tougeFB

I've had this problem before. But it's gotten worse.
88 TII 10th Anniversary.


I dont know what the deal is. I took off my old TPS. I installed the new one and ohmed it out as told. My car would only hunt when cold, so it was better than it hunting all the time.
The reason I believe it is the idle would fluctuate still from 1300-1500rpms. then once it's warmed up, it will idle high, say around 2k.

I just re-checked the readings on the new (used) TPS that I got. When I would test it outside of the car, it gave me a decent reading. 1k-5k sweep, approximately.

I read the instructions found here:
FC3S Pro

and it tells me since I have cold assist (which I'm pretty sure I still do)...
Can anyone tell me if I know I have it or not...??? Are they talking about the thermowax pellet?

But since I have cold assist, I need to warm the car up to operating temperature, and then set the TPS. so I did.

When I ohmed it at idle, it read 0.6k ohms, so I raised it to 1.0k ohms.

Then when I would do the sweep, from 0 to WOT, it would go 1.0-1.5 then start counting down to 0.5k.

not 5k, but 0.5k. is my TPS fucked or did i do something wrong?

i'm using a DVOM method... black lead on back side of TPS connector (blk wire) and red lead on (red/green wire).

I dont understand. This is the second TPS I've gone through.

So my question is... judging by my readings...

Did I mess something up, or do I need to try another TPS?


Thanks in advance.

HAILERS

The TPS plug is supposed to be disconnected when doing the ohm thing.

I'd take a better run at this.

Drive the car til the engine is fully hot.

Connect the TPS connector up as it normally should be.

Put the meter on DC Volts and its negative lead on the batt neg post or a KNOWN good gnd point.

The using your positive probe, back probe the CONNECTED UP TPS connector at the GREEN/RED wire on the HARNESS side of the TPS connector.

With the engine HOT and the key to ON (preferably idling), the meter should read approx one volt dc. If not, then turn the TPS screw til the meter reads ONE volt dc. Done



WEllllll with a turboii it's a little more difficult getting at the TPS plug. Either take the intercooler off and then read the GREEN/RED wire at the TPS with the key to ON or backprobe the green/red wire with a piece of spare wire long enough to reach say the strut tower, then reinstall the intercooler and idle the engine and read the one volt at the end of the spare wire you just installed in the back of the green/red TPS connector.

Or read the output of the green/red wire a the ECU middle plug while the engine is running.

Or install some PVC piping in lieu of the intercooler and idle the engine that way ......then backprobe the tps's green/red wire on the harness side of the tps connector.

Using the PVC in lieu of the intercooler also enables (sort of like the ENABLING ACT they're using in Venesuela these days [ Adolf used it in '33}.) .....you to LOOK at the throttle stop screws/thermowax/fast idle screws/etc while the engine is actually running to see if anything is amiss.

That's NZCONVERTIBLEs PVC ducting, almost as good as mine.

tougeFB

HAILERS...


I have never heard of the DC volt, find 1v method.

I've always read that you're supposed to check for resistance with a DVOM or you can do the 2 bulb DIY way.

I just read what you were talking about. I did have the TPS connected when i ohmed it. so i'll disconnect it and try again.

and i should have looked at the picture:

the TPS is being backprobed while disconnected in the picture...

oops.

i dont have the means of doing the PVC piping method. none is available to me, and i really dont feel like going anywhere. it's a really good idea, and something that's easy and i may do in the future.
then again, you said to drive the car hot.

so i may have to.

anyway, i have one question though HAILERS. my friend brought it up to me.


my symptom is a hunting idle.
my TPS reads 1.0k ohms. (which is in spec)

assuming that my TPS truly is in spec (at idle only), shouldn't it not be hunting because the ECU is reading the correct signal at idle? it's a good point, and i was wondering if that sounds correct to you.

does this mean i may have other problems on top of the TPS?
such as vacuum leak, stuck throttle plates, etc, stuck injectors, etc?


thanks again. i'm glad i got a guru on my side to help me fix this thing!!

