99 TJ 4.0 won’t start

[MeanMomma]

Jeep Wrangler Sport 4.0 1999

Hey guys and gals, my hubby has always been able to fix anything... but this time he’s stuck!!
Please help him brainstorm this issue. We are supposed to go out with our kids on Thursday, that might not happen. (Yikes)
No codes come up. But the Jeep won’t start. It tries to turn over, and we can smell faint gas scent. He's already replaced the relay, new distributor, new coil, new crank position sensor, removed after market alarm system. He had it running for a few minutes but it sounded as if it was only running on two cylinders. He's gone through all of the wiring looking for shorts because at one point he was blowing fuse 18... but that does not seem to be happening any more.
My husband is handy, but he’s stuck and discouraged. I know it’s Valentine’s Day... but if you have any ideas on a repair we would appreciate it! Thank you for your time.

Adding: any chance that this is a PCM issue? Thoughts?

 

[never monday]

What is the fuel pressure?
Is he getting spark?
Any codes in the ecu?

 

[MeanMomma]

No codes, and yes spark. Needs to buy a fuel pressure gauge I guess.

 

[never monday]

You can rent/borrow them at the chain parts stores

 

[MeanMomma]

He probably knows that... but I'm clueless. Thank you for trying to help us!

 

[qslim]

Fuel pressure is always a good thing to verify. You need fuel, air, spark, & compression (timing) to make it work.

Did this happen out of the blue or it is an intermittent thing that's been getting progressively worse?

 

[MeanMomma]

Good question. First time it happened as I was driving down the road... no warning. Towed it home and husband replaced the crank position sensor, ignition coil, ignition switch, spark plugs and spark plug wires. It was not until he replaced the ignition switch that he created spark that time. It drove fine for a few months, then it broke down on a trail. Husband has worked on it off and on for the last 6 weeks. No luck. This time he's replaced the distributor and once again the crank position sensor.

 

[qslim]

Good question. First time it happened as I was driving down the road... no warning. Towed it home and husband replaced the crank position sensor, ignition coil, ignition switch, spark plugs and spark plug wires. It was not until he replaced the ignition switch that he created spark that time. It drove fine for a few months, then it broke down on a trail. Husband has worked on it off and on for the last 6 weeks. No luck. This time he's replaced the distributor and once again the crank position sensor.

What brand crank position sensor? The OEM units are hard to find these days, but some of the aftermarket units are apparently garbage. I don't know which ones because I've been fortunate enough to have not had to deal with that failure so far, but @Jerry Bransford probably knows.

 

[MeanMomma]

Husband has been buying the OEM units at Autozone. If somebody can steer us to something better that will solve this frustrating issue we would be thrilled!

 

[never monday]

You can test a CPS by putting a volt meter across the terminals and waving a screwdriver in front of the tip. It should generate some voltage.

 

[MeanMomma]

Interesting... he didn't know that. Thank you.

 

[Modoc Guy]

If it’s getting spark, and he set the timing correctly when he replaced the distributor, I’d try shooting a little starting fluid into the intake.

If it tries to fire with the starting fluid, you might be looking at a fuel issue. Then I’d check fuel pressure, no pressure then it’s probably a bad fuel pump.

If it doesn’t want to fire with starting fluid, then I’d re-check the ignition.

Double check ignition timing. Having spark with the timing off will not allow the engine to start. Maybe pop and backfire, but not start.

 

[Jerry Bransford]

Husband has been buying the OEM units at Autozone. If somebody can steer us to something better that will solve this frustrating issue we would be thrilled!

Keep in mind that the phrase OEM Replacement that stores like Autozone use does not mean the part is the exact part the factory installed. It just means it will fit where the OEM part fit but it will not be the exact same brand and model the factory installed.

Autozone's Duralast brand is probably the worst of the bunch of aftermarket sensor brands. Where sensors are concerned you really want to try to find a Mopar replacement. Or at least steer away from low-end auto parts stores like Autozone. If I needed a critical part like a sensor and couldn't wait for it to be UPS'd I'd probably go to NAPA and request their best quality. Or see if your local Jeep dealership's parts department is open and try them.

Sensors are critical components and it pays to do your best to only install top quality replacements.

 

[MeanMomma]

Update, rented the fuel pressure gauge, and the results show pressure 49 psi, we do have spark, it tries to start up, but it can't do the deed. Throwing code 1391. Just replaced CPS once again.

 

[never monday]

Google
https://autoservicecosts.com/obd2-codes/p1391/
verify all connections with the dist and crank sensor.
verfy the dist is in time