No start problems

[456]

Thanks for the fuel line help guys.

 

This is a 1990 4.0 5 speed mj. The PO has put a fair chunk of new parts into it with no luck. New plugs, cap, rotor, wires, fuel filter, air filter etc. You know the usual shotgun method of problem solving. I received this truck as a non runner so I went in not really knowing what could be wrong. Reading and talking to some friends lead me to the CPS. By the looks of it its not a bad idea anyways so I changed it. Still nothing. More reading and poking around and I thought maybe the ignition switch. Pulled it apart and sure enough its very worn inside. So new one of those. This may have actually made an improvement. I can get it to run while in the crank position but not when releasing the key to run.

 

Are there some fusible links some where I'm missing. I've metered the fuel pump at the ballast resister and I have power for a second when I turn the ign on and during crank. This sort of makes sense, but why once its firing does the power go away. This isn't the complete issue as if I bypass this with a jumper lead the problem persists. What I'm wondering is what other circuits are not turning on in the run position?

 

Thanks in advance.

 

Eric

[JENSSEN]

After a skype call seems like the auto shut down may be kicking in can anyone take a picture of it and post it as well as the required voltages in and out?

[cruiser54]

Starting in the start position and dying when the key goes to the on positon is typical of a faulty fuel pump ballast resistor located near the air cleaner on the driver side inner fender. It's a ceramic white deal about 3/4" by 3" with a wire at each end. To test it, just hook the wires togither bypassing the resistor.

[JENSSEN]

Starting in the start position and dying when the key goes to the on positon is typical of a faulty fuel pump ballast resistor located near the air cleaner on the driver side inner fender. It's a ceramic white deal about 3/4" by 3" with a wire at each end. To test it, just hook the wires togither bypassing the resistor.

 

First thing He did, also changed the electrical part for the ign switch in the column,..

[Pete M]

if it's not the ballast resistor itself, it sounds like that circuit might have a break in it.

[maddzz1]

I had the same problem when I got my truck. It was one of the wires near the starter relay next to the battery. This is where the fusible links are. I'm not sure if it was one of the fusible links or one of the other wires. I couldnt figure it out so I took it to a shop near my house that does auto elec problems.

[456]

Thanks guys I will look into those areas.

 

I'm slightly preoccupied with the aftermath of this, but I will get back to the MJ soon. Sorry for the crappy cell pic.