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View Full Version : 89 XJ won't start - At least not with the Key



YellowSub2000
11-11-2009, 07:18 AM
Ok, I have a little issue I'm trying to resolve. There is a lot of information, so I will try to keep it organized. I hope.

Short:
I turn the Key. Power turns on. Fuel Pump will not turn on. Engine will not turn over with the key.

Long:
I turn the Key - Don't need help here, I think I have that down.

Power Turns on - Needed to replace the wiring harness. Most everything seems good now.

Fuel Pump will not turn on - I found that the problem is at the relay plug. It's not switching, although the relay is found to be good. As well as several other relays. Let me see if I can explain the problem. Picture a relay in your mind. Numbers 85 & 86 are used to actuate the relay (One Positive, and One Negative). Well both sides are receiving 12v power. (Both Positive) I traced the wires and the negative (Or what would be negative) goes to the ECU under Fuel Pump Relay Negative. Since I am receiving positive from this line, would it be safe to say that the ECU is bad? The wires trace correctly, I think. Dam, I gotta double check that. Any other ideas? Number 87 & 30 are correctly wired (Jumped, and the fuel pump turned on. Also tests good with a volt meter)

Engine will not turn over with the Key - This happened both before and after I replaced the harness. When I turn the Key to start, nothing. The previous owner changed the system to push button, but I was thinking about changing it back. (Might keep the Push button though) With replacing the harness, and making sure all the wires are correct. Still nothing. The wire is correctly connected at the starter relay, and the Ignition switch is new. I found the Green wire from the Ignition switch and there is no power going to it when the key is turned. Any ideas?

Hope I didn't confuse anyone.

BlueXJ
11-11-2009, 07:53 AM
First I would double check your splice. The ECU is nearly bullet proof on an 89. Convert it back from pushbutton start while you are at it. Check the NSS while you are at it. It can cause a no-start too. Get back with us after all that has been done.

YellowSub2000
11-11-2009, 02:54 PM
I will check the splice tomorrow night. Tonight is free dinner at Applebee's. As far as the NSS, I know it's fine. I can jump the relay to start the fuel pump, jump the starter relay, and the Jeep starts. Runs fine. Needs to be cleaned, but runs fine. But the Key has to be in the on position.

AJ99
11-13-2009, 12:14 AM
CHECK GROUNDS!!!!! I had this issue with mine when i did my tranny swap and it was my grounds. Check on the passenger side towards the last spark plug. make sure those are all connected!!!!

YellowSub2000
11-16-2009, 06:52 PM
Turns out the ECU is bad, only on the circuit that controls the Fuel Pump. Weird. Opened it and found the burnt circuit. Trying to by pass it.

AJ99
11-17-2009, 02:18 AM
man too bad you are in FL i have three laying in my back room.

YellowSub2000
11-17-2009, 05:52 PM
How much to ship one? It's an 89.

AJ99
11-17-2009, 06:17 PM
Mine are from 87s. Im not entirely sure it will work. Do some research and let me know.

pvt.Tadpol xj
11-17-2009, 06:48 PM
Mine are from 87s. Im not entirely sure it will work. Do some research and let me know.

hey scottyadd here. im not sure your ECU from the mid 80s will work for his 89xj but i am running a new 94 ECU on my 91 xj. :driving:

AJ99
11-17-2009, 09:05 PM
ya i mean its only 2 years different but it might..

xj4life2
11-18-2009, 10:48 AM
Post up the factory numbers and I check to see if they will interchange.

AJ99
11-18-2009, 05:11 PM
1987 Jeep Cherokee 4.0 AW4

YellowSub2000
11-19-2009, 10:07 AM
Mine is the same, just 89

xj4life2
11-19-2009, 10:34 AM
Ok according to A1Cardone the 1987-1990 will interchance as long as they are both 4.0 with the automatic aw4.

YellowSub2000
11-19-2009, 02:17 PM
Ok according to A1Cardone the 1987-1990 will interchance as long as they are both 4.0 with the automatic aw4.

Haha, I just got back from the local junk yard to post the same information. Number is 5300 5428 from 87 - 90.

AJ can you send me one of yours?