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Jeep no start problem

Jeepguy91

Jeepguy91

NAXJA Member
NAXJA Member
Location
Warsaw, IN
Well we went down to Harlan this weekend to do some wheeling for naxja 15th birthday. Jeep decided to be a pain on Thursday while down there and decided to start blowing fuses. It started out with the Jeep blowing the asd relay and shutting down the Jeep. After we got it back up and going it decided to blow the fuel pump fuse. Changed that out and about 15 minutes later it blew the fuse again.

We got it back to camp and it's showing a "no bus" on the cluster and will crank but not start. It just keeps blowing the fuel pump fuse. I can put a new fuse in it and it will for right up and run. Then after a while of it running it blow that fuse and shut off.

So far I have put in a new asd relay, fuel pump fuse, swapped out fuel pump with different one, and also swapped out fuel pump relay. I have checked over all the wires and nothing I can find is burnt or in a spot to short out.

Any help you guys can give for this would be great. I just don't know what else it might be that will keep it running without blowing fuses.
 
A reoccuring blown fuse will be a short to ground. Your power wire is touching the chassis somewhere or melted into the ground wire of another circuit
 
But it's not an immediate blown fuse. It's almost like it is running at the max watts that the fuse will stand till it finally burns thru and pops.
 
Along with the fuel pump relay, the asd relay also powers the O2 sensor heaters, the ignition coil, the alternator field and the fuel injectors.
 
So what area should I be looking in to get this fixed? Is it something within the asd circuit
 
On my first read, I thought you meant it was blowing the ASD relay fuse...not the relay itself.. that creates this into two unrelated failures.

Back on track, the only thing powered by the fuel pump fuse is the fuel pump. There must be a short in the harness.

It is possible there is corrosion in a connector, or inside the insulation somewhere along feed wire to the fuel pump.

Another possibility is a poor fuel pump ground, which the diagram says is near the left tail light. (G402)

a funny thing about grounds, if a gang ground is loose, funny things start happening due to back feed.
 
The ASD relay feeds the coil rail, and the fuel injectors.


It could be related to the fuel pump fuse if the problem area turns up where the wires run along together in a harness.
 
Well I found a wire that feeds the fuel pump and it was grounding out against the fuel rail. Got that fixed and now I have a code for the cam shaft sensor. Gonna replace that and hopefully get it to start.
 
Note from DJ
This is a QUOTE from WildcarRider in the thread link I posted for you.
QUOTE: “Discovered that there was a short being caused by the bracket holding the connector end of the Crank Angle Sensor, it was rubbing against the harness right where it takes a 90 degree turn to go through the firewall near the center/driver side of the engine bay”.

Please keep us posted as to your progress so we know what the final outcome was so advice can be offered to the next person with a similar problem.
 
Well put a new cam shaft sensor in the Jeep and it still won't start and I'm still getting the po340 code. I checked the cam sensor plug and I'm getting 5 volts to the 2 outside plugs. Is this how much in suppose to be getting?
 
Jeepguy91 said:
Well put a new cam shaft sensor in the Jeep and it still won't start and I'm still getting the po340 code. I checked the cam sensor plug and I'm getting 5 volts to the 2 outside plugs. Is this how much in suppose to be getting?
Click to expand...
your readings are correct and perfect, as long as the third one had a good ground.
 
Well I went and made sure I had reference vintage at the pcm for the cam and crank sensors and also removed and cleaned the crank sensor. Jeep started right up and is running like normal.

Now the problem is it doesn't want to shut off when you turn the key off. Has anybody ever had this problem?
 
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