jonnie_r Posted August 16, 2014 Share Posted August 16, 2014 I have my MS setup running, but seem to have an issue with the TPS. It is a bit all over the place, and the calibration point always changes. One minute it will be reading -10% or more then a quick flick of the throttle and it will be at 15% or so. I'm guessing that the TPS is fubared, and with disco 1 units costing £100, I was wondering how easy it is to swop the idle system from my 3.9 plenum on to the plenum for the 4.6 engine that I recently fitted. Is it worth it or do I just fit PWM control? The engine is running and I've managed a few drives in it, but with the TPS seemingly somewhat erratic it's hard to get everything set properly. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted August 16, 2014 Share Posted August 16, 2014 welcome With Megatune connected, go to Tools > Calibrate TPS there are then 2 x Boxes, With ignition on click 1st box and notenumber - report back then push throttle to floor and click, note number and report back your looking for something like 10-30 top box 250+ - 300 bottom box What do you have ? Nige Quote Link to comment Share on other sites More sharing options...
jonnie_r Posted August 16, 2014 Author Share Posted August 16, 2014 Thanks for the welcome, I've been here a while reading bits and pieces. I took my knackered 3.9 out and put a 4.6 tophatted GEMS in my disco. Took me about 6 months of an hour or two here and there but anyway now running. Back to the problem. It reads anywhere from around 480 to 570 at the bottom level and around 900 at the top. I've calibrated and recalibrated but it does seem like the TPS is knackered as it is never the same every time, unless I've got it connected wrong, but I don't think I have. Jon Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted August 16, 2014 Share Posted August 16, 2014 I would check the throttle mechanism is going all the way to the stop. Some people fiddle with the cable to alter the idle rather than using the bypass and it can mean the butterfly doesn't always stop at the same point and therefore neither does the tps . You might get away with turning it a bit to get it in range. Also check the wires, mine was irratic as the sheathing was broken near the tps body but was ok after I covered it with a bit hot glue or silicone. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted August 16, 2014 Share Posted August 16, 2014 Er...thats either wide open Trottle or even wider open throttle ! Quote Link to comment Share on other sites More sharing options...
Cheesy Posted August 16, 2014 Share Posted August 16, 2014 I put a 4.6 plenum on a 3.5, it mostly bolts straight on. A few things to consider though, it doesnt have the butterfly bypass that the 3.5 did (not sure about the 3.9), it uses shorter bolts to hold it on and the idle circuit is different, it may be worth opening the butterfly stop a little bit while it is off the engine, I didnt so had to put the idle valve on to be able to drive it. What I did was use the stepper motor gasket as a pattern to make a 3mm steel flange and then welded a tube to it, this goes to the PWM valve. Then (with the plenum off the motor I roughed up the inside of the hole that goes through to the inside of the throttle body, put some tape around the inside of the throttle covering the hole and poured some Devcon in there, Making sure it didnt cover the passage that bypasses the butterfly. I actually did the same thing with the breather tube there as well. It seems to work, I just ran out of argon before I managed to make mounts up for the air filter. It is probably one of the last pictures in my build thread. Quote Link to comment Share on other sites More sharing options...
jonnie_r Posted August 17, 2014 Author Share Posted August 17, 2014 I would check the throttle mechanism is going all the way to the stop. Some people fiddle with the cable to alter the idle rather than using the bypass and it can mean the butterfly doesn't always stop at the same point and therefore neither does the tps . You might get away with turning it a bit to get it in range. Also check the wires, mine was irratic as the sheathing was broken near the tps body but was ok after I covered it with a bit hot glue or silicone. The throttle mechanism is functioning fine, I've tried the cable slack and with just a little bit of tension on it. I'll look at the TPS wires though I think the TPS is actually knackered. Cheers. Er...thats either wide open Trottle or even wider open throttle ! Lol, I guessed it wasn't right. So I need to either replace the TPS or fit the 4.6 plenum along with the idle kit. Thanks Nige. I put a 4.6 plenum on a 3.5, it mostly bolts straight on. A few things to consider though, it doesnt have the butterfly bypass that the 3.5 did (not sure about the 3.9), it uses shorter bolts to hold it on and the idle circuit is different, it may be worth opening the butterfly stop a little bit while it is off the engine, I didnt so had to put the idle valve on to be able to drive it. What I did was use the stepper motor gasket as a pattern to make a 3mm steel flange and then welded a tube to it, this goes to the PWM valve. Then (with the plenum off the motor I roughed up the inside of the hole that goes through to the inside of the throttle body, put some tape around the inside of the throttle covering the hole and poured some Devcon in there, Making sure it didnt cover the passage that bypasses the butterfly. I actually did the same thing with the breather tube there as well. It seems to work, I just ran out of argon before I managed to make mounts up for the air filter. It is probably one of the last pictures in my build thread. Thanks for the info Cheesy, I've still got all the parts from the top of 4.6 and the TPS connector is still on the engine loom, so may look at going down that route. Jon Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 18, 2014 Share Posted August 18, 2014 It reads anywhere from around 480 to 570 at the bottom level and around 900 at the top. As MS1 can't count past 255 I guess you're using an MS2 at least? It helps to tell people what your setup is or you'll get the wrong answers, or the answer to the question we think you asked! Short version: If the TPS jumps about, calibration changes day to day etc. then the TPS or wiring is probably dodgy. 2nd hand ones aren't too expensive. Quote Link to comment Share on other sites More sharing options...
jonnie_r Posted August 19, 2014 Author Share Posted August 19, 2014 Apologies, yes I have an MS2, on a 4.6 GEMS engine, with GEMS coil pack and the plenum from my old 3.9 to allow me to use the idle air control. The calibration changes as you blip the throttle, so a new TPS is called for judging by the answers I've received. I would prefer new as I've been caught out with used stuff before that was supposed to be ok. Jon Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 19, 2014 Share Posted August 19, 2014 If you have MS2 surely you could use the 4.6 plenum with stepper idle valve? Quote Link to comment Share on other sites More sharing options...
jonnie_r Posted August 20, 2014 Author Share Posted August 20, 2014 I hadn't even looked at the 4.6 plenum closely, as I never intended to use it, but I can now see I've been an idiot and should have used it all along............. If I fit the 4.6 plenum, I presume the set up for the connections would be similar, as the stepper has 4 pins, and then I can just select my idle valve type in the MS config software. Thanks for pointing out my stupidity Fridge sometimes the easiest things get overlooked. Quote Link to comment Share on other sites More sharing options...
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