Jeep Cherokee: Heat Soak & Vapor Lock Explained (Cylinder 3 Misfire, Rough Warm Start) ['00-'01 XJ]

[@idleprechaun]

Hey man! Just swinging by to thank you for all your tips in previous vids. Girlfriend and I drove from the Chicagoland area to LA. We are currently headed back but got a busted TPS mid way through the mountains of CO. You mentioned in previous vids to always carry spare sensors and thank god I did. 10 minute repair in a Taco Bell parking lot and we’re back on the road. If you’re ever in the area I owe you one

[@dhatsuyuki]

This is actually why I 2.5L swapped my XJ

[@WAEMIDIV]

chad move

[@Trevosamo]

Great video, lots of good info here! My 2001 developed heat soak AFTER installing a banks torque tube header and new CARB walker pre cats. No idea why that seemed to make it hotter than the cheapo ebay header and old cats. I even started stumbling while parked and idling for long amounts of time (damn popeyes drive thru!!) But I eventually wrapped the fuel supply line and did the fan switch which "cured" it. I get a lot of concerned comments from friends and passerby's when I park and have the loud ass fan on but at least it works!

[@gearsnstuff7330]

Fun fact, a lot of old tractors have reverse flow engines, to the point that some of them have the intake and exhaust manifold cast as one unit. I have a 1923 Mack truck that has coolant plumbed through a jacket inside the intake manifold, for the express purpose of (as stated in literature for the truck) preheating the fuel-air mixture for 'Maximum efficiency'. Now, this was in part due to lower quality fuels in 1923, but that still makes me chuckle every time I think of it.

[@WAEMIDIV]

Ah yes, "wet manifolds" they call them, my white Comanche also had a coolant line through the intake with that same purpose. On carbureted or TBI engines, where fuel has to travel through the manifold, it helps it not condense on the walls inside of it, and remain an atomized mixture. Very interesting stuff

[@gearsnstuff7330]

That may have been the effect that it had, but the pamphlet clearly states that it preheats the air-fuel mix for better efficiency, which to my understanding isn't how that works. I'm sure it does help with what you mentioned, whether by design or happy accident, since there's over a foot of updraft tube between the carb and the intake manifold. And I really shouldn't be surprised that AMC was borrowing design features from 1920s industrial trucks, should I?

[@WAEMIDIV]

well think, technically, when fuel *isn't* condensing on the walls of the manifold, more of it is reaching the engine and actually being burned, which does mean it's more efficient than it otherwise would be

[@gearsnstuff7330]

I suppose you're right, I'll give the Mack engineers the benefit of the doubt, and chose to think that that was their intent, not 'More heat= More better". Then again, it's a 255 inline four that supposedly made forty horsepower brand new, I think that torque was a little higher on their priority list than efficiency.

[@drgil65]

Thanks for your video, I’m in Arizona the weather here gets into the 3 digits plus. I honestly have to say I have never had a heat soak issue, but then I do have a 99 XJ.

[@WAEMIDIV]

@drgil65 yeap I've never seen it happen on the older ones, I've only heard alleged stories of it

[@AnonymousAnonymous-xl7mf]

It has happened to me once. I was in Wickenburg AZ in 90 degree weather. Was rock crawling uphill slowly for about an hour before I shut off the XJ for about 5 minutes to find out how I was turning around and getting back. Turned it back on and I had heat soak. It’s a ‘98 auto with hood spacers but after about an hour of the rock crawling the temp was creeping up around 225 when I shut it off, knowing the XJ I’m sure it got even higher. My fan clutch and cooling system have seen better days though so it’s not too surprising.

[@seiser42]

I solved mine with aluminum HVAC tape around the fuel rail. I really like that fan idea.

[@rachelfrew8596]

I love your videos and look forward to anything new regarding Jeep XJs. You’re amazing, please keep them coming. Nice job

[@the-pezinator]

That fuel chart is so real, I can only attest for two of them but I have noticed when I get the Valero I have more instances of bad heat soak as compared to Sunoco, Sunoco I barely have issues, when I do have you soak I just push the pedal a couple of times to force more new fuel into the fuel rail and that seems to fix the problem faster, also great finally seeing this mod in "person" technically, I always have trouble comprehending diagrams and implementing them to the actual thing, being able to see both really helps me and I might actually do this mod.

