Can't get TPS voltage above .15 volts - part 2

[90topdown]

Sorry I haven't been around lately but with the holidays and all, I havent had any time to work on the Stang.

Here is a re-cap of my prior thread:

Problem - Cant get TPS voltage above .15 volts between black and green wires at TPS , KOEO, engine warm. So far I have

So far-

- Replaced TPS sensor (no difference, still .15 volts at TPS )
- Replaced EEC power relay (no difference, still .15 volts at TPS )
- Swapped ECU with known good one. (no difference, still .15 volts
- Wiggled the engine and injector harnesses as best I could (voltage held steady at .15)
- If you open the throttle, the voltage moves linearly from .15 at idle to 1.3 at WOT
- Checked voltage between 26-VREF and 46- SIGTRN at TPS, sensor disconnnected, KOEO. Got 4.89 volts (within range)

Pulled codes again today for the umpteenth time. This is what I got

KOEO- 67,10,11
KOER- 21,94,44

67- clutch safety switch ( have had this code for a long time) I do not think that it is related to this problem
10,11- system pass

21- ECT sensor out of range

94,44- I removed the smog pump and piping


ECT Sensor - I replaced the ECT sensor a few months ago when I put the new motor in so I doubt that the sensor itself is the problem so I checked the two wires going to the sensor.

With KOEO, there was no voltage or resistance across the two wires at the sensor with the sensor connected or disconnected at the pins on the ECT.

"lightbulb" Looks like I have a wiring problem in the injector harness. Since the TPS and ECT share the 46 SIGRTN wire.

At this point, it looks like I need to remove the injector harness and unwrap it to see if I can find anything. It looks ok from the outside.

Or should I just get another injector harness and swap it in??

FWIW- When I put the new motor in, I put a different injector harness in from the original. The original injector harness was pretty beat up with broken connectors, etc. etc. so I chucked it.

I know that the engine harness is unique to a 90 but is the injector harness also unique to a 90?? I do not know what year the injector harness is out of as I got it at a swap meet.

What do you guys think??

 

[joel5.0]

From the results of both tests, you might be involved in a "witch hunt"........ trying to fix a nonexistent problem. A TPS signal reading at the ECM below .49 vdc will cause codes 23 and 63 to get logged + a KOER self test would not run due to the "hard failure" code the TPS will cause.

Code 67 might have been logged if you ran the KOEO with the transmission in gear or the A/C on...... if code 67 is a hard failure code, a KOER self test wouldn't run either.

Code 21 might have been caused by running the KOER with the engine coolant temp below 170° F..... IOW.... engine temp was too cold for a KOER.

Suggestions...... make sure the DVOM you're using has a fresh set of batteries, check DVOM leads for continuity, test drive the car for ~5-10 minutes.... rerun the self tests. If no TPS failure codes show up, no need to fix a problem not registered by the EEC. Just a thought.

 

[hotcobra03]

part 2

hey can you start story history again,i just delt with another story with code 67 and thier found it was an engine swap and harness changes,,maybe some thing is being over looked..?????

 

[90topdown]

Update

DVM batteries are good. Not sure what you mean by check leads for continuity.

Fired it up and took it for a 15 min ride. It now has a nasty surging idle. In fact, until it warms up, it wont idle. When I took it out for a ride, everytime I came to a stop sign, it died.

Pulled codes again and got-

KOEO- 67,10,63,96

KOER- 94,44

.16 volts between green and black at TPS - KOEO

4.93 volts between VREF and SIG RTN at harness connector (According to Probst, should be between 4-6 volts, so that appears ok)

.16 volts - 1.32 volts linearly between TP SIG and SIG RTN, KOEO, when moving to WOT. (According to Probst, should be variable voltage form 0 to 5 volts without any breaks as throttle moves through range, so this appears ok)

So according to Probst book - Ford Fuel Injection- TPS should be fine. but yet I have a code 63 - low TPS voltage.

Code 96 - Secondary fuel pump failure- I am sure that this is because the car died at every stop sign with the surging idle.

All the wiring seems to check out ok. I am at a loss on this.

Ideas??

HOTCOBRA03- I highly doubt that the 67 code is part of this problem. I have had it for a couple of years now. The clutch safety switch doesn't work.

 

[hotcobra03]

code 67

his was code 67 also and was the o2 harness plug found to be where wire needs to be moved and clear code 67...it took 2months but well worth the class...we were passed on some great pics or wire lay-out,can pass them on if needed .on ect what are the wire colors?

 

[SFC_R0CK]

FWIW- When I put the new motor in, I put a different injector harness in from the original. The original injector harness was pretty beat up with broken connectors, etc. etc. so I chucked it.

There is a ground on the injector harness that is usually grounded to the back of the heads and I was having voltage problems like you are describing and moved that ground to the firewall and it fixed those voltage problems right up. How are you running a KOER with a code 67?

