This issue has persisted since purchasing the vehicle. I turn the key to the start position and release while the engine cranks for the "timed" ignition sequence and vehicle does not start (most of the time). I turn the key a few seconds later (without the timed sequence, so I have to hold the key to "start") and vehicle fires right up within one second.

The engine has 100,000 miles on it (approximately) and is a 2008 3.7L I5 (with swapped reluctor wheel & camshaft sensor).

So far: re-grounded engine, new air filter, cleaner MAF sensor, cleaned throttle body, cleaned injectors, cleaned intake valves, cleaned O2 sensors, & replaced ignition switch housing (passlock system).

Here's a video depicting the issue and me describing it in greater detail. Any help is greatly appreciated! I am purchasing an Autel MK808 this weekend. If I am unable to solve this issue, I may bring it into a dealership service center for diagnosis.

 

Fuel pressure regulator not holding the prime. Try KOEO 2x, then check for start up.

 

I tried KOEO 2x about 5 times now and it has been hit and miss each time, as usual.

Is the fuel pressure regulator a part of the fuel pump assembly?

 

Yes it is. Fuel pump only runs a couple seconds during startup, yet if the prime is lost=no start, key on pump runs, x2 key off, key on pump runs, prime is back, ready to start. Cycle the pump twice, and crank on the 2nd to verify.

 

Another thing to check, crawl under by the fuel tank, with a clear nose, check for a fuel smell, reach above the tank with your fingers, touch everything you can up there, then sniff your fingers. Just like the old days when dating.

 

leaking fuel injectors also cause fuel pressure to bleed out.

 

Starting issue persists with trying this method several times.

I blew my nose and put my sniffer to work. I do not feel, see, or smell anything unusual (also good news in the good old days).

Leaking fuel injectors make sense, too.


I am going to try starting it with starting fluid through the intake the next several starts to see if the issue still occurs. If the issue ceases with starting fluid, I will at least know it is due to no fuel reaching the cylinders. If the issue persists with starting fluid, it must be a lack of spark or air during the initial "timed" start sequence. I with I had a recessed spark plug tester... I may order the tool kit with noid lights to also check the injector pulse.

Also, I purchased HPTuners. I am hoping to receive the tool in the mail by next week. The previous owner who did the 3.5L to 3.7L swap did not have the PCM tuned nor did a crank position relearn (to my knowledge). Someone suggested the possibility of it being related to a crank position sensor, and since this one is not "learned" by the PCM, I think it is super reasonable to think it could be related.

 

Did you perform fuel pressure leak down test?

 

I did do a fuel pressure leak down test. It was a few weeks ago, but I think it dropped 3-5 PSI in two minutes. While it didn't hold perfectly, I think the pressure loss is marginal and not the cause. I will do another leak down test to double check. The tester I used was not in good condition and leaked a bit of pressure out of the release valve the whole time (which likely was the cause of the 3-5 PSI loss).

 

Is Harbor Freight in Idaho? I would be concerned with any drop when considering your symptoms. Get a cheap tester, that doesn't leak and check for pressure drop, it should hold, if it does, eliminate fuel delivery from the list.