Cherokee Stroker Overheating

ty20404

Member
Joined
Feb 14, 2011
Location
Wilmington
Alright, so I'm sure that anyone that's clicked on this is like... "what a dipsquat, it's your fan hub!" or "did you check your e-fan fuse?" Well unfortunately, I'm going to go through the details, start to finish and hopefully someone can pinpoint where I may be having a problem.

I'm going to recollect all of the events as best I can and place them in somewhat of a timeline:

  1. Purchased 1996 Jeep Cherokee Classic, 4.0L, AX-15, 4WD, January of 2011 with a "blown motor" at 241k miles
  2. Thought, this is easy! Replace head and head gasket, done! No........ Bought refurb'd head, installed, bad compression, time for new motor.
  3. Craigslist.................................... Found 4.7L stroker built by Precision Engines from local guy w/ approx 40k miles. Heard it run in his 200X Wrangler, something sounded a little off while running, but not bad at all.
  4. Bought motor. While guy was tearing it down (removing all of the components to sell as long block) he called me and said "My cam gear for distributor is worn, I'll drop the price for a new cam and lifters." Done, and purchase (for 550 bucks).
  5. Received engine and bought a new camshaft and lifters (COMP Cams CL68-232-4), installed camshaft and lifters, replaced head gasket with FELPRO, and replaced ALL other gaskets, new head bolts, used timing chain and gear from the stroker, used everything else from my 242k mile engine (oil pan, timing chain cover, valve cover, water pump, intake manifold, exhaust manifold, A/C, PS, pulleys, etc.). I also traded injectors so that I received the proper (24lb injectors, I believe) for the stroker). Used all specs from my Haynes Manual, break-in lube, etc...
  6. Installed engine, fired up on the first crank.
  7. Overheating issues begin....
  8. Driving around would be fine, but would overheat slowly if sitting still (which continues to be my problem)...
  9. Replaced water-pump and thermostat, still continued to have issues.
  10. Replaced the radiator with a used one... That one leak so I continued to have issues.
  11. Wired in a relay and switch override for the e-fan (as of now, I don't even turn it off)
  12. Replaced the fan hub with one from Advance Auto Parts... That didn't work.
  13. Replaced the radiator with a 3 core from DPG... That didn't work.
  14. Replaced the water pump with a Flow Kooler high flow pump... That didn't work.
  15. Thought maybe I have an idling issue as far as air goes, and my dumb-ass didn't check the pre-load on the lifters when installing the cam originally (which who know, this could be my issue). I had noticed that my idle itself isn't rough but the engine does vibrate a little more than it should. So I took measurements and found that I needed some slight shimming (between .030 and .090 inches depending on valve). That didn't fix my idling issue... And it didn't fix the overheating.
  16. Thought that maybe my manifolds aren't tightened down enough and I've got exhaust gas escaping into the bay or intake runners... Tightened those down and that actually made a slight difference in running temps (when on highway), instead of running at 207ish, I would run right at 199* most all of the time while consistently moving.
  17. So because that made a difference, I decided to loosen the manifolds then follow torque sequence and tighten them down... Well it didn't improve. Once I sit in my driveway for 3 minutes, the temp starts to creep up... 203, 205, 207, 210... and so on.
  18. I will note that when it's cold outside, I don't have an issue... It's been at least 90 degrees out while this has been occurring lately so I've had the A/C on. If I turn the A/C off, I have yet to notice the engine temp creep up. The hottest I've let it get lately, in these temps, is 227*.
  19. Thought maybe I have an ignition issue, replaced plugs, wires, dist. cap and rotor... Didn't affect the idle or the overheating.
Now, another issue that I've noticed the entire time that may be related... Whenever I'm slowing down, it doesn't necessarily mean I'm stepping on the brakes, the idle drops to near 200 rpms... Basically if I press the clutch in when I go to slow down, the rpms drop really low, sometimes more than others. As soon as I come to a complete stop, the engine almost immediately recovers to normal idle, albeit kind of rough. I notice this problem more often when I'm pressing on the brakes, but it has happened when NOT pressing on the brakes.

