dvn11129

My wife and I both drive XJ's. Mine is a 93 and hers is a 97. She called me at work yesterday and told me she was driving and thought she may have run it out of gas. I left and brought her 5 gallons,but it still won't start. I work at a salvage yard, so I had it towed here so I can work on it easier.

So far, I have verified theres fuel at the schrader valve in the rail, replaced her dizzy cap,rotor,and spark plugs. Her rotor was so worn I actually got excited thinking I solved the problem. No dice however. I also pulled a plug and grounded it to confirm I was getting spark. I used a multimeter on the CPS and confirmed infinite resistance between pins B&C. I've tried cranking it over while holding the pedal all the way down, half down and all other combinations. I still can't get it to start.

When I let of the key after cranking for a bit, occasionally it runs very rough, sounds like it's idling around 50 rpm maybe. When it does this, It's sputtering,popping,and pouring smoke out of the throttle. The intake area smells strongly of gas as well.

Tomorrow, I'm going to rent a fuel pressure gauge and verify fuel pressure at the rail, hook up a scan tool and see if any sensors are reporting weirdly, and try to verify timing. I'm thinking I should be able to set cylinder one to TDC, and see if the marks on the crank are lined up. Is this correct?

Has anyone had a no start condition like this? Any thing to check I may be missing? It's her only vehicle, and since mine is a stick, I've been playing chauffer all day and missing a lot of work. Does this seem like a mechanical timing problem to you? Or is it possible something is telling the ECM to spark at the wrong time, hence the intake smoke? I'm really beating my head against a wall so all help or suggestions are appreciated. No codes are showing, but I will check for pending ones tomorrow. I get most parts free at my work, so I am able to swap sensors with other used ones to try it out before buying new ones.


EDIT: Forgot to mention, at one point when I was pulling the old plugs out, I had someone turn it over while I put my finger over each plug hole. All cylinders had compression, but I haven't measured how much yet. Also the old plugs were wet with gas. It almost acts flooded, but I tried pulling the fuel relay and cranking it a lot and it didn't change anything.

tjwalker

I think you're on the right track.

Job #1 is to test fuel pressure. For a 97, you need 49 psi, plus or minus 5 psi. Start there.

You mention you have spark, but how about spark "quality". You need a strong, blue, snapping spark to run properly. White/yellow/orange indicates a weak spark which won't cut it. Weak spark is most often caused by a failing ignition coil. The coil can be easily tested for both primary and secondary resistances with a meter and a manual.

If this happened all of a sudden while she was driving, the problem is not likely compression but if you want to test that, it's easy enough. Spec is 1200-150 with no more than a 30 psi variation between cylinders.

Yup, definitely check for any pending codes.

Good luck and let us know how it goes!

dvn11129

Small update. I had 30 minutes or so after work to try and figure it out. I tried using starting fluid again and of course it was futile. I thought maybe the temperature sensor could be telling the ECM to dump fuel in so I unplugged it thinking it may work on just the base tune. I unplugged the CPS, cycled the key then plugged it in. Also no such luck. Before I left I pulled the CELs. I managed to trip a few trying things. They were 11 12 23 42 and 43. The only ones I don't believe I caused unplugging things are codes 42 and 43. Perhaps 42 but I won't know until I reset the codes tomorrow and see if it pops up again. The code 42 is the most curious to me. I did swap some relays yesterday but I'm not sure if the was one or not. I had the impression that problems with the ASD relay result in no spark/no fuel. However I have both. Should I research this more, or wait and see if it pops up again in the morning?

dvn11129

Forgot to add that I called the person watching for spark while I cranked and they said it sparked bright white. I'll probably toss a coil in, but I don't think k that's the whole cause.

tjwalker

Do one thing at a time so you know what the root cause is. If the XJ was running fine and then stopped out of the blue, it's likely one thing.

Before replacing any component, test fuel pressure. Something like a ruptured fuel pressure regulator is in play here. Turn the key on/off a couple of times to fully prime the fuel rail. Test pressure before you try to start. If the engine starts, continue to monitor and track fuel pressure. 49 psi, plus or minus 5 psi is your target here.

As for codes, you have a 97 so with a scan tool or a code reader, you should be able to full the FULL code, like P0123, etc. The full codes are much more valuable in troubleshooting than the 2 digit codes are. Post up the full codes for comment.

Good luck!

dvn11129

Well I left my keys at home to my work, and my scan tool is locked in.

I​​​​​​ did borrow a fuel pressure tester from my buddy and it's reading solid at 45 psi. Close enough to 49 I'm thinking.

​​​​​​At this point, I'm going to throw a few more gallons in, and maybe it's a volume problem and she did simply run it out. If it ends up being that, I'm going to require her to keep a spare jug in her jeep at all times. This would be the 3rd time she's run it out.

If this doesn't work, anywhere else to look or am I SOL until I get my scan tool. She has to go to work soon so I'll be watching our kiddos the rest of the day. And waking them up at midnight to pick her up. Ugh.

dvn11129

Ok, I added more gas and predictably it still did not start. I was more stabbing in the dark with that anyways.
​​​​​​
I confirmed all fuses again, swapped relays, and check for wiring breaks with an OHM meter. Everything checked good.

I unplugged the battery to reset codes and got codes 11 12 and 42 again. I realize these aren't nearly as helpful as the p codes a scanner would give, and I'm going to pull those tomorrow.

Has anyone had a bad CPS still give spark? Most of what I've read seems like it causes a no spark condition. Mine Sparks, but since it pops out of the intake, I'm wondering if the CPS being faulty is telling the computer to fire at the wrong time.

I couldn't do too much today without my keys since my tool box key is also on that key ring. Tomorrow I'll be sure I have them. Working an hour away sucks sometimes.

​​Although with the OHM meter I suppose I still eliminated quite a few possible causes today.

tjwalker

*Code 11 can be related to the camshaft position sensor, located inside the distributor. It can be tested with a meter and a manual.

*Your crankshaft position sensor is still in play here too; can't completely trust your test results.

*And if spark is white, don't eliminate the ignition coil yet either and that is easy to test or swap.

My gut feel is that your issue may be a cam or crank sensor but you really need the full codes as these 2 digit codes are somewhat generic and can be a bit misleading. The full PXXXX digit codes are the ones to research and chase.

Post up the full codes and be ready to do some more testing.

caged

even with all the info posted, i would agree with the crank position sensor on the back of the engine.

jeeps are a simple machine, and the cps is a very common issue.

i would try that next.

dvn11129

Alright guys, I want to thank you for all your help.

She's alive finally!! The ignition coil was indeed bad, but good enough to still cause a spark, yet not strong enough to fire as was mentioned.

I hate people who don't update with a solution on there posts so if anyone else has a problem with similar symptoms, check your coil!

I guess now I should stick around and try to help others here. What a wonderful forum. Thank you.

tjwalker

Good to hear that it's running again and that I could help.

Another happy Cherokee Forum ending!