I swapped out my 2000 engine with a 98 with out doing much research but asfter it backfiring and not starting I saw a video on YouTube saying that they motors are diff … I see the 2000 has a 0331 which cracks inbetween the 3&4cylinder and that’s what happened to me . I was losing heat quickly and it was eating coolant an low and behold it all mixed with my oil soooo instead of finding another 2000 I swapped the engine with a 98 and got it all back together and found TDC and dropped in the cam shaft positioning sensor either the toothpick trick an it would turn over but backfire out the intake ! what should I do? Try to swap the whole entire wiring harness with a 98 ecu ? Or try to find an 0630 head an just swap that ? I also realized as I put the 98 in that the motor mounts may have been a tiny bit different as well so maybe I messed up by not reading enough but I def need to get it back up an going asap . Any input would help thanks in advance

 

Are you using coils or distributor? What year ecu are you using.

 

My Jeep is a 2000 so I have a coil pack . The ecu in it , is a 2000 , the motor I put in there is a 1998 ( which ran off a distributor) I assumed that I could just find top dead center an drop the cam shaft positioning sensor in there and call it good but I think I’m mistaken lol 🤦🏻 it was backfiring when turning over and I am jw what the easiest route would be to get it right … do I replace the motor AGAIN !? Or attempt to also swap out the whole wiring harness ( which means I have to go all the way into the heater core an all that junk ? Thanks for the reply !!

 

Are you sure the synchronizer shaft went in correctly? What is your timing advance with a light?

 

Yep, need to make sure your #1 piston is at TDC and the mark on the harmonic balancer and timing cover are on "0". A 1998 engine should have no problems running in a 2000 model XJ. I have a feeling that your timing is off........maybe 180 degrees? But I have no experience with the cam shaft positioning sensor that was used on the 2000.

 

I agree, it's likely a timing issue. A 2000 with the coil pack can't be 180* out though, since it fires on both compression and exhaust strokes.

 

I definitely cranked it to tdc with a long screw driver in the first (closest to the front of the Jeep ) spark plug hole … and the lil mark on the flywheel lined up also and then dropped in the csps the way it’s supposed to go in … although I did just bolt up the exhaust manifold without realizing that the holes where slightly diff from 98-2000… I guess my question is would that cause it to backfire out the air intake ? Ps I drove the donor Jeep to the shop where I swapped the motors so I’m guessing it can’t be too far off on timing although I did NOT use a light gun on it so would my next step be to go find a 98 manifold ? See if that makes a significant difference?? Thanks again for all your guy’s reply’s !!! Finger’s crossed 🤞🏻

 

You're timing it out 180°. While that may not affect spark, the computer looks to the Camshaft Position Center to determine whether it's on the compression or exhaust strokes so that it knows when to fire the injectors... The manifold isn't the issue. Lots of people install the 99+ intake on earlier motors, such as my 94, for a bit of power gain.

 

Oh duh. Forgot about injector timing....

 

the #1 piston is at TDC and 0 on the timing plate twice per engine cycle..you have to make sure the valve are closed or its making pressure as you approach the 0 mark or its tdc on the exhaust stroke . I would not recommend taking out an entire engine harness.I did not see if you had 4 or 2 oxy sensors on your original motor. If you have Federal emissions-2 sensors then the oxy sensor part is a snap. As implied in some of the prev posts...you cannot just bolt a pre 2000 exh manifold to a 0331 head, and you cant use a 2000 manifold on a 99 and down head without adapter plates and such. I run a 98 motor in my 2001 but had to modify the 98 exh manifold to accept 2 oxy sensors in the upper manifold and had to modify the pipes downstream of the 3rd cat for the other 2 sensors. The coil rail eliminator was basically a plug and play using the stock 2000 cam synchronizer, and the mid 2000's wrangler 6 prong coil pack plugs right into the stock coil rail harness plug. The hardest part was bending a piece of sheet aluminum into a top hat shape to fit around the coolant bottle brackets and then bolt the coil pack to the bracket. given some simple measurements, any metal shop can bend it in about 15 min.

 

photos of my coil pack mount...somewhere someone sells a complete kit, coil pack-mounting bracket and wires, just dont know who or how much

 

I made a 3D printed version that could be revised for a v6 minivan coil.

 

I got the Bracket and Harness from K Suspension for $55 plus shipping, then got a Mopar Coil Pack and Plug wires elsewhere.

I think they do a whole "kit" also.