Need help ASAP Please!!!! Have to drive to work tomorrow!!!!!
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 58
Likes: 0
Year: 1988
Model: Cherokee
Engine: 2.5
Ok heres the deal, Had a bad crank sensor, replaced it today after work, test drove fine, no problems at all, get it home turn the engine off, try and re-start it and nothing just turns and turns, have the wife come out while I test the coil, Lots of spark, take the main fuel line off going to the TB, and had her turn it over, lots of fuel, still no start, spray some starting fluid down in the TB and bam fires up perfect, idles perfect, revs perfect like nothing is wrong. Turn it off, try and re-start, same problem, The injector is not spraying fuel out when you are trying to start it, Spray the starting fluid in and it starts up fine and works great, but only starts with Starting fluid??? WTF????? HELP ME PLEASE!!!! I have to drive this to work tomorrow.......
1988 2.5 litr





1988 2.5 litr





CF Veteran
Joined: Mar 2009
Posts: 28,068
Likes: 6
From: Tenn. and Mich.
Year: 2004
Model: Grand Cherokee
Engine: 4.7L V8
JMO I'd say fuel pressure regulator isn't holding pressure after shut-down. I'm new to Jeeps but that's the cause when that happens to the Chrysler 2.2/2.5 F.I. engines. The regulator could have a damaged diaphram causing a low fuel pressure at all times, and pressure bleed-off while shut-down. Any possibility you unhooked the vacuum line to the regulator while you were working on it?
Last edited by ol"blue; Apr 6, 2009 at 07:55 PM.
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 58
Likes: 0
Year: 1988
Model: Cherokee
Engine: 2.5
I like that better than the pump......I have my pump hard wired to my own Relay with 10 gauge going back and a kill switch (My jeep locks dont work) this is my security system. When I took the fuel line off, and turned the pump on, how much pressure should be coming out? It seemed like it had the same pressure as a house hold faucet sink, but its only 1 injector so is that good enough?
MJ>XJ
Joined: Mar 2009
Posts: 17,836
Likes: 7
From: Griffin, G.A.
Year: 1990
Model: Comanche
Engine: 4.0 I6
on a 96 motor anyways with the jeep running (pump on) it should have 31psi... disconnect the vacuum tube to the fuel pressure regulator and it should jump up to like 49psi... know this cause i just had to check mine but it was good...
Trending Topics
MJ>XJ
Joined: Mar 2009
Posts: 17,836
Likes: 7
From: Griffin, G.A.
Year: 1990
Model: Comanche
Engine: 4.0 I6
eeww... uhhh... sorry man... couldnt help ya there... dont even know what the 4cy looks like... should be able to google the fuel pressure... or if you hurry run to autozone and look at a haynes manuel right fast...
As you or someone else cranks it over get a rubber mallet and smack the tank and it should start, therefore it is the pump, or get a fuel test gauge to test to verify. Did it have a long crank before the start?
MJ>XJ
Joined: Mar 2009
Posts: 17,836
Likes: 7
From: Griffin, G.A.
Year: 1990
Model: Comanche
Engine: 4.0 I6
if one of them other two guys is write i would think it would be the regulator out of the two... in my experiance the fuel pumps either worked... or they didnt... could also be a fuel filter if its backed up and take the motor running to "pull" the fuel threw to get it by the crap inside... if you get a pump plan to get a stainer too... be crazy not too...
CF Veteran
Joined: Mar 2009
Posts: 28,068
Likes: 6
From: Tenn. and Mich.
Year: 2004
Model: Grand Cherokee
Engine: 4.7L V8
Don't go on my opinion as I'm just going from my experience on my 4 cyl. Turbo mopar's which are different. I'm telling you what I would "guess" is your problem. DON'T throw money at it until you KNOW what's wrong. Seriously. If I were in your shoes now I'd carry starting fluid until I fixed my car.
Last edited by ol"blue; Apr 6, 2009 at 08:46 PM.


