98 Grand Cherokee will not start has spark no gas pressure

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morris340

New member
1998 Grand Cherokee cranks will not start . Has spark no gas pressure, gas gauge not working. I unhooked the battery for a week as I swapped out header panel light etc. No damage to wires in that area. Hook up battery now it doesn't start. I also attempted to scan it and it could not communicate with PCM. I swapped all relays. I pulled ASD fuse and and when I plug it back in the ASD and fuel relays do click. Also when you turn on key fuel relay clicks.
I did notice it took a little a few seconds to crank before I ran into this.
 
morris340 said:
1998 Grand Cherokee cranks will not start . Has spark no gas pressure, gas gauge not working. I unhooked the battery for a week as I swapped out header panel light etc. No damage to wires in that area. Hook up battery now it doesn't start. I also attempted to scan it and it could not communicate with PCM. I swapped all relays. I pulled ASD fuse and and when I plug it back in the ASD and fuel relays do click. Also when you turn on key fuel relay clicks.
I did notice it took a little a few seconds to crank before I ran into this.
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Have you hooked a manual fuel pressure gauge on to the fuel rail then turned on the key to ensure fuel pressure is present. If it's not, verify that you have electrical power at the fuel pump connection itself. If you have electrical power and ground back there and still no pressure, it's a bad fuel pump. It helps to have a helper available on this, because you'll only have a few seconds of a electrical power at the pump after turning on the key, so you have to check it quickly. You can also check if fuel pump has power by listening, it should make a light audible buzz when energized, but the more proper way to check it is with a DVOM. And of course, ensure you actually have fuel in the tank.

I recently had a dead battery on my 1999 due to a hood light hanging down and staying on. After charging the batteries, mine would start and die right away. Even after revving up, as soon as it hit idle again, it would die. Found out the PCM sometimes has to do a idle relearn after the battery is dead for so long. In my case, I just kept the rpms up around 2000 for about 30 seconds, then let it idle for awhile and it corrected itself. But I later found out there is a proper idle re-learn process, you can search for it. Not sure if this applies to a 1998 though.
 
WJCO said:
Have you hooked a manual fuel pressure gauge on to the fuel rail then turned on the key to ensure fuel pressure is present. If it's not, verify that you have electrical power at the fuel pump connection itself. If you have electrical power and ground back there and still no pressure, it's a bad fuel pump. It helps to have a helper available on this, because you'll only have a few seconds of a electrical power at the pump after turning on the key, so you have to check it quickly. You can also check if fuel pump has power by listening, it should make a light audible buzz when energized, but the more proper way to check it is with a DVOM. And of course, ensure you actually have fuel in the tank.

I recently had a dead battery on my 1999 due to a hood light hanging down and staying on. After charging the batteries, mine would start and die right away. Even after revving up, as soon as it hit idle again, it would die. Found out the PCM sometimes has to do a idle relearn after the battery is dead for so long. In my case, I just kept the rpms up around 2000 for about 30 seconds, then let it idle for awhile and it corrected itself. But I later found out there is a proper idle re-learn process, you can search for it. Not sure if this applies to a 1998 though.
Click to expand...
Has no pressure at all. Jumped fuel pump and it works fine. Will get someone help me check for wiring to it hopefully later today.
 
morris340 said:
Has no pressure at all. Jumped fuel pump and it works fine. Will get someone help me check for wiring to it hopefully later today.
Click to expand...

Strange. Hope it's not a security issue. I would double check all ground wires or any other wires around the area you worked. Weird issue.
 
It shouldn't crank at all if the neutral safety switch is bad. Just because the asd and fuel pump relays click doesnt mean they are working and transferring power
 
my wag = Crank Position Sensor

been there, done that several times to the point that i actually carry a spare
 
WJCO said:
Have you hooked a manual fuel pressure gauge on to the fuel rail then turned on the key to ensure fuel pressure is present. If it's not, verify that you have electrical power at the fuel pump connection itself. If you have electrical power and ground back there and still no pressure, it's a bad fuel pump. It helps to have a helper available on this, because you'll only have a few seconds of a electrical power at the pump after turning on the key, so you have to check it quickly. You can also check if fuel pump has power by listening, it should make a light audible buzz when energized, but the more proper way to check it is with a DVOM. And of course, ensure you actually have fuel in the tank.

I recently had a dead battery on my 1999 due to a hood light hanging down and staying on. After charging the batteries, mine would start and die right away. Even after revving up, as soon as it hit idle again, it would die. Found out the PCM sometimes has to do a idle relearn after the battery is dead for so long. In my case, I just kept the rpms up around 2000 for about 30 seconds, then let it idle for awhile and it corrected itself. But I later found out there is a proper idle re-learn process, you can search for it. Not sure if this applies to a 1998 though.
Click to expand...

I have no voltage to green with white. Green with yellow and green with black shows 5 volts.
 
morris340 said:
I have no voltage to green with white. Green with yellow and green with black shows 5 volts.
Click to expand...

Are you talking about at the fuel pump? I would get a wiring diagram to see which wire each of those are. Also, when you're vehicle doesn't start, the engine is cranking correct?
 
WJCO said:
Are you talking about at the fuel pump? I would get a wiring diagram to see which wire each of those are. Also, when you're vehicle doesn't start, the engine is cranking correct?
Click to expand...

Yes. I am going track one down. Engine fine iu can jumper fuel pump and runs. Thanks!
 
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