Glanza_Mike Posted March 8, 2017 Author Share Posted March 8, 2017 Certainly, as would a drive by wire throttle body potentiometer issue, which is sadly now common as the VVTi's age. Thanks Chris, just went out and checked again and now i'm not certain it is only when the car warms up, it's just not as noticeable when the idles higher because it still feels okay as it's not dropped below 500. What or where is the potentiometer? If you are going for a decent standalone ecu cry at some point, I would ditch the stock throttle assembly for a Whifbitz true dbw conversion. The throttles are pretty common, reliable, support big power, and can be had used from £50 (or £150 brand new) I may well do mate but at the minute an ecu is out of the window cost wise, i'm having some walls removed in the house and having a new kitchen, some windows and doors fitted and the only thing the Mrs is putting towards it is her opinion. Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 8, 2017 Author Share Posted March 8, 2017 Anyone know if the TPS sensor on a vvti is the same as preface lift.? There's one for sale I feel like I should maybe try it? Quote Link to comment Share on other sites More sharing options...
conorj Posted March 8, 2017 Share Posted March 8, 2017 Whilst i had this adapter plugged in the car nearly stalled...came back to life, but the engine check light came on and the car went into limp mode, so accelerator did nothing until last 10% of it's travel. I've never had this happen before and it happened twice in a row with this adapter fitted so i'm presuming it's an adapter fault. The car then threw up fault code P1633 which is ECM malfunction: ETCS circuit. But again, i'm presuming that's only down to the adapter fault. The cheaper end of these adaptors are notorious for causing electrical issues unfortunately, I went through a number of these before getting a decent wired adaptor. The first few wouldn't hold connection but one caused a clio to go into limp mode and the dials stop working. Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 25, 2017 Author Share Posted March 25, 2017 Okay chaps this issue has gotten worse recently. Last two days when I warm start the car unless I feather the throttle the idle is so lumpy sometimes it drops so low it stalls. Doesn't seem quite as bad when it's in gear but still bad. Apart from that the car is running fine as far as I can tell. Boosts fine, no misfires and otherwise drives smooth apart stalling and bad idle. I bought maf cleaner, removed the maf sensor and sprayed it down. Made no difference. Any ideas? I got a quote for a new TPs but I don't want to buy one unless I know it's that. Quote Link to comment Share on other sites More sharing options...
GreaseMonkey Posted March 26, 2017 Share Posted March 26, 2017 By the DTC's posted the only items the Toyota Manual Trouble shooting suggest in the order of 1. Circuit Sensor Wiring or Electrical Connector. 2 Sensor. 3. ECM/ ECU. Seeing the Number of and type of DTC's maybe worth inspecting the ECU Plug Connectors in the Passenger Footwell incase any damp or water ingress has affected it or disconnect and reconnect the ECU to see if a dodgy connection. I've posted up inspection and adjustment of both Throttle Body Sensors (Non VVTi, but being Toyota, part maybe the same) and also the Idle Control Valve. hth Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 27, 2017 Author Share Posted March 27, 2017 Thanks mate that's a great help. I'll work my way through these checks. Quote Link to comment Share on other sites More sharing options...
GreaseMonkey Posted March 27, 2017 Share Posted March 27, 2017 No drama's dude . Will watch with interest to see what the issue turns out to be. Quote Link to comment Share on other sites More sharing options...
sebas Posted March 28, 2017 Share Posted March 28, 2017 Okay chaps this issue has gotten worse recently. Last two days when I warm start the car unless I feather the throttle the idle is so lumpy sometimes it drops so low it stalls. Doesn't seem quite as bad when it's in gear but still bad. Apart from that the car is running fine as far as I can tell. Boosts fine, no misfires and otherwise drives smooth apart stalling and bad idle. my supra was doing that with MAF fitted to 4" air intake pipe (supplied by whifbitz with single turbo kit). all turns to be alot better when I change my intake to 3" pipe. apparently something to do with volume of air going throu air filter and around MAF that was designed to be fitted in to 3" airfilter housing, and not 4" Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 28, 2017 Author Share Posted March 28, 2017 Thanks mate, when I originally fitted the maf into the 4" intake it wouldn't even run. It started and ran for like 10 seconds then stopped. So I reduced the inside down by fitting 2 lengths of silicone inside, it's pretty much exactly the same diameter as the stock airbox now. It ran fine like this for at least a week before developing this problem so I'm hoping it's not this. If the spark plugs don't fix it that I've ordered I will look into it though thanks. Quote Link to comment Share on other sites More sharing options...
rider Posted March 28, 2017 Share Posted March 28, 2017 No one has mentioned this but why not check the coil packs. I did read somewhere once that the resistance inside a coil pack raises 0.4% per degree Celsius so if you have a failing coil pack then the impedance could cause weak spark idling issues when hot, that wouldn't be apparent when cold. You may be effectively running on 5 cylinders at hot idle. Should be easy to check out. Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 28, 2017 Author Share Posted March 28, 2017 Seems like i have about 400 things to check at the minute will add it to the list though thanks. Quote Link to comment Share on other sites More sharing options...