Another issue that seems somewhat related to the one just mentioned, is that sometimes (rarely) when I go to accelerate, the engine hesitates even when I'm pressing the gas, then all of a sudden it surges.... But like I said, it rarely does this.

I've honestly looked at practically everything with the exception of fuel pressure, or searched elsewhere for vacuum leaks... I've run MMO and Seafoam thru the crank case, Seafoam thru the intake and fuel. From my OBDII scanner I get a MAP of about 10-12 "Hg while idling which seems normal.

I've got gobs of power with this thing, it's super easy to chirp tires, first to second... I can dump the clutch at 2000 rpm in first and chirp tires easily. It's got balls and will get up and go so there isn't any loss of power really except for those rare times that it hesitates.

Someone, for the love of god, and my wallet, please find something in here. My daily driver was recently totaled and now I have to drive around staring at my temp gauge or OBD scanner :( Please let me know if you need ANY clarifications.
 
xjdrew said:
I had a similar issue but it was on a stock 4.0, and ended up being a clogged cat. Just a thought
Click to expand...

Not ruling this out, but it has what appears to be a fairly new cat welded in.... The inlet and outlet are also both bigger than the factory piping so it seems as though it may flow better??? Like I said, not ruling it out, but not sure how a clogged cat would cause overheating while idling and run fine while moving. Everything I've heard about clogged cats talks about inability to rev high and no difference whether moving or stopped.
 
I had the same heating issues when I stroked my 4.0 to a 4.6. I had upgraded to a "heavy duty" 3 core radiator (brass/copper), and was running a "2000cfm" electric fan from Advance auto or something. It was fine in the winter, but I practically couldn't keep it under 220F in the summer. I put those things in quotation marks, because I finally bit the bullet and bought a Novak aluminum radiator for a TJ, and installed a Ford Taurus 2 speed fan, and now it never gets over 200F in the summer with the AC on going up Daniel at Uwharrie. Basically the radiator was not providing enough cooling due to the design. The brass/copper material has a better heat transfer coefficient (flows heat through it faster), but the aluminum is stronger, so the walls/tubes/fins can be made much thinner and provide better overall cooling characteristics.
 
What thermostat are you using? If its too low of a temp and opening up too early and staying wide open its letting water flow through the radiator too fast and not letting it cool.
 
Have you checked the temps in and out of the radiator? Exhaust gas temps at the manifolds? Shooting them with a temp gun can give valuable info.

If the temp drop in the radiator is negligible its likely that you have a tstat issue and the water isn't staying in the radiator long enough to cool. If the exhaust gas temps are rising it could be a lean condition a idle, possibly the IAC motor, vacuum leak or some sort of EGR issue.

Have you pulled the plugs to see what story they tell?? That could easily rule out cooling system or fuel system.
 
If the old engine dumped coolant into the exhaust when it blew it could have damaged the cat. I would check it to see. Also a lean air fuel ratio can raise temps. This could be caused by a clogged injector or to small of injector.

Sent from my Kindle Fire using Tapatalk 2
 
Well I could see the issue with the Radiator, but that almost seems like a band-aid and not a true solution.

As for the T-stat, I'm running what I believe is a 200 *F Stant, which could be preventing the fluid from cooling sufficiently.

As for the Cat, it could be possible that the coolant could have ruined it. What do you think I should do to diagnose it? Remove everything from after the headers and see if it runs better? I'd just be afraid the hot gasses will release too close to the engine bay and cause the intake to heat up. Is there a way to see if the Cat is clogged once I have it removed?

I cleaned the original IACV, that didn't affect the idle or change the issue as well as bought a newer one from a junkyard XJ and that had no effect either.