HAILERS

The FSM in the Output/INPUT section describes the output/input of each wire on the ECU's plugs. When it comes to pin 2G for the TPS, it says that at idle with a HOT engine the output should be approx one volt dc.

So to make life easier on me, I just warm the engine up and at idle read the output of the green/red wire at the TPS connector and or at the ECU and at the piece of wire I installed in the back of the TPS plug (harness side of the plug) or lately from the RTEK2.0 Palm where I see a percentage that reads 20 percent (one volt being 20percent of five vdc) and at other times I can read the voltage on a SAFC if installed.

One volt give or take a couple of tenths is just fine. I'd ohm one out IF and only IF I really thought I had a problem with the TPS. It bothers me not which way someone sets the TPS, the end result will be...........approx 1vc at idle if done right.

Using the two LED light method, the results are ..........approx one vdc at idle WITH A HOT ENGINE.

So I do it the easiest way for ME. I care not what others do with their time and effort.

Hot or fully warmed engine is a must due to the water thermowax and the fast idle cam etc. When the water is cold, the water thermo and those other things drive the linkage/throttle plates open a touch. Move the throttle linkage and......you move the TPS plunger by default. The voltage will read higher on a cold engine due to that. If you set the thing with a cold engine, then once warmed up the TPS output will be welll below the one volt dc range.

Hunting at idle isn't something I've seen in ages. IF the TPS is set right, then it could be a small vacuum leak possibly. OR a vacuum line not connected where it should be. I know that if you put say, the fuel injector bleed vacuum(really air) line to a source of vacuum ....funny things happen at idle. That's an example.

Maybe a leaking grommet on the bottom of a fuel injector could cause a air leak and cause a idle problem and might even clear up a bit after things get fully warmed up.

I spray with starter fluid with the engine idling to find vacuum leaks.....like most people do.

About the bes way to check out the fast idle cam/thermowax, is with the PVC in place. Now NZCONVERTIBELE has a fairly good setup excect he ran the cross tube of PVC across the area where he should be looking at the cam/screws/stops etc. Now MY PVC makes nintye degree turns, and everything is readily visible. humor, don't take it seriously. Enough scribbling.

tougeFB

I'm definitely going to try the starter fluid method. after i try the ECU input to the TPS and check it for voltage.



I know the injector grommets or o rings, or seals are good, as well as my vacuum lines BECAUSE i replaced them all myself when I was leaking fuel. also the PD as well.

ALSO, i dont know if it has any difference, but when i was ohming out the TPS... I was probing from the backside of the TPS connector, not the harness side.

I know some things, so I'm not a complete idiot, but I am not sure which side i would have to probe.

Obviously to do a sweep, one would have to be checking the back side of the TPS.

I dont have an RTEK, just stock unmodded ECU and no SAFC or anything.

mods are listed in sig, but none of my mods should really be affecting it.



and something weird is happening as well. i've never seen a case like this before, and i 've searched numerous times on the topic. no one seems to have the problem i do.


when the car is finally warm and idling. it will idle at 2k. which obviously is too high.

then when i put my foot on the gas slightly and keep it there, the idle lowers to 1300 but then starts to hunt to 1500, until i take my foot off the gas then it raises back to 2k.

sticking linkage maybe as well? such weird problems and i'm getting fed up. haha

and i REALLY appreciate your help HAILERS. truly.

HAILERS

I think you should invest in the PVC piping and then start the engine. Then maybe you can see what is wrong.

What I'd look for is to see if the throttle stop screw is touching the throttle linkage or not.....when the engine is fully warmed up. If it's not touching then that means the throttle plates are being held open by something. Might be the thermowax holding it open, might not.

You should be able to put your finger on the throttle cables inner cable near the throttle bellcrank and press the cable up/down at least a 1/8th inch without the throttle linkage moving. If the throttle linkage moves with the smallest movement of the cable then it's too tight.

