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raw fuel in intake manifold/rough start after sitting

i ordered the 4 of them, figured for the rockauto price of 4 was a tad bit more than oriely price on the two and i can return the two still hell why not. highly HIGHLY doubt its gonna resolve anything but its the thought that counts.

theres no way in hell my cats are plugged. I have ZERO symptoms of this.

the replacement injector should arrive today or tomorrow, gonna throw that in(currently running five 784's and one OE cant be a good thing) and then shes got another date with a different shop monday, gonna leave her overnight on sun, that says its $90 for a diao but free if they dont find whats wrong, they "will" find it though haha.
 
87manche said:
the NTK ones are good stuff. Bosch seems ot be the same china crap everyone else is selling marked up with a fancy box.

I'd suspect that you've got an injector that's leaking if you've got puddles after it sits.
Click to expand...

that was my original thought and that one i replaced seemed to have been leaking. but now ive deduced that if the heep is warm, like even from sitting in our current hot sunny weather, it doesnt seem to do the rough start.

possibly a vacuum leak that once the heat causes expansion it seals? that'd give the lean fuel symptom and trigger the comp to dump fuel would it not? i checked all the top bolts on my intake mani and all are tight but i don't have the tools for the unders with without disassembling all kinds of stuff :( thatd piss me off it its all it is haha but at this point id probably hug the mechanic haha
 
A vacuum leak large enough to screw up the computers fueling should also cause a ridiculous high idle situation. It would be massive.

Have you investigated the MAP sensor? it's speed/density, so if the computer isn't getting the right density measurement it will not give the right fuel map.

Check the vacuum hose going to that thoroughly. I just had an off idle stumble that was a tiny cut in the rubber boot. Wen the motor rocked accelerating from a standing stop it would stumble because the crack opened up.

http://troubleshootmyvehicle.com/jeep/4.0L/map-sensor-diagnostic-tests-1#4

a vacuum pump and a multimeter is what you need to test it.
 
If you did indeed have puddles in the intake manifold, you probably had puddles in cylinder(s), and gas build-up in the exhaust /cat as well. When firing up the engine, the gas in the exhaust would ignite and could melt a cat. When I first installed the stroker, the pcm had to relearn the fuel trims with the 24#ers. A 6 month old magnaflow cat melted in the process.
 
87manche said:
A vacuum leak large enough to screw up the computers fueling should also cause a ridiculous high idle situation. It would be massive.

Have you investigated the MAP sensor? it's speed/density, so if the computer isn't getting the right density measurement it will not give the right fuel map.

Check the vacuum hose going to that thoroughly. I just had an off idle stumble that was a tiny cut in the rubber boot. Wen the motor rocked accelerating from a standing stop it would stumble because the crack opened up.

http://troubleshootmyvehicle.com/jeep/4.0L/map-sensor-diagnostic-tests-1#4

a vacuum pump and a multimeter is what you need to test it.
Click to expand...

ill check this out, i have a meter and it says u can use your lungs as a vacuum haha. still got those

gradon said:
If you did indeed have puddles in the intake manifold, you probably had puddles in cylinder(s), and gas build-up in the exhaust /cat as well. When firing up the engine, the gas in the exhaust would ignite and could melt a cat. When I first installed the stroker, the pcm had to relearn the fuel trims with the 24#ers. A 6 month old magnaflow cat melted in the process.
Click to expand...

there did seen to be an oddly large amount. i know ive had that tb off in the past and iirc it was dry in there and most definitely did
not give off that STRONG odor that it did upon removal this time. interesting note here is when i flash my pcm it doesnt do it for the next few days, which annoyingly results in me thinking ive fixed it haha. I figure it IS doing it its just the system is ignoring whats going on and powering thru it
 
raw unburned fuel from a misfire will show up as a false lean mixture and cause the PCM to run the engine rich, which compounds the problem
 
well the shop called me and said the motor mounts needed to be replaced... :) to which i informed him they were brand new. he called me back to say its cause they are solid and not rubber, to which i informed him that i payed the extra for the rubber :)

but it got me thinking about why i got new mounts, to avoid cracking my new headers which got me looking into what a cracked header does. tapping sound, check(only after that rough start for a bit), loss of mpg(i was a avg 15 now its like high 14.xx), check, false lean mixture(thats what one dudes got off their comp), check, exhaust smell(i noted this previously), check...

hmmmmmmmmmm i called then and informed them of my thinking
 
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Are you saying that your Jeep is still at the shop that called you twice about the motor mounts as per your first line above? Rhetorical question....
 
yea i wont be able to go get it till like 5. his "guy" said its the motor mounts, I told then they were new and he said he'd talk to his guy and call me back, which he did with the claim that its cause they are solid not rubber to which i corrected him, reminded him that if i flash the pcm it wont do it for a few days and how the would flashing a pcm clear up a motor mount issue. I mean only doing it cold, olay i guess maybe it could heat up and secure better due to expansion but naw, not likely. it is most certainly not the motor mounts so he said they check some more things out and get back to me. i then looked into symptoms of a cracked mani(why my brand new banks tubes would crack is beyond me but hey anything possible or maybe its the down pipe) called him and mentioned its worth looking into
 
you could just unplug the upstream o2s. Yes, it will set a code, but it should just default to open loop fuel map.

easy way to diagnose your theory that a cracked manifold is freaking the PCM.
 
no, as in unplug the o2 sensors and force the PCM to run in open loop.

and the shop it's at sounds like they suck. Even the most basic OBD reader should allow them to pull fuel trims and o2 sensor readings.
 
87manche said:
and the shop it's at sounds like they suck. Even the most basic OBD reader should allow them to pull fuel trims and o2 sensor readings.
Click to expand...

naw they're alright. so it in fact was my motor mounts causing the issue the only problem being that the fact that she vibes quite a bit now is NOT the issue i brought to them. miss comm apparently? anyways the guy claims that it didnt do anything like i was describing when he started it. luckly itd been sitting the rest of the day and i had him stand at the tailpipe there as it did it for me! only did it a lil but it did it. claimed it felt like "small misfire" said his snapon majigger might not even pick it up but, didnt charge me anything, said if it gets worse or gets to where it doesnt have to wait six+ hours in between and theyll take another crack at it.

back to square one
 
87manche said:
no, as in unplug the o2 sensors and force the PCM to run in open loop.
Click to expand...

imma see how the new ntks(well, 3 of 4 that is... the front downstream will NOT come out. ill be PBing periodically but i did at three spaced out times last night and this morning still bot a budge :( always something eh) react this morning and then ill give this a shot after school.

I the mean time I think I'll make a little video of it to give y'all helpful folks a better idea of whats going on. It'll be from the tailpipe as any video I make from the engine bay sounds like my AEM intake roaring to life
 
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MrAnderson said:
disconnecting the O2's gave no change

shouldnt that change something? it didnt even throw a code
Click to expand...
should have chucked a code, at least for the heater circuit.

MrAnderson said:
well i guess that fourth O2 sensor is permeant :( soaked it in pb the last fer days put a wrench on it real good and it sheared a corner clean off haha
Click to expand...

you using an O2 sensor socket?

you can always cut the pigtail so you can get a prper deepwell on it, but there's no going back after that, you're comitted to getting it out and replaced.
 
87manche said:
you using an O2 sensor socket?

you can always cut the pigtail so you can get a prper deepwell on it, but there's no going back after that, you're comitted to getting it out and replaced.
Click to expand...

yes on the O2 socket

yup i already sized her up and know my plan of attack haha. i can hammer a 13/16 on her and fit a breaker bar to it over my lca
 
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