Bare with me, its a story.
Brothers car. A Frankenstein build
Initially a budget build, but I told my brother, the cheaper you go, the more problems. Taddaaa - here I am in his behalf.
2003 Mustang GT
2003 GT PCM
5.4 4v swapped Navigator engine.
SCT handheld tuner - with GT style tune
Car was running good initially with karkraft intake spacers with 99 Cobra Intake Manifold.
Then more parts came. and so did the problems.
MMR intake spacers
5.0 Coyote Velocity Intake Manifold
1993 year 5.0 style - 90mm Accufab Intake Plenum
Appropriate spacers to make it all work.
Notching the slots for the 99-04 style TPS sensor, I was once able to get it in the KOEO closed throttle 0.90v range but the sensor was not a direct fit to the 1993 Accufab mounting points, so it wouldn't stay within range because of the circular mounting lip elevating sensor from plenum.
Fast forward, we instead opted to get a 1993 style TPS sensor since it would theoretically mate up perfectly. Matched wires from 93 sensor to 99-04 harness and crimped them down for now.
Went online, found forums on TPS over the past 15 years. Nothing matched my scenario, or if it was close, the OP never posted results or ignored the community on advice.
So I took my FLUKE Voltmeter and started at it. Fast learner - here I go.
The issues:
Surging idle, RPM's would rise as the temperature of the car would rise. ~1,100 through ~2,200 rpms.
If I disconnect the IAC, absolutely nothing happens to the idle.
The MAF is an 2001 style MAF; so no integrated IAT.
&
The IAT is currently missing and plan to add that this weekend. PID's show this sensor at 100 degrees constantly in the SCT handheld scanner.
KOEO
TPS - 93' 5.0 'Standard' brand
Signal Wire (red probe) / White/Grey Ground Wire (black probe)
Closed: -0.252v
WOT: -1.600v maximum
yes, increases from low value to WOT value at good rate
Question: Why negative values & Why is it soo low?
KOEO
5v Reference -
Brown/white (red probe) / white/grey (black probe) = 4.779v
Brown/white (red probe) / Accufab Plenum = 5.036v
Brown/white (red probe) / Shock tower ground = 5.040v
without key - engine off
Resistance test
Brown/white (red probe) / negative battery terminal while connected = 2.626
Brown/white (red probe) / negative battery with terminal disconnected = 0.846
This realm of car electronics is new to me, please critique and help me figure this out.
94-04 Haynes Manual
Brothers car. A Frankenstein build
Initially a budget build, but I told my brother, the cheaper you go, the more problems. Taddaaa - here I am in his behalf.
2003 Mustang GT
2003 GT PCM
5.4 4v swapped Navigator engine.
SCT handheld tuner - with GT style tune
Car was running good initially with karkraft intake spacers with 99 Cobra Intake Manifold.
Then more parts came. and so did the problems.
MMR intake spacers
5.0 Coyote Velocity Intake Manifold
1993 year 5.0 style - 90mm Accufab Intake Plenum
Appropriate spacers to make it all work.
Notching the slots for the 99-04 style TPS sensor, I was once able to get it in the KOEO closed throttle 0.90v range but the sensor was not a direct fit to the 1993 Accufab mounting points, so it wouldn't stay within range because of the circular mounting lip elevating sensor from plenum.
Fast forward, we instead opted to get a 1993 style TPS sensor since it would theoretically mate up perfectly. Matched wires from 93 sensor to 99-04 harness and crimped them down for now.
Went online, found forums on TPS over the past 15 years. Nothing matched my scenario, or if it was close, the OP never posted results or ignored the community on advice.
So I took my FLUKE Voltmeter and started at it. Fast learner - here I go.
The issues:
Surging idle, RPM's would rise as the temperature of the car would rise. ~1,100 through ~2,200 rpms.
If I disconnect the IAC, absolutely nothing happens to the idle.
The MAF is an 2001 style MAF; so no integrated IAT.
&
The IAT is currently missing and plan to add that this weekend. PID's show this sensor at 100 degrees constantly in the SCT handheld scanner.
KOEO
TPS - 93' 5.0 'Standard' brand
Signal Wire (red probe) / White/Grey Ground Wire (black probe)
Closed: -0.252v
WOT: -1.600v maximum
yes, increases from low value to WOT value at good rate
Question: Why negative values & Why is it soo low?
KOEO
5v Reference -
Brown/white (red probe) / white/grey (black probe) = 4.779v
Brown/white (red probe) / Accufab Plenum = 5.036v
Brown/white (red probe) / Shock tower ground = 5.040v
without key - engine off
Resistance test
Brown/white (red probe) / negative battery terminal while connected = 2.626
Brown/white (red probe) / negative battery with terminal disconnected = 0.846
This realm of car electronics is new to me, please critique and help me figure this out.
94-04 Haynes Manual