This is gonna be a long post. im sorry in advance

ok so i bought a 1999 WJ 4.0, it has a small lift and JK rubicon wheels and tires
the old owner said that the engine had been replaced last year but had no proof.it is coil on plug. was that an option in 99? he told me that engine was from a 2001. and he said the ECM was never swapped. he said he drove it a year without having to do the computer.

so the problem im having let me start from the beginning. so when i bought the jeep it ran ok. it had a misfire, and fealt like it was fuel starving from a bad pump. The old owner was convinced the ECM was going bad, swore up and down that it was the issue. so i bought it, drove it home it ran ok just missed. so i did a basic tune up, i did plugs. the oil was clean, the coolant nice and bright. after i did that i borrowed a fuel pressure tester from autozone, i hooked it up and it read nothing.... so again figured the fuel pump was bad. i had the pump so i did it. anddd it runs better and smoother but still has a miss and now im having weird electrical issues.
now sometimes when you go out to start it, it wont do anything when you turn the key but the gauges will kinda move and make a relay clicking noise. hook it up to a booster pack and it will start and ill have a CEL for loss of crank or cam sensor and it will do the normal CPS shut off if its bad. i cleared the code and it came back almost immediately
so im kinda at a lose.
could the cps be bad?
could this jeep have a external fuel regulator?
why would after a new fuel pump would it still show no fuel pressure?
could the coil be bad? it did throw a cylinder 1 misfire code when i first got it

when the CPS in my XJ went bad it shut off much more nicely (for lack of a better term)
any help is appreciated

 

Okay, the coil rail ignition was standard starting with 99. The fuel pressure regulator is in the fuel filter and may be not holding pressure on shut-down. Random shut-downs and misfires are common symptoms of a failing CPS, but won't set a code unless the PCM isn't getting a signal at all. Check all the wiring for frayed or broken wires, mutilated connectors, or even spliced and taped connections. Check the cable plugs on the PCM for bent or corroded pins. Most sensors operate on 5v, so clean connections are vital.

Check the battery cable clamps for corrosion inside the wires or loose connections on the battery posts. They may feel tight, but are they really tight on the posts?

Most importantly, check all the ground cables. sometimes with an engine change, some aren't reinstalled.

The coil rail has only 3 coils that fire 2 plugs at once. For instance, when #1 fires, #6 fires on the exhaust stroke as well. This is called "waste spark" and is designed to help burn whatever wasn't burnt already.

 

ok so 3 weeks later and i still don't have an answer. this is going to be another long post.

so i couldn't figure out the issue so i brought it to a (what i thought was) reputable jeep/offroad shop locally, because i didn't wanna drive it too far and didn't wanna pay for a tow.( sold my full size truck and downsized to the wj). any way drove there on valentines day, my girlfriend is still pissed, and its now march 7th.

so when i brought it down i asked them to look it over, told them what i thought(cps, fuel pressure regulator, coil. i did the fuel pump so they could skip that). a week went by and then had nothing. told me it ran worse when all the new parts were put in.(cps, FPR. they replaced, said it ran worse and put the old ones in. i'm not paying for them if they cant prove they're in the jeep) so they reassured me and said they'll figure it out and guaranteed me the ECM was bad. when i say guarantee they really drove the point home. okay so went on the internet found a remaned ECM, vinned and everything, took 3 days got it on a friday afternoon, left it over the weekend figured they d look at it monday.
week 2. monday no call. okay so i called tuesday, they said"maybe we'll get around to it this week."(they're not a particularly busy shop) that shoulda thrown up a red flag. ok brushed it off let them go. called friday, "we have no idea whats wrong with it. its a lost cause. BLAH BLAH blah" this is after they guaranteed me they knew what was wrong. so now i sit here car less for 3 weeks, having to borrow my parents car to go to work and now they jeep doesn't even start. i will refuse to pay until i can drive the jeep away, and that they can prove to me they replaced anything.
keep in mind i drove the jeep there.

so i will update again tommorow when i have a word with the owner and tell him my thoughts on the situation. i'm still at a loss with what the problem could be. im sorta in a bind here too.

if they have no idea the jeep will be going to a reputable jeep shop in orange county ny.

