Rchaxj98

So the story goes like this i own a 98 XJ 4.0 4wd with 235,XXX. The engine had very low compression on piston 1 and I had stupid amounts of blow by. Spiting oil trough everywhere. To the point that I had to install an oil catch can while I could save to build an engine on the side. Acquired a 2000 XJ engine took it apart, bought a rebuild kit from enginetech. Bored the engine .30 thousands over and resurfaced the block and head, got new valves shop did the valve work. New oil seals and stuff. Purchased an Elgin pro-stock E-1122-P camshaft to add s little extra. Purchsded the bolt and pin to make the 98 camshaft work with the new block that comes with the flange to hold the cam. New timing chain and sprockets set. Put everything back together, last weekend pulled the old engine and place the new one in the XJ. Now the jeep starts but it won't idle. I have to step on the gas to kind of jeep it running. Took me a little to get the new timing right with the camshaft to make it start. I would just crank because it was out of timing. Now it runs but dies. Then check engine light came on and now I have a P1391 "loss of cam or crank" to test i unplugged the crank sensor and I don't get spark. Plug it back on and I do have spark. Them disconnected the camshaft sensor and it won't start. Plug it back in and it will start but won't idle. RPMs need to be above 1900 or it will stall...

What did I do wrong ? according to my research the camshaft is mild enough to not need extra "tuning". By the way I do have K&N intake, throttle body spacer, 2.5 full exhaust, performance headers and a high flow cat. Still have the stock single hole injectors.

I appreciate any help to guide me in the right direction. The jeep is parked at home and I'm literally driving the wife's car and I'm not very pleased driving a gladiator with pink/purple flowers on it.. lol 😁

Griffyorcono

Bump

tech

It almost sounds like the the cam timing is wrong . you need to look up how to set up the cam timing .

97grand4.0

So you put an engine from a 2000 into a 98, correct? The pcm's don’t match would be my first guess. In fact I would have thought of that before I did the swap. Could be the timing slots on the flywheel aren't the same. Just speculating tho I really don’t know for sure but I would have researched all that first.
Another coffee-fueled thought is are the cam sensors are different?
Who rebuilt the engine, you?

awg

was the dizzy ever out?, if so, could be the common "one tooth out" problem

97grand4.0

I just checked rockauto. Yep, the PCMs are totally different. It wont run. You could put in a 2000 pcm and hope the transmission works, but I doubt it.

Rchaxj98

Yes i built the engine myself. According to what i had read the engine block just differs from the use of coils and the camshaft holder plate. Instead of the pin. So i installed the same crank, same connecting rods, new pistons .030 thousands over witj matching machine shop honing, installed the new camshaft and the new timing chain and sprockets that came with the kit. New lifters to mate with the new camshaft, same rods, same rocker arms, re-seated valves and new oil seals, same valve springs, new gaskets everywhere. I had read somewhere in here that the engines crossreference besidea the usage of coils on the head and the distributor. So I proceded with the engine buid on the side. Once completed swapped it and now it runs. But it does not idle. Oh i forgot to mention also the timing cover had to be replaced to work with the bolt and pin system. The older system has a nipple on the timing cover to prevent camshaft walk that will eventually ruin camshaft and lifters.

Rchaxj98

I did took in considerstion that maybe the timing chain might of jumped a tooth but I don't think its the case because when I rotate the harmonic balancer to the TDC marking on it in fact it does match and its visible that the piston is at the top trough the spark plug hole. I will be messing around with it today by removing the distributor and maybe trying one or 2 tooth back or forward and throughout all weekend. See if I can make it to idle and not die.
This is a quick view of the progress of last weekend. Thanks for the help

97grand4.0

Hmm no mention of the PCM but good post. Good luck

Rchaxj98

Lol.. I apologize.. I did forgot to mentioned that I kept the same PCM from my 98 and used it to run the engine. I mean the new PCM is meant to run with the coil packs not a distributor system which is what I have on my 98 XJ. I do have the PCM from the newer XJ. I bought the whole 2000 Xj for parts. It was a limited 2WD so I swapped the gray leather seats, the door speakers along with the tweeters that go on the plastic molding corners of the door/ window. And obviously used the engine. Still have the spare transmission. Whole interior. It had an over head console with outside temperature amd trip/fuel info that I kept but don't use because my 98 XJ is a sport and it came with a sunroof. The body of the 2000 im building it in to an off road camping trailer to match my XJ. Already build the trailer tongue. Removed all interior. Cutout the transmission hump and welded a flat piece so that its just a flat floor. I'm still on the process of closing the nose/front but I haven't come up with a good idea for the front to look good. Anyways thatsb far off from my current issue . Lol got sidetracked there for a minute. So yea 😁😁😁

