17
1995 cherokee 4.0 i6 4wd. Tittle says it all. Usually only when cold starting.. ill turn the key to acc (you expect mr pump to whuuuuur) but nope. Sometimes it takes 20 seconds to 3 minutes. Sometimes itll whuuur right away.

Side note, was just chasing bleed off issues so i KNOW the pumps good. 110%. Good. Bosch and good.

I know it is an electrical issue because know how the check engine light comes on when you turn the key to acc? Well... Whenever the fuel pump DOESNT whuuuuur, the check engine light DOESNT come on either. They are both delayed. They will come on at the same time... Wether its a 25 second delay or 5 minute delay. Sure enough, whenever the whuuur finally happens, than i see mr check engine illuminate.

Odd part, when the delay happens, the radio, headlights, abs light, ebrake light, all work fine....


I have a seperate forum open that i was informed my above issue is the ignition switch, so im replacing that today. Ill report back. But the other forum is for the fuel bleed off issue. Figured id have one for electrical too, to keep it clean around here.

(Abs light is on cause i clipped the lines when i got rid of my turdy 35, and brake light is on cause ebrake is up, ebrake also does nothing when i swapped axles i deleted it)

My bleed off issue wouldnt even be an issue issue if i solve this electrical issue because the bleed off is 5 hours. So slow that a single prime.. maybe two.. gets pressure to where the jeep needs to be to crank. (Ive hooked a gauge up, if the pump/jeep/check engine decides to act electrically good, i just key it, let the pump prime, than crank, and no issue)


Side note, anyone ever hot wired a switch to the pump? Imagine its a terrible idea.

Maybe hotwire for priming purposes not for 24/7 purposes?

No ballest resistor.. 1995 return style.






New fuel pressure reg, pump, injectors, filter, etc. Bosch and name brands. Warrantied multiple parts multiple times to eliminate them from possibilities.


Back to topic at hand... I researched it for hours. Here and other forums. No direct answers. Ecm,pcm,ignition switch etc. I can use a multimeter if someone can help me. It sucks cause its an intermittent issues.



Also , ONLY WHEN COLD usually. Florida.."cold"... If its been running i can usually recrank within an hour no issues...

Intellect
November 20th, 2017, 18:53
1995 cherokee 4.0 i6 4wd. Tittle says it all. Usually only when cold starting.. ill turn the key to acc (you expect mr pump to whuuuuur) but nope. Sometimes it takes 20 seconds to 3 minutes. Sometimes itll whuuur right away.

Side note, was just chasing bleed off issues so i KNOW the pumps good. 110%. Good. Bosch and good.

I know it is an electrical issue because know how the check engine light comes on when you turn the key to acc? Well... Whenever the fuel pump DOESNT whuuuuur, the check engine light DOESNT come on either. They are both delayed. They will come on at the same time... Wether its a 25 second delay or 5 minute delay. Sure enough, whenever the whuuur finally happens, than i see mr check engine illuminate.

Odd part, when the delay happens, the radio, headlights, abs light, ebrake light, all work fine....


I have a seperate forum open that i was informed my above issue is the ignition switch, so im replacing that today. Ill report back. But the other forum is for the fuel bleed off issue. Figured id have one for electrical too, to keep it clean around here.

(Abs light is on cause i clipped the lines when i got rid of my turdy 35, and brake light is on cause ebrake is up, ebrake also does nothing when i swapped axles i deleted it)

My bleed off issue wouldnt even be an issue issue if i solve this electrical issue because the bleed off is 5 hours. So slow that a single prime.. maybe two.. gets pressure to where the jeep needs to be to crank. (Ive hooked a gauge up, if the pump/jeep/check engine decides to act electrically good, i just key it, let the pump prime, than crank, and no issue)


Side note, anyone ever hot wired a switch to the pump? Imagine its a terrible idea.

Maybe hotwire for priming purposes not for 24/7 purposes?

No ballest resistor.. 1995 return style.






New fuel pressure reg, pump, injectors, filter, etc. Bosch and name brands. Warrantied multiple parts multiple times to eliminate them from possibilities.


Back to topic at hand... I researched it for hours. Here and other forums. No direct answers. Ecm,pcm,ignition switch etc. I can use a multimeter if someone can help me. It sucks cause its an intermittent issues.



Also , ONLY WHEN COLD usually. Florida.."cold"... If its been running i can usually recrank within an hour no issues...Bump

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Intellect
November 20th, 2017, 18:58
Just went out. Even after the pump delay catches up, and i can cycle the key to prime the system, with a gauge hooked. Solid 50 psi, so it had pressure. But will take 2-10 cranks (complete turnovers) to get the thing to actually run. The first or second time i can hold the throttle and make the rpms bounce crazy and the exhaust backfire (all due to lack of fuel?) Or i can just crank it and let it fail a bunch than 8th time crank semi normal.

This is only on a cold cold start. A day of sitting or more. Or sometimes 4+ hours sitting.

Very very seldem if ever on a warm start.

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