Yeah, it seems to be sticking linkage of some sort. When you step lightly on the pedal and the rpms drop, that must be the TPS influencing things.

EDIT:::: Attached is a picture of the throttle body looking FWD.

See the screw the arrow is pointing at? It is at the rear of the throttle body near the damper (that toad stool looking outfit).

Even if the engine is stone cold, IF you lift up on that screw, it will release the linkage off the fast idle cam and NOW the linkage should be the same as if the engine is fully hot.

So lift up on that screw, THEN look for the throttle stop screw. The throttle stop screw is about a 1/4 inch long and has a jamnut holding it in position. The throttle linkage should be touching the bottom of that screw when the forementioned screw is lifted upwards.

If the linkage is not touching the throttle stop screw, then SOMETHING is holding the throttle plates open. What? Got me. Might be something at the front left side of the throttle body where the double throttle diaphram/cam etc are. Can't say from here.

About that attached picute.....in real life its difficult to see those items as shown in the picture. A mirror and flashlight help...sometimes. But that screw head should be easily seen. The one with the red arrow.

HAILERS

The following is out of a NON TURBO seciton of the FSM. Fuel section. It replicates what is happening with your car, even though there is no such test for a turbo car.

See? It's at 2000rpm and the guy slowly pushes the TPS plunger in a little bit and the engine responds to the pushing of the TPS plunger. Except YOU have been pushing the TPS plunger with your foot/pedal.

So your problem for sure is not the TPS. It's a throttle plate open too much. Stuck linkage. Too tight a cable. Jammed cam on the front of the throttle body where there is a thing called a double throttle diaphram and a DAMPER. The DAMPER has a BLACK cam that rides on the DAMPER plunger. I had one of those CAMS fall apart on me and jam the throttle linkage in the past.

Or your problem could be something else all together. Who knows.

tougeFB

HAILERS,

thank you so much for going out of your way (beyond my expectations for sure... )
to help me out.

i wish i could go try this now, but it's dark outside, and i dont have a light.

i'm kinda working on my TII in a uncovered spot in my apt. complex.

not ideal, but you gotta do what you gotta do.

i think i know which screw you're talking about anyway. that picture does make it difficult, but posting those diagrams for me is awesome, and I really appreciate all your help so far.


like i said, these weird symptoms are like nothing i've ever seen before, so looking at people's threads with other TPS problems, or idling problems only kind of helps me. i always search before i post anyway. i know better than that.

the PVC pipe idea does seem like a good one, and i'll definitely try it so if i have any other problems, i can use it and get the damn tmic out of the way.

technically i still dont even know if i have a TPS problem.

but through searching, #1 most common cause of hunting idle= TPS
so that's what i went with..


by the way, i must be doing something wrong with the 1v method. i'll try again tomorrow.

as for the ohm method and checking resistance... I tried one more time.

set the TPS (disconnected) back probed on the TPS side of the connector
(which is a white connector, btw)... may be an N/A TPS. I think i was told there was no difference between TII and NA throttle position sensors.
the one in the pic from FC3S pro is black, i just wonder if there's too much of a difference.

i back probed it, set it to 1k ohm again, and with it disconnected, it sweeps fine
1.0 to highest reading of 5.6k ohms. (at WOT)

once i connect it and backprobe either side of the TPS connector (harness or sensor side) then it gives me the weird readings. where idle is 1k and highest it will go is 1.5k ohms, then it counts backwards where 0.5k ohms is WOT.

it's the weirdest thing. i've run out of daylight, but not out of ideas, thanks to HAILERS.

tougeFB

sweet.

i'll have a look around again.
i still wonder if the throttle position sensor i have is any good???

what a pain.

many thanks.

ps im leaning towards stuck linkage... i may have caused it back when i took my UIM off, but not all the way. hopefully i didn't rest the entire UIM with stress on the linkage, but it's very well possible i might have.


this doesn't explain though why the problem had just suddenly arose though? the hunting idle i mean.
the weirdest part is the 2k idle once it's warm, then slightly touch the gas and hold it (push pedal down about 1/8 of the way and it will hunt again) until you release the gas then it raises back to 2k.

so here's my plan of action.

