'01 XJ Hard Start Issue

[Bullitt4113]

I posted about this a few days after I bought the truck, but since I've owned it for about a month now, I've gathered some more info. I am having a hard start issue that is very odd. When I wake up first thing in the morning to go to the gym, it fires up first shot pretty quickly with no issues. The gym is only a half mile away so the truck definitely doesn't get hot by the time I get there. When I leave the gym, it always takes 5-10 seconds for it to crank over. I come home, shower, eat, and leave for work, and same thing happens. Throughout the rest of the day, every time I start it, I experience the same issue where it takes a long time to start.

I was led to believe that it was the check valve in the tank, but today I finally got a chance to throw a fuel pressure gauge on the rail, and as soon as I turn the key, it goes up to 45 psi, no problem. I repeated the test with the car completely cold, and with it warmed up...same result.

Now I'm not sure where to start diagnosing this problem. I've done a lot of reading, but nobody seems to have the same issue. Thoughts?

[CntStpTheStnk06]

my 03 wrangler does this if i just start it and move it a short distance.. it is not always my daily so i will move in in the am to get a car out and if i start it later it does the same thing...... cranks a little longer but then fires up..... it has never not started so i just figured it was normal..... interested in seeing what other people have to say as well!

[Ruepart Hoaxley]

My 99 XJ did this as well, stopped doing it after swapping a new starter in (the hard starts not being the problem I was fixing at the time). Maybe unrelated, but it worked.

[Hudson]

While there are a few possibilities, one of the first things to consider is a faulty "coolant temp sensor". Located on the thermostat housing for your 01.

It provides input on temperature to the computer, which then can decide on the proper mixture, etc. for a quick start. What the computer decides on for a cold engine is a lot different than a hot engine.

The CTS can be tested, but testing is kind of a PITA. Refer to a service manual for more information, or many guys just swap them out as they aren't that expensive.

[Bullitt4113]

While there are a few possibilities, one of the first things to consider is a faulty "coolant temp sensor". Located on the thermostat housing for your 01.

It provides input on temperature to the computer, which then can decide on the proper mixture, etc. for a quick start. What the computer decides on for a cold engine is a lot different than a hot engine.

The CTS can be tested, but testing is kind of a PITA. Refer to a service manual for more information, or many guys just swap them out as they aren't that expensive.

Great thought, cheap and easy. Although it looks as if the one I have in there is new, or at least fairly new, I'll probably go ahead and change it and see whats what. I also talked to Drew (Jeep Creep) over at Napa yesterday and he suggested the crank sensor. I may try that as well.

[justtorchit]

Great thought, cheap and easy. Although it looks as if the one I have in there is new, or at least fairly new, I'll probably go ahead and change it and see whats what. I also talked to Drew (Jeep Creep) over at Napa yesterday and he suggested the crank sensor. I may try that as well.

i dont think its a crank sensor because it just wouldnt start..... coolant temp sensor i doubt aswell, that shouldnt effect the time it takes to start the engine.

try priming the fuel pump by turning the key on and off a few times before you crank it over.

[Bullitt4113]

i dont think its a crank sensor because it just wouldnt start..... coolant temp sensor i doubt aswell, that shouldnt effect the time it takes to start the engine.

try priming the fuel pump by turning the key on and off a few times before you crank it over.

I've tried that at least 100 times and it makes no difference. Also, this weekend and yesterday I was away on a business trip and I fired it up this morning and it took half a second. It's like the longer it sits the quicker it starts. I don't get it...

[1cleantj]

once it fires up , does it idle or run rough for a few seconds ?

[Bullitt4113]

once it fires up , does it idle or run rough for a few seconds ?

Yes, I've noticed that as well. Probably for about 7-10 seconds, then it runs flawless.

[Bullitt4113]

UPDATE: Very weird, it seems as if the longer the car sits, the easier it is to start. I was away at a conference for work again Monday and Tuesday, and when I fired the truck up Wednesday morning for work, it fired IMMEDIATELY! Thoughts?

[Bullitt4113]

UPDATE: Got a check engine light this morning, pulled codes and I have P0118 and P0301. I know the first one is the coolant temp sensor, that's because the plug clip is broken and if I bump into it (which I did with the wrench tightening the belt tension) it sends a CEL, but the P0301 (CYL 1 Misfire) doesn't make much sense, EXCEPT for the fact that the truck has had a hard time starting as mentioned in this thread.

CPS??? I read in another thread they are related. Thoughts?