Jeep cranks, but won't start. I've tried many of the typical things.

[JasterMereel42]

About a week ago, I drove the TJ to work. When I left work that day, it wouldn't start. It would crank, but wouldn't actually start. The only indication I had before this was that morning, it took about 2-3 seconds to finally start. Prior to that, no real issues. Luckily, I had a coworker that has a TJ and more experience than me. Here is what we tried and have eliminated. Oh, this is a 2000 so it has fuel injection instead of a distributor.

• Battery is good
• Alternator is good
• Starter is good
• There is fuel getting to the fuel rail (pressed the Schrader valve and fuel came out)
• Checked the fuses and the relays in the engine bay fuse box and all of the fuses and relays are good. Swapped a bunch of relays and fuses around and they all work.
• Disconnected the PCM for about a minute and reconnected it

The other guy that owned a TJ said that the only weird thing that he noticed was that the INJECT fuse was not getting power. The fuse was good, but it wasn't getting power.

I got the Jeep towed home and pushed it into my garage. Since then, I have hooked it up a scan tool to it and it didn't return any codes. I also got a replacement crankshaft position sensor and still had the same problem.

Right now, it seems to be a very narrow potential issues: fuel pump is bad, PCM is bad, or something is going on with the ignition system.

Any recommendations on what to test next and how to test it?

 

[JKP]

Spray some starting fluid in the throttle body. If it runs on that, you def have a fuel problem.

 

[B1Toad]

Have you tried a Noid light to see if the injectors are firing?

 

[JKP]

Also, did you swap out the ASD with a known good one? Verify horn works then swap it to ASD.

 

[JasterMereel42]

Also, did you swap out the ASD with a known good one? Verify horn works then swap it to ASD.

Yep, did that.

 

[JKP]

Well, I'm pretty sure the ASD supplies 12 V to the injectors, so I'd take a look at the wiring. The PCM pulses the injector ground.

 

[KennethS]

Oh, this is a 2000 so it has fuel injection instead of a distributor.

I am not sure what you mean by this.

 

[TheManWithNoName]

I am not sure what you mean by this.

Yes OP. To clarify, the TJ was never produced with a carburetor. From 1997–1999, TJs used a distributor-based ignition system. Starting in 2000, Jeep switched them to a coil pack ignition system.

 

[TheManWithNoName]

OP, an engine is a simple machine. It needs fuel, spark, and air. It sounds like you have fuel and air. Assuming you’re actually getting fuel, the next step is to check if you’re getting spark.

 

[Rickyd]

I am not sure what you mean by this.

It means someone else should probably be working on it.

O.P. use starting fluid as advised. It is an easy first step with diagnostics

 

[JasterMereel42]

It means someone else should probably be working on it.

O.P. use starting fluid as advised. It is an easy first step with diagnostics

You're absolutely correct that I shouldn't be working on it. There is no opportunity for me to learn from this situation.

 

[JasterMereel42]

Spray some starting fluid in the throttle body. If it runs on that, you def have a fuel problem.

Alright, I'll try that when I get a chance.

 

[JasterMereel42]

Have you tried a Noid light to see if the injectors are firing?

I'll add that to the list of things to try soon.

 

[JasterMereel42]

Yes OP. To clarify, the TJ was never produced with a carburetor. From 1997–1999, TJs used a distributor-based ignition system. Starting in 2000, Jeep switched them to a coil pack ignition system.

Thanks for that clarification.

 

[JasterMereel42]

Have you tried a Noid light to see if the injectors are firing?

Just tried noid lights and they are not lighting up indicating that the injectors are not firing. This also tracks when my coworker was saying that the INJECT fuse wasn't getting power whenever I would crank the engine.

 

[JasterMereel42]

Alright, results from testing this weekend.

• Noid lights are blank so it indicates that the fuel injectors are not firing.
• Fuel pressure test showed that the fuel is at about 45psi. So, fuel pump is good. I let out all the fuel pressure from the Schrader valve and kept priming the fuel pump until it hit the 45psi reading.
• I sprayed some starter fluid into the intake. There definitely was combustion going on, but it wouldn't fully fire. This is better than before where it would crank, but wouldn't start.

It it is looking like there isn't a signal being sent to the fuel injectors to fire. I know the PCM is still the prime suspect. What are some other things that I could check?

 

[JKP]

Pull up the FSM for your yr under Resources. The cam sensor is used to time the injectors. On my 06, it will default to batch firing the injectors with no cam sensor input, but I believe the older ones don't.

 

[JasterMereel42]

Pull up the FSM for your yr under Resources. The cam sensor is used to time the injectors. On my 06, it will default to batch firing the injectors with no cam sensor input, but I believe the older ones don't.

I already replaced the camshaft position sensor and still have the same problem.

 

[JKP]

Time to talk to wranglerfix about the PCM.

 

[JasterMereel42]

Time to talk to wranglerfix about the PCM.

I already emailed them on Friday.