i need help from the mj tech gods

[bigd44889]

ok

when i drive during the day i have no problom.

At night with the lights on the mj stdders like you shut the fuel off.

Ok now for the odd part.

When it studders i can shove the gas pedal down some and it picks right back up.

so i need ideas what to look at.

i have changed the throtle body to a different one.

88 mj

2.5

ax4

4x4

[Eagle]

Warm it up to operating temperature and put a voltmeter across the battery terminals to measure the actual voltage in the system. Try to do it with the engine at operating RPM, maybe 1200 or 1500 RPM.

 

Turn on the headlights and repeat. If the measured voltage is lower, your alternator isn't able to handle the amperage draw of the headlights, and you aren't getting full power to the ignition, the injectors, or the fuel pump.

 

Since you have an '88, you have a ballast resistor for the fuel pump. Another quick test would be to rig a jumper wire and toggle switch across the terminals of the ballast resistor. Make the wires long enough so you can have the switch inside the cab. Drive it with the headlights on, and when you feel it stuttering flip the switch to bypass the ballast resistor. That will send more voltage to the fuel pump. If that smooths it out, either the alternator isn't keeping up or the fuel pump is weak.

[Pete M]

x2. along with that, you can try cleaning up the ground behind the drivers side taillight. that's where my fuel pump grounds.

[bigd44889]

ok

i had the altinator tested on the truck at advanced

thay said it was working right

cleaned the ground

i have never found a ballest resister on this truck

i will go look over it and see if i can find one

thanks for the ideas

just thought of something

wonder if the fuel pump relay could cause this to

[bigd44889]

i figured it out

replaced ground strap from the fire wall to block

and replaced negative battery cable

running fine now