I definitely think that I could possibly have a vacuum leak, just not sure how to approach that... It could definitely be running lean causing the rough idle as well as heat issues. I removed the plugs that were in there and they were what you could call "over-heated". They were mostly white with some red with zero carbon build-up what-so-ever. I could actually probably get a picture of one if anyone is a spark plug guru.

I also think that I could have a fuel issue, causing a lean condition.

From this, let me know which route I should take first...
 
Maybe silly to ask, but when you put new head gaskets on it you made sure that every single passage and opening was not blocked by the gasket, partially or entirely?

If your vacuum problems seem to be worse when you step on the brakes, pull and plug your vacuum booster line and try driving it again. The diaphragm could have a leak.
 
OnlyOneDR said:
Maybe silly to ask, but when you put new head gaskets on it you made sure that every single passage and opening was not blocked by the gasket, partially or entirely?

If your vacuum problems seem to be worse when you step on the brakes, pull and plug your vacuum booster line and try driving it again. The diaphragm could have a leak.
Click to expand...

The head gasket was fine and centered perfectly from what I remember. It was FelPro so it should have been fine anyways... I didn't cheap out on the gaskets.

I guess I'll try this first, but driving without the booster is kind of sketchy... I guess I will try to do it on some empty roads and drive slow enough to make sure I have enough stop time.
 
ty20404 said:
Well I could see the issue with the Radiator, but that almost seems like a band-aid and not a true solution.
Click to expand...
Its about the only true solution to a cooling issue when you thin the cylinder walls and increase the amount of combustion inside of them. Not sure why you would consider it a bandaid, particularly coming from someone who had the same problem after doing a 4.0 stroker, but to each his own...
 
with it being a 96 you can not go to a 180 degree tstat or else the check engine light will remain on. the oem 195 stat is fine. as far as the fans go you need to upgrade them to something that actually pulls some cfm. the electric a/c fan and mechanical fan barely does anything for the stock 4.0. what you should really consider is finding a fan(or fans) that will correctly mount to the radiator (with a shroud, not just bolt it to the radiator, that way you get maximum cooling). next. another possibility is with it being a stroked 4.0, it will naturally put out more heat. you may need to cut a couple vents into the hood for ventelation, the 98 zj 5.9 had to do this. as far as the converter goes it is a very strong possibility that it may be clogged. whenever the exhaust becomes clogged there is excessive backpressure on the valves of the motor and it cannot breath. try pulling the exhaust off at the manifold and see if there is improvement. you could also be running too lean although you have the 5.0 injectors in there, try and find a way to figure out what the air/fuel ratio is.4.0's are designed to run on the leaner side but if too lean can cause overheating. also you may have an air pocket in the cooling system in the head. try jacking up the front end of the jeep a little to help burp any air out of the system. if that bubble happens to be around the Coolant temperature sensor then it can send a false reading. my 4.0 is lightly modified and i drive the dog crap out of it on the interstate with my taurus fan off and it still doesnt reach 200 .
 
The more that I think about it the more that a clogged cat seems to add up. I will hopefully unbolt the mid-section tomorrow and give that a whirl... If need be the local Advance has walker replacements.
 
It was a clogged catalytic converter.

I removed everything after the headers and let it run for a while. Eventually the temperature started to creep up but not nearly as fast as it had before so I popped the hood and to my surprise the temperature started to drop. Every other time I had popped the hood while the engine was idling the temperature continued to creep up. I went ahead and cut the old cat out of the pipe and to my surprise everything looked okay, the honeycomb was in-tact on both ends. But when I took a flashlight and stuck it in one end then looked down from the other side, the light only shined through about a 1.5" diameter hole through the middle of the honeycomb. Everything along the outsides appeared to be clogged.

