Hey guys I’m new to the forum but like the title says my 88 4.0l Jeep Cherokee will not start unless push started. It will crank over just fine and will sometimes start like that but sometimes will just crank and crank without firing up. If that happens I give it a push start and it fires up just fine. I just put new cap, rotor, wires, plugs and ignition module in and made no difference. Any help would be appreciated! Thanks

 

It sounds like you can have a bad ignition switch that's not turning the computer or the ignition on when you are in the crank position .

 

I did replace that and still no luck.

 

Look at the starting relay, under the relay cover inside the RHS engine compartment. Besides the threaded stud, list the terminals on yours. The '87 has one terminal in particular, and if yours is the same, I want you to check for 12V when the ignition key is turned to crank.

 

Which one do you want me to check? I can check tomorrow when I’m in the shop.

 

I meant if it isn't like the 87. On the 88, if I recall, there is a fuel pump ballast resistor, and that resistor is bypassed when the ignition key is in the crank position. Is the fuel pump pumping fuel so the injector rail has pressure when cranking?

 

I’ll check if it does tomorrow. The problem is it only happens sometimes so I might have to wait till it happens again.

 

^^ yeah.. those intermittent issues on any vehicle can be the biggest PITA.... as you can't replicate the issue on command in order to diagnose.
Let us know what you find out.

 

Coming from a complete noob here, but I had all sorts of similar/odd charging issues and changing the starter relay and connections was a game changer for me (as AJ suggested). With that said, I'm in the same boat right now w/ a crank/no start on my '89 auto!

 

Could be low CPS output.

On cranking, the engine speed isn't enough to get the CPS to generate a signal.

Pull or push starting does generate a stronger signal because it's dependent upon engine RPM.

CPS can be easily tested.

http://cruiser54.com/?p=50

 

Started testing the starter relay and the connector going to the ignition terminal was not making a good connection so I cleaned that up and it fired right up and I haven’t had a problem so far!

 

That's why I wrote this Tip:

http://cruiser54.com/?p=35

 

There you go. Done.

 

That's great to hear. So much important stuff "going on" in that little area.

 

Tips 1 through 5 completed thoroughly makes for fewer headaches down the road!!!