Thank you... TPS gurus
10-05-11, 06:04 PM
#1
Thank you... TPS gurus
Yet another issue fixed by RX7club members' insight.
When I bought my car it idled at about 1900 rpm, traced that to an issue with the BOV and the duct that the BOV mounts on... that was about a year ago, and it brought the idle down to about 1400rpm.
I finally cleaned up the engine bay a bit, and noticed that a (then) black connector was turning green the more I cleaned it
now I could have fun with the TPS. I always thought that the check connector was by the actual TPS... not in my case.
After building the TPS test light (also thanks to RX7club members) I cranked down on the spring almost all the way clockwise, then back about 1/4 turn. BAM... only one light on. This was about 20 full turns clockwise from where it was. Started the car, and idle (when the clutch is depressed) is now surging between ~750-1100 rpm. Definitely an improvement in throttle response... and as much as I hate to say it, no more backfires/fireballs
Any more guidance would be appreciated... I know about checking the full range of the TPS, but haven't gotten to it yet. With it adjusted per the FSM, does it sound like a bad TPS?
When I bought my car it idled at about 1900 rpm, traced that to an issue with the BOV and the duct that the BOV mounts on... that was about a year ago, and it brought the idle down to about 1400rpm.
I finally cleaned up the engine bay a bit, and noticed that a (then) black connector was turning green the more I cleaned it
now I could have fun with the TPS. I always thought that the check connector was by the actual TPS... not in my case.After building the TPS test light (also thanks to RX7club members) I cranked down on the spring almost all the way clockwise, then back about 1/4 turn. BAM... only one light on. This was about 20 full turns clockwise from where it was. Started the car, and idle (when the clutch is depressed) is now surging between ~750-1100 rpm. Definitely an improvement in throttle response... and as much as I hate to say it, no more backfires/fireballs
Any more guidance would be appreciated... I know about checking the full range of the TPS, but haven't gotten to it yet. With it adjusted per the FSM, does it sound like a bad TPS?
10-06-11, 09:10 AM
#6
if your idle was solid before, and the only thing you changed was the TPS adjustment then I'd blame that first.
From my experience, using the light method, or really any measured method (ohms/volts), is just good for getting you CLOSE. I suggest just adjusting it a TINY bit, test drive, TINY adjustment, test drive. That was the only way I could get mine to work well.
then again, bouncy idle usually means vac leak. Just check and see if you find anything obvious. and if you can't get the idle solid after all that. replace all your vac lines with new RUBBER ones, not silicone.
From my experience, using the light method, or really any measured method (ohms/volts), is just good for getting you CLOSE. I suggest just adjusting it a TINY bit, test drive, TINY adjustment, test drive. That was the only way I could get mine to work well.
then again, bouncy idle usually means vac leak. Just check and see if you find anything obvious. and if you can't get the idle solid after all that. replace all your vac lines with new RUBBER ones, not silicone.
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10-06-11, 10:39 AM
#8
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Are you sure your throttle plates are set properly? You could be adjusting the TPS, but allowing way too much air though to begin with. I always get the car to idle at 800rpm or so without the BAC, and then fiddle with the TPS.
10-06-11, 10:52 AM
#9
honestly, no, I'm not. I blocked off the BAC valve last year... and maybe that has something to do with this. When I unplugged/blocked it off, I didn't notice any difference at all in throttle speed, so I didn't worry about it. I'll dig through the FSM to find a procedure for setting throttle plates, if there is one?
10-06-11, 08:17 PM
#10
I had the bouncin idle forever and ever. Resettin the TPS to spec would cause it to go away most the time. In reality though my bouncing idle was caused by the one and only vacuum leaks! Be sure to look into in, i thought for sure i had zero leaks because i refreshed everything...i was wrong..
10-07-11, 09:45 AM
#11
While I was driving home yesterday, I noticed that this isn't only at idle... I tried to hold the RPMs steady at 2K, and the surge was still pushing/pulling... +/- 200 RPMS. I dont think its a vac leak due to it not surging pre-TPS-adjustment. But I'll put that on my list anyway.
10-09-11, 03:03 PM
#16
so i just took off the throttle body/plenum... found that the coolant intake WAS blocked, by some nasty crap in the throttle body. Compressor cleaned that out.
Throttle was DIRTY, so bought some carb cleaner and cleaned that out. everything looks as per the FSM with regards to the plates and the secondaries opening at 1.5mm after the primary. Any good mods while the intake is off?
Throttle was DIRTY, so bought some carb cleaner and cleaned that out. everything looks as per the FSM with regards to the plates and the secondaries opening at 1.5mm after the primary. Any good mods while the intake is off?
11-25-11, 04:41 PM
#22
Thread revival... also trying to sort out idle issues on a JDM S5-swapped vert. I've got the TPS adjusted to 1kohm and the idle is still surging from 1200-1500. Where is this idle set screw you speak of? Is that the mixture screw by the AFM? I toyed with that and it smoothed the idle out temporarily, but then went back to surging after a drive. Can you adjust the BAC on JDM engines?
11-25-11, 05:41 PM
#23
Thread revival... also trying to sort out idle issues on a JDM S5-swapped vert. I've got the TPS adjusted to 1kohm and the idle is still surging from 1200-1500. Where is this idle set screw you speak of? Is that the mixture screw by the AFM? I toyed with that and it smoothed the idle out temporarily, but then went back to surging after a drive. Can you adjust the BAC on JDM engines?
What screw by the AFM are you talking about. An S4 has a Variable Resistor to help adjust fuel mixture and it's located by the passenger fender well, but you state you have an S5.
11-25-11, 07:45 PM
#24
I set the TPS using Aaron Cake's resistance method, full warmed up. I might check it with voltage tomorrow and see if there is any variation.
Mine seems to have that screw by the passenger fender well. I turned it to its stopping point and that yielded a somewhat smoother idle, at least until I drove it. I also noticed there is only one TPS. Starting to wonder if this is really an S5 motor. Clearly I've got some poking around to do on this car.
Edit: I just realized something I've been overlooking since I first checked out this car - it has a rod connected to the throttle linkage for the OMP! Didn't all S5's have an electric OMP??
Mine seems to have that screw by the passenger fender well. I turned it to its stopping point and that yielded a somewhat smoother idle, at least until I drove it. I also noticed there is only one TPS. Starting to wonder if this is really an S5 motor. Clearly I've got some poking around to do on this car.
Edit: I just realized something I've been overlooking since I first checked out this car - it has a rod connected to the throttle linkage for the OMP! Didn't all S5's have an electric OMP??
11-25-11, 09:11 PM
#25
The block could be an S5 but the throttle body and sensors could be S4. The Variable Resistor should be set basically a bit more than half way to the right which is more "rich" than "lean." The FSM explains how it's to be set. You also set it after the car is "fully" warmed up and not when cold.