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Motor swap now a miss

85xjwoody

85xjwoody

NAXJA Forum User
Location
Little Suamico Wi.
Hello all, I recently swapped a 1997 motor into a 2000. She fired right up but has a miss. I went to the local mechanic and had him put it on his scanner to show #1,3,and 4 coils or plug missfire. So I took it back home and took off the coil rail and checked all the plugs and boots with everything checking out good. So I went ahead and did the toothpick trick to see if the timing was off. After I put everthing back together again it still has the same miss.
Am I missing something here as the 2000 electrical sysetm for running the motor is new to me.
 
# 3 and #4 sometimes have that misfire issue since i believe and correct me if im wrong they share he same intergral coil in the coil pack itself. What was your ohm read out with the coil pack? What plugs are you running, gapped to .035?
 
It is very common that when you do a motor swap, the injectors actually have the fuel leak / evaporate out, leaving a sticky injector. I personally have had this happen twice. A can of BG44K quickly cleaned up the miss. If nothing else, I do it every 10k miles in every vehicle I own.
 
These are basic Bosch plugs properly gapped to .035. Old Man I have never heard of BG44K, where would I find this? Parts store, hardware store? I honestly want to say that I don't think it is the injectors causing the problem but understand where you are coming from as to why I want to try your suggestion.
I am getting a fair amount of blue smoke when I let it sit and idle while it is running poorly also. Just to put my mind at ease I checked the timing again with the #1 at TDC and the harmonic balancer in line with the 0 on the timing indicator and I can put a drill bit through the alligning holes on the camshaft.
I am going to change the plugs to see if that changes things but I am not hopeful with this route. The jeep ran just fine before the swap except for the awful rod knock as to why the motor swap took place.
 
The coil rail requires good grounding to fire all the coil packs. Clean the mounting bosses and mounting points and put dielectric grease on all grounding points and plugs for them. Friend had a 2000 that would misfire after sitting for a while. I removed the coil rail cleaned up all corrosion on the mounts and did like I stated and he has not had a problem since. Good luck.
 
blue smoke is oil, maybe you have some damaged cyls and the low compression is causing the issues.
 
I made brackets to hold the coil rail in place but I did not ground out the mounting holes, guess that is on my to do list this morning. Thanks for the help everyone!!
 
Well I got all four mounting points for the coil rail grounded out and still runs like crap. Runs VERY rich and no CEL at this point. I just don't understand what could be left to be a problem. Last thing on my mind to do is some injector treatment, but I really don't think they are my problem. Any other ideas out there?
 
Right now the plan is to try a new coil rail and new plugs. Other than that I am at a loss. All the grounds are there, timing is correct, everything seems to be where it is supposed to be. I have done my share of motor swaps and this one has me at a loss so far. :(
 
Just got done replacing the coil rail and all brand new plugs gapped to .035. Jeep still runs the same, not better or worse. Injectors are my last thought but I really don't think they are the problem here. Any other thoughts or ideas out there cause I am out.:dunno:
 
Well, I tried different injectors last night, no worky. Still have the same problem. I am at a total loss with this thing and am out of money for this project. Onto craigslist it goes, I am sick of stressing out over this jeep.:puke: Unless someone else has an idea of what is wrong with this thing, it goes on the list this afternoon. Thanks to everyone who tried to help me diagnose the problem.:wave:
 
This motor checked out just fine before the motor swap, I drove it for 10,000 miles with no smoke before I pulled it and scrapped the jeep. There is only smoke when I let it idle for a minute or so and give it some RPM's to clear out the engine. I will try a compression test on Monday as I have nothing here to do so at the moment, unless it sells by then.
I am going to check all my grounds again also just to see if I missed something, but I am not going to get my hopes up. :D
 
ah ok didnt know that part of the story.
you check the fuel pressure regulator?
 
On a 2000 isnt't the regulator in the tank with the pump? But to answer your question, no I did not.
 
I just got through checking all the grounds they are all clean and tight. So lets see where we are at here. I have:
1997 motor and head into 2000 cherokee
2000 intake with 1997 exhaust federal emissions
New injectors
New plugs gapped to .035
New coil rail and is grounded at all four mounting holes
Timing set by going to TDC and 0 on timing mark, toothpick for timing was done
Jeep starts right away but within 10 seconds of running it runs poorly with a miss and dark smoke out the tailpipe indicating to me running rich.
No backfiring unless I let it sit and idle for a couple minutes and they I have to rev it up a few times to clear it out.
I just cannot figure out what is wrong with this beast. I am going to try messing with the timing tomorrow to see if it helps or not. I am just out of ideas and am going to keep trying things.
So far no engine codes.
 
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