Still Don't Know What to Do About My TPS!

Justen · 12-15-2009, 12:41 AM

So i'm not really sure what i should do about my idle problem. 90' TII, rebuilt the motor myself, streetport. I'm trying to get the idle steady, but i haven't had much luck. Floods and backfires on start-up. So naturally a bad TPS could very well be the culprit.

I checked the TPS with both a multimeter for resistance, and also with the 2-tester-light adjustment method... Failed the multimeter test, and i cant get the one tester light to come back on when i open and close the throttle plates after i adjust it.

I explained this to people on a number of forums and everyone seems to say that I definately need a new TPS, But then I hear from one of the guys at ROTARY-RESURRECTION that the multimeter test is not an accurate way of testing it. He said that he has seen TPS sensors that have passed the Multimeter test but performed like crap on a running car, and some that didnt pass and worked fine on runnning cars.

So what the hell should i do?

New TPS's are pricey, i just want to know for sure that its the problem.

Max777 · 12-15-2009, 01:22 AM

did you delete the thermowax pellet on the throttle body or any emissions?

RotaryDiagnostics · 12-15-2009, 08:32 AM

Get a copy of the factory service manual (free for the download at http://foxed.ca/foxed/index.php?page=rx7manual) and work through the troubleshooting matrix in section F2. Your problem could be related to something other than the TPS. For instance, if the problem lays with the air flow meter signal to the ECU, the system will go into a fail safe mode where gobs of fuel will be dumped into the system and the timing will be modified. Don't ask me how I know.

Justen · 12-15-2009, 01:07 PM

Quote:

Originally Posted by Max777

did you delete the thermowax pellet on the throttle body or any emissions?

yes... thermowax removed, rats nest gone, air pump, emissions, etc.. gone

Max777 · 12-15-2009, 05:46 PM

/\ Well, if that is the case, then your idle issues are from the thermowax and BAC being removed. Usually, you keep these things on the engine to improve it's idle quality.

Your TPS might be shot, so first go get another TPS, and thow it on and see what happens, this usually isnt the best way to fix problems, but for around $20 on the forums, it's nice to have a spare anyway...

You should build a twin-led tps adjuster( search) and adjust the tps to where only one led lights up... two leds mean it's too far and none means it's too close. Also check your throttle cable for smooth operation and binding. The cable on my TII sucks, atkins rotary and mazdatrix can get you replacement cables.

Depending on how cold it is in your area, when you remove the thermowax, you have to hold the gas pedal down a bit on a cold start.

The BAC valve then helps with idle quality.

Justen · 12-16-2009, 07:37 PM

Quote:

I checked the TPS with both a multimeter for resistance, and also with the 2-tester-light adjustment method... Failed the multimeter test, and i cant get the one tester light to come back on when i open and close the throttle plates after i adjust it.

Yeah i've already tried this test, but i think you may be right, I haven't really checked my throttle cable...

But considering the Flooding problems, i'm thinking it could be a combo of that and a bad sensor (maybe even something other than tps) since it seems to be running in fail-safe mode

My5ABaby · 12-16-2009, 08:53 PM

What are you trying to get it to idle at? I removed all that stuff on my car and finally gave up on getting a steady 750 idle. I just upped it to 1100 and it's solid. How often do you really idle your car? Just a thought...

Justen · 12-17-2009, 06:57 PM

Quote:

Originally Posted by My5ABaby

What are you trying to get it to idle at? I removed all that stuff on my car and finally gave up on getting a steady 750 idle. I just upped it to 1100 and it's solid. How often do you really idle your car? Just a thought...

that is true... but i'm not worried about the idle being perfect when i'm actually driving it, i'm really just trying to get it at a steady 750 for at least a few minutes so that i can set/check the ignition timing, because as far as i understand the timing is automatically advanced a smidge as your revs go higher than idle. Can someone verify this?

....If so, how did you get your timing right without idle at 750?

My5ABaby · 12-17-2009, 10:12 PM

I've never set the timing. Kevin did it when he rebuilt my engine and I've had no reason to think it would be off.

FlybyRE · 12-18-2009, 06:57 PM

Yeah if you remove all the emissions stuff, thermowax, BAC secondary plates etc yoru idle will be jacked.. Its not a TPS thing...

