Knucklehead97 Posted October 17, 2014 Share Posted October 17, 2014 I've been annoying Cruiser for about 3 months trying to figure out what my trucks problem is. I've decided that I would post a topic on it and get more opinions as I am completely stumped and aggravated with the thing. The problem is that when I rev the engine it tries to kill itself and even when I push the gas a little bit to keep it alive, once I let off again it tries to die again. Also I have mini backfire "poofs" out the exhaust once the truck warms up. When the truck warms up my idle is VERY low and fluctuates A LOT. Here is a list of everything I've done.Changed to Volvo injectors.Changed EGR.Tried a different IAC valveChanged sparkplugs.Changed cap and rotor.Checked the timing.Cleaned throttle body and set the butterfly set screw per Cruisers instructions.Changed MAP hose.Changed O2 sensor.I don't have a cat so the exhaust isn't clogged (new Thrush Welded muffler)Upgraded and refreshed grounds. All negative cables (and soon to be positive cables too) are 1 AWG welding cables.Sprayed carburetor cleaner EVERYwhere and haven't found a single vacuum leak.Snugged up exhaust/intake manifold bolts.I have tested the MAP and made sure it was to spec.And most recently... the TPS was changed.I replaced the TPS earlier today and the problem was fixed!... The first time I cranked the truck. Thats what has me stumped. The first time I crank the truck after adjusting the TPS it runs GREAT. Doesn't stall out at all. (still has a low idle though) but as soon as I shut the truck off and crank it again it runs like crap until I mess with the TPS again. It's like the computer isn't remembering that the TPS is set correctly until I set it again. But the Renix computer doesn't hold information, does it? I have backprobed the TPS plug after revving the engine a few times and it NEVER returns back to where I had it adjusted. It usually is about .95-.102v when it's supposed to be .83.ANY help is appreciated guys. I just really need to get my truck going asap. Link to comment Share on other sites More sharing options...
1989 Eliminator Posted October 17, 2014 Share Posted October 17, 2014 Take a look at the thread in my signature about rough idle. It is a lot of pages but I had the same issue as you and cleared up my problems. I would try: -cleaning all electrical connectors -check for high resistance for all your ground wires. I'm not just talking about your big ground cables, I'm talking about sensor ground wires and ecm ground wires. You would have to get a electrical manual to really see where everything is -make sure your O2 sensor is getting the 12V to heat it up. -This also could be a intermittent bad CPS Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 17, 2014 Author Share Posted October 17, 2014 I forgot to add that I tested the CPS and the truck starts right back up with no problem. So I doubt it being the CPS. The problem is really weird. I went out and started revving my truck, shutting it off, and revving it again. And today it just wasn't stalling out as much. It tried to stall maybe twice out of multiple revs. The idles still crazy... But wasn't stalling. I'm almost positive it has something to do with the TPS in some way. Whether it be connection or the adjustment itself. Is there a electrical manual on the internet which could tell me the where the grounds and all that are? Maybe I should mess with the air bypass screw on the throttle body (the one that fixed your problem)Yet again any help is appreciated and your thread has been very informative :thumbsup: Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 17, 2014 Author Share Posted October 17, 2014 After reading 100% through your rough idle topic. I noticed 2 things. 1, my positive cable that goes from the battery to the relay center (or whatever its called...) is VERY small compared to yours. Mine looks to be around a 14 gauge wire. Could the size effect the way the sensors work? Like I said I have big cables to install, I just haven't installed the positives yet. And 2, my air bleed screw is very far out compared to yours. I mean it's maybe 1/8" away from the edge while yours is far inside the tunnel. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 17, 2014 Share Posted October 17, 2014 After reading 100% through your rough idle topic. I noticed 2 things. 1, my positive cable that goes from the battery to the relay center (or whatever its called...) is VERY small compared to yours. Mine looks to be around a 14 gauge wire. Could the size effect the way the sensors work? Like I said I have big cables to install, I just haven't installed the positives yet. And 2, my air bleed screw is very far out compared to yours. I mean it's maybe 1/8" away from the edge while yours is far inside the tunnel. Interesting on the bleed screw. Did you expose it or was it already exposed? You did Tip 5, correct? Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 18, 2014 Author Share Posted October 18, 2014 The cap was already off before I even knew the bleed screw existed. So I'm guessing the previous owner had messed with it. And yes, I did number 5 and the ohms did not flucuate at all and were almost 0. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 The cap was already off before I even knew the bleed screw existed. So I'm guessing the previous owner had messed with it. And yes, I did number 5 and the ohms did not flucuate at all and were almost 0. If the cap was off, you're probably right. I don't happen to know where it was originally set. Try setting it like the one you saw. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 18, 2014 Author Share Posted October 18, 2014 First off, here's where my idle is. Super low, right? And it sometimes goes even lower. And secondly here's the real update and possibly the cause of my problems... Isn't that bottom lever supposed to be touching the top one? Yes, yes it is. Ends up when I only rev to around 2500 and hold it for a bit the spring inside the TPS doesn't have enough unf to put it back to .83. When the lever was like this my voltmeter was reading about .300 which is so high an A/F ratio that it kills the engine upon letting off the gas pedal. Or at least thats what I THINK is going on. Do I REALLY have to go to MOPAR and spend like $60+ on an OE TPS? I thought Standard Motor Products were supposed to be good quality, or at least thats what everyone was telling me. And lastly I screwed the air bleed screw all the way in and backed it out a little bit. Didn't really change anything. Let me know what you guys think on this.Thanks. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 Need to get tPS issue straightened out first. $60 is sounding like a deal now compared to the aggravation you went through........ Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 18, 2014 Author Share Posted October 18, 2014 Well $60 didn't sound bad. But the $120-$172 that Mopars website says, does sound bad. If I send this sensor back then that'll be almost $30 just in the shipping for the two TPS's I've bought being sent here and sent back. Does no where sell Mopar brand for less? I honestly can't even afford the sensor for another few weeks at least... Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 Get the PC307 from RockAuto. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 18, 2014 Author Share Posted October 18, 2014 PC307? Thats a CPS according to Rock Auto. I've bought all TPS options from Rockauto for the Auto trans. The only Standard trans one they have is made by the same company that made the auto one I have currently. Another weird update, though. Sprayed the TPS lever with some WD40 and it's not sticking nearly as much, hardly is really. And the truck only tries to stall on the first rev of every start. Otherwise seems to do good. Still low idle/backfires and all that too though. It's just really crazy the fact that it's only doing it on the first rev for some reason. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 Brain fart on my part. Sorry. Have you tried loosening the attaching screws so there's no bend or bind on the TPS itself? Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 19, 2014 Share Posted October 19, 2014 Good example in this post detailing the fun you can have with Renix sensors. :P Link to comment Share on other sites More sharing options...
cruiser54 Posted October 19, 2014 Share Posted October 19, 2014 Good example in this post detailing the fun you can have with Renix sensors. :P Oh come on Eeyore. We're having a ton of fun!!!! Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 19, 2014 Share Posted October 19, 2014 Good example in this post detailing the fun you can have with Renix sensors. :P Oh come on Eeyore. We're having a ton of fun!!!! Hey Knucklehead! You having fun too beatin' on that dead horse? Hang in there mate. :cheers: Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 19, 2014 Share Posted October 19, 2014 http://www.ebay.com/itm/Throttle-Position-Sensor-TH20-Cadillac-Jeep-Eagle-82-9-/110328488272?pt=Motors_Car_Truck_Parts_Accessories&hash=item19b0172150&vxp=mtr http://www.ebay.com/itm/Throttle-Position-Sensor-Cadillac-Jeep-17078259-GM-/131188450876?pt=Motors_Car_Truck_Parts_Accessories&hash=item1e8b70e63c&vxp=mtr Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 22, 2014 Author Share Posted October 22, 2014 ^ I appreciate the links :thumbsup: I'm not purchasing ANOTHER TPS just yet. I tinkered earlier but didn't get around to loosening the TPS. I added my big positive cables and cleaned all connections on the distribution block, then turned the key to ON (didn't crank cause I didn't have time to let it idle.) and wow... the fuel pump kinda sounds more lively. Possibly