[@hanaguz73]

Interesting video, I have a 1994 Jeep XJ Sport and so far I have not had any problems with overheating, after putting the electric fans directly to the battery with a relay And it turns on with the key, while with the aw4 transmission I have not had temperature problems either.

[@anthonypereira7204]

I’ve got the e fan switch and heat shielding on my 2000. It wasn’t until I wrapped the fuel line in the heat shielding also that my heat soak completely went away. That fuel line runs right next to the exhaust manifold, so all the fuel in there would turn to vapors very quickly.

[@WAEMIDIV]

that's also a good idea, I haven't ever seen that done. I think I'll do that

[@FIRE-OWL.]

I heard the hood spacers don't really do much, I drove my 00 cherokee to mexicali for a week, so hot dessert air plus allready hot engine air, the electric fan with a switch, is def the best thing for it.

[@Sinfulsnoflake]

Heat shielding is a must in fl

[@kylemandt527]

Great video. Thanks for the details. This is awesome.

[@tomkatinokla1]

Very good video! Years ago I installed the factory shields (which had little effect), then discovered the kit sold on Summit, which I installed over the factory parts. Helped slightly. Then installed hood vents, that helped a bit more. Use of pure gasoline vs E-10 was biggest help, though I sometimes still have issues, presumably due to inconsistent fuels. I've thought about modifying the electric fan, but have never gotten around to it. Your success with it has inspired me to get to it. Thanks.

[@WAEMIDIV]

I can always tell when a station is selling actual ethanol free 87 vs when they're not, because I get heat soak if there's any ethanol in it. There's a Casey's near me that sells "87 Ethanol Free" for like $1 over what E-10 is, but it acts like regular 87, I'm fully convinced it's not ethanol free. I've used ethanol free from MurphyUSA and I can instantly tell the difference, perhaps we have a new conspiracy on our hands

[@kjohns236]

Thanks for the help! Always enjoy the videos 👊🏽

[@motownXJdad9565]

i did that D&E Bueller relay set up on a 2000 4 door i had, Doug and Eric are cool dudes. it worked great. the 2000 XJs also have a ECU problem with turning the Efan on when the AC is turned on like its supposed to, they dont do it at all, lol supposedly the dealer can fix it though, theres a TSB on it. i used my rear wiper switch on mine to be able to turn the Fan on, ive never used a rear wiper on any vehicle ive ever owned.

[@grad0n]

Ditch the pre-cats, buy the walker federal emissions downpipe, weld in two bungs post big cat, then extend the two downstream o2 wires.

[@KyleSVT]

Great video sir

[@hannahvaipulu3631]

Keep up the great content! Can you get the high idle switch to work on a manual swapped XJ?

[@WAEMIDIV]

No, that's what my second toggle switch on the dash used to be for, but the manual ECM simply doesn't have the programming to understand what "extended idle" means. I've tried to wire it up anyway but it just doesn't do anything. ):

[@hannahvaipulu3631]

@@WAEMIDIV Thank you for the follow up, I can give up on it now. Much appreciated.

[@Wrencher_I6]

Great video !!!! I have a 2000 xj I had to do the switch thing as well , wired it different but hay if it works it works !!!!

[@clevelandcarpenter8535]

Great video!

[@ProjectXJ]

I have a 97 with a new radiator and heater core. Driving down the road it never gets heat soak but when i stop or when i offroad, its been really bad. I tried the heat sheild and it helped some but not much. I got the fan override switch and hood vents that i need to install. I am hoping this will solve the issue.

[@josephjoestar3275]

Wow nice blue cj5!!!

[@WAEMIDIV]

JosephJoestar would love it

[@davidk7132]

Lmao the spongebob ending 😂

[@firesorcererfs6029]

I’ve personally never had this issue at all or even overheating i always hear a lot about overheating on this engine but I have it on 4.5lift on 33x12.5R15 with auto trans and I do drive it heard especially on the expressway and never had overheating issues

[@firesorcererfs6029]

And as far as fuel I use Non-ethanol since I have a gas station down the road that provides non ethanol

[@iAmJankus]

