1992 MJ Starts, runs briefly, dies.

[palesmythe]

About 18 months ago, I drove home a 1992 Comanche 4.0, 5spd, 2wd. My new toy had a bit of an overheating problem, so I pulled it into the garage and started tear down. I had intended to sort out the cooling system and drive it. Things got out of hand. It now has a champion 3 core aluminum radiator with 3 electric fans, high flow thermostat housing and water pump, new hoses, thermostat, and heater core. I flushed it until it ran clear. Since I was in there and had the tools out, I did the distributor, cap, rotor, plug wires, plugs, and put in an accell coil. I put in a new timing chain and gearset and fixed the leaking pan gasket while I was at it. I installed new bosch 4 hole injectors. I cleaned the ground near the battery, at the firewall, and in the taillights. Today, I put fresh gas in it and after cranking over a few times it fired up and ran. Rough. It sputters like the fuel isn't right. It will idle for about 30 seconds and then it dies. If I press the accelerator, it either bogs nearly to death or it revs clear through the rev range. I've checked over my wiring connections but I'm not sure whats gone wrong. It was running better when it just overheated. Help please?

 

[Catch22]

Did you check the fuel pump ballast resistor?

 

[ehall]

My knee-jerk reaction would be to check the coil. Did you save the old one? If not, buy a Standard brand coil from rockauto and try that. They are pretty inexpensive and good to have on hand for emergency anyway.

You should also check fuel pressure to be sure

 

[palesmythe]

I'll check the resistor tomorrow. I'm going to put a stock replacement fuel filter back in as well. I used a clear aftermarket filter so I could see if anything chunky was coming out of the tank. I'm wondering if I got the wrong fuel injectors. I searched around but there's a lot of choices and I'm thinking I may have ordered wrong.

 

[ehall]

post a link to the injectors you bought

 

[87manche]

did the HO units have a ballast resistor?

AMC deleted it in 90ish.
87 had one, 88 has one, 90 didn't.
typing that out makes me realize I've owned too many comanches...

 

[ehall]

91 XJ has one, think it was still there until 94ish

 

[87manche]

interesting.

 

[831_xj]

Yup my 92 had it and I bypassed as well. CPS CPK Coil Fuel pump Fuel Filter or a taco bell wrapper in the intake could be some causes


You say you did timing chain. Is the dizzy cap clocked correctly?

 

[831_xj]

Definitely sounds like timing