Jeep wont start?????

[KnuckleHead]

Here's the deal......
The wife owns a 95 Jeep Grand Cherokee limited V8. About 4 months ago she went out to start it and go to work but the truck would not start, just turn over. We let it sit for about 4 days before I could really look at it. After checking for spark and fuel, had spark no fuel, I was off to get a fuel pump. Get back from the junk yard and get ready to push the truck into the driveway, I give the key a turn and it fires right up. Tested it like 5 times, on off on off on off, every time starting right up. Well that lasted a week and then dead again. So I once again thought fuel pump. I checked for power at the pump, no power, checked the relay, was clicking so thought its working. I google a little to get info and find that the factory alarm is tied into the fuel pump. If the alarm goes off it shuts power to the pump off. So I then look at the auto shut down relay, bamo it's back up and running.

Now here we are 4 months later and we are back to the same thing. The wife wakes me up saying her Jeep won't start. On the way home I stop and get 3 new relays and change fuel pump, auto shut down and alarm. Still no luck. Checked all fuses and find only one blown, change it, still nothing. The truck turns over fine, everything works but there is no fuel pressure at the fuel rail. I'm thinking the alarm has tripped and won't turn the power to the pump on. I have googled how to disconnect the alarm and it seems like you have to do some re wiring as it is really tied into the truck. I would rather leave it and get to the root of the problem.

So if anyone has an ideas or has had this problem ( I know we have some Jeep guys here ) please toss them my way if you don't mind. I really don't want to spend 300 on a pump for it not to be it and there is a full tank of fuel.

Thank you.....

[Squshiee1]

Check the fuel pump ground.

I had an incident a couple of months ago, the car would start if i moved the trans with a jack, or even if i moved the trailer wiring. i spent hours trying to figure out the problem, the ground was spliced after a 4 wheeling trip and was connected most of the time but it would slip off of the metal and the pump would shut off, i would be able to get it home but after that it was WOT to keep it going. Its worth the check.

[Brad]

You may also have a fault with the alarm wiring not related to the pump. Are you able to check OBD for faults?

[KnuckleHead]

I have an OBDII reader and I think hers is OBDI...? The check engine light is not on but I know that doesn't always say much. She did just inform me that the other day when she made a turn the " security " light flickered on then off.

We were having a problem when we would look the doors ( electric ) from inside and close the door. About 30 minutes later the alarm would go off. The only way to turn this type off alarm off is to unlock the drivers side door. If you just lock the door with the key, the alarm would not set and thereforth wouldn't go off. I think something has to be up with the alarm also, just can't figure out how to disconnect it to test it.

as for the checking the ground...... I did do that as I was checking to make sure the plug to the pump was good. There are like 5 a7 wires in that plug....?

[xaza]

The control module for the alarm is behind the glove box. Farthest module to left I believe. Unplug it while vehicle is running, no more alarm. There is a response here telling of another way but if you scroll down good description to remove module.
http://www.fixya.com/cars/t12561194-permanently_disarm_alarm_1995_jeep_grand

[Serious Offroad]

try unplugging the crank Position Sensor and then reconnecting it.

If it starts...bad sensor.

[carpenle]

Ground? Easy to check, I had a truck and that is all it ended up being.

[sunk]

Is it factory alarm?

I just had a similar problem with the truck, it turned out to be the ign module. Funny thing about it was that would test it while it was broken down and would not get fuel. My immediate response was fuel system (fuel filter, pump, relay) but it turned out that the ign module had some impact on the fuel system and would shut it down.

[Rick]

http://www.frontrange4x4.com/forums/image.php?u=525&dateline=1363987620Love the Avatar!! Sorry, Hijack

[tonkatoy]

IT IS A JEEP THING YOU WOULDN'T UNDER STAND:lmao::lmao:

[KnuckleHead]

Ok so went out today and did some testing. Grounds-good, relays-all good and working, pulled the security box-no difference (still would not start), check fuel pump-working, check power to fuel pump-no power.
With that I tried looking for a short but could not find one so I tapped into the wire at the kick panel and straight tithe battery, fired right up. As its cold out there I just cut the wire and ran a jumper to the ignition, this way it's on with the key off with the key.

I get everything back together, fires right up. After clearing the drive way and moving my truck to get hers out for a test drive the stupid thing won't start now..... Wtf. You can hear the pump working so I know the wires didn't come undone. Now I'm even more puzzled. Now I'm back to square 1 again...... Any ideas????

On a good note, I did come across her headlight delay box that was a fire just waiting to happen. 3 of the wires were melting together and therefore melting the control box.

[Adaa60]

ok, so when it didnt start the last time today did it still have power at the pump?

if so i would check the crank sensor, what happens is the sensor dosent see the crank moving, so it will prime for a few seconds then stop and not spray again till it sees the motor moving. its built this way to prevent fires.

Also when i was 19 i had a 94 318 grand Cherokee limited. i had a simmilar issue, i found a bad map sensor and a very dirty maf combined with a new air/fuel filter's and she was happy again.

there is also a fuel pressure sensor that could be acting up as well i believe

Also this could help you http://www.jeepsunlimited.com/forums/showthread.php?t=418265

[Adaa60]

and i know this sounds stupid

but try this, turn on the key but dont start it, wait for the check engine light to come on and stay on, then start it.

[KnuckleHead]

So finally figured it out with a little help Keith. I had him turn the ignition on while i was under the truck listening for the pump, nothing. So i went to unplug the connector and bam she was humming. Turns out 3 of 5 wires were toast coming from the pump causing it to short out. New plug and shes been good so far.
Thanks for everyones help input.