Krister Posted March 28, 2017 Share Posted March 28, 2017 I would try with a second hand throttlebody, your idle issue is because of the TPS error code most likely. Maybe try JDM Distro, they are selling second hand 2JZ's, so maybe they have an extra TB or may part with it. Most who change the VVTi engine on a Supra or other cars will use the stock non-VVTi mechanical TB, so there should be plenty laying around. I might source one for £100-150 if you need one. Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 28, 2017 Author Share Posted March 28, 2017 I presume i wouldn't be able to use the non-vvti throttle body on stock ecu though? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted March 28, 2017 Share Posted March 28, 2017 Why do people mess about with MAF sensor tubes?? Unless you remap they must be in the same intake ducting and the same distance from the ports as stock. If you have a mappable ecu you'd throw the abortions away and go MAP anyway...You have now made a crude venturi inside a too big a diameter pipe and air velocity, which is what it reads, is still not what the ecu is mapped for. Put the stock MAF tube on for a start, put SIX (yes 6...) new plugs in it, check coil pack connector shells and more importantly connector terminals and their leads minutely, measure plug lead resistance while waggling nthem, and see what happens after that. You really need a 2 channel scope to check the throttle body DBW stuff properly. Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 28, 2017 Author Share Posted March 28, 2017 The maf isn't sitting a housing too big Chris, and there is no way to run the stock maf housing on a single turbo trust me i tried, at least not without chopping up a perfectly good airbox. The diameter of my intake is within a few mm either way of the stock intake as i measured it, also it wouldn't run right until the diameter was correct and it ran fine for at least a week before experiencing any problems. As said in my post above if i find out the problem is the plugs then i'll buy the other 4 of course. I just don't want to spend £50 on iridium plugs when i only replaced them 18 months ago and have no idea if that's actually the problem or not. I've recently replaced the coil pack clips but will definitely try and inspect the other things mentioned when i can. Quote Link to comment Share on other sites More sharing options...
rider Posted March 28, 2017 Share Posted March 28, 2017 The diameter of my intake is within a few mm either way of the stock intake A few mm on the diameter of a small pipe makes a massive difference to the volume. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted March 28, 2017 Share Posted March 28, 2017 Could you 'Jerry rig' the stock air box and maf housing to the turbo intake, just for the purpose of eliminating the maf mounting as the idle problem? (Do an ecu reset at the same time). It wouldn't need to be mounted properly or anything, just connected safely and air tight. Also, I still have my MAF sensor which came off when I went single if you need a spare Quote Link to comment Share on other sites More sharing options...
Krister Posted March 28, 2017 Share Posted March 28, 2017 I presume i wouldn't be able to use the non-vvti throttle body on stock ecu though? Nope Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 28, 2017 Author Share Posted March 28, 2017 Could you 'Jerry rig' the stock air box and maf housing to the turbo intake, just for the purpose of eliminating the maf mounting as the idle problem? (Do an ecu reset at the same time). It wouldn't need to be mounted properly or anything, just connected safely and air tight. Also, I still have my MAF sensor which came off when I went single if you need a spare Thanks mate, i don't think the problem will be the sensor it self though if the maf is the problem. I bought some good maf cleaner and removed it and sprayed it down and made no difference what so ever. That's not to say the sensor hasn't gone faulty over the last few weeks i just think it's unlikely. As for rigging up the stock air box to see if it fixes the problem i could do that yes but i sold my airbox to westy so not really Quote Link to comment Share on other sites More sharing options...
Krister Posted March 28, 2017 Share Posted March 28, 2017 If you have a TPS sensor error and the stock throttle body handles the idle, isnt it obvious where to look first? Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 28, 2017 Author Share Posted March 28, 2017 A few mm on the diameter of a small pipe makes a massive difference to the volume. It ran fine for at least a week though why would it change? - - - Updated - - - If you have a TPS sensor error and the stock throttle body handles the idle, isnt it obvious where to look first? I'm not sure i do have a TPS sensor error. I have the error codes the car is giving me but i have no way to check them because the vvti ones are different to non and i can't find a manual or guide. Quote Link to comment Share on other sites More sharing options...
Krister Posted March 28, 2017 Share Posted March 28, 2017 (edited) Check a Gen 2 GS300 error codes. It has a 2JZ-GE VVTi engine, I think it should be the same for the most part and most OBD1 Toyotas have the same codes anyway so Im pretty sure the TPS is the right code. Edited March 28, 2017 by Krister (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted March 28, 2017 Share Posted March 28, 2017 Does it ever need a huge amount of accelerator pedal travel to go anywhere? If there's an intermittent failure from one of the sensors in the TB it reverts to limp home and the throttle plate is operated solely by the cable, with very limited opening with lots of unused pedal travel. not definitive, but that often occurs if the two throttle angle sensors don't give out of phase, matching signals to the ecu. Are you trying to run a single turbo on the stock ecu??? Quote Link to comment Share on other sites More sharing options...
Glanza_Mike Posted March 28, 2017 Author Share Posted March 28, 2017 Does it ever need a huge amount of accelerator pedal travel to go anywhere? If there's an intermittent failure from one of the sensors in the TB it reverts to limp home and the throttle plate is operated solely by the cable, with very limited opening with lots of unused pedal travel. not definitive, but that often occurs if the two throttle angle sensors don't give out of phase, matching signals to the ecu. Are you trying to run a single turbo on the stock ecu??? No never goes into limp home mode, and apart from the idle issue seem to run and boost fine apart from being a little rich. And yes, until i have enough money for a standalone it's on low boost on the stock ecu. Check a Gen 2 GS300 error codes. It has a 2JZ-GE VVTi engine, I think it should be the same for the most part and most OBD1 Toyotas have the same codes anyway so Im pretty sure the TPS is the right code. Alright mate thanks. Quote Link to comment Share on other sites More sharing options...
T2 MSW Posted March 28, 2017 Share Posted March 28, 2017 Quote Link to comment Share on other sites More sharing options...
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