I bought a project xj off a guy who started a motor swap and got bored, now im trying to to fix his screw ups. ita a '90 xj, that started life as a manual. he pulled the original 4.0 and stick, and swapped in a '98 4.0 ho with an aw4, kept the old accessories and harness.
i got it all home and started messing with it, and i cant get it to start.

I started off with the obvious things, fire and fuel... had good fuel pressure, but a yellow spark.

I swapped the cps, distributor, and coil just to make sure everything was new and up to snuff, but much to no avail.

Since it used to be a manual, is it still looking for a clutch sensor, or the NSS? Is the fly wheel different from the 90 to the 98? Im about out of ideas guys, any advise is very appreciated. Thanks Beau.

 

I would think the 98 aw4 is looking for an obdII auto trans computer, not a manual renix one

some aw4 info here:

http://www.naxja.org/forum/showthread.php?t=1053970

 

Do you have the '90 (Renix) control system, or the '98? I'm assuming you have the '90 Renix system on a '98 block if you still have the original harness installed?
The flywheel is different between Renix and the '98, as is the CPS and basically every other engine sensor. You have to have the flywheel and CPS that matches the engine control system- if you still have the Renix you need the '90 flywheel and CPS, the '98 won't work correctly, and vice-versa.
.
The transmission and TCU won't keep it from starting and running, they are pretty much a separate system. If the NSS (or clutch interlock) were bad it wouldn't crank over at all.

 

Like Radi points out, there are big differences you just really can't steer around. Basically you treat the new engine as a long block, and put all the stuff from the 90 on it to match the ECU in your 90. (flywheel and CPS included there). Cruiser has a deal on the swap found in my signature.

Interesting question there with the switch from manual to auto. I'd juess that would be a major pain. Maybe with a PCM for an auto...if the harness has the plugs for the TCU you will need as well a other sensors.

You might contact cruiser54 if he doesn't find you here....

 

Cruiser’s HO into Renix Swap
This swap is easier than some will lead you to believe, generally those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.
The HO and Renix have some differences but none that can’t be overcome very easily.
Any HO engine from an XJ or ZJ through 1999 can be used. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from the HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head for the sender.
You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use the Renix gasket. Exhaust ports are identical.
You will need to use your Renix distributor as it is different than the HO because they use different fuel management systems. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.
The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16" square drive or a modified 3/8" drive that has been ground down to fit. Do this before installing the engine.
As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.
　
Revised 03/28/13
　

 

This may help at some point also. Then click on the link in my signature and do #13.

Setting Your 4.0 at #1 TDC
　
With #1 spark plug removed, turn the engine over clockwise using the 3/4" front crankshaft bolt. You will see the degree marks on your front cover. Mark the 0 with chalk or white-out.You will see the timing mark on the balancer. Mark it with chalk or white-out. While turning the engine over, put your finger/thumb over #1 spark plug hole. As the mark on the balancer approaches the marks on the front cover, if you are coming up on #1 TDC, pressure in the cylinder will push on your finger. If there's no pressure, you're at #6 TDC and need to crank the engine over until you see the marks coming together and you get pressure. Set the mark on the balancer to the 0 mark on the front cover.

 

Awesome guys, i really appreciate it, looks like I'll be picking up a new flywheel. As far as setting TDC, i cant find the mark on the front cover, so I've been pulling the #1 plug and doing it visually. the 98 motor/tranny was installed as a combo, just pulled from the doner, and stabbed into the '90.

Since this was bought as an unfinished trail rig project, I've been dealing with alot of stupidity.



So it looks like I'll be headed to the parts store to pick up a new flywheel then.

 

And yes, the renix system is being used. the manifold where swapped onto the 98. I didnt know anything about the knock sensor, I'll look this afternoon and see if he put that into the new motor. Before i tear into the fly wheel, the torque converter out of the 98 will bolt right up the the 90 fly wheel correct? That being said, it came with a d44 swap up front, 6" of lift and a sye already done with a lincon locker out back. it will only be a trail ride, as it has way to much going on to get it back to street legal. so i think I'll figure out a electronic shifter.

 

The hole for the knock sensor might not be tapped. I didn't fully read through all, but I thought somewhere Crusier mentioned the Renix (87-90), knock sensor is easily mounted on a later block. Maybe there is a hole there to tap, near the engine coolant sensor low on the left side of the block. The hole does not need to go through, the knock sensor just needs to be screwed in. I'm not aware of any issues bolting up the torque converter, just that Crusier says to keep the Renix flywheel with the renix systsm/ECU, so it can signal the, (two wire) CPS.

 

As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.

 

you guys are freakin awesome, the part of the engine harness that holds the connector to the o2 sensor has three conection ends, one is hooked to the o2, one im guessing goes to the knock sensor, does anyone know offhand what the third goes to?

 

From front to rear:

Coolant Temp Sensor goes into the coolant gallery.

Knock sensor screws into block at just above oil pan level.

O2 sensor screws into exhaust manifold.

Be careful how you route the wires down off the intake manifold so they don't get kinked or worse yet, burned by the exhaust manifold.

 

My little brother is going to hook me up with a flywheel that they had at the off road shop in Amarillo. Should have the flywheel some time this week but I've been taking a break while I renovate our spare bedroom but will get back on the xj as I can. Thanks again
-Beau

 

man... i hope whoever decided to put e torx bolts in the top of the bellhousing contracted a rare affliction that caused fingernails to grow out of his nose... those things are a freakin nightmare

 

LOL...I agree!!