I did this and upped my idle to about 1000 RPM and I was happy.. however when the car was cold it never wanted to idle..

Justen · 12-19-2009, 01:59 AM

Quote:

Originally Posted by RotaryDiagnostics

Get a copy of the factory service manual (free for the download at http://foxed.ca/foxed/index.php?page=rx7manual) and work through the troubleshooting matrix in section F2. Your problem could be related to something other than the TPS. For instance, if the problem lays with the air flow meter signal to the ECU, the system will go into a fail safe mode where gobs of fuel will be dumped into the system and the timing will be modified. Don't ask me how I know.

...lol Well i'm sorry if its a sore subject, but i have to ask.. did it throw any particular codes when this happened? and what turned out to be the problem?

Justen · 12-19-2009, 02:10 AM

Quote:

Originally Posted by FlybyRE

Yeah if you remove all the emissions stuff, thermowax, BAC secondary plates etc yoru idle will be jacked.. Its not a TPS thing...

I did this and upped my idle to about 1000 RPM and I was happy.. however when the car was cold it never wanted to idle..

I would be completely content with an idle at 1000 rpm as well,
and i really won't mind any inconsistency of the idle once everything is set (tps, timing, ect..).
I just don't want the motor to blow at anything over 5k rpm while i'm driving it, after all the work and money spent on the rebuild.

Has anyone had similar symtoms after a rebuild?
Or does anyone have any experience setting their own idle?

I don't know what to tackle first, Timing or Potential Sensor Issues?

FlybyRE · 12-19-2009, 06:14 AM

IME This is 100% normal with the throttle body modification that you have done.. My question is what kind of vacuum do u see at idle...

After the car warm up does it idle fine on its own?

I manual set my idle to about 1000RPM (by adjusting the idle set screw on the throttle body).

As long as this is all related to the thermowax you wont have any problems with your engine blowing up.

This was exactly how my engine ran after I did my last build.

Justen · 12-24-2009, 08:33 PM

Quote:

Originally Posted by FlybyRE

This was exactly how my engine ran after I did my last build.

Okay, thats very good to hear. So hopefully once i put a fpr in there it shouldn't run quite as rich as it is now.

it is still throwing codes however...

Justen · 12-24-2009, 08:45 PM

Alright, these are the codes its throwing:

9.....water temp sensor
25....solenoid valve (pressure regulator control (PRC))
31....solenoid valve (relief)
32....solenoid valve (switch)
34....solenoid valve (bypass air control (BAC))
42....duty solenoid (turbo boost pressure control)

now, given that i have all emissions/rats nest/idle control removed, is there anything else besides the water temp sensor that i should be worrying about? I also have elect. boost controller installed.

12-15-2009, 12:41 AM	#1
Justen In Too Deep Join Date: Jun 2009 Location: Clifton, NJ iTrader: (3) Posts: 112 Rep Power: 16	Still Don't Know What to Do About My TPS! So i'm not really sure what i should do about my idle problem. 90' TII, rebuilt the motor myself, streetport. I'm trying to get the idle steady, but i haven't had much luck. Floods and backfires on start-up. So naturally a bad TPS could very well be the culprit. I checked the TPS with both a multimeter for resistance, and also with the 2-tester-light adjustment method... Failed the multimeter test, and i cant get the one tester light to come back on when i open and close the throttle plates after i adjust it. I explained this to people on a number of forums and everyone seems to say that I definately need a new TPS, But then I hear from one of the guys at ROTARY-RESURRECTION that the multimeter test is not an accurate way of testing it. He said that he has seen TPS sensors that have passed the Multimeter test but performed like crap on a running car, and some that didnt pass and worked fine on runnning cars. So what the hell should i do? New TPS's are pricey, i just want to know for sure that its the problem. __________________ 1990 TII, fresh rebuild Atkins rebuild kit, RA apex seals Med. Streetport, TB mod, rebuilt turbo, ported wastegate, GodSpeed FMIC RacingBeat Turbo-back straight exhaust, Bonez test pipe, emissions/nest removed hks intake, Walbro, Profec B spec-2

12-15-2009, 01:22 AM	#2
Max777 Pirate Join Date: Mar 2008 Location: Central IL iTrader: (5) Posts: 1,323 Rep Power: 18	did you delete the thermowax pellet on the throttle body or any emissions? __________________ Rotaries:They are NOT that complicated!

