Problems with Tps
 

The hose above the Tps leaked on my sensor and ever since I either Got 18 CEL
and would buck if i tried to drive it even just backing up in driveway
and recently started idling really rough, CEL goes on and off
I depin(one at a time) and retaped each wire where there were cracks to reseal and see if it helped

I am 80% my TPS is toast the other 20% is because it decides to work some time

After digging around and looking at different threads and cewrx7r1 that lead to nothing unfortunately I concluded these are my 2 best options
Expensive option- buy from atkins
Buying used with or without TB

Some people have done with differnt ones but they have different ECU's, I have the Pettite ecu.

Now I do have questions,
1.Does the Supra TPS actually work as someone said?
2.Are any other Mazda/Ford TPS's interchangeable?
3.Is there any success with any of these?
4. Just buy used and call it a day?

Thanks.

Buy used and call it a day. They are really hardy all things considered, my car has the original TPS at 135,000 miles with zero problems.

Shouldn't be too hard to find a good used one and it shouldn't cost too much.

Dale

Connector for harness side is a Sumitomo 6195-0030, in case you need that too.

Well ill keep an eye on classifieds. thanks Dale

thanks. I think mine is still good though I do plan to extend the connector on the harness, I hate the almost 180 dergree bend that the stock harness has,
part of the reason the wire cracked with all the heat

I would PM FritzFlynn and TomSN16 on the forum, they have tons of parts and would be an easy place to start.

Dale

Im hoping to revive this a littel bit before having to post.

Ive searched and only found so far bouncing idle issues when there is electrical load.
I am now having issues when there isnt any electric load.
my bouncing idle cleared up when i turned on the dash lights. also tried it with ac-same result

I did just replace the TPS with one a member sold me, I dont think that is the problem at all so i want to try and look at some possible other causes
prior to this i did have cel 12 and 18 but after removing throttle body and re aligning it to some marks I had I got no codes and it didnt die

You may need to adjust the TPS. It's kind of a pain to do with a stock ECU. Read up in the shop manual, you'll need to get a multimeter on the wires to the TPS. Recommended setting is .50v and 1.25v for the 2 sensor wires.

But before doing that you probably want to clean the ISC. It's easy to do and solves the bouncing idle problems more often than not.

Dale

After adjusting and testing
3F closed-1.03v and open-4.9v
3G closed .49v and open-4.2(maybe this one needs to go higher?)

They all seem to fall within recomendations
3F ECU connector. Closed throttle +V range is 0.75 to 1.25. Fully opened throttle +V range is 4.8 to 5.0.
3G ECU connector. Closed throttle +V range is 0.1 to 0.7. Fully opened throttle +V range is 4.2 to 4.6

Thought I was good to go but now if I slowly give it throttle it starts to have problems around 2.5-3k rpm
Ill adjust some more and try some differnt numbers within the range.

Those numbers are dead on at this point, tenths of a volt aren't going to make a huge difference.

At this point what are the problems/symptoms?

Dale

I also checked for any dead spots and all good from closed to full open

Would unplugging the isc help the bouncing idle, bypass?
i did clean it.

Issues right so far
-bouncing idle
-rough acceleration 2-3k
Cel 18 and 50


Smooths out when add electric load
blipping the throttle past goes up fairly normal

This video has the idle bounce, it used to be worse, there is a click that lowers the idle and smooths it out

this video I slowly pressed downt the accelerator
i noticed CEL goes away and comes back

not best way to up load video but only way i figured it out

Are you sure the codes are 18 and 50?

Code 18 means the ECU detected a problem with one of the signals from the TPS (narrow range signal). From what I've seen in the factory service manual, that signal might be related to for idle and light-load behavior. There is a different code for the other TPS signal (full range).

Code 50 is the Double Throttle solenoid valve, which is located in the rat's nest under the intake manifold. The connector for the double throttle solenoid is pretty far from the throttle, although the wires do run in the same harness. That harness is named the Emission harness in the factory wiring manual, and has most of the fuel-related things like fuel injectors and turbo control solenoids and coolant temp sensor.

the idle bounce can be a few things. the ECU actually will seek its target speed, and it uses timing, and then the BAC valve to do it. if the engine speed is too far outside the range that the ECU can adjust, the idle will get bouncy.

i would suggest setting the idle speed. when you ground the TEN pin it turns off the timing feedback, so you can set the idle speed with the TEN pin grounded and then when you remove the ground the timing should not move

the engine codes are set for open or short circuits, so you should start there.