wasn't getting enough power at times? Long shot but maybe. Also found that the fuel pressure regulator vacuum line had slid out a little bit and MAYBE had a vacuum leak from it. Possibly the pressure being 40 PSI when disconnected instead of the 31 when it's connected made the truck have mini backfires and low idle? Both long shots. But slightly make sense in MY mind. The connections on the distribution block were extremely corroded... Also I have no idea how the 14 gauge wire going to it was giving anything enough power to operate properly before the alternator kicked in.Hoping to tinker more after work and before church tomorrow. I'll keep ya'll updated. Oh and Hornbrod... I'd be having as much fun as Cruiser if this wasn't my truck :yes: I'm hanging in there though. Can't even begin to imagine giving up on my dream truck. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 22, 2014 Share Posted October 22, 2014 ^ I appreciate the links :thumbsup: I'm not purchasing ANOTHER TPS just yet. I tinkered earlier but didn't get around to loosening the TPS. I added my big positive cables and cleaned all connections on the distribution block, then turned the key to ON (didn't crank cause I didn't have time to let it idle.) and wow... the fuel pump kinda sounds more lively. Possibly wasn't getting enough power at times? Long shot but maybe. Also found that the fuel pressure regulator vacuum line had slid out a little bit and MAYBE had a vacuum leak from it. Possibly the pressure being 40 PSI when disconnected instead of the 31 when it's connected made the truck have mini backfires and low idle? Both long shots. But slightly make sense in MY mind. The connections on the distribution block were extremely corroded... Also I have no idea how the 14 gauge wire going to it was giving anything enough power to operate properly before the alternator kicked in. Hoping to tinker more after work and before church tomorrow. I'll keep ya'll updated. Oh and Hornbrod... I'd be having as much fun as Cruiser if this wasn't my truck :yes: I'm hanging in there though. Can't even begin to imagine giving up on my dream truck. You're doing fine. Keep up the good work. Link to comment Share on other sites More sharing options...
deziped1 Posted October 22, 2014 Share Posted October 22, 2014 Had similar problem it was a bad vac connection at fuel valve pressure relief/return line. I think it was letting fuel go through the line back to the tank and reducing fuel pressure. Any way just pulling the vac line off and pushing it back on cured the problem. .. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 23, 2014 Author Share Posted October 23, 2014 Had similar problem it was a bad vac connection at fuel valve pressure relief/return line. I think it was letting fuel go through the line back to the tank and reducing fuel pressure. Any way just pulling the vac line off and pushing it back on cured the problem. .. The line that goes from the manifold in front of the TB and connects at the fuel regulator on the end of the fuel rail? Thats the exact line I found pushed out a little bit and thought might be the problem. As soon as I get the time I'm going to add some sealant to it to keep the line sealed and see if the truck runs right now. Glad to hear that a theory I had could be the fix :thumbsup: Link to comment Share on other sites More sharing options...
cruiser54 Posted October 23, 2014 Share Posted October 23, 2014 If that line is loose, Vacuum is reduced to the fuel pressure regulator and fuel pressure increases. That can cause a rough idle. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 23, 2014 Author Share Posted October 23, 2014 Sealing the line better helped the idle a little bit, not much though. All other problems still persist. I decided to test my MAP and O2 sensor again to be sure, the new O2 sensor works perfectly. But the MAP sensor seems to be failing. It has the correct voltage with the engine off and key ON. But when the trucks temperature is at 190-200 degrees (the test says use a HOT idling engine) It stays from 1.4-1.5 volts and SOMETIMES goes up to 1.6. Also is the MAP's volts supposed to go up or down when you rev the engine? Because when I revved the engine the voltage went down below 1 volt. I expected them to go up. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted October 24, 2014 Author Share Posted October 24, 2014 http://www.rockauto.com/catalog/moreinfo.php?pk=40694&cc=1181674 What do you guys think about this MAP sensor? It's Standard Motor Products good series (not the cheap T series) and it's a wholesaler closeout so they're only 21$! Link to comment Share on other sites More sharing options...
cruiser54 Posted October 24, 2014 Share Posted October 24, 2014 Should be just fine. Link to comment Share on other sites More sharing options...
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