Good day to all. I'm not new to jeeps, just these newer ones. I got a 1995 grand cherokee that came in for repair from a friend of a friend. Any ways, pretty sure fuel pump is shot, do I need to drop the tank or is there an access panel like in a Grand wagoneer? Both rear windows won't go up, but one seems to have a bad regulator, can move it by hand, and has a nasty electrical draw until i pull the fuse for the fuse panel from the PDC, but when I pull each fuse in the fuse box no difference. All his battery cables, positive and negative look like crap so gonna start there.Any one got any suggestions or know about having to drop the tank?

 

Sorry to say it but the tank has to come down.
And Welcome to CF!
Dan

 

well lucky for me i don't think it's the pump. I disco'd the fuel filter and pumped about a gallon into a gas can in like 30 seconds. But I can say i don't have any spark. Hooked up a timing light to the coil output and one of the plug wires. No spark on cranking. Someone else has been in there because there is a new coil cap and wires on it. Doing some reading, what's up with the cam, crank sensors in these? Seems to a common culprit. You don't have to give a step by step but where are they? thanks

 

Welcome to CF!
Dan
On the 4.0L I6 the Crankshaft Position Sensor is here:

 

wow that looks like fun, my fault forgot to mention this has the V8 in it. Question about the security system. Truck came to me with a dead battery, guy says he has a draw. Well when i disco'd the security box the draw stopped.Now I know it triggers relays and light s flash on and off, but voltage started going up past 15v. So i'm guessing problem maybe there. My question is does the security kill ignition or fuel? That maybe my no spark condition. any thoughts anyone?

 

I believe that's your problem. The security system.
Fill in your details to avoid any confusion in the future.
Dan

 

sorry dan, my fault. I belong to a few forums and usually yell at people for doing the same. I can't magically crawl through the internet and into your vehicle to diagnose something. Well the security I'm not sure is new, owner says he had some trouble with it and key in door gets him going. he just bought it a few weeks ago so eh is still learning, according to him. I may have a couple of problems, could be security for no start, could be crank sensor. I'll be back on it tomorrow. I was reading on here, pulling fuse for security, kills security system, but let's vehicle run? Don't sound right to me. Vehicle died while driving, that's why I'm thinking CPS, not so much alarm, but gotta find the draw to. I'm guessing car won't start with security module removed right?

 

You need to PM Willys55 and get his opinion. He's the electrical wizard.
Dan

 

Well i got some updates. I replaced the crank sensor (I'm still making up words that F-ing thing) no start, went to replace the cam sensor and when I removed the distributor cap, the tip of the rotor was gone, like missing and the contacts on the inside of the cap were VERY badly eroded. So I replaced the sensor and cap and rotor. Guess what? no start. Still no spark. Decided to play with the relays, pulled the one for the auto shut off, placed it back in and voila! Fired right up. Let it run for an hour, unstuck the serpentine belt tensioner, started and stopped a few times, then she quit while idling, now, no start again. I'm thinking gotta be a ground or possibly PCM flaking out. For those that have done 5.2 crank sensor, my hat's off to you, what a PITA!!!!!!!

 

ok hopefully end of this saga. The one thing I never did, that shoud have been first, was check the dam ground at the battery. I knew it looked like garbage, but I took it apart, restripped the ends, sanded the contacts at the fender next to the battery and she is fired up. I did check before I did this and no start. Hopefullt that's it. Now I gotta deal with the rich smell and kinda rough idle. I pulled codes for the battery being disco'd, egr circuit (that's all it says but I did have it apart when I did the crank sensor) and the 55 at the end. I'm going to recheck the EGR valve bolts and lines. Thank you so much for the advice and help.

 

Glad you got it firgured out! It never fails that it is the easiest and most over looked part!

 

Back to the drawing board. Went to go start it today and no spark again. Finally started ran about 2 minutes and quit. Now no spark yet again. I removed the engine grounds and cleaned, sanded those, pulled the pcm connector and sprayed contact cleaner in there, no change.Now I'm at a loss. As posted di change the ASD and fuel pump relays, new crank and cam sensor. Is there a main ground for the pcm? I don't have a schematic or locations for it.

 

I had a thought. Doing some more reading, is it possible one of the sensor grounds would keep it from running?There was one thread I read where the O2 sensor could prevent the PCM from sending the signal to the coil. Or is there a way to test the PCM to see if it's malfunctioning?

 

ok if anyone is paying attention to this, I went through the schematic in a hayne's manual. Says I should have 8V at the crank sensor and cam sensor, and 5V everywhere else. I have around 5.3 at the other sensors, but only 6.3 to 6.4 at the crank and cam sensors. I'm guessing that the supply and groundto the PCM is good due to the consistent 5.3V. My guess maybe a bad PCM due to the 6.3V? Any thoughts??????

 

Willys55 is your answer pm him he will deffintley help you he just helped me with electrical problems