Northern Utah BS thread #2
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 1,179
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From: Lehi, Utah
Year: 90' 93'
Model: Cherokee
Engine: 4.0
How's the cap and rotor? Battery connections? factory alarm? fuel pump ballast on driver fender? timing chain skip? does it stay running if there is starting fluid used?
Fuel filter be clogged?
Fuel filter be clogged?
Last edited by Mr Talon; Sep 12, 2012 at 11:49 PM.
CF Veteran
Joined: Dec 2010
Posts: 2,366
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From: Spanish Fork, Utah
Year: 1989
Model: Cherokee
Engine: Renix 4.0L
Originally Posted by Mr Talon
How's the cap and rotor? Battery connections? factory alarm? fuel pump ballast on driver fender? timing chain skip? does it stay running if there is starting fluid used?
Fuel filter be clogged?
Fuel filter be clogged?
Originally Posted by dev_daddy
Cap and rotor good. Battery connections good. Alarm? Ballast resistor bypassed. Timing chain skip is the only thing I'm still second guessing. How common is that? Haven't tried starter fluid. And fuel filter is brand new!
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Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
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 1998 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 07/24/2012
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Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Wasn't looking for a pat on the back. Just addressing the comment that I had alot of time on my hands. Thanks though.
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From: Salt Lake City, UT
Year: 2000
Model: Cherokee
Engine: 4.0L
LMFAO! awesome! 
Not very, more likely to break then jump. you would also get a slap sound from a loose chain and it would make noise before it jumped... any rattle engine noises before the last wheeling trip? how is timing? if the distributor timing is good, then the cam timing is good (chain is ok) as the chain drives the cam, cam drives the distributor. if the chain is off the distributor would be out of time to the crank (only way to set it) 
if the chain was off even a tooth it would start and run, would have a poor idle and lack of power, but run. unless it jumped multiple teeth... but this is a very unlikely and would not be caused by hitting a rock. the chain would jump from a stretched chain and worn chain bumper (would be making noise as well)
have you checked grounds? the block grounds, distributor ground? Ecm ground? main battery ground?
things that pop into my head off the start,
Map sensor, the engine has preset fuel trims and "start" maps for initial start-up. then relies on sensors to run once started. a failed map will cause the engine to choke its self out thinking it has to much/to little air causing a supper ****ed fuel ratio.
Could also be the ignition module, I have seen them cause a "start" and "die" condition a few times, but should be tested with a multi meter.
Coolant temp sensor, when they fail most fail in the cold position causing it to run rich and dye, will not run.... but most do idle until the engine starts to warm up)
I have a packed schedule for the next week or so, If I could come take a look what days/times work for you? I'll see what fits and bring some tools (unless you get it before our worlds align LOL)
Do you have power to the injectors while cranking/starting? they may have fuel but no trigger.
any thing abnormal once it "runs" for a sec? If you give it throttle does it stay running for a little? just curious of any hints based on its behavior. Dose it actually start or stumble off the starter?
sorry for the novel, just trying to help....


if the chain was off even a tooth it would start and run, would have a poor idle and lack of power, but run. unless it jumped multiple teeth... but this is a very unlikely and would not be caused by hitting a rock. the chain would jump from a stretched chain and worn chain bumper (would be making noise as well)
have you checked grounds? the block grounds, distributor ground? Ecm ground? main battery ground?
things that pop into my head off the start,
Map sensor, the engine has preset fuel trims and "start" maps for initial start-up. then relies on sensors to run once started. a failed map will cause the engine to choke its self out thinking it has to much/to little air causing a supper ****ed fuel ratio.
Could also be the ignition module, I have seen them cause a "start" and "die" condition a few times, but should be tested with a multi meter.
Coolant temp sensor, when they fail most fail in the cold position causing it to run rich and dye, will not run.... but most do idle until the engine starts to warm up)
I have a packed schedule for the next week or so, If I could come take a look what days/times work for you? I'll see what fits and bring some tools (unless you get it before our worlds align LOL)
Here's what I've done, and here's what I know. Fuel pump is supplying the motor with the correct fuel pressure. Cps was replaced and checked. I have spark. Timing, I went so far as to take the distributor out and reset it. That wasn't the problem. The engine will still start, run for a couple seconds, then immediately die.
any thing abnormal once it "runs" for a sec? If you give it throttle does it stay running for a little? just curious of any hints based on its behavior. Dose it actually start or stumble off the starter?
sorry for the novel, just trying to help....
CF Veteran
Joined: Dec 2010
Posts: 2,366
Likes: 0
From: Spanish Fork, Utah
Year: 1989
Model: Cherokee
Engine: Renix 4.0L
LMFAO! awesome! 
Map sensor, the engine has preset fuel trims and "start" maps for initial start-up. then relies on sensors to run once started. a failed map will cause the engine to choke its self out thinking it has to much/to little air causing a supper ****ed fuel ratio.
Could also be the ignition module, I have seen them cause a "start" and "die" condition a few times, but should be tested with a multi meter.
I have a packed schedule for the next week or so, If I could come take a look what days/times work for you? I'll see what fits and bring some tools (unless you get it before our worlds align LOL)
Do you have power to the injectors while cranking/starting? they may have fuel but no trigger.
any thing abnormal once it "runs" for a sec? If you give it throttle does it stay running for a little? just curious of any hints based on its behavior. Dose it actually start or stumble off the starter?
sorry for the novel, just trying to help....

Map sensor, the engine has preset fuel trims and "start" maps for initial start-up. then relies on sensors to run once started. a failed map will cause the engine to choke its self out thinking it has to much/to little air causing a supper ****ed fuel ratio.
Could also be the ignition module, I have seen them cause a "start" and "die" condition a few times, but should be tested with a multi meter.
I have a packed schedule for the next week or so, If I could come take a look what days/times work for you? I'll see what fits and bring some tools (unless you get it before our worlds align LOL)
Do you have power to the injectors while cranking/starting? they may have fuel but no trigger.
any thing abnormal once it "runs" for a sec? If you give it throttle does it stay running for a little? just curious of any hints based on its behavior. Dose it actually start or stumble off the starter?
sorry for the novel, just trying to help....
The motor was put in last spring, I've put maybe 200 miles on it.
Originally Posted by dev_daddy
No i appreciate the help! The MAP sensor here gets my attention. Same with the ignition module. When I've pulled the spark plugs, they aren't wet, but they smell pretty bad, like it were running rich. The motor hadn't made any funny sounds, and has really low miles on it for a renix. Once it starts, hitting the throttle really doesn't help anything, it usually dies before i can get to the throttle. It'll start off the starter, and If I actually keep the starter engaged, it'll keep the motor running, but limping.
The motor was put in last spring, I've put maybe 200 miles on it.