 

[hotcobra03]

code 67/63

SFC___ROCK is who had the nitemare i was learning from,,,with other replys and pics sent of wire diagrams sfc--rock found a neddle in a heystack,,,, looking at pic from rock,,,your tps runs thru someother componets...code 63 is a low signal...even the orange wire splices in with other componets in the harness...lets think about that?????/

 

[joel5.0]

Update

Pulled codes again and got-

KOEO- 67,10,63,96

KOER- 94,44

.16 volts between green and black at TPS - KOEO

4.93 volts between VREF and SIG RTN at harness connector (According to Probst, should be between 4-6 volts, so that appears ok)

.16 volts - 1.32 volts linearly between TP SIG and SIG RTN, KOEO, when moving to WOT. (According to Probst, should be variable voltage form 0 to 5 volts without any breaks as throttle moves through range, so this appears ok)

So according to Probst book - Ford Fuel Injection- TPS should be fine. but yet I have a code 63 - low TPS voltage.

Code 96 - Secondary fuel pump failure- I am sure that this is because the car died at every stop sign with the surging idle.

All the wiring seems to check out ok. I am at a loss on this.

The fact that a TPS code (any) does not show up in a KOER + the sign it runs the full test (codes 44 & 94 = system pass when thermactor system is disabled)..... does point to an intermittent wiring or ground problem. Suggest to monitor the TPS signal wire voltage near the ECM connector with the DVOM using a frame ground for reference, and check how it does while a KOER is run, and while driving it. LUK

 

[go4it]

It has been a long time since I have had a TPS unbolted from a throttle body, or even read the voltage on one, so this is a shot in the dark. What if you unbolted it and turned it by hand, does the voltage increase up to 5 volts? Assuming there is nothing wrong with the wiring, it sounds like the TPS needs bolted down at the position of where it reads the 1.3 volts when you have the throttle open. So is it possible to turn the pot 90-180 degree and bolt it back down? Like I said this may be off base but thought I would throw it out there.

 

[hotcobra03]

its all in the wording?

tps is also tied to say 3 other items,thru 2 different circuits...code 63 is a low signal,,,what is signal,,,,amount of current going thru wire?????his test showed he had good volts,,when i first started with you and SFC-Rock,my pc was down,,rocks pics help with understand were wires go..no guess work....i was assuming the orange was a straight shot to pcm and its not ,you have already tryed another new tps ,,its going to be a bad wire

 

[90topdown]

The fact that a TPS code (any) does not show up in a KOER + the sign it runs the full test (codes 44 & 94 = system pass when thermactor system is disabled)..... does point to an intermittent wiring or ground problem. Suggest to monitor the TPS signal wire voltage near the ECM connector with the DVOM using a frame ground for reference, and check how it does while a KOER is run, and while driving it. LUK

Will try that , Joel



HOTCOBRA03

The injector harness ground is at the firewall and is good. With a DVM pos lead on pos post and key off I get 11.96 volts at neg batt post and 11.96 volts at firewall ground point.

Assuming that the original TPS sensor wasnt really bad, I have had 3 different TPS sensors on the car- all read .15 volts

 

[hotcobra03]

sti wire colors?

got a wire layout from SFC-ROCK,,,in thier i see circuit 355 DG/LG goes from tps to sti than (zone 47A )that is where wires change ,between sti and main harness 14401,,,wire is involved with changes to ..malfunction light,eec power relay,tps signal return,o2s and a in-line fuse,,,wires at sti will tell if thats it?

 

[SFC_R0CK]

Ok after looking in my Probst book for your codes these are what I came up with

KOEO -
67- Neutral Drive Switch (NDS) circuit open; A/C switch on
10- not listed
63- TPS below minimum voltage
96- Fuel pump secondary circuit failure or CM code 96 - Secondary air bypass not working

CM (Continous Memory)
44- Secondary air injection system inoperative (right side)
94- Secondary air injection system inoperative


code 67 will not let you do a KOER. Check here for more information on code 67 from jrichker http://forums.stangnet.com/767387-check-engine-light-help-4.html#post7748920 on how how to bypass it for testing.

 

[hotcobra03]

this is a long story

Ok after looking in my Probst book for your codes these are what I came up with

KOEO -
67- Neutral Drive Switch (NDS) circuit open; A/C switch on
10- not listed
63- TPS below minimum voltage
96- Fuel pump secondary circuit failure or CM code 96 - Secondary air bypass not working

CM (Continous Memory)
44- Secondary air injection system inoperative (right side)
94- Secondary air injection system inoperative


code 67 will not let you do a KOER. Check here for more information on code 67 from jrichker http://forums.stangnet.com/767387-check-engine-light-help-4.html#post7748920 on how how to bypass it for testing.

this is part 2 of the story...he has done all of the pin test already for tps and referance volts ...some he did fail and i didnt have your pick yet ..fwicr the test that he failed fit with wire change just like yours did at o2 plug,,,in your page 29 pic sti connector and dotted lines ...eec relay to sti connector is where test done after tps pin test passed... 46 to 47 passed .. but pin test c failed

 

[hotcobra03]

just a thought...if you had the other harness the BK/W wire would be affected.and low volts would be the fault....pin 68 in the eec relay runs thru haness and than cuts curcuit 359 out at zone 47 plug... codes can include ,,iac,fp,maf,canp,tps,erg,ect,amoung others,,,,circuit 361 can also be affected..on just 1 wire change

 

[SFC_R0CK]

Ok I just searched and found your original post, so now I got the full story. I still think there is a ground not making good contact somewhere.

