4.0 wont start. Need help!!!

Crank position sensor was changed less than 6 months ago. But just for shiz, i changed it last week with no luck.

But i checked all my fuses and swapped all relays tonight all seemed good and still no luck. BUT, just as i was about to give up for the night, i decided to try one more time. Got in, turned the key, it did the same thing as usual for a few revolutions and then it fired!!! It wouldn't stay running without giving it throttle but eventually it got to idling fine by itself. let it run for a few minutes and shut it off. Went to crank it again and it went back to doing the same thing its been doing. Progress but still not good.

Any ideas on what would cause it to not start back?
 
If it was sputtering like that, it sounds like fuel supply to me. Check the fuel filter and pump. There may be pressure at the rail but maybe not enough or not consistent.
 
Well the thing is, after i got it running and it starting idling by itself, it was fine. I could rev it up like normal and then it'd idle like it should everything was fine. Then i shut it off and it wouldn't start back. May change the filter just to be safe since its been awhile. Possibly TPS since it wouldn't idle at first?
 
I know. and technically i didn't change anything. I put all the fuses back in the same spot as before. Still wont fire over after multiple tries. Then when i was about give up and tried one last time it cranked. Completely baffled!!
 
My TJ was doing the same thing back before i sold it. I had spark and fuel but would not start. The code said cylinder 3 misfire. I checked the cps like you did and the I pulled the fuses and relays and it still would not start. It ended up being a wire arcing on my flat fenders causing the problems. taped up the wire and it started right up. So check your wiring running from the fuse box.
 
I just dont get what i did between unbolting the manifold and installing the new one. Fuse block is on the complete opposite side of the engine bay. But i'm at a loss so ill try anything. Thanks.
 
It sounds like you have a wire loose in one of the plugs or a grounding issue. I had a problem quite similar to yours on that old farm truck i drove to uwharrie a couple of times. It ended up being the computer had burnt up but you could clearly smell it when you put the computer up to your nose.
 
check wires like crazy since it sat, those a very same symptoms to what our explorer did when a squirrel had a fuckingballs field day under the hood and chewed through the oil cap, throttle cable, and TPS. he also left a mess of the heater box and left pecans everywhere.....
 
did you hook up a fuel pressure gauge to the rail?.. if its not at 39lbs then its your fuel pump screwing up.
pushing the valve in and it squirting fuel means nothing. Mine had 10lbs of pressure and still squirted fuel.

also MAP sensor can cause the hard start and stall.
 
I'll try and check all the wires tonight and see if any of them are exposed and arcing somewhere.

yeah. i actually did check the ASD relay. That was one of my thoughts but no luck.

And no i haven't hooked up a gauge to the rail. I hear it cut on like usual, prime the rail, and then shut off. I guess i should check the actually pressure just to be sure.
 
if you werent so far i d bring mine over. $40 purchase and used once :)
jiggle the map sensor on the firewall.. you d be amazed what i've seen.
Since it ran before you put the headers on, i would retrace all the wires or check things that might have been bumped off during the manifold removal.
 
GreyZJ93 said:
I just dont get what i did between unbolting the manifold and installing the new one. Fuse block is on the complete opposite side of the engine bay. But i'm at a loss so ill try anything. Thanks.
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It makes sense that it had something to do with the manifold swap....are you sure you didn't forget or miss a ground strap on your swap ? Back to basics..it ran fine before the swap..right?
 
Hey hey hey!!! It was the jack that leaked down not a jack stand. and the tranny was attached, thats why my fan was pointing skyward. But i got it running after that incident. so watch it! Im just glad that accident didn't rip everything off the firewall.

But i have looked and looked and looked and cant find a missing wire or strap or line or plug.
 
See if advance will let you borrow there's. If not Marcus has one you might could wiggle away from him.

Maybe the grocery getter is just acting out since you have been neglecting it with the 4wheeler and bro-ram. Mine shat on me by busting my windshield, and stripping my pinion after not driving it for several months. I'm still waiting on the call that it caught on fire for cutting everything off of it.
 
But i have been driving it alot and trying to work on her. Been fixing all the little things to make it even better. Thats why i did the manifold swap. I was driving it almost everyday untill this. And I just want it back. I even got new chromos for her so i wont break front shafts every trip.

And the bro-ram has not been touched, other than wiring trailer brakes. All i do is drive it. But the 400 is understandable, I have been doing alot to it.
 
Well, im not sure if its progress or not. It is still doing the same not firing over thing no matter what i do with the throttle but after the second or third try, it will stutter like normal and then fire off. Then i have to give it gas for a few seconds otherwise it'll cut off on me but after about 10 seconds, it will idle by itself and run like normal. I let it run for about 15 minutes, get up to operating temperature and then shut it off. Tried to crank it again and wounldn't fire as usually and about the third try, it would shutter again and then fire off.

So it is starting more frequently now but still not right. I tried to "clean" my IAC while i had the throttle body off and i wonder if i goofed something up on that?
 
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