Mr.T

Maybe I mentioned this earlier, but using a spark tester while someone else turns the key is a good way tell whether there is spark or not. I have two or three three like this one: https://www.lislecorp.com/specialty-tools/spark-tester An old-school tool that's still very useful. The dimmer the light the better, especially when cranking -- Won't be able to see the light if well lit. About $10 to $15, small enough to carry all the time.

KClight01

Hey thanks, you did mention that before. I have an inline spark tester somewhere, but that looks like a handy tool! You just press against the coil wire? This would at least show me if it's getting spark or now, my guess is that it is not. Sounds like a test for next weekend.

Mr.T

Yep, just hold against a plug wire -- No batteries, reliable, but not bright.

KClight01

Another update, after learning that the Jeep did a "no crank" recently, I rechecked the battery and alternator and grounds. All tested good. I decided to go ahead and replace the starter with refurbished OEM. After replacing the starter, it started fast and strong on 3 starts, no delay. But on the 4th start after sitting warm for about 45 mins, it did the long crank again. I feel like it's been starting better but not enough to overcome whatever the main issue is. I still need to reverify fuel pressure after sitting to see if it keeps pressure to the fuel pump and then to the injectors, still no codes though and fuel trims look good. I also tested the plug wires using a spark tester, and it's getting good spark, which is good. I've been researching about the WCM, but I think that is good too because the red dot goes out. and starts fine most of the time, not sure if it can fail under the right conditions and cause any of my symptoms.

Mr.T

Are you using a scanner like JScan that can read the "enhanced" codes from all the modules?

KClight01

No, I am using a decent OB2 scanner that gives live data different component tests. Do you really think the "enhanced codes" would really help me figure out my issue?

Mr.T

Yep, the TIPM may have DTC's related to the problem and the typical low-end scanner only reads the standard data from the PCM. It's not that expensive, and you'll use it over the life of the Jeep. Check your existing scanner first and see what it's capable of.

KClight01

I am in a big debate with friend after replacing the starter. He now thinks it's an electrical issue. I switched gears and now think its fuel related. I think most of the main arguments have discussed on here. I am probably going to get the Jscan app, I need to get the obd2 connector. It's hard to say if it will give me any new information. Does it check the computer and sensors? Will it check voltage to the starter or relay or ASD relay, etc.? I doubt there are any codes for fuel pressure dropping off or leaky injector flooding the plugs. His biggest argument is that the Jeep starts right up every time after cycling the key (let it crank for split second and shut off, try again and it starts right up), if you go straight to crank for any wait time longer than 10 mins, it does the long crank. He thinks for some reason you have to "wake up" computer or starter. I NOW think it's probably due to a leaking injector or seal that only happens when hot, after 15 mins enough leaks to flood it, after some time it cools down, and acts normally until it heats up again. But the main problem with my theory is that, why would cycling the key for split second magically change the flooded or low-pressure condition? Even if the engine is losing pressure at the fuel pump, it seems like I could just let the pump prime first by turning the key to "run" so that the fuel pump kicks in for a couple seconds. But this is not the case, even if you try that, after sitting15 mins, it still does the long crank. But after going to START for a split second, then off, then it starts up immediately just like when it was new. I still plan to check fuel pressures at different times, thinking of just leaving the pressure gauge on for a day. I also plan to try adding a battery in parallel (as suggested) or a charger to give a little extra voltage to see if it makes a difference.

Mr.T

For the OBD connector, I'd highly recommend the OBDlink MX+. It has Internet updates, a free phone app that works on most vehicles, and it's compatible with most everything.

The DTC's cover a wide range of faults, every input sensor gets checked, often a variety of ways including wiring shorts to ground and power. Each module (computer) has internal self-checking, and communications are checked too. I did a quick search for low voltage codes and found them for the ABS and Dynamics sensor. There's a PID for voltage that could be graphed too. EDIT: There's also P0627 for a fault with the Fuel Pump Control Circuit, but it looks like this one lights up the check engine lamp.

Bottom line is that if there is an enhanced (proprietary) code it will probably save a lot of time, and graphing something like internal voltage during cranking might help too. If no help on this problem your out some bucks, but will still have a great tool that will eventually pay for itself many times over.

KClight01

Well, I ordered the obd2 connector and Jscan app and paid for the advanced features. Guess what, no codes, all systems checking good. While waiting for the obd2 connector, I checked grounds again and even ran an additional ground from the battery to the engine block, all checked good. Still, same symptoms, starts great first crank of day or if warm and sitting ~30 mins less, longer than that it does long extended crank. Then always starts immediately, if turn the key off then try again immediately. I have a voltage display thing that plugs in the cigarette lighter. So, I started watching the voltage before and during crank. The battery is at 12.5v and during long crank, it dropped to 10.8v, maybe just under 11v at the battery because there is a slight difference between the reading at the battery vs the voltage meter at the cigarette lighter. I'm not sure if any of this information is getting me any closer.

I did play around with Jscan and saw the option setting for the TIP start duration, it was default set to 10 seconds, which seems like a very long time to let the engine crank. I am considering of disabling it, so it does do the tip start at all, thinking that this would at least help me save the starter I just replaced. Any new ideas?