1. check linkage, and throttle stop screw with jamnut, as you said. make sure it is touching.
(if i read that correctly)

2. check for vacuum leaks (again)... for now i'll have to do it WITH the TMIC on.

3. run the car till its hot, and idles at 2k. then see if i can force the linkage to move, which may lower the idle by default (if it's stuck).
if that works, ill have a better idea of what's going on. and will be one step closer to finding my problem.

HAILERS

Here's a picture I stole off this site. I labled and show the throttle stop screw. The vies is from the rear of the throttle body.

This person has removed his thermowax so that's not visible, BUT the stop screw and jamnut/linkagei is shown.

tougeFB

awesome. i figured that's what you were talking about, and that's a great picture, and VERY helpful. i may bust out the flashlight tonight after all!

i editted my previous post by the way. to give a further analysis of what i'll be doing.

HAILERS

Just suddenly arose? Oh. Could be another thing then.

TPS is good.

Try removing the plug to the BAC and see what happens.

Or maybe a turbo inlet duct crack under the clamp where the duct attaches to the turbo.

Or?

tougeFB

I have had a bad TID also. hahahaha. here's the picture from that nightmare.
it's been replaced, but with a used one, so perhaps the new one may be showing signs of stress. especially with the airbox that doesn't move, and the engine always hunting and moving around because of it.

old TID:



yikes.

do I remove the BAC plug WHILE engine is running?

oh let me fill you in on something else.
i'm running premix. oil injectors are blocked. if a oil injector is leaking vacuum, how much might it affect the idle?

HAILERS

Remove the BAC plug either before or after the engine is running. There's a small chance its stuck open further than allowed. Just a quick thing to check out.

I like to think the oil injectors wouldn't be causing this problem. Seems the leak would have to be larger...to me. Just a dab of RTV on the injectors would have been enought to stop them from leaking. A dab on the top and a dab on where the oil once entered the injector.

tougeFB

also i forgot to add this as well.

initially this problem started at sevenstock. i drove from arizona to california, no problems. it didn't do it at any gas stations along the way or anything either.
i started my car up saturday morning, and it was doing this. i drove into ss9 with my 10ae idling this way.
but anyway.
we tried making an adjustment (ohmeter method) back when we were in california, but it did nothing, and the idle continued to hunt.

i arrived back in arizona, and parked the car, and did not drive it for 2 days.
i went to start it up one morning, and the hunting idle was gone, and my damn near perfect idle was back (i worked HARD to get it to idle that way)
it stayed that way for a couple days, maybe a week.

then out of nowhere the hunting idle had returned. with the old TPS i was using, it hunted all the time.
the new TPS i installed, only hunts at idle when cold. then when warm, it idles high.

perhaps coincidence, like you said because of sticking linkage.

i just want to give you as much info as possible, because then possibly we can single things out, and figure this beast out.

i'm very grateful for your help, i can't express that enough!!

tougeFB

my ongoing problem continues... details soon enough.

tougeFB

latest news:

kinda hard to spray starting fluid to hear if the idle raises, if the idle is already fluctuating on it's own. yet. i found no luck with that.

i unplugged the BAC, (just in case) and not only is the connector completely broken, but unplugging it had no effect.
i did notice one thing, i already know my throttle cable is effed (and possibly sticking)
it has done that before.
but also what i noticed, the grommet for the throttle cable so it fits into that bracket near the back of the TB... the grommet was almost all the way out.
and on top of that, the throttle cable was also tucked under the power steering resevoir disptick cap thing. when i went to grab it, and make it so it's not stuck, the idle raised.


still no reason why my car should be hunting.

one other thing.

the car continues to hunt if you raise the idle (with your foot) and hold it.
for example: it normally hunts from 1300-1500rpm.
if you push the gas a little harder, and hold it, it will then hunt from wherever you stop your foot
ie: 2300 and hunt to 2500. and goes as high as around 3000-3200 rpm before it no longer hunts
(possibly because of vacuum pressure in the manifold)

it's still sounding like a vacuum leak to me, i just can't seem to find it.

tougeFB

anyone?

tougeFB

latest update: nothing.

i cant figure out my problem for the life of me... =\

tougeFB

well i discovered something today...

after driving my car, it having a hunting idle, and after me working on it, my roommate needed to go somewhere cuz his TII powered FB isn't up and running yet.