Patman

I was working with a guy that had a 4.0 that he was working on. It’d start but as soon as his rpms reached into the 2400s or so, it’d choke out and die. It ended up being his ECU/PCM. I know that your issues are different but its a simple replacement if its faulty. Others members have suggested that it my be PCM related the year of the motor. That is a real possibility and with researching as well. Please do keep us posted.

97grand4.0

I see. So....I’m confused. All I can say is if that flywheel, I think they call it a flywheel, with the slots that trigger the crank sensor, isn't the same, it won't run even if you do change the pcm over to the new vehicle. You would need the flywheel to match the pcm. So maybe you could put the 2000 pcm back in the 2000 if it still has the 2000 flywheel.
But it seems that wont work either because the 2000 is set up for coil packs...you might be ska rood here.
So yea .

Griffyorcono

Hey guys, I don't mean to be a jerk. Please do not post on this thread if you have not attacked this problem ever or done any sort of swap in the XJ or as a matter of fact ever even pulled a motor out of an XJ do not post your advice on this thread specifically because you are only going to confuse the guy. This problem starts to move a bit into more technical things and less common sense. I apologize if I offended someone I am not trying to **** anyone off or attack anyone specifically, just want to make sure he doesn't end up chasing his tail cause timmy said you need to check your grounds after he just did a whole rebuild XD.

Rchaxj98

None taken. I appreciate the honesty and the willingness to help. This is my second engine that I fully build myself. The first one was an M50B25 which is a straight 6 that went on my drift car a 90s BMW 325i. Now I've done many swaps where all I do is take the old engine and just place another v used one that's not blown. It's simple just connect everything back together. The problem is that i modified the engine with slightly larger pistons and a performance camshaft and I'm not sure if this require a tune. Or if the PCM will compensate accordingly. I've never modified engine internals before. My intentions are to have just a little b more power to pull my camping trailer. And retain the reliability.

I appreciate the guidance of whomever might be able to steer me in the right direction. I think it might be a timing issue. But then again I might be wrong. Ive only done repairs to the jeep. Not something that might of messed around with the fuel/air ratio that much. So this is the current set up i have going on on the jeep

-1998 jeep Cherokee Sport 4.0 4x4 auto

-K&N intake
-Rough Country throttle body spacer
-Insulated fuel rail and fuel injectors to prevent heat soak and improvise fuel delivery/atomization.
-horse shoe style intake manifold from a 2000 XJ
-oil catch can to help relieve crankcase waste gases and remove the recirculation of oil contaminants in the air going in to the intake manifold so that the air can be cleaner for the air/fuel mix and keep the inside of the intake manifold clean too without the black oily residue.
-180 degree thermostat with high flow housing
-FLOWKOOLER high volume water pump.
- dual core aluminum radiator with 3 pulling fans and 1 pushing.
-PACESETTER high flow headers (also insulated to prevent heat soak on the intake manifold)
-High flow catalic converter
-Gibson cat-back exhaust
-4.5 Rough Country lift kit
-Rough Country slip yoke eliminator
-Dana 30 ARB air lockers (front)
-Chrysler 8.25 ARB air lockers (rear)
-ARB dual air compressor
-4.56 gears on the axles
-33x12.5 r15 Dick Cepek Extreme country tires
-Rough Country front bumper with stinger
-Smittybilt XRC rear bumper
-Rough Country 9500lbs synthetic line winch
-Rough Country light bar and side pods.
-Rough Country Power distribution controller for the lights (replaces cigarette ash tray)
-Rhino Rack Full Roof Pioneer Platform.
-Smittybilt Roof tent Overlander XL (wife and daughters)
-Fire extinguisher
-Biometric Gun Safe
-ARB Freezer Refrigerator

I think that's it for now.

-Upcoming is chromolly shafts. To better and safely handle the torque. 😁😁😁

cruiser54

Aren't the intake ports different between 89 and 2000? You have a bit of a mish-mash of parts there.....which intake did you use?

I'm moving this to OEM tech in the hopes of getting more eyes on the thread.