Cooling System - mods run cooler

F9K9 · Post by **F9K9** » Thu Jun 12, 2008 5:39 pm

HenryJ wrote:Mines on #8

Thank you, Sir!

F9K9 · Post by **F9K9** » Fri Jun 13, 2008 4:21 pm

Well, I was going to give the new VSC credit for solving my overheating problems tonite but, I can't do it. It helped tremendously but, didn't totally solve my issue. During my lunch break I gingerly asked a muffler shop if, they would remove my precat and weld in a straight pipe. They agreed to do it after telling me it was covered under warranty and much discussion. The CC was running the entire time. I didn't have time to have it done then but, on my way back to work I was in heavy traffic. The gauge hit 225° but, didn't climb any higher. Normally I would have had to turn the AC off and drop the windows to keep it from climbing further. I am getting close to a solution thanks to Brule and much reading. If, my precat turns out to be clogged, then the removal will solve my overheating and bad gas consumption problems.

F9K9 · Post by **F9K9** » Sun Jul 06, 2008 3:32 pm

Update. Early indications are that the the removal of an unclogged pre-cat along with replacing my VSC may have solved my issues but, the jury is still out for me.

I stumbled across some interesting reading about relocated IATs in a heep forum but, again, nothing verified.

With permission from from JimmtyC on Rubicon Owners Forum.com

JimmyC wrote:..............................I don't know the Jeep PCM programming. But the GM i worked on in the past works like this. The PCM will not command MORE ignition timing for any reason reguardless of the IAT. But, once the IAT reaches a threshold (~120ºF) the PCM will begin reducing total timing. So, by getting the air temp as close to ambient, you will not loose timing. You will also gain from having a colder/denser air charge. Also, by having the sensor close to the TB, you are allowing the system to error on the side of caution. Meaning if the temp does get high, it will pull timing to help keep the engine from overheating.

With my problem possibly solved, I am somewhat confused with this concept. The confusion lies in moving the IAT closer to the TB when I understood it should move farther away. Again, remember we are mixing apples and oranges. The particular set up he was talking about had the IAT on the intake and not the tube.

F9K9 · Post by **F9K9** » Sat Jul 12, 2008 10:59 am

Another Update
Looks like the the over heating issue is finally solved. The removal of the pre-cat was the final piece of the puzzle. I just completed a minor highway trip with temps at 95°. My gauge never went over 205° and I was in stop and go traffic for awhile. An added bonus was that I got 15.4 mpg which may not seem like much to you but, it's about 5 mpg better that I got going to Hot Springs last year. That's with rolling 33/10.50 meats and the roof rack. I would venture to guess the rack eats 2 mpg easily.

Post by **HenryJ** » Sat Jul 12, 2008 11:23 am

Nice! That mileage is average for this set up. About what I get most days.

Interesting that though the precat looked good it still was the culprit. Post that information in the plugged precat thread too so others will find it easily. Thx.