I will check the wiring for the tps
I noticed my air pump goes on and off a lot right now especially after touching the accelerator

scotty- the 18 code makes sense if you say that the narrow signal is for idle and light load,j9- a lot of the idle issues now are happening while its warming up, the really noticable one now is it feels bubbly or hiccups extra bit of pops if this makes sense

mine does that too, its fine cold and hot, but there is a temp range in the middle where it surges for a bit. the ecu has an rpm range with temp and if you're outside that it'll hunt.

you can jump TEN (Test ENable) and ground when its running if you're setting the idle. if you're trying to pull codes you need to connect it with the key off.

j9-Ahh ok maybe im just noticing more since im more activly paying attention

Sorry if im goin in circles but to get it within the rpm range the ecu likes- where do i adjust from. So far ive only adjusted from the screw under TB
should i be looking at other parts as well?

i guess when should i try it i should ask- after is warmed up or when its cold

you would set the warm idle speed first with the screw under the TB, this usually fixes everything, if not then you can adjust the thermowax. the thermowax has an adjustment for rpm as well as the amount of time it is on. the FSM is a little vague and i would make small changes, its easy to get lost

goodnews/badnews my double thottle solenoid is not activating when given volts so at least that takes care of one issue
now i gotta buy one

I have finally
-replaced double throttle solenoid
-redid tps wiring, checked for continuity on each wire,
-tried to set warm idle with ten/grnd and tried to adjust thermowax(maybe im not doing this one right
-cleaned out spark plugs,
-cleaned isc,
Tps calibration all checks out
Abslutely no codes pop up

this is where I am at, bliping the throttle feels great very responsive
electrical load(ac or headlights) smooths out rpms but causes idle to go to almost 2k
in the video i held the rpms at one point and still bounced
i slowly pressed on the accelerator and as it went up in the rpms it still did it while bouncing

First off, I'm assuming you're on a stock ECU. The air pump is hooked up and working, correct?

Have you checked your clutch switch? A bad clutch switch will do all sorts of idle weirdness.

Did you set the TPS with the car warmed up or with it cold?

Dale

Yes stock ecu(pettit chip)
air pump works i can hear the clicking of it on and off

Did not know this existed,
how do i check ? Jumper or disconnect

I did it both ways, i set it up cold so as to "ball park it"
then when the car managed to warm up i readjusted
to fall within spec

Here's a thread on the clutch switch -

https://www.rx7club.com/3rd-gen-arch...switch-495391/

There's others out there. The spring in the switch can rust over time.

You can't really bypass it, it needs to be fixed for the ECU to see that input properly. But you should be able to test it out, I think there's a test in the shop manual too.

Dale

I opened it up and it appeared good
spring was good and tested the continuity with it
Disengaged(constant beep from multimeter
engaged(pressed down multimetter doesnt beep)

is there constant voltage on the connector or activated at different times?

also just got codes,
5 knock sensor(this one has gone on and off on me a few times) idk if thats good or bad
edit- they went awa and havent comeback again
28 egr illreplace solenoid just iin case( does this affect my idle though?
***i reset to see if they would come back again doing the same thing and they havent

Good, you can rule out the clutch switch.

Knock sensor is probably wiring or something to the sensor itself.

EGR valve really doesn't do anything that will affect drivability.

Dale

I went back to re check tps just because just about every thread points to it
i made it worse. It seems to be running on one rotor
vacuum in guage is low, Increadibly rough and lots of vibration. Plus the sound

checked spark plugs and front was "wet" the rear "dry"
however there was no bouncing idle for the moment that it ran. Could my bouncing idle be injector related?

Well, at least you made it more interesting! :)

I doubt it's injector related. It may be partly flooded if you've started and stopped it cold while working on it. Or, you may have knocked the vacuum line to the MAP sensor off or something.

With the TPS you just want to check it with the engine fully warm. Get the voltages as close as you can and you're done. You typically don't have to mess with it past that. The FD TPS works well, it doesn't really have problems or need adjustment long-term. Once it's good, it's good.

Dale

I like boring in this case as in nothing going on!
Map sensor is ruled out,

it was rough all the way to op temp and re checked my tps numbers after its warmed up, again good
there is lots of smoke now and it smells like gas

something i came across on a different post, they took off the lines to the pressure chamber and nothing was in there
i did the same and nothing came out, unless this only happens with boost
i took the one off the Vacuum chamber and there was air coming out

I will probably take manifold off again and check vacuum lines again

So did you remove the upper intake manifold when you adjusted the TPS?

Did you do anything with the plug wires?

Dale

i only removed it when installed tps and installed double throttle solenoid - planning to remove again since my vacuum now started reading at about 10 in. Hg

i didnt remove them from coils, when i checked spark plugs i did one at a time
and when i did the 2 leading one a different time i checked online before putting them back
i made sure i heard the little click of it snapping on tho the plug on each one

T1 L1 T2
__-L2

Trick to remember -

Trailing is Top, Leading is Lower.
1 is the front rotor, closest to the front of the car. 2 is the rear rotor, closest to the firewall.

For it to suddenly run THAT bad something major is up. Also if you have stock ECU check for codes.

Don't be afraid to post up pictures.

Dale

I do not have any codes regardless of how bad its running right now

tps settings are still withing 2nd from top 1.08 closed to 4.99 open and bottom .5 closed to 4.2 opened
It went from having a bouncing idle yesterday morning to running worse in the evening

heres a cold start up and it jus stays like that. it vibrates a lot more than what the video may be able to show
and smoke that wont clear up
maybe i need to do a compression test

It's worth doing a compression test just to be sure. I had a friend once who chased his tail for AGES trying to figure out why his car didn't run right. I finally came over and did a compression test, he had a stuck side seal so he was dropping compression on one rotor face.