I worked on my TII yesterday, and forgot to tighten an IC clamp before i left, but i figured it wouldn't be too much of a problem, since i wouldn't be boosting much.

i kinda actually forgot about it, i thought i tightened them at least enough to drive. on my way back, i blew the IC line off, and the car died so i pulled over, and fixed it. and drove home carefully.

when i got home, the car was idling, without hunting. i thought it was perhaps a miracle!

when i looked, the IC line was slipping off again, and this
(see picture)

line had come off.

thus causing the car to idle well. creating another vacuum leak
(if my first problem is a vacuum leak to start) makes the car run better.

any ideas?

my roommate seems to think it's the caps i have in place of my oil injectors.
i don't think that would really cause the problem, but i was trying to get opinions from you guys.


sorry i always write so much. i really want to fix my car, and i think i'm on the right track to doing so.

hopefully someone responds.

(not the bypass air control valve, but the solenoid next to TMIC)

PS. yes i know my throttle cable is jacked up.

tougeFB

here's what i was talking about in the previous post




except, all along (as well) that connector has been disconnected. but the vacuum hose has been plugged in.

and like i said, the problem pretty much came out of nowhere

Digi7ech

iTrader: (1)

You saw my NZvert Homedepot intercooler piping. You can use it if you need.

As for all that crap. you know my stance. Get rid of it all and you have less things that can leak. As for the electronics. These wires are pretty shady.

Last harness I pulled apart had bad oxidation 2 feet down line from the injector plugs so anything can be wrong there too. Don't forget that you had the oil mist all over **** from sevenstock. Maybe some of it got in some where it shouldn't have.

tougeFB

okay well the woes are over.

the problem is solved.

it was NOT:

a TPS problem or
a vacuum leak

my roommate seriously figured out my problem. i take no credit.
my BAC wasn't fully seated, or fully closing so that was perhaps why the idle was over compensating, or not giving a correct idle, or signal.

we took off the BAC, and applied 12v power and gnd to it and realized the spring inside of the BAC was not fully moving.
so next step was:
to take off the BAC, find out why it's not fully closing.

also during this time, the connector for the BAC broke, so while we were at it, he spliced in a new connector (from a spare injector he wasn't using). and it worked like a charm.

at the same time, we also reconnected my o2 sensor, because the wires for that had broken as well. it's an old car, right? these things happen.

anyway...


the previous time i had taken off my BAC, i did not use a gasket for it. i used silicone RTV type stuff. the right stuff for the job, for a temporary seal.
it seems that some of that gasket material came off and perhaps got stuck in the actual BAC itself, causing it to not close fully.
i dont know why i didn't think of this.

so I took the BAC off, sprayed it down with starter fluid and made sure it was clean and that the spring inside was seating before reinstallation.
my roommate made a gasket for it, and we applied power and gnd to it and tried again. it was moving around and seating it appeared, as it should... so we then re-installed it.

also since my air bypass solenoid valve wasn't even plugged in, we decided to just cap that line off, or the big nipple off on the TMIC.

and then all we needed to do, since the car was idling poorly
(mainly because we put the BAC screw in all the way)... was jump the intial set coupler, raise the L/R to when the car idles the highest, turn the BAC screw until it hit 650, and disconnect the initial set coupler.

NOW MY CAR IDLES LIKE A DREAM!!!!

i owe my roommate dinner now. lol. cuz i'm broke and dont start work till thursday.

thanks everyone for your help!