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the fuel pump when i turn the key on doesnt get full power after i turn the key on and of several times it all the sudden kicks on full power and then it will start. have installed new ignition switch new computer and checked wiring when i put thenew computer in it it kinda worked okay for about a week
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I’m a little confused on what the issue is if I’m honest. When you say the fuel pump isn’t getting full power what do you mean by that? How are you checking for this?
We need a better description of the issue.
If you suspect a electrical issue, you need to do some voltage drop testing on the feed and ground side of the fuel pump.
I have done some testing and at the relay in the fuse block under the hood when you turn on the key and check it at the relay terminals the test light will barely light up and if you turn the key on and of all of the sudden it will get full power n light up strong and until it does this it will not start but as soon as full power kicks in itstarts up and runs like new until you shut it off again then same thing when you try and restart it again. tomorrow me and a friend are gonna go thru all of it with a ohms meter and test lights etc and try to fig it out we got a wiring diagram also this time
i had a test light on the relay and it was real dim and the fuel pump willrun but it quite you can here it but not real good then when you keep turning thekeyon and off it will all the sudden get real loud and the test light will get bright and when that happens it will finally start up and run fine until you try and start it back up again
If the test light is dim at the relay.then the problem
is from there back. when your testing power at the relay.
your on the line side or control side? here is a site for a
wiring diagram.If the jeep will not start when you turn the key normaly but will start after cycling the key on and off ( with out cranking ) 3 times then you probably have a fuel pump pressure regulater prob. there should be a shrader valve on the fuel rail near the t/body. attach a fuel pressure guage and check key on but not cranking pressure. then crank normal and see what it reads. then cycle three times to start and read pressure and finally shut motor off and watch how fast the pressure drops. compare the readings to the specs in your shop manual.if you end up having to replace the fuel pump go with a bosch pump if you can afford it if not then go with a carter pump ( napa has them just rebranded as napa ) avoid the airtex pumps.
the pump has been replaced with a carter whenthis problem started all the wiring checked out okay yesterday I’m gonna replace the fuel pump relay again and the auto shut down relay and if that doesn’t do it it has to be in the ecm unit which i’ve replaced already and it was fine for a week then started this problem again and i’ve found some forums online and they talk about a delayed start issue and they all say its the ecm. we did all the wiring checks yesterday with meter and test light and wiring diagrams
Perhaps instead of testing at the relay you might want to check and see what the fuel pump is getting directly. If you measure the voltage there then you’ll have a better idea if the problem is on that side of the relay or not. Also I think consulting the wiring diagram is a great idea at this point so that you can get an idea of how the circuit is suppose to work. This will help focus your diagnosis and will be much more effective than guessing and replacing parts.
well changing the relays worked good for 2 days now it doing the same thing again this driving me nuts lol!
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