I grabbed a walker replacement from my local advance for $112 and slapped it on there. Let it idle for a little bit with my code reader pulling live data and the temp floated between 187* and 190*. Drove a few miles down the road and back with the e-fan off and the temperature didn't go above 194* (ambient was about 85*). Parked in front of my house and let the car idle with the e-fan off until the temperature got up to 200* then flipped the e-fan back on.... Within about 5 minutes the temperature was back down to 192* and the temp stayed there. And I did all of this with the A/C on MAX blowing full blast.... Now, the next question is why isn't my aux fan blowing with my A/C but I have noticed that before which is why I wired in my bypass relay and switch to control the fan as I please.

I did notice a difference in my top end of revs as well, it pulls much harder in the upper range of rpms :) Well, now that problem is solved, but I think I am going to go ahead and put in a 200 or even 210 degree thermostat sometime soon... I'm not sure the 190 degree is really necessary.

Thanks for the help y'all
 
the auxilary fan has a relay that are common to go out, whenever that clutch on the ac locks the fan should kick on. should also kick on when the temps reach 220
 
So the new Cat significantly changed my operating conditions, but if I have the A/C running full blast and cut the aux fan the temp runs up.

When I'm warming the car up, the gauge gets to almost 210* then it appears the T-stat pops open and the temp goes down so that the needle is covering the "2" which I believe is about 192 from the numbers I've pulled off of my scanner. Which seems shockingly low... The only time I got the needle to come up to the point where the T-stat opens was when I would sit still for about 20-25 minutes, A/C on, aux fan on. It didn't seem to go past that point. Today I killed the aux fan and let the car sit but the temp ran up fairly quick. For the most part, the engine seems to stay pretty cold, except if I'm sitting still...

Another issue: I replaced my pre-cat O2 sensor because I wasn't sure if that might be causing my rough idle that I'm having, low and behold, 2 days later, CEL. I'm getting p0132 and p0135. It's a brand spanking new Bosch O2 sensor that is PnP and listed on Advance Auto's website as being the proper sensor for my car in the pre-cat location... I'm curious if this has something to do with my heat issue or if maybe I just have a bad sensor? I replaced the sensor that was there because I was afraid when the previous owner blew the old motor, the oil/coolant/etc possibly fouled it up.
 
dude all jeeps do that when it just sits there with the ac on. the only thing to fix that is a better efan. just put the original o2 sensor in it, put a triple fan setup on the radiator and be done with it. about the only other thing you can do is cut slots in the hood
 
My old MJ had a 4.8 liter stroker, about 10.5:1 compression and was by all means, abused when I used it. Know what the "cooling system" was? A stock radiator, stock water pump, stock fan clutch, stock electric fan and a stock rated thermostat. I raced most races in low range with sustained RPM's around 3-4000. It never, ever, under any circumstances ran hot.

IMO, you don't need any super-duper cooling fixes. You need to diagnose what is wrong. You may have 2 different issues here.

To start with, take a dollar bill outta your wallet. Start the Jeep, let it idle, Hold the dollar at the tailpipe and watch. Does the bill ever get sucke dup into the tailpipe? If it does, then you have a valve or two that are not sealing. Do that, and check back in.
Now, while it's still at idle. Put that same dollar in front of the grille. The fan(s) should hold it against the grille. The electric fan certainly will, but I wanna see if the mechanical fan clutch will also.

Also, are you SURE the timing chain was installed correctly? Incorrect cam timing will cause an engine to run poorly and too hot. Are you sure that any timing related components are indexed right?

I'll help you all I can...I know a thing or two about this sorta stuff. :)
 
Well, the dollar bill doesn't get sucked into the tailpipe, but the mechanical clutch fan will hold it against the grill as well as the e-fan... It really takes the jeep a while to heat up now since I've replaced the cat and o2 sensor but the gas mileage still sucks and the idle is rough. The engine does not idle smoothly in a physical aspect.... the RPMs don't change but you can almost tell something isn't firing right, like there is a miss occasionally but I don't have any codes. you can hear it at the tailpipe and the engine physically shakes a decent bit as if there's a miss.