12-15-2009, 05:46 PM	#5
Max777 Pirate Join Date: Mar 2008 Location: Central IL iTrader: (5) Posts: 1,323 Rep Power: 18	/\ Well, if that is the case, then your idle issues are from the thermowax and BAC being removed. Usually, you keep these things on the engine to improve it's idle quality. Your TPS might be shot, so first go get another TPS, and thow it on and see what happens, this usually isnt the best way to fix problems, but for around $20 on the forums, it's nice to have a spare anyway... You should build a twin-led tps adjuster( search) and adjust the tps to where only one led lights up... two leds mean it's too far and none means it's too close. Also check your throttle cable for smooth operation and binding. The cable on my TII sucks, atkins rotary and mazdatrix can get you replacement cables. Depending on how cold it is in your area, when you remove the thermowax, you have to hold the gas pedal down a bit on a cold start. The BAC valve then helps with idle quality. __________________ Rotaries:They are NOT that complicated!

12-16-2009, 08:53 PM	#7
My5ABaby Sigh..... Join Date: Feb 2008 Location: Murfreesboro, TN iTrader: (6) Posts: 2,377 Rep Power: 19	What are you trying to get it to idle at? I removed all that stuff on my car and finally gave up on getting a steady 750 idle. I just upped it to 1100 and it's solid. How often do you really idle your car? Just a thought... __________________ 1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles Community Service Manual RotorWiki "Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."

12-17-2009, 10:12 PM	#9
My5ABaby Sigh..... Join Date: Feb 2008 Location: Murfreesboro, TN iTrader: (6) Posts: 2,377 Rep Power: 19	I've never set the timing. Kevin did it when he rebuilt my engine and I've had no reason to think it would be off. __________________ 1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles Community Service Manual RotorWiki "Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."

12-15-2009, 08:32 AM	#3
RotaryDiagnostics Compression Tester Man Join Date: Feb 2009 Location: Mont Alto, PA iTrader: (1) Posts: 137 Rep Power: 16	Get a copy of the factory service manual (free for the download at http://foxed.ca/foxed/index.php?page=rx7manual) and work through the troubleshooting matrix in section F2. Your problem could be related to something other than the TPS. For instance, if the problem lays with the air flow meter signal to the ECU, the system will go into a fail safe mode where gobs of fuel will be dumped into the system and the timing will be modified. Don't ask me how I know.

12-18-2009, 06:57 PM	#10
FlybyRE Rotary Fanatic Join Date: Dec 2009 Location: michigan iTrader: (3) Posts: 180 Rep Power: 15	Yeah if you remove all the emissions stuff, thermowax, BAC secondary plates etc yoru idle will be jacked.. Its not a TPS thing... I did this and upped my idle to about 1000 RPM and I was happy.. however when the car was cold it never wanted to idle..

12-19-2009, 06:14 AM	#13
FlybyRE Rotary Fanatic Join Date: Dec 2009 Location: michigan iTrader: (3) Posts: 180 Rep Power: 15	IME This is 100% normal with the throttle body modification that you have done.. My question is what kind of vacuum do u see at idle... After the car warm up does it idle fine on its own? I manual set my idle to about 1000RPM (by adjusting the idle set screw on the throttle body). As long as this is all related to the thermowax you wont have any problems with your engine blowing up. This was exactly how my engine ran after I did my last build.

12-24-2009, 08:45 PM	#15
Justen In Too Deep Join Date: Jun 2009 Location: Clifton, NJ iTrader: (3) Posts: 112 Rep Power: 16	Alright, these are the codes its throwing: 9.....water temp sensor 25....solenoid valve (pressure regulator control (PRC)) 31....solenoid valve (relief) 32....solenoid valve (switch) 34....solenoid valve (bypass air control (BAC)) 42....duty solenoid (turbo boost pressure control) now, given that i have all emissions/rats nest/idle control removed, is there anything else besides the water temp sensor that i should be worrying about? I also have elect. boost controller installed. __________________ 1990 TII, fresh rebuild Atkins rebuild kit, RA apex seals Med. Streetport, TB mod, rebuilt turbo, ported wastegate, GodSpeed FMIC RacingBeat Turbo-back straight exhaust, Bonez test pipe, emissions/nest removed hks intake, Walbro, Profec B spec-2

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