jeep problems.....HELP!

[Jross1]

I am having the same problem with my car. We tested the alternator and it was fine. We changed the spark plugs and spark plug cables, we also tried the new fuel filter and pump. None of the above worked, but we believe there was water in the gas tank. We treated the tank heavily over the next three fill ups and its running fine now. Give it a try and see what happens. It's worth a shot.

 

[jeremy]

ok i dont get why you guys keep saying the alternator......It starts everytime then dies. If it was the alternator it would run till the battery was dead. It wouldnt start then die over and over again.

Cause it is a common problem...

I think we have narrowed it down to the ballast
resistor. I had never heard of that before and was about to start swapping sensors starting with the MAP, but we tried skipping the ballast resistor and it started and didnt die, woo hoo. Now the problem is trying to find someone that sells them. Orielly's doesnt even have it listed and Advanced Auto said they cant order it (i guess dealership only) hopefully its just a cheap part not to pricey from the dealer (scared of that lol)

[/IMG]

I would like to take 2 seconds to warn you away from AutoZone and O'rielly Stores...

OK, got that out of my system. What you are looking for is sometimes referred to by a couple of different names. Ballast, Ballast Resistor, Fuel Pump Resistor, Fuel Pump Ballast Resistor, and I am sure I am leaving a couple more names out...

The OEM Part Number you are looking for is 33000682 it should cost you between $6 and $10...
https://www.trademotion.com/partlocator/index.cfm?action=getJointLocator&siteid=214538

 

[Clay]

Ive never heard it refered to as anything but a ballast resistor, but Ive only worked on Mopars with mopar people for the most part, so who knows. That particular resistor has nothing to do with the fuel pump.

as for the OEM number, I dont know where that number came from but Im pretty sure its not an OEM number. As a long time Mopar guy who knows their part numbers, it has way to many numbers to be a factory/OEM chrysler part number.

 

[jeremy]

Ive never heard it refered to as anything but a ballast resistor, but Ive only worked on Mopars with mopar people for the most part, so who knows. That particular resistor has nothing to do with the fuel pump.

Uhhh...
It should do something with the Fuel Pump in a Stock application...

as for the OEM number, I dont know where that number came from but Im pretty sure its not an OEM number. As a long time Mopar guy who knows their part numbers, it has way to many numbers to be a factory/OEM chrysler part number.

I was told buy my Jeep Guys that was the OEM Number....
I will double check that...

 

[Clay]

Uhhh...
It should do something with the Fuel Pump in a Stock application...

On everything Ive ever delt with it only ran to the ignition coil.

Granted, the only vehicle I owned with one that had fuel injection was an 89 Cherokee and I never had any issues with it. I do know that typical to chrysler vehicles the ignition coil and fuel pump are tied together in the wiring scheme, but Im pretty sure the ballast resistor feeds the ignition coil only, with maybe the fuel pump having a common ground.

On a side note, NEVER disrequard the craptastic Renix fuel injection system on the 89/90 4.0L in the Chreokees. Pain in the arse to diagnose, especially with out a manual. I should still have en electronic copy on my home computer if someone needs one.

 

[jeremy]

On everything Ive ever delt with it only ran to the ignition coil.

Granted, the only vehicle I owned with one that had fuel injection was an 89 Cherokee and I never had any issues with it. I do know that typical to chrysler vehicles the ignition coil and fuel pump are tied together in the wiring scheme, but Im pretty sure the ballast resistor feeds the ignition coil only, with maybe the fuel pump having a common ground.

As per most of the Jeep Schematics I have, the Ballast Resistor serves to reduce Line Voltage to the Fuel Pump to a constant 11.3VDC (working on old memory for that number) instead of the the Supplied Voltage of 14VDC of a healthy charging system. Makes the Pump run quieter...

So when the Resistor fails, no fuel pump running. and when you jump across it the vehicle runs again cause you are allowing power to get to the fuel pump again...

 

[mx_chick_42]

my question is what caused it to go bad now? i got hte part ordered from the dealer for $13. So did something cause a jump in volts that blew it or do they just get old and wear out?

 

[Clay]

just get old and wear out. In the old mopars I had I used to keep a spare in the glove box.

jeremy - thanks for the info! Never knew that on the jeeps, then again, I've only had 1 jeep with it, and I haven't had it for a long time.

 

[eldirector]

Likely wore out. They reduce voltage by simply producing heat. Just like a light bulb. Eventually, the metal "filament" inside burns out or breaks. Broken filament = no connection. Once it is replaced, be careful touching the ceramic when the Jeep has been running for a while. It may get pretty hot!

The Jeep starts because the "start" circuit bypasses the broken resistor. The pump pressurizes the fuel line, and the Jeep starts. You let the key kick over to the "run" position, which routes current to the broken resistor, turning off the pump. The Jeep runs until the fuel line pressure drops too low.

These served the same function as the old ignition ballast resistors. They dropped the voltage to the coil from 14V (charging volts) to 12V (running volts). This one drops the voltage to the pump for quieter running and longer life. The pump gets 12V starting (on battery) and then 12V running (via resistor).

 

[csaws]

jeepsunlimited.com will be your best friend

Also if you think it may be the alternator... charge the battery for a while then see if it will run if you can get it to stay running pull the battery cables if it is the alternator it will die.

My guess though is it is distributor related.


I too would order a second one and keep it in the Jeep, being a Jeep and Mopar guy I can tell you I have about 5 of them on hand.