The good thing is when you crank the car it sounds good to me. A blown engine typically sounds different when first cranking, you can hear the missing compression pulse. But, it could be a side seal or something, it's worth doing. This can be done with a plain piston compression checker, that's how I diagnosed my friend's side seal back in the day. The rotary testers are nice and make the job easier but a piston tester will tell you what you need to know.

It may be worth throwing in a brand new set of leading plugs and double-checking the plug wiring. I would also take a hard look at anything else you touched in this process to see if you have a damaged wire or something loose or not connected. It was doing somewhat OK at the start of this thread, need to see what was touched in the mean time, that's typically where the fault lies.

Dale

Ill be doing a compression test to hopefully rule that out

This is how my leading plugs look when i take them out from the car after "running"
To me they dont look that bad, but ill still get a fresh set,
only difference is the wet(front) and dry(rear)

How do you test coils? Or would i need one of those tools that lets you see the spark through a clear "tube"
https://cimg6.ibsrv.net/gimg/www.rx7...c567e908b8.jpg

You may want to check and make sure you are getting spark on all the plugs. The fuel smell/smoke seems like something is going on with fuel or ignition, unless you do find an issue with the compression test.

My first line test with coils is one of those inductive sensors that lights the bulb when the coil fires. Not super accurate, but gives me an idea if one is flat out not firing. There are better ways to test where you can actually observe the spark as well.

Unrelated but in your video it looks like your airbag light is blinking. I think the diagnostic modules eventually burn an internal fuse if you run them with an error for too long. They don't make them anymore, so I hate to see one burn out even if you don't want the system functioning.

Stock coils really don't spontaneously go bad, they do get weaker over time. There is a test in the shop manual to test the resistance of the coils, that test is pretty accurate I've found.

But, that's a good deal more work to get to them, you would really need to pull the UIM to get to them.

I'd start with a fresh pair of leading plugs and triple-check the plug wires VERY carefully to make sure the right wire is going to the right plug. The plugs you have there aren't very worn but if they are fouled they will fight you.

Dale

I should probably take this secret to the grave, but upon close inspection
I had 4 trailing plugs. IDK how this happened, so for 2 years my car has had 4 trailng plugs
probably should not completely trust in autoparts stores to know rotaries so thats my mistake
annnnywaaayys
now it starts up smooth no more shaking smoke goes away. ive got 18-20 in hg of vacuum
and now im back to just the bouncing idle

I will still do a compression test maybe. but coils and plugs and probably compression is good now

Spinning- yea i have the protege wheel on which i like more than an aftermarket wheel with a hub. gives it a nice more oem look, I didnt want to mess with the airbag wiring
I read somewhere about solderingin a resistor? is this true and which one? I only have the horn(orange) connected but the blue plug is disconnected under dash

It's common to run all 9's instead of 7's and 9's. The 9's will foul/flood more easily, but are more resistant to detonation since they run cooler.

I think the new plugs did the trick in this case, you just had a fouled out plug.

At this point what is it doing? I'd also drive the car around and get some heat in the engine and exercise it a bit.

Dale

Its just like the video i posted hanngs out 1k-1.5k rpm
up n down

I have thought about taking it out and drive it sort of like a
"walk it off" type of deal. I know when my old tps was bad it
Would buck and codes flash. If this doesnt happen then i can potentially cross off tps.

Also now with correct plugs ill try to see if I can adjust the idle so it stops hunting

Yeah go put some miles on it and see how it does.

Dale

small update. Almost thought problem solved itself, that is until it warmed up. so close
for the first time it warmed up normally
it used to go immediately to the bouning after a few seconds of starting up, not this time, but still happened

May want to post another video of how it's idling/running now.

No codes/CEL at this point?

Dale

no codes as of now.
i recorded the whole thing untill it started to have its issues
2 noticeable moments to me were at 3:20 and at 5:20, tho this is when it actually starts bouning


i didnt get it on video but i decided to hold the rpms for a bit at 4k and it was fine
anything below that seemed to still bounce.



Is this how the thermowax supposed to be at op temp?
https://cimg1.ibsrv.net/gimg/www.rx7...a2d0edcdb4.jpg

Good new!, I think im Finally on the right track
I took the car out for a drive and unless i had the ac on or light it wouldnt stop bouncing
no change at all

However today I just decided to start it up and let it warm up
I covered both holes on the the throttle body to see if it would change perhaps let me know its
getting more air from somehwere else. IT worked. the first time. after giving it some throttle it hunted again
I decided to press on the bottom TB valve to sort of force it close
and it stopped hunting. I repeated and stopped hunting.
I dont think its the thermowax, because it has extended and I've even completely moved it but didnt really move
it must be something else related to the side of the thermowax side, maybe ishould add some lubricant to it?

Welp shes purring now.
Out of all things it was the throttle cable. It was not letting the bottom valve close completely
even after the thermowax disengaged it.
but now it closes and no more hunting or bouncing
Thanks for the help Dave and anyone else who chimed in

Nice! Yep, an over tightened throttle cable can do that. You want a little bit of slack. Also it needs to be adjusted with the engine warm, with it cold the thermowax can throw the adjustment off.

Dale