But hotcobra03 may be on to something with circuit 361.

 

[hotcobra03]

maybe a link?

got a wire layout from SFC-ROCK,,,in thier i see circuit 355 DG/LG goes from tps to sti than (zone 47A )that is where wires change ,between sti and main harness 14401,,,wire is involved with changes to ..malfunction light,eec power relay,tps signal return,o2s and a in-line fuse,,,wires at sti will tell if thats it?

after studying Rocks big pic,,,your map has three wires,351,358,359,,,one goes to pin 45 of pcm the 0thers go to tps and others,,,also to zone 47f,,im assuming fprelay, how many of the red 361s are not hot? on the eec relay ,,,68/361 share pin,,68 runs to 361 in pic at the tab/tad.its alittle tricky cause it has dotted lines that show cal-emissions,,,...pin 11 and 51 are different for cali emissions//////i have followed what i was telling you and i can now understand what your readings were?how many wires are at the plug that goes from eec to fp-relay?

 

[90topdown]

The fact that a TPS code (any) does not show up in a KOER + the sign it runs the full test (codes 44 & 94 = system pass when thermactor system is disabled)..... does point to an intermittent wiring or ground problem. Suggest to monitor the TPS signal wire voltage near the ECM connector with the DVOM using a frame ground for reference, and check how it does while a KOER is run, and while driving it. LUK

Update-

JOEL50

Engine running-

Pos DVM lead at Dk/Lg Grn TPS wire at ECM and neg lead at ECM ground point on frame - .16 volts

Pos DVM lead at Dk/Lg Grn TPS wire at ECM and neg lead at neg batt post - .16 volts

Engine running during KOER test-

Pos DVM lead at Dk/Lg Grn TPS wire at ECM and neg lead at ECM ground point on frame - starts out at .16 volts, when idle goes up during test it continuosly modulates up and down- .16v-.17v-.18v-.17v.16v.17v.18v.17v.16v (I was holding the pos probe steady on the green wire. Neg lead hard wired to ground point. ) As soon as the test was over and idle went back to normal, voltage went back to a steady .16v

Did not check it driving the car as I could not figure out how to get a solid connection on the green TPS wire with the pos DVM lead without cutting and splicing the wire. I dont want to cut any wires unless there is no other option.

SFC ROCK- I think that it is probably a bad ground/wire somewhere. I just cant seem to find it. I cleaned and tightned all the ground points that I know of. Voltage stays steady at .16v when wiggling and shaking the harness as much possible.

HOTCOBRA03- Can you explain circuit 361 more clearly and what to check? I am not sure that I follow your line of thought.

 

[joel5.0]

Ok after looking in my Probst book for your codes these are what I came up with

KOEO -
67- Neutral Drive Switch (NDS) circuit open; A/C switch on
10- not listed
63- TPS below minimum voltage
96- Fuel pump secondary circuit failure or CM code 96 - Secondary air bypass not working

CM (Continous Memory)
44- Secondary air injection system inoperative (right side)
94- Secondary air injection system inoperative


code 67 will not let you do a KOER. Check here for more information on code 67 from jrichker http://forums.stangnet.com/767387-check-engine-light-help-4.html#post7748920 on how how to bypass it for testing.

Codes 44 & 94 are not CM codes, they are KOER codes exclusively.

90topdown....... the following is the potentiometer diagram of the TPS.....

Since in one of your previous tests you confirmed the presence of VREF at the TP wire when a jumper wire was installed, I suggest the following...... cut the SIGRTN wire from the TPS harness (in a section you can repair afterward)..... reconnect the TPS, turn IGN ON, measure TP wire voltage throttle closed and through its range to WOT...... LUK the results.

BTW..... did you get any TPS codes from that KOER self test run?

 

[hotcobra03]

Codes 44 & 94 are not CM codes, they are KOER codes exclusively.

90topdown....... the following is the potentiometer diagram of the TPS.....

Since in one of your previous tests you confirmed the presence of VREF at the TP wire when a jumper wire was installed, I suggest the following...... cut the SIGRTN wire from the TPS harness (in a section you can repair afterward)..... reconnect the TPS, turn IGN ON, measure TP wire voltage throttle closed and through its range to WOT...... LUK the results.

BTW..... did you get any TPS codes from that KOER self test run?

am i understanding this right...vref to sigrtn passed with 4.65volts..now he is testing ...tp to vref ang volts thier should change up/down,,is yes the orange wire goes thru other componets,will a break in that circuit mess up his readings?also would that be input volts as if current runs from map to tps..