thelebowski69

Alright i tried searching similar threads but it dont really answer all my probs, so:
2001 cherokee
0630 head swap (p/o)
found it in a impound lot for 800$, abandoned
it started and ran, drove it around the block. Had o2 sensor code and a heat soak misfire on cyl 3, and a pretty bad header leak, so i pulled everything off to replace the gasket.

three injectors were cracked so i got used green 4 hole injectors with new orings

new spark plugs

0630 manifold gasket

put it all together, started, immediately redlined, looked it up, intake manifold misaligned, cool. Pulled it all off, put a 0331 manifold gasket OVER 0630 manifold gasket so my headers wouldn’t leak, cause i still have 0331 headers and i’m not trying to swap headers and not have o2’s.
put everything back together, primed the fuel pump.
now it doesnt want to start.
floored it will start, as soon as rev limiter hits or i take my foot out of it, it dies. Cant maintain revs at any speed.
sometimes will start without throttle, will sputter for two seconds then die.
no codes cause it wont run long enough to make em stick.
weird sucking sound coming from intake before it dies, almost like its choking out or something.

tried swapping old injectors back in, still same issue.

im lost at this point.

jpz

Hopefully someone with 1st hand experience will chime in with a better answer than mine. But I would suspect using the 0630 head, and 0331 header would create an incomplete seal regardless what gasket, or combination of gaskets you are using and create a vacuum leak to cause the issue you are describing.

My 2000 has a TUPY head, and I have replaced the gaskets when doing freeze plugs, and from what I remember there wasn't a lot of "extra" gasket to offset for a different style head.

I think you may need to look into a matching header/gasket combo.

thelebowski69

yeah i might. The vaccum leak is a possibility, the 331 gasket i re-used and it didnt fit the best, but its made of metal and the 630 is not, figured it might help seal. There’s an adapter plate i ordered for it, but till then i figured i could make these work. There are no visible gaps, intake dowels are in their holes, all bolts are tight, im wondering if either:

The mismatch exhaust ports are enough to cause too much backpressure

the cats are clogged to the point that it wont run now its not leaking

if i cracked the intake (no visible cracks with big spotlight underneath and above)

or if i messed something up along the way (everything that was plugged up before is correctly plugged up now, including vaccum lines, i think)

awg

have you run an OBD2 scanner on it to see if any codes are setting?

They also be used to read manifold vacuum with free Torque Lite, although you may not be able to get a good reading,

does sound like some sort of vacuum leak would be the first thing to look for

bluejeep2001

A 2001 exhaust will not bolt up to the 0630 head, its that simple, might not be your only issue but its your main culprit. I have never seen the adapter plate so I can't offer advise on that.

thelebowski69

Alright so i got this adapter plate and its running decent now. Turned out my coil pack wasnt all the way on, oops lol. No exhaust leak, no intake leak, idles etc. revved up perfectly fine.
drove down the road, ran great for five minutes.
popped codes and started running in the weird limp mode, acts like it hits limiter at 2500rpms.
code is same as before when i firdt started all this, po303, misfire cylinder 3.

all new injectors
spark plugs
plug boots
manifold gaskets etc all good
also heat wrapped headers and heat shielded injectors to prevent the heat soak issue to cylinder 3
when i cleared the codes and started it it ran perfect, revved it all the way up sounded crisp, then the code registered again and all the sudden limp mode.
im thinking it might be wiring to injector three? Or vaccum leaks near the center of the plenum manifold

2001 cherokee sport
4.0l aw4 4x4
0630 head swap

bluejeep2001

You can get a set of noid lights on ebay or amazon cheap. They plug into your injector connector. Will tell you pretty quick if the signal to your injector is bad. Have you run a compression test on all the cyls. That will quickly point out any mechanical issues

thelebowski69

havent compression tested yet, i stethoscoped the injectors while it was running today, found that injector three is not firing at all. Test drive showed consistent blinking engine light, so its definitely not firing at any point. Test drive was done while engine was still cold to rule out heak soak issues, also everything is shielded/heat wrapped. Got a new connector, gonna wire it in tomorrow and see. Thanks!

thelebowski69

So changing the connector out didnt work. Stethoscoped injectors, all seemed to be firing on cold start. Drive down road one mile, same place as yesterday, i felt it start to miss. Check engine constantly blinking, shuddering, limp mode kinda symptoms. Bring it back, temps were good but engine was hot as hell to the touch after running 20mins total, like the fuel rail and anything around it were burning me. Stethoscoped injectors again, everything firing but cylinder three. Keep in mind, new heat shield, every injector is insulated, three layers total of heat shielding plus header wrap. Might have a small header leak, but still i dont see heat soak being probable with all the preventatives in place.

new battery
new alternator
new injectors
new spark plug boots
new spark plugs
0630 head with two new manifold gaskets and adapter plate for 0331 exhaust manifolds
new connector to injector three

im temped to buy a coil rail but being that it is a batchfire system i feel like that might be a waste of money

considered fuel pressure issues but if so i feel injector six if anything would miss, not one in the middle of the fuel rail.

plan to do a compression test, just dont see how it’d cause a misfire when things warm up but wouldn’t on cold start