TPS with 75MM TB and ECU

[90GSX]

Anyone running a large aftermarket throttle body, (i.e. BBK, Accufab) with stock ECU? What TPS did you use?

I found a ford TPS, however the voltage output by the ford TPS was not calibrated correctly for the ECU in the car. i.e. in closed position the ford TPS output roughly .05v, which the ECU interpreted as approximately 9% open throttle. Note: the TPS was not attached to the TB during the test and I could not close the TPS any more to lower voltage, 0.05 was the lowest it would ouput. At the wide open TPS position it output roughly 4.90v (+- .02v), which corresponded to roughly 90% open throttle. I tested 2 different ford TPS's, both had similiar ranges.

As an alternative to the ford TPS I fabbed a plate to mount the mits TPS on the Accufab TB. At closed throttle, I can achieve 0%, per the logger, which will alow the car to idle without fouling plugs, however at WOT the TPS does not reach 100% even with the mits TPS. Max voltage/percentage with the mits TPS at WOT (while attached to the TB) was still 4.90v (+-.02v) 90% WOT.

Now if I keep the ECU/VPC/Logger system in the car and do not upgrade to a standalone how do work around this TPS dilemma?

I've devised some electronic trickery in which I will use the WOT switch I have mounted to activate the Nitrous to activate two relays. One relay to activate the Nitrous, of course. The other will, at WOT, act as a jumper between the 5v TPS sensor power wire and the TPS signal output wire. The relay(s) will disable the TPS, and redirect the 5v to the ECU. There will of course be a "dead spot" in the throttle, just before WOT, between the time when the ECU is seeing max sensor output voltage and wot when it sees 5v. However, I don't think this will be a problem, since I don't spend much time at 97% pedal deflection

Any thoughts? Comments? Suggestions? Or better yet, a part number for a ford TPS that is calibrated correctly for our ECU's?

Thanks,

 

[CraigB]

You don't want your tps to read 0 volts at closed throttle. It should read between .5 and .75 volts. Any TPS that is a 5 volt TPS which most are will work.

 

[90GSX]

Originally posted by CraigB
You don't want your tps to read 0 volts at closed throttle. It should read between .5 and .75 volts. Any TPS that is a 5 volt TPS which most are will work.

To achieve 0% per the datalogger, the sensor must be at 0.02v. I'll verify this again next time I'm at the shop.

 

[DSMu4ia]

This is one of the mods on the TMO "RACE" ECU mods.

Basically it removes some idle codes from the stock ECU.

There is alot more to it, I'm not a 1g guy, but if you shoot me a private email ([email protected]) I'll forward you to someone who could explain it in much detail.

 

[spoolints04]

I'm running the Accufab 75mm TB with ford tps set at 1.100 volt, approximate 23% on the logger. These were Tym's instructions when I bought the "RWD Eprom" also known as the race TMO. The isc is locked, I'm running this with VPC/AFC, BR sheetmetal intake and all the goods.

The car runs pretty well, been to the track once and managed a [email protected] with a 1.845 60' without nitrous, I'm looking for a setup.
The problem is with the idle, I done everything but pull my hair out to get this thing to idle. It surges very bad, dies alot. Talked to Tym a number of times, he sent another eprom, I bought another set of 660 injectors, tried both 550 and 660 chips in the vpc, 550 chip runs better. put the vpc in wifes car, runs perfect, tried different ECU. Ign timing is not it, played with cam timing (272/272) played with tps voltage. Fuel pressure is at 40 (static) have tried anywhere from 30 to 60 (static) no luck. Can get it to idle decent for a minute or two, then it goes back to surging. I'm thinking to myself, how in the hell can it surge if it doesn't have a ISC motor. It surges from 600rpm to 1600 rpm.
Someone please help

 

[niterydr]

Originally posted by spoolints04
I'm running the Accufab 75mm TB with ford tps set at 1.100 volt, approximate 23% on the logger. These were Tym's instructions when I bought the "RWD Eprom" also known as the race TMO. The isc is locked, I'm running this with VPC/AFC, BR sheetmetal intake and all the goods.

The car runs pretty well, been to the track once and managed a [email protected] with a 1.845 60' without nitrous, I'm looking for a setup.
The problem is with the idle, I done everything but pull my hair out to get this thing to idle. It surges very bad, dies alot. Talked to Tym a number of times, he sent another eprom, I bought another set of 660 injectors, tried both 550 and 660 chips in the vpc, 550 chip runs better. put the vpc in wifes car, runs perfect, tried different ECU. Ign timing is not it, played with cam timing (272/272) played with tps voltage. Fuel pressure is at 40 (static) have tried anywhere from 30 to 60 (static) no luck. Can get it to idle decent for a minute or two, then it goes back to surging. I'm thinking to myself, how in the hell can it surge if it doesn't have a ISC motor. It surges from 600rpm to 1600 rpm.
Someone please help

My opinion, vacuum leak. Have you seriously pressure-tested the system? Or does that not matter with the VPC?

