2005 4.0 auto sputtering at start up

[MrUnderhill]

Hi, still trying to figure out why my 2005 jeep wrangler TJ 4.0 auto. has a rough idle at start up.

situation. i drive 15-20 min to publix. then get in my jeep , start it up and it starts to sputter , like the engine wants to die. i just quickly give it gas and go. no issues after that. i can always replicate it. just needs to be a hot start. so never an issue in the morning on cold starts.

i did get the p0300 error code. but then it resolved itself. and check engine light disappeared.

i searched the forum and found similar situations and replaced the cam shaft sensor. didnt fix it. so took to shop and they said it needed the ignition coil replaced. so replaced it. not much, under $300. but the problem is still there


the shop did recommend i put in champion spark plugs. i just put in denso about a month ago. but i declined

rather than go back and get into an argument with the shop. just gonna chalk up the $300 loss and move on. so i am looking for a trusted mechanic in central florida. thanks

 

[Chris]

Could very well be a wiring issue (a short in the wiring somewhere). It could be a lot of things actually. Your going to need someone with a live diagnostic scanner so they can see what the engine is doing in real time.

As for finding a trustworthy mechanic, good luck! They're harder and harder to come by these days and I don't know any at all in Florida. This is why so many of us work on our Jeeps ourselves as much as possible. I know that isn't a good answer, but it really is getting damn near impossible these days to find trustworthy mechanics.

 

[macleanflood]

What's your fuel pressure?

-Mac

 

[MrUnderhill]

What's your fuel pressure?

-Mac

havent checked as i do not have a fuel pressure gauge. this is why i prefer a trusted mechanic. i doubt the previous shop did this.

 

[macleanflood]

Here's the adapter you need to add either a Schrader valve or a gauge to the fuel rail. I added a gauge. It's useful on a 25 year old vehicle to check fuel pressure at a glance.

https://www.racetronix.biz/p/adapter-qdf-5-16qdm-5-16-1-8-port/qda-56f56mp

-Mac

 

[JKP]

What Denso plug?

Factory plug would be NGK.

 

[TJ Jim]

Have you got the heat shield wraps around your injectors? Blocking the heat coming off the header?

 

[TJ Jim]

 

[MrUnderhill]

View attachment 653871

i will upload a pic tomorrow

 

[MrUnderhill]

Have you got the heat shield wraps around your injectors? Blocking the heat coming off the header?

 

[TJ Jim]

I think I’d start with wrapping those injectors. Especially number three. You’re about halfway covered with the exhaust barriers but no injector covers. Cheap place to start. Mine will vapor lock on really hot days even with those covered did it one time year before last.

 

[MrUnderhill]

replaced ignition coil. still having the same problem. however, a new issue arose while driving from orlando to tampa

I had been driving for about 2 hours. As i was sitting at a red light, i felt the engine start to sputter. so i put it in neutral and rev'd it up to 2000 rpms. held it there for 10-15 sec. left off. then repeated. did this numerous times. then put in drive and took off.

then as im driving, i hear a ding and look at the dash and my gas gauge dropped to empty(it was half full) and CEL popped up.

took it to a shop in Holiday FL. they drove it for a few days. tried every combo, couldnt replicate the sputtering

but these are the codes they pulled

lost comm with security system U0168

batt temp sensor low p0516

fuel level sensor p0462

multiple cylinder misfire p0300

i am taking it to one more shop, owner has a TJ. i will have him fix the possible heat soak issue. after that, if no fix, im selling

 

[ItchyDong]

replaced ignition coil. still having the same problem. however, a new issue arose while driving from orlando to tampa

I had been driving for about 2 hours. As i was sitting at a red light, i felt the engine start to sputter. so i put it in neutral and rev'd it up to 2000 rpms. held it there for 10-15 sec. left off. then repeated. did this numerous times. then put in drive and took off.

then as im driving, i hear a ding and look at the dash and my gas gauge dropped to empty(it was half full) and CEL popped up.

took it to a shop in Holiday FL. they drove it for a few days. tried every combo, couldnt replicate the sputtering

but these are the codes they pulled

lost comm with security system U0168

batt temp sensor low p0516

fuel level sensor p0462

multiple cylinder misfire p0300

i am taking it to one more shop, owner has a TJ. i will have him fix the possible heat soak issue. after that, if no fix, im selling

Listen… wrap your injectors and thank @TJ Jim later. Wrap it per the TSB that’s out there. Summit sells the actual product you need. I’ll look for it and post it for you.

 

[ItchyDong]

https://www.scribd.com/document/489346372/Jeep-TSB-18-031-03

https://www.summitracing.com/parts/...itPOvks7rn28sZ9MWQndsmh6xMyWfuwdJuP5ABxqN4TDB

You’ll be a happy man.

 

[MikeE024]

replaced ignition coil. still having the same problem. however, a new issue arose while driving from orlando to tampa

I had been driving for about 2 hours. As i was sitting at a red light, i felt the engine start to sputter. so i put it in neutral and rev'd it up to 2000 rpms. held it there for 10-15 sec. left off. then repeated. did this numerous times. then put in drive and took off.

then as im driving, i hear a ding and look at the dash and my gas gauge dropped to empty(it was half full) and CEL popped up.

took it to a shop in Holiday FL. they drove it for a few days. tried every combo, couldnt replicate the sputtering

but these are the codes they pulled

lost comm with security system U0168

batt temp sensor low p0516

fuel level sensor p0462

multiple cylinder misfire p0300

i am taking it to one more shop, owner has a TJ. i will have him fix the possible heat soak issue. after that, if no fix, im selling

Consider the below information before you potentially waste money having a shop chase an issue that might not be heat soak (even though it looks like one).

I had had similar hot idle problems with my 2005, and all the normal ideas about wrapping the injectors and fuel rail didn't fix my issue (#3 injector is still triple wrapped and clocked (per the TSB)). I even wrapped the fuel line that comes off the frame near the cats, wrapped the exhaust, and added a hood louver. Didn't solve it.

My issues were almost always while sitting at an intersection with a warmed up engine. Revving the engine in place was the only way to calm it down. To be clear, this wasn't just a random hot start problem...it was an idling after stopping at an intersection problem.

The fix was installing a @Wranglerfix PCM over two years ago, and I never looked back. I'd talk with Mark about this, especially since you are getting codes for many different systems in addition to the issues I had.

 

[Link]

Usually the bad PCM will start with oxygen sensor heater circuit codes. But, lots of random codes are also a hint you have a failing PCM. My 2005 has a WranglerFix PCM now and working great

 

[Link]

I used to get an occasional cylinder 3 misfire code. Wrapped the #3 injector per the spec and then added a new aftermarket cover over the fuel rail and also wrapped the fuel line where it passes near the pre cats