 

https://www.cherokeeforum.com/f5/wj-...233661/index2/
this is a close representation of whats going on. does it seem like a viable option?

 

ok so i got the jeep back they charged me nothing, well because they didn't do anything. and 3 hours after picked up the truck we got it running, it had no fuel and and no spark. the cam sensor was 180 degree out of time, so it wouldn't run at all but the crank sensor was the major issue, so i bought a real jeep CKS and it ran! but then the next ridiculous problem, so somewhere along the line someone replaced the engine with a junkyard one. when they did they sorta hacked up the engine wiring harness. so there was no oxygen sensor harnesses. nothing they weren't hooked up at all. so the only that was reading was the down stream one which wasn't right either. so i bought a junkyard harness but made the mistake of getting a california emissions harness and my jeep is a federal harness, so it has to many plugs plus when they took it out they cut the harness to the trans. so i have to find a parts jeep and take the correct harness

 

Okay, at some point in time, NY decided that all vehicles sold in the state should have CA emissions. You may have trouble finding a Federal harness in a boneyard for this reason. I'd like to cut off the gonads of anyone who hacks up a harness for ANY reason! There is no reason to except laziness unless you know EXACTLY what you are doing! The PCM (CPU or whatever) is designed to look for data from the sensors it was designed with and won't play nice without them. Without 02 input, it relies on programmed chip memory and that's why it misses, because it's not getting data to trim the fuel mixtures. You also might have a weak coil pack. My 2000 4.0 had a problem with cylinder #5 carbon bridging it's spark plug if allowed to idle for a long time and would always throb slightly at idle, but run strong any other time. Changing the coil pack fixed that.

You may find a harness on the internet if you talk to the guys at a salvage yard. They know where to look.

 

welcome to the east coast california!
Thanks man, its really hard to find a harness for these. and theyre too new people havent been destroying them. so theres really none being parted out and scrap yards do not really have them or when they do have them theyre cut at the trans SMFH. ive been checking the internet but people either want 200+ for one, or theyre destroyed. so im sorta stuck again.
If its not one thing with this jeep its another.
another question i have since 99-04 they were all the basically the same jeep should a harness work? what about from say an xj? this is the first time ive had to do something like this

 

The only other option I can see is to change the exhaust to the CA setup and get the PCM reprogrammed by a dealer.

 

i think im gonna keep digging for a real harness, i dont wanna deal with the cut plugs. ive been calling every use auto parts place i can find. i am detremined to findd one now. its kinda a challenge

 

okay so little update.
i havent done anything to the jeep in 2 months i dont have the time now but im still looking. so i figured i would just do a full list of what has been done
-New Fuel pump
-New reprogrammed ECM
-New spark plugs
-New jeep crank position sensor
-New battery
-New upstream 02 sensors
-New engine wiring harness(this is where im having the problem)
so the last time i played with it, i had thrown another wiring harness in it. so from what i was told that there were 2 different emissions systems(federal and california) so my jeep conforms to Federal standards. but i was told that its a possible that i bought the wrong harness. i can see that, i have to open plugs that would connect to things on the passengers fender, and the middle plug on the ECM is upside down... i didnt realize till i got the whole harness on. so thats where im at. the jeep has been sitting since then and im kinda at a loss. i wanna fix it and make it my girlfriends so she can wheel with me but i dont want to give her a POS. or i wanna sell it and cut my loss. so now i have to find a new harness but they're either really expensive or really far plus i have no idea if theyre right till theyre on the jeep.
some one did replace the motor in this jeep and did a very hack job. so thats where im at if any one has any insight. i appreciate it.