Engine cranks but wont start
 

I parked my 87 Cherokee yesterday and when I went to start it, it wouldnt work. The engine cranks but it wont start. The gas pedal seems like it isnt doing anything at all. It felt like it wasnt getting much gas before this, and it usually took a couple of seconds to start up. Any thoughts or advice would be helpful. Thanks.:cowboy:

Got a voltmeter? Here's where I'd start with a diagnosis.

Renix CPS Testing and Adjusting
　
　
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.
　
Revised 11-29-2011

That's normal for a Renix, it has to crank up to a certain RPM for a period of time before it'll spark.

You don't need to touch the gas pedal for it to start. BUT have someone push it while you watch the linkage on the back side of the throttle body, or just check it...

Besides the CPS, right next to that on the top of the list is do you hear the fuel pump run a couple secs when you turn on the key?

Okay I will check out the cps, and yes I do hear the fuel pump, but someone told me it may be the fuel filter, not sure if that would cause it to do this though? And thanks Radi I had been wondering about that since I got it.

It ain't the fuel filter. That's a standard answer from those who are generally not in the know but feel obligated to throw something your way.

That said, do you know when the last time yours was changed? How about spark plugs, wires, cap and rotor? Throttle body cleaned?

All stuff to address once you get it to start again.

Okay that's what I assumed. I'm not sure the last time those have been replaced, I looked at the fuel filter and it definitely hasn't been changed in a while. I will take a look at all of those, and I know I'm going to have to replace a power steering pump hose, the serpentine belt is long overdue for a replacement, along with the valve cover.

Heh. Your to-do list is shorter than mine. :icon_cheesygrin:

what all do you have to do to yours?

Oh, where do I start, lol.
230K miles, still running the *factory* radiator and water pump. But it's starting to run warm so the clock is ticking.
Front u-joints are starting to squeak again, left front axle seal is dripping, right wheel bearing has a growl on turns, muffler sprouted a rust hole, windshield cracked, and my floorpan repairs need to be re-done, of course now the cargo floor in the rear is going soft too.
The rear springs are frowning again (I shouldn't have gone OEM last time)
Most of this stuff has already been fixed once, lol. We're on round 2.

On the plus side, I did replace the tires, fix the A/C, replace all the brakes and put a new Cat on, so the list has shrunk a little.

I'm trying to decide if I want to fix everything, or just drive it until it drops and find a younger XJ. Dunno. This one is rusting underneath fast, to the point where I really can't keep up with it properly. I can't spend much time under a car like I used to either thanks to arthritis in the shoulders, I have to do a bit here and a bit there. Kinda frustrating.

WOW. Sounds like you should just drive it til it drops, but I guess that's easier for me to say considering I didn't put money into it lol. What was wrong with your A/C? Mine hasn't worked since I got it and it's definitely not that it needs freon.

Only shoulders? (Lol). I hear you. (I'm starting on the 2-1/2 cords of wood for next year)(give me two weeks, not two days) Same "boat" with my Jeep. By and large the parts are OK, just what they are attached to has about had it.

Cameron, you could always give it a shot of starting fluid, see if it fires. I don't mean the CPS shouldn't be tested, just that's one heck of an easy way to rule out a fuel delivery problem.

Mine had a slow leak. Had to replace o-rings and have it recharged.

Problem is it won't "drop", lol. The drivetrain willl still work long after rust has made it unsafe to drive. I've gotten my money's worth out of it several times over, so no complaints. I'm thinking a 98-99 with lower miles is looking pretty good.

Hey Radi, Djb has a great pic of a water pump with just a disk...the impellers are gone gone gone.....Potential Hydrogen issue? I'm not sure if what I replaced was stock, but waz 100,000 mi ago at about 160K. (Seal, not the bearing).