So I used 14ga + 10amp fuse and wired my TDR following the D&E video diagram, but I grounded to my battery. Last night, I stopped somewhere for a few minutes, hit the switch, the fan did it’s thing, I tried to start the car a few minutes later and everything shut off. Seemed like the car shorted out. Instantly went under hood, no smoke, no fire, no melted wires, fuse still intact. I wasn’t getting any power. Wiggled my battery a bit and saw a spark. I guess the negative terminal was loose. Still no power. 5 minutes later, I had power. No idea what caused it. I’m looking at all the connections and wires again now, still looks good. My best guess is it wasn’t a good ground connection? Hesitant to reconnect again. Any input is appreciated. I’ll update if I can figure out what caused this. Also, I’m watching this video thinking it’s years old haha but it’s only a few weeks. Strangely comforting knowing someone can be going through same issues as you. 😂

[@WAEMIDIV]

@iAmJankus The symptoms you're having are of loose battery terminals. Make sure they're both clamps down good I doubt you compromised anything running a fan override

[@iAmJankus]

@@WAEMIDIV my lack of electrical knowledge is what makes me scared to tamper too much haha. My fears had me instantly worrying of my xj catching fire. But my logical sense tells me it was loose. Reconnecting it now w a better connection than before. Will update

[@elibrown8539]

What about wrapping Exhaust all the way up to the intake, manifold properly be good idea

[@WAEMIDIV]

@@elibrown8539 Yes that's a good one, probably the best solution as it keeps the intake air colder too

[@elibrown8539]

Buying Cold air intake. yeah got it

[@kp7100]

Does anyone have the mopar part number for a 98 Cherokee xj 4.0 for the crankshaft position sensor. I keep getting different part numbers and in those part numbers some say they don’t fit or they do fit. Please help

[@nothsa1107]

Electric fan override is the best cooling upgrade. Especially for an engine with a cooling system that isn't in perfect running shape. My block is super rusty, I flush the system once a year and it still comes out brown every time. Only solution is to pull the engine and have it cleaned. And who has the cash for that these days?!?

[@s3viking_Y2K_Sport]

Add route 66 to the good gas list. Its another midwest station. at least in missouri. keep in mind also my 2000 with fed emissions has vapor lock sometimes. just depends.

[@WAEMIDIV]

Yep I've had good experience with Phillips 66 I kinda forgot it was a thing

[@s3viking_Y2K_Sport]

@@WAEMIDIV look up top tier gas. It’s a gas rating given to gas station with verified best gas. More detergents, stability, etc

[@hannahvaipulu3631]

Ok ok last ask, 2011 - 2017 Compass/ Patriot steering wheel swap with the cruise control board that adapts the new steering wheel buttons to the xj's cruise control! Need a write up... video up?.... you know what I'm trying to say.

[@WAEMIDIV]

uuuuuuuuuuhhhhhhhhhhhhhh

[@hannahvaipulu3631]

@@WAEMIDIV I see that people swap with the patriot steering wheel into the XJ, they even make a board that retains the factory button usage. You down to do to a video on the swap?

[@jacob7007]

miss those prices

[@WAEMIDIV]

@jacob7007 one of the very few benefits of IOWA lol

[@seankonzman58]

If the injectors are swollen, heat soak will happen more often too

[@danhambrick6331]

Too bad you cant just get rid of the two pre-cats.....

[@WAEMIDIV]

@danhambrick6331 now that is an interesting prospect I have been tossing around an actual full conversion to a federal emissions setup, including an ECM reprogram and wiring harness and everything to remove the pre cats in a "factory" way, but that's pretty low on the priority list

[@gamersplaygroundliquidm3th526]

92-94 Octane gas has 10% Ethanol in it not, 0% REC-90 is the only non-Ethanol gasoline

[@WAEMIDIV]

oh I see.

[@gamersplaygroundliquidm3th526]

@@WAEMIDIV yeah I always thought that 93+ didn't have ethanol, till about a year ago when I had my generator sitting for a year and had only 94octane sitting in it, well it ate the carb seals and anything not metal in the carb was gone not to mention it didn't even smell like gasoline. The carb damage was the same as my buddie's commercial mowers carbs look like after sitting all off season and someone forgets to use stabilizer or the stabilizer didn't work too great. Ever since they started adding ethanol to the gas every single line trimmer needs a carb rebuild every season. It's so problematic the Stihl actually makes a rebuild kits for their commercial lawn equipment specifically for the carbs and they make them in mass quantities compared to how many they made before ethanol came out. We used to go seasons without an issue on the carbs but run some good old Ethanol through them for the mowing season and after the winter half the seals are dry rotted and the carb is clogged and float bowl is stuck. 😂