I cleaned up all of my ground connections on the engine and it didn't change a thing. The RPMs still drop occasionally under braking and as soon as I come to a complete stop they go back up to normal... The voltage readout on my radar detector is showing 13.8V no A/C, 13.0V w/ A/C, and when the RPMs drop under braking w/ A/C it drops to 12.5ish Volts...?

As far as the timing goes, the gears and chain were from the stroker when I bought it. I simply removed the two gears and chain and laid them down without separating them while I swapped out the camshaft and returned them to their respective location... From what I remember there is a notch on the driveshaft for the lower sprocket to go on only one way and a little protruding pin on the camshaft to do the same thing for the upper sprocket. In addition to that there were two dots on the sprockets that were to be pointing one another when installed. If all that sounds right to you, then yes that was installed properly.

With the distributor... The housing can only go in one way.... right? And the shaft was lined up so that when cylinder 1 was at TDC, the arm was just before striking the shaft for plug 1 (i think that's right)?

What stumps me is that if any of this were done improperly, like the timing chain being off by one tooth or the distributor being indexed one tooth to far, I'm almost certain I would have more issues than a slowly overheating, rough idling engine????
 
Alright, so I went and picked up a new camshaft position sensor (the stator inside the distributor) on a whim that maybe the current one was reading correctly. It was a crap BWD part from Advance. Put it in, no change in idle or anything else... And then there was a code that came up: P1391 which has to do with either that sensor or the CKP sensor intermittently failing to read a signal. So I read somewhere that if you unplug this sensor while the engine is running, it should continue to run, so I unplugged it and the engine just crapped out. So I put the old one in because there wasn't any difference and I wanted my $40 back, reset the code and the Jeep just continued running as crappy as it always does.

I thought the P1391 code would be related to the old sensor but it's back. I reset it again earlier today and it is back on the pending list using the ELM software and ScanTool OBD scanner. I can log data now so if there is anything that someone wants me to look for please let me know.

What I gather from this P1391 code is that I may have too much slack in my Timing Chain?????? This timing chain and gear was on the long block when I received it and as far as I know it only has 40k miles on it.... But I could be wrong. Also, as I said earlier (I think) when I bought the engine the owner told me that the camshaft gear for the distributor was chewed up. He said that it was because of a bent distributor shaft, but I'm starting to think that it could be as a result of too much slack in the crappy timing chain that he had on here?

I get a lot of noise coming from the bottom front that sounds like it could be the timing chain having too little tension. Looking back to when I did the assembly of this engine I feel as though there may have been a good bit of slop in the chain, but it was just so long ago, and how much is "too much"? If the cam and driveshaft were too out of sync, this could cause my rough idle, I'm guessing, and the CKP and Cam position sensor to be out of sync just enough to throw the P1391.... Please, anyone, help!

I'm going to remove the distributor cap tomorrow and rotate the engine forward to see if the rotor moves immediately or not... may just go ahead and replace the timing chain tomorrow and see what happens.
 
So I replaced the timing chain...

A.) The old chain had a boat-load of slop. On the loose side of the chain i could move it probably a total of .75"-1" from side-to-side.
B.) The timing marks were off by one tooth (advanced cam I believe), so either I did that or the previous owner/builder (I don't ever remember separating the timing set).
C.) The chain was so stretched it was slapping into the little holder piece for the chain guide on the inside of the timing cover. Which is what all that racket was...

Once I put the new chain on, timed properly, it wouldn't start. Indexed the distributor rotor forward by one tooth and voila! So the chain that was in there was stretched (retarded cam) and off by one tooth (advanced cam) and the distributor was off by one tooth (retarded) that somehow it ran, albeit like shit.

For the last two years I wondered what all the hoopla was about with these strokers and now I freaken know.... This thing screams up to redline and has gobs on gobs of power. So stoked now but I'm keeping my fingers crossed that this solves the overheating issue once and for all but will have to wait for a warmer day as it is frigid outside.

