Hey Ya'll,

I have a 1990 jeep cherokee 4.0L and my jeep will not start, It cranks over fine just no start. i already replaced my CPS and my fuel filter. I know its a fuel issue because it will try and start when i spray starter fluid in the intake. I don't have a fuel pressure gauge to test the fuel pump..and no store near me has one to rent...any other way? i hear it turn on and then off just like it normally would. any advice would be helpful!!! Thanks!!

-Jay

 

The fact that it is trying to start makes me think either weak fuel pressure or weak spark. You really must verify both before moving onto other possibilities.

1. Must get that fuel pressure gauge. Hearing the pump turn on and off means literally nothing as far as verifying how it is performing. For a 1990, you need 31 psi for the engine to start.

2. Check the quality of the spark. Pull a plug, keep it attached to the plug wire, place the plug electrode near a good engine ground, have a buddy crank the engine while you watch. You're looking for a strong, blue, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine.

 

you need spark -fuel pressure -and injector pulse -to run eliminate the ones you have leaves the one you dont

 

So it has no spark coming off the coil and unless I'm doing it wrong which I may ......there is no injector click.....could it be ECM? Guess I need to buy a noid to know for sure ...any other ideas?....help!!

 

you can check them with test light also but no injector pulse is most likely the stator in the dist also known as cam position sensor or the other cps

 

http://wiki.answers.com/Q/How_do_you...injector_pulse

 

http://www.lunghd.com/Tech_Articles/...lse_Stator.htm

 

read the two links i posted with out being there this is what shoud be done

 

Make sure all the ground wires are clean and making good contact. Engine to battery and the engine to firewall. I have seen this fix no start Jeeps twice and it's free.

 

Thanks for the replies will definitely be looking into this.....if I'm getting no spark off the coil could it still be the cam posn sensor? Im getting more signs then no injector pulse. Thanks again!

 

***please help*** because I work I'm just getting around to work on this ...I replaced the crank and cam shaft posn sensors and the fuel pump....still no spark no fuel but cranks over fine.....I think it's dieseling when I shoot starter fluid into the throttle body....I'm going to get it towed to a shop if I can't figure this out I hate to admit defeat but its about that time....I checked the grounds as well and they look good. ECM? I got nothing.....please
help!!!

 

Correction I get fuel to the rail but I do not hear the injectors opening when I put my ear to a screwdriver

 

Silly question, do you have spark past the ignition coil?

 

No I put a screwdriver into the wire coming off the coil and get nothing

 

Then I'd suspect an ignition coil itself. I've seen them go south before quite a few times.

BWD part #E94P. Also, if you can get ahold of an inline spark plug tester, you can run it inline with coil and visually watch for spark.

Just my $0.02. Hope that helps!