• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

99 Won't start.

O

OnorOffroad

NAXJA Forum User
Location
Enterprise, Alabama
Drove it around all week, parked it two nights ago and now it won't start. When I turn the key I don't hear the fuel pump. I checked the fuses under the dash and the engine bay. Everything looks normal. I've read in other threads that the CPS or the ASD relay are usually the culprits, but would either of those keep the fuel pump from priming?
 
Did a couple more checks.

1. no fuel at the rail. Makes sense as the pump is not priming.
2. Check engine light doesn't come on with key in and on, but check gauges does.
3. Voltage indicator doesn't budge with the key in and on.
4. Fuel indicator also does not come on with key in and on.
 
I tried to hotwire the Fuel pump but I don't know if I'm doing it correctly. Initially I disconnected the plug on the wire that runs from the pump. I then ran a 12V wire from the battery to that connector. I used one of the holes that had a thick red wire running from it. No joy. I ran a ground from one of the holes that had the black wire running from it and power. No joy.

Assuming I hotwired the pump correctly I'm thinking the pump isn't working. Seems pretty random for the pump to just FAIL without showing signs of failing. I drove the jeep home the other night and the following morning it wouldn't start.

Any insight on how to properly hotwire the pump? I'm really hoping it's just the CPS and that I didn't hotwire the pump wrong.
 
FUEL PUMP MODULE - BLACK 6 WAY CONNECTOR
PIN WIRE CIRCUIT FUNCTION
1 16DG/WT FUEL PUMP RELAY OUTPUT
2 not used
3 20DB/LG FUEL LEVEL SENSOR SIGNAL
4 20BR/YL SENSOR GROUND
5 not used​

6 16BK GROUND

so to hot wire the pump.
put 12 volts on pin 1, (the Dark Green with White stripe wire)
put pin 6 to ground (Black wire)

 
Gauges are not working. I did try to put it in neutral when I first started trouble shooting. Based on reading these boards I am going to try disconnecting the CPS to see if that brings back the gauges. I will probably hot wire the pump (properly) again to make sure the pump is working.

Thanks for the fuel pump module text based schematic!
 
Check fuse #11 in the passenger kick panel area.
Junctionblock.png
 
I checked that fuse yesterday, I think you posted that same schematic on another thread that I was reading. Today I went out and unplugged the CPS, turned the key in the ignition and all gauges worked as well as the check engine light etc. I'm going to replace the CPS. Will post if that gets the rig started.

Thanks for all the help.
 
When I replace sensors such as the TPS, IAC, CPS and C(K)PS; I recommend purchasing the OEM part.
Too many members have problems with the electrical aftermarket parts from autoparts stores...
 
I'd rather not buy from my local dealer. My XJ is an AUTO. I can't find any OEM on the mopar websites for an auto.. Does anyone know the P/N? Any recommended online stores?
 
Last edited:
I bought a BWD, I couldn't wait for it to ship as I need the Jeep for work. The new CPS worked, and the Jeep started right up. Another thread for the CPS culprit archives.

If it goes out again I'll buy the one from mopar.
 
You must log in or register to reply here.

Similar threads

Ecomike
87 Renix XJ No fuel, No brake lights, cranks fine
2
Replies
27
Views
862
Anak
Anak
J
Cranks, Fires, Dies - 1991 Briarwood Restoration
Replies
17
Views
3K
Jam Master Jay
J
W
1999 XJ - No start - PCM?
Replies
1
Views
2K
Tim_MN
Tim_MN
S
No Start No Bus
Replies
16
Views
3K
Rob Mayercik
R
S
98 XJ manual ignition problem
2
Replies
20
Views
4K
SurplusFan98
S
Back
Top