Hey guys I have a 2005 4.0 and I just replaced the fuel pump due to it being my last resort with a p0300 code and now it won’t start I’ve gotten new spark plugs, coil rail, tps sensor, crank position sensor, primed the fuel lines, and new fuses and relays. If anyone has any insight on what to do that would be greatly appreciated because I am at a loss right now
Fuel pump issue
- Thread starter Jwatts
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- 2005 tj 4.0 engine 6 speed
What do you mean it won't start?
Does it turn over or nothing at all? Have you tested fuel pressure at the rail?
Does it turn over or nothing at all? Have you tested fuel pressure at the rail?
It sounds like it really wants to turn over. I’ve gotten it to idle for a little bit while opening the throttle body then it backfires
I'd start by checking fuel pressure at the rail. Report back with that information!
What brand fuel pump did you use?
What color were the tips on the old spark plugs?
You gotta diagnose things one at a time. If you replaced the fuel pump and it’s running worse than it was, put the old fuel pump back in.
For a P0300 I’d be looking at the crankshaft position sensor, clogged catalytic converter, maybe a lean condition due to an air leak.
One rule of diagnosis is, if it was running but now does not, what changed? Revert back to when it was running (even if not right) and continue diagnosing from there.
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So I’m attempting to test fuel pressure but I can’t get the right fitting since my fuel rail doesn’t have a schrader valve (uses the quick disconnect)
Here's one that I used...
https://www.racetronix.biz/p/adapter-qdf-5-16qdm-5-16-1-8-port/qda-56f56mp
@Chris found a Glowshift version on eBay.
Here's that adapter directly from Glowshift...no Canadian shipping...
https://www.glowshiftdirect.com/5-16-quick-connect-efi-fuel-line-adapter/
View: https://youtu.be/zzUSR2w1G9E?si=XOR2HKXz4yJiPKXs
You can order a gauge and transducer from them as well and have fuel pressure displayed in the tub.
This is my Glowshift pressure and temperature gauge plumbed in for oil pressure. I plan on eventually adding the same gauge for fuel.
-Mac
https://www.racetronix.biz/p/adapter-qdf-5-16qdm-5-16-1-8-port/qda-56f56mp
@Chris found a Glowshift version on eBay.
Here's that adapter directly from Glowshift...no Canadian shipping...
https://www.glowshiftdirect.com/5-16-quick-connect-efi-fuel-line-adapter/
View: https://youtu.be/zzUSR2w1G9E?si=XOR2HKXz4yJiPKXs
You can order a gauge and transducer from them as well and have fuel pressure displayed in the tub.
This is my Glowshift pressure and temperature gauge plumbed in for oil pressure. I plan on eventually adding the same gauge for fuel.
-Mac
Agree with this, you need to do one thing at a time as you go. I do know that not all ignition coils are created equal, for example - but you messed with plugs, sensors, pumps, relays....
Kind of embarrassing but I got the pump from a- premium and I wouldn’t know where to start for the cats or an air leak. I had a thought of it being the harness that goes to the pump might be damaged but the pump works.
I’m unable to find the correct fitting in my area so I’m going to have to order one here soon
Again it will help if you add more information. You're asking us to throw guesses at the wall.
How many miles are on your engine? Has it had the chain replaced before? How was it driving from before you starting having issues?
With an 05, it may be your PCM, they are junk.
Does the check engine light come on then go off if you turn the key to ON? Will it communicate with a code reader? If you don't have a reader, turn the key ON, OFF, ON, OFF, ON quickly and the codes should display in the odo.
Does it currently show any other codes?
Does the check engine light come on then go off if you turn the key to ON? Will it communicate with a code reader? If you don't have a reader, turn the key ON, OFF, ON, OFF, ON quickly and the codes should display in the odo.
Does it currently show any other codes?
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