I have pics and video of a lot of this stuff.... Mind blowing.
 
Here's some more stuff that may help people with this in the future:

Video of the timing chain noise from the front end:


Video of how loose the chain actually was:


Here's a picture of the inside of the timing chain cover, you can see where the chain was hitting the little tab that holds the plastic guide in:
ai20.photobucket.com_albums_b220_ty20404_2012_11_01_18_12_53_735.jpg


Picture of the actual assembly. Kind of hard to see the timing marks but I have the crank sprocket center and timing marks on the straight edge... Cam sprocket center doesn't line up:

ai20.photobucket.com_albums_b220_ty20404_2012_11_01_18_42_57_75.jpg
 
Also, just to clarify on a couple things that I didn't really follow up on... The O2 sensor that I had put in gave me some codes, but I returned it and got a new one and it's totally fine now. Just a bad Bosch part.... Actually surprised there.

Also, the P1391 is gone. I believe when I bought a replacement BWD cam position sensor the plugs on it were just of bad design and screwed up the female pins on the inside of the engine harness. I took apart that plug and cleaned up each pin and made sure they were "round" and held onto the male pins. Code hasn't come back.

As for the T-stat (I may have covered this), the part number that I ordered from RockAuto was a Gates 195* thermostat... Whether it is truly a 195* stat I do not know, because driving down the road it stays right at 189* for the most part, sometimes a little colder. The thermostat opens on initial warm-up just prior to hitting the top-center mark (210*) but never goes back anywhere near that. I'd be curious to see if this radiator/water pump/thermostat combo isn't allowing the engine to warm up enough....? I also wouldn't be surprised if my dumb self sometime after installing this Gates thermostat went to the auto parts store and bought a 185* stat and threw it in there but don't recall doing that.......... That would almost make more sense given the temperatures that I'm getting.

I do have a Stant thermostat (their best one) that is a 195* thermostat that I will switch into the Jeep when I get a chance, maybe this weekend. Also, I haven't looked really hard but where would I buy a higher than OEM temp t-stat? If the radiator/water pump are keeping it too cool I would want to switch over to a higher temp t-stat right?
 
So this thread never ends..... It's finally a little warm out today so I let it idle... and it got hot.

Just idling, the temperature slowly, ever so slowly, creeps up. Even still it runs ice cold driving down the road (always between 187 and 195 while read with a code reader).

So I turned on the A/C because I know the aux fan doesn't come on with the A/C (which is another problem) and got it to heat up to 220* (and of course the A/C fan still doesn't kick on even though it's supposed to at 218*). I then turned the A/C off and the engine slowly cooled down to 212* then over the next 25 minutes it got back up to about 219*.

Clearly, the biggest issue here is that the engine gets hot while idling. We know for a fact that the timing is right also... I'm thinking I may have computer issues or ground issues and this is why:

I have wired in a relay to the ground trigger wire for the AUX fan relay. Basically the ECM sends a signal to turn on the aux fan when the temp gets above 218* or when the A/C comp is on. So the relay I put in has a ground trigger from the A/C as well as a ground trigger from the switch in the cabin (wired the opposite way from a typical relay for something 12V+ signaled). The switch in the cab WILL turn on the AUX fan w/o sending a ground signal back to the ECM so no CEL from this. As I said the A/C won't turn on the AUX fan and neither will the temp. So as I've read online, the last thing to check if your ECM will send this ground signal is to pull the plug off of the temp sensor on the T-stat housing which should trick the ECM into going into a failsafe mode. Unplugged this and still no AUX fan...

So I'm starting to think that I'm not getting a good ground to my ECM which could be making it run the engine lean as well as not let it turn on the AUX fan. I'm just saying this because people have state elsewhere online that a bad ECM ground will cause the vehicle to run rough. Someone please help me with this. I'm pulling my hair out.
 
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