 

[GalantVR41062]

I thought the data logger, in the 1g's at least, read 10% throtle with the throtle plate closed?

 

[niterydr]

.05 is the lowest it should go I believe (maybe .02) since the datalogger does read some percentage (8-10 percent) i believe, unless its a program error in the logger or a really bad connection.

 

[DELTA_Rotary]

Originally posted by niterydr


My opinion, vacuum leak. Have you seriously pressure-tested the system? Or does that not matter with the VPC?

I agree I had a surging idle and I found out later the intake manifold gasket was blown. I could never hear it while the car was on but we pressurized the system with it off and you could easily hear it.

 

[Wizard]

Minimum TPS voltage should be about .495-.5 volts at closed throttle. WOT should be 4.8-5.0 volts.
How about this. Remember the 90-94 Throttle bodies had the closed throttle switch on the opposite side of the throttle body. And then in 95-99 they integrated it with the TPS? That is a good poss. of what your idle problem is. Easiest way (and cleanest), is to get a 2g TPS, hard wire your old harness to accept the CTS wire.

Not sure if that is your problem, but it sounds good.

Wiz

 

[talon91tsi]

well why don't you just use the stock tps and ohm it to spec @ warm idle? the tb is after metered air so the ecu does even know what tb is on there. if it does not open 100% then adjust the throttle cable and isc valve adjustment screw to idle @ spec for warm engine, then readjust tps to spec.

 

[TurboGarageTech]

Talk about thread resurrection. In any case, I wanted to ask what the part number for the Ford TPS you used was. I need a 0-5V sensor, but the one that came with the 75mm throttle body I have is some mongrel 2.5-3.2V or some crap. It basically useless, I can't even compensate for it's stupidity with DSMLink. Let me know if anyone knows what sensor should be used.

Ryan

 

[JohnTSI]

I have a accufab and a eprom with a keydrivers stage 3 and a afc/maf translator. Just plugged in the stock mustang tps and set the idle screw car runs perfect. I know of 3 cars here like this and have no problems. As far as the dieing and such, I had a leak at the tps itself on the accufab used some rtv now idles fine.

 

[arknyd]

I am trying to wire the 3 wire ford tps on my 9omm accufab tb and i have a 97 spyder get 4 wire tps plug. I have done some searching, but to no avail.. anyone outthere point me in the right direction?
thanks

rob

 

[JohnTSI]

1gs have 3 wire tps, not sure what is going on with the 2g setup. I am not even sure what a 4th wire would be unless it is for CTS, power, ground, and signal wire. But just curious, a 90MM acufab? Are you building a tube frame race car? Why are you putting such a large tb on the car? With 3" IC piping it matches up to a 75mm.

 

[arknyd]

i am a moron, it is 75mm accufab tb. I am using a garret t66..turbo to ic pipe is 2.5 inch then from ic to tb is 3 inch, iam also using 3.5 gm maf. This is a 1g in a 2g setup. 2g wiring harness has 4 wires the ford tps uses 3 wires....consequently I am trying to figure out a possible wiring solution for this dilemma.

Rob

 

[JohnTSI]

If that 4th wire is the CTS and you are installing a accufab You might try wiring in the stock mustang 3 wire and leaving the 4th wire capped off.

 

[jamiesibley]

The ecu used the CTS wire to determin when the car should have the closed loop idle active. Because of the electrical noise and voltage drift with temperature, the ecu cannot use just the 0-5v signal to know when to idle. The 0-5v signal is used to find dv/dt and to turn off the a/c and such. The CTS is for idling. Either a closed throttle switch or a 2g TPS with internal CTS must be used.

 

[JohnTSI]

He cannot put the 2g tps on the accufab. And if going in closed loop is its main funtion you can do without it. THe gt35r powered car here has NO o2 sensor period gets 25mph on the highway and runs 11.0@132. You can tune out idle with the afc, depends on what other functions the CTS serves.

 

[na90dsm]

what mustang sensor is used. model make a which motor in the mustang.

im gonna use a 75mm in future most liekly and am reading up on this.

 

[Mirage2LTurbo]

Eric,

Might want to call Bill @ Autolab. He used some Mustang sensor from Napa to get working on my BBK 70mm. It was on the Autronic, so any voltage output would work.. is this on your car or on some stock'ish ECU powered DSM?

-Colin

 

[JohnTSI]

Just use the 89-93 stock mustang tps that mounts up to the 89-93 TB you will be using. Its 5 liter of course

 

[1995badgsx]

what throttle cables are you guys using on these throttle bodys???

 

[Mirage2LTurbo]

what throttle cables are you guys using on these throttle bodys???

Stock...

 

[jaycoy]

ok i have a 2g and need to know the wiring also. the tps has 3 wires and my 2g harness has 4. also if you are using the stock throttle cable how did you connect it to teh accufab t/b???