# OBD1 VR TPS sensor?



## hoodita (Jul 25, 1999)

I have a VRT OBD1 C2 #30 tune in my rado. And i had a boost leak and had to take off the plug going to the throttle position sensor and I forgot to plug it back in. and i just noticed that today. So i was driviing with it unplugged all week since sunday.

Wouldnt i notice drivability issues with it unplugged? with it unplugged for days it drove the same with it plugged in. 

Wideband shows the same a/f ratios as with it plugged or unplugged. basically 14.7 at idle. no boost 11 to12.5. under boost instant lean im talking 13+. i know if i dont find the problem my motor will pop. 

Ive had a lean condition while under boost. Do you guys think the TPS is my problem?

This is the only component left that hasnt been replaced. if this isnt the problem im going to assume i have a software issue.

BTW i have no faults.


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## ade007 (Jun 12, 2007)

check your tps in vag-com see what value it reads at idle usually around 12 ish and slowly press tps and check see if values gradually climbs with pedal movment i forget but i think around 96 i think mine goes to max if yours is same then tps is ok :thumbup: 
boost leak would be rich in boost....try reseting the ecu fuel adaptations disconect battery leads and touch leads together to discharge the ecu seems to work well.... check the fuel pressure 
http://www.corrado-club.ca/mods/vr6_fp_test.html plus see what your fuel pressure is under boost if you can 

ps why did you have to unplug the tps because of the boost leak ??


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## vergessen wir es (May 12, 2010)

luckily an aftermarket TPS is $36 if you are willing to go aftermarket. I guess I am not too surprised about the car running decent without it. I mean probably the idle control, if you still have yours, is defaulting to an opening that works. Plus I have this sneaking suspicion that our cars run anywhere in boost is like wide open throttle, meaning just pointing to a table cell based on MAF since the narrow band O2 can't be giving useful info right?


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## hoodita (Jul 25, 1999)

thanks for the info. ill let you know what i find.

btw i unplugged the tps plug so that i tighten the hose clamp on the throttle body.


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## hoodita (Jul 25, 1999)

well i ran some live data. TPS at idle was at 3. WOT i got it to 44.

So i checked the MAF. at idle was at 2.5/MS and WOT 9/MS.

looks like the MAF is trash!!! Kinda strange i think cause its only 6months old.

but what about the TPS. u think that might be bad also?


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## vergessen wir es (May 12, 2010)

Definitely not good values. The TPS is a brush contact so it doesn't last like solid state. That said it could also be a reduced signal from a bad contact since your idle and WOT values are both low.


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## 'dubber (Jun 15, 2004)

If your tps circuit is malfunctioning for some reason, the ecu looks at the maf signal for a primary substitute. If the maf is also bad along with no tps, I'm not sure exactly what happens ecu-wise, mabye batch fueling mode like when the a cam sensor dies, but im guessing that the car isn't going to begin to run better. 


What software are you using to check maf values? I'm pretty sure vagcom has no provision for outputting obd1 maf signal info. See if you can pin out the signal wire and look at the voltage going back to the ecu. It should be low, around a volt at idle and you might see 4.5 or a little more at high rpm/wot.


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## hoodita (Jul 25, 1999)

I was using the VW 5051 scan tool. i dont have vag com. i wish i did. and running c2 30# tune if i didnt mention it before.
basically i have a running lean under boost for a long time. and runs super rich under no boost. 
im going to get a new maf under parts warranty today. and ill get me a new tps sensor also.

let you guys know how it runs afterwards.


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## hoodita (Jul 25, 1999)

i replaced the MAF and no change. the idle is better thats about it. im going to get a new TPS and if that doesnt fix it. im going to C2 for another chip.


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## slcturbo (Apr 19, 2010)

Had a bad tps sensor on my 93' SLC. Setting a code and verified a "dead spot" with my DVOM.

I saw no change in driveability, A/F ratio, etc. after replacing it.

I know the tune is good so lean under boost/ WOT is probably a MAF or a fuel pump. 

Rich out of boost- O2 sensor/wiring, coolant temp sensor, MAF.

Just to verify. You're running a stock 4bar fpr?


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## hoodita (Jul 25, 1999)

btw im running a walbro in line as well. intank pump is about a yr old. i have an adjustable FPR set at 4bar.
I have verifyed that im getting enough fuel under load as well.

Coolant temp sensor is new as well.

just ordered a TPS. but what you mentioned and other people told me it probably wont fix it.


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## slcturbo (Apr 19, 2010)

Hmm, tough one. How is your intake setup done specifically?

MAF, air filter etc.

My car ran the best like this as have a few other 30# setups.

Air filter inside the RF fender well, ~18" long 90 degree bend cold air intake pipe into the engine bay through the carbon canister hole, coupler, MAF, Kinetic intake pipe, coupler, turbo.

What 2 letters is the ECU? Mine was a CD I think as was the test car. 

At WOT, if the MAF is sending a good signal and you have enough fuel at the injectors I don't see why it's running lean. Mine was always 11-11.5:1.

ECU/sensor grounds etc.


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## slcturbo (Apr 19, 2010)

Also are you absolutely sure you have no leaks on the exhaust side? Manifold to head, turbo to manifold, downpipe, bungs, 02 sensors. A leak there can give you that rich out of boost b/c it's getting a "false" lean signal. 

Intake leaks etc. ? My 30# ran like garbage for a bit and I finally found the lower manifold to head bolts had come loose causing a vacuum leak probably due the phenolic spacer contracting.


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## hoodita (Jul 25, 1999)

thanks for the heads up on some of the issues youve had when you first had your #30 setup.

basically i have the MAF hooked right up to the turbo inlet pipe that kinetics supplies with the kit. then the filter right on the other end of the maf.

and the reason i never put the away from the MAF is cause for the first couple months that i had my turbo setup it ran great! but now it runs awful. but i dont see that could be the issue. i guess its possible.

Also i have smoked tested fro leaks in the intake. And couldnt find any leaks. ive checked for leaks numerous times. and never could find any.

I have to check for exhaust leaks from motor back. I never thought of checkin there.


Ill have to check again for leaks on the exhaust and intake.


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## 'dubber (Jun 15, 2004)

What is the min/max scale for the maf signal on your logger? I'm just trying to figure out what you expect to see when you logged it. 



Did you see if your maf values got better on the logger with the new sensor?


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## 'dubber (Jun 15, 2004)

Hoodita, I was wondering if you ever get anywhere with your issues, and also also what unit of measurement the MS stands for with the maf readings.


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## hoodita (Jul 25, 1999)

i was assuming MS stood for milligrams a second. and i was expecting 3.5 at idle and over 100 at WOT.

i havent fixed my problem yet. i bought a TPS sensor.but they sent me the wrong one. so im still trying to get the right one. 

I have to put this problem on hold for now. Since i hit a massive puddle and got water in the intake a couple days ago.

Now i got a misfire under boost that im still trying to figure out.


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## Corsten (Sep 26, 2005)

Hey,

Did you solve the problem? a follow up would be great!.


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