1999 XJ is getting the best of me. No Start.

[Pete]

Hi All,
Pete here, Im new to the board and in search of answers I hope because this one is driving me nuts. Here is the back story, last night my daughters called saying her (younger daughter) jeep steering wheel is locked and they cannot turn the key. I told them to turn the steering wheel in the direction the wheels are facing then turn the key at the same time, That got the wheel unlocked now they told me the jeep will not start, but it cranks. Ok so I jumped into action grabbed some tools and items and off I went. When I got there I tried to start it and they were right all it did was crank. It cranked over as normal. I checked under the hood and looked at what was going on. I first checked the ignition coil wire because that bit me on another jeep a few months back. while checking it I got a zap so I figured we have spark so onto the fuel system. I checked the srader valve on the fuel rail and it just dripped. I removed the intake air hose and gave it some starting fluid and after a few times it started. It sounded ok so I drove it home and my older daughter drove my truck home with my younger daughter driving her sisters 2018 cherokee. All the way home (about 10 miles) it drove and accelerated fine. I did not try to shut it down and restart it at this point incase it did not start. When we got home I checked the fuel pressure with my gauge and it was only about 41-41 psi running and would drop off real quick once it shut down. We shut it down and waited a minuite and tried to restart it. was having a hard time restarting but did restart twice after holding the pedal down a little. but no more after that. time for bed it was after 11 pm.

Here is some more info on this jeep, it is a 1999 XJ sport, 4.0, 4 wheel drive, automatic. The Jeep has 295,00 miles on it and has been pretty trouble free, its pretty rust free other than a-little under the passenger side floor and of course it is purple....we have owned it since 2003. My wife has delivered mail in for a while and all 4 of our daughter have learned to drive with it. Overall I consider myself pretty knowledgable when it comes to troubleshooting or fixing this jeep.

So for today drama, since I had low fuel pressure and the quick drain off and 300k on the original pump I was pretty sure (Never assume) it was a fuel pump, it also had a fuel gauge that would stick sometimes. I have a wrecked 2000 XJ that runs and has been my go to parts car for awhile so I decided to just swap fuel tanks from one jeep to the other. this was easy and took about an hour, when I was done I checked the pump cycle and let it prime a couple of times and I was reading 50 psi at the rail. however my happiness was short lived because it did not start just cranked again. So back to the drawing board. I reinstalled the tank from the 99 into the 2000 and it started right up, so much for the pump/reg valve. I then hooked up my scan tool and the jeep had no codes, I did notice no rpm when checking live data so now I'm thinking PCM, CPS. First I checked the fuses and swapped around all relays, no joy still just cranks, has good fuel pressure. next I swapped the pcm around still no starting, put the pcm into the 2000 and it starts, so I dont think it is the pcm, now it getting bad I checked the CPS and was reading 545 omes so I swapped the CPS and still nothing. I checked under cap changed the rotors and pick up nothing changed a coil and still no spark. I do not have a check engine light on, the gauges seem to be responding, I tried to start from neutral and still nothing. Check visually wiring connections all look good until this happened it was running fine. One other item i did change the started, NSS and battery out about 4 months ago. So at this point it is time to sit down and talk to jack, jim and old grandad for any new guidance..... I'm sure this will turn out to be any easy fix and then I'll say why didn't I think of that and any ideas are welcome.

We are a jeep family, wife drives a Gladiator, Daughter 1 had a Cherokee, daughter 2 has a Wrangler Unlimited, daughter 3 has a TJ and Daughter 4 is driving my XJ while I finish building/rebuilding a TJ just for her so then I can get my XJ back, I love this old jeep!! I know a little long winded but had to try and get everything in.

Thanks
Pete
Chesapeake VA

 

[Saudade]

Pull a plug and visually check for spark. Got spark? Then spray some starter fluid down the TB and crank it. Does it fire up? This should help determine if it's a fuel or spark issue.

With the key on (Run, not Start), check for 12v at each injector. Each one should read battery voltage. The injectors ground through the PCM. If no 12v, check Fuse #21 in the PDC.

 

[Tim_MN]

Got bight blue and snapping spark, or a weak yellowish spark?

Cranking and not starting usually is a faulty Crankshaft Position Sensor. If you are swapping them around test all of them.

I have had corroded wire plug pins, bent/pushed back wire plug pins, failed wire splices near the throttle body, loose relay socket contacts, bad fuses, and internally corroded wires cause a no-start. I have also had the magnet break loose from the Cam Pickup Sensor in the distributor. Clean, check, and snug all the grounds.

One time the fuel pump relay socket had one terminal break loose. The XJ would run fine for days on end and then just die. Sometimes it would restart, sometimes it wouldn't. After lots of checking and poking at things, I noticed the loose relay contact. I put some 5 minute epoxy on the underside of the PDC socket for that relay, and that fixed that.

 

[Pete]

Thanks all, with the work I did today I still/do not have any spark, I checked with the spark plug out and even tried the spark plug on the coil wire with no spark. Changed the coil wire same, i did check all underhood fuese and they were good. In the morning i will check the ones inside. I also disconnected the battery for now to see if that does anything.
Wish me luck!

 

[lawsoncl]

I'd bet crank sensor. They die either of two ways. They either get weak and low rpm resulting in a hard or poor start, or the cut out when they get hot.

 

[Pete]

I agree but i changed it out with a known good one and then put the one i removed on my parts jeep and it started right up. this is why I'm so fustrated at it.

 

[lawsoncl]

Possibly the camshaft sensor?

 

[75SV1]

Possibly the camshaft sensor?

Also, check the distributor shaft for play. It should have one .001 play. Also, I'd suspect the coil. Coils can be intermittent. I did have the ignition key electronic board go out on my 2000 XJ.

 

[Pete]

Good morning, So this morning so far I checked the following. The battery was left disconnected overnight. Checked all inside (kick panel) fuse are good, took each one out and put it back did not see any corrosion. Next check voltage at/going into the coil, I got 12 volts for a second then it dropped off key on, same while cranking. Then I checked No.1 injector for voltage I also got 11.8/12 volts constant. Still no start, just cranking, FP is still at 49/50. I had a PCM from a 1998 XJ so I tried it in case the 2000 PCM with coil packs had something different, still no fire. So right now I'm thinking the wiring is doing what it is suppose to do and I think I down to a bad coil or a bad ground? I will re-check and test some other connections first. Yesterday i did check the distributor shaft and it is turning and the shaft did not seem to have any play. Thanks again!