Comanche County Posted December 15, 2012 Share Posted December 15, 2012 Still getting a high idle upon start up. I've changed the TPS, MAP, and IAC. I sprayed soapy water trying to find a vacuum leak. I've put my eyeballs a few inches from every vacuum line and still, I'm getting a high idle upon start up. It's around 2.8-3k. Really annoying. It stopped for about a week and ran fine, now it's doing it again. Any ideas? Thanks, Jay Link to comment Share on other sites More sharing options...
ComancheKid45 Posted December 15, 2012 Share Posted December 15, 2012 Was the new TPS set to the correct voltage? Link to comment Share on other sites More sharing options...
jpnjim Posted December 15, 2012 Share Posted December 15, 2012 Check the wires leading to your TPS I would get an intermittent high idle like that, move the wires around a bit, and it would calm down. On a different 4.0L it would take 20 seconds or so to start when cold, always followed by a high idle, till the excess fuel pumped in cleared out. On that Jeep, turning the key forward to the run position for a few seconds before cracking 'cured' the problem. On your Jeep, I'd check the whole harness for obvious issues (tho sometimes you can't see it) & look for a leaky injectors. If you haven't yet, taking the throttle body off, and completely cleaning it helps too. Something might be intermittently stopping the IAC from moving. Link to comment Share on other sites More sharing options...
Pete M Posted December 15, 2012 Share Posted December 15, 2012 soapy water for a vacuum leak? :hmm: I've always used that for air escaping out (like a tire leak), not air going in. use a flammable substance like starter fluid or propane (unlit of course). when the vacuum sucks in it the leak, the engine rpms will change and alert you to the problem area. :thumbsup: Link to comment Share on other sites More sharing options...
Comanche County Posted December 15, 2012 Author Share Posted December 15, 2012 Thanks for the input guys. Still under the hood now. I've got the TPS adjusteded according to guru Cruiser's guidelines. Input and output voltage is within 17%. Now my idle is up to 4k! You're right Pete, soapy water probably isn't the best for a sucking vacuum leak. Kinda scratching my head right now. Link to comment Share on other sites More sharing options...
Comanche County Posted December 15, 2012 Author Share Posted December 15, 2012 Jim, if I can't figure this out tonight the I'll take the TB off and clean it good like you recommended. Link to comment Share on other sites More sharing options...
Comanche County Posted December 15, 2012 Author Share Posted December 15, 2012 Just took the TB off...cleaning it like a starving Pakistani now. Link to comment Share on other sites More sharing options...
Comanche County Posted December 15, 2012 Author Share Posted December 15, 2012 Cleaned the TB, still idling at 4k. Link to comment Share on other sites More sharing options...
Pete M Posted December 15, 2012 Share Posted December 15, 2012 tried the starter fluid yet? carb cleaner works too. heck, wd 40 might even work, but I recommend using something that evaporates cleanly and quickly. :thumbsup: Link to comment Share on other sites More sharing options...
Comanche County Posted December 15, 2012 Author Share Posted December 15, 2012 Yup, tried carb cleaner on all the tubes and hoses. Still idling around 3.5-4k. I've decided to retire for the night and consume some hallucinatory beverages from the New Belgium brewery company and offer a small sacrificial offering to the jeep gods by placing multiple pins in a small voodoo doll of Kim Jun Un. Link to comment Share on other sites More sharing options...
ftpiercecracker1 Posted December 15, 2012 Share Posted December 15, 2012 What would it do if you disconnected your TPS entirely? Link to comment Share on other sites More sharing options...
jpnjim Posted December 15, 2012 Share Posted December 15, 2012 You could also check to see if your intake manifold bolts are tight. They do loosen up. I also unplugged my TPS when diagnosing my issue, I just can't remember what that did :) I'm running out of ideas. Link to comment Share on other sites More sharing options...
ftpiercecracker1 Posted December 15, 2012 Share Posted December 15, 2012 What would loose intake bolts have to do with excessively high idle? :hmm: Loss of vacuum? Link to comment Share on other sites More sharing options...
Biotex Posted December 15, 2012 Share Posted December 15, 2012 Any type of a vacuum leak causes a high idle. Link to comment Share on other sites More sharing options...
jpnjim Posted December 16, 2012 Share Posted December 16, 2012 What would loose intake bolts have to do with excessively high idle? :hmm: Loss of vacuum? Yep, big vacuum leak. Crazy idles on Renix's are usually electrical issues, but it still could be a mechanical/vacuum issue. You said the idle races at start up, does it calm down afterwards? Link to comment Share on other sites More sharing options...
88blackpearl Posted December 16, 2012 Share Posted December 16, 2012 My vacum block had a leak...I think....so i just straight hosed them together. It resolved my high problem. Link to comment Share on other sites More sharing options...
ftpiercecracker1 Posted December 16, 2012 Share Posted December 16, 2012 ....so i just straight hosed them together. What ? :hmm: what do you mean straight hosed? Link to comment Share on other sites More sharing options...
mountainman Posted December 16, 2012 Share Posted December 16, 2012 Hes saying he bypassed the vac block. I'm renix impaired (and proud) so I'm of no help. lol. Link to comment Share on other sites More sharing options...
Goose Posted December 16, 2012 Share Posted December 16, 2012 Have you tried applying bfh? Link to comment Share on other sites More sharing options...
cruiser54 Posted December 16, 2012 Share Posted December 16, 2012 Did you do the sensor ground test in my TPS write-up? You did your 17% adjustment off the flat plug, right? Where output voltage is 17% of input voltage? Your description of your results has me concerned. Link to comment Share on other sites More sharing options...
Comanche County Posted December 17, 2012 Author Share Posted December 17, 2012 Did you do the sensor ground test in my TPS write-up? You did your 17% adjustment off the flat plug, right? Where output voltage is 17% of input voltage? Your description of your results has me concerned. Roger, I'm at 17%. It seemed to have settled down, no more 3-4K idling. But now its idling at 1200 rpms, still a tad high. One good thing happened though, probably from swapping the sensors, it is running noticeably better. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 17, 2012 Share Posted December 17, 2012 That's too high an idle. Has this always been a problem? Anyone ever mess with the throttle butterfly screw? Link to comment Share on other sites More sharing options...
Comanche County Posted December 17, 2012 Author Share Posted December 17, 2012 Nope, I've never touched it. I'll check it out in the morning. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 17, 2012 Share Posted December 17, 2012 So, it didn't have this issue when you got it? Link to comment Share on other sites More sharing options...
cruiser54 Posted December 17, 2012 Share Posted December 17, 2012 Have you sprayed around the intake/hoses with throttle body cleaner to find vac leaks at idle? Ever done a ground refreshing? Link to comment Share on other sites More sharing options...
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