I'm not closed to the idea of a bad ECU, but the one I have has less than 1000 miles on it. I suppose things could go south pretty quickly. Though.I'm starting to wonder if you don't just have a bad computer. I hate wiring/electronic issues. Good luck.
An ECU swap would be the easiest fix as opposed to chasing my stinkin' tail. All I gotta do is wait 3-6 weeks for a replacement.It does start to sound like maybe there's a bad capacitor in the ecu. I was chasing all sorts of similar recurring issues. Final priest to the exorcism was a new ecu.
They. Are. The. Worst. How can the car run [perfect] for 11 miles then crap all over itself within 1.5 miles after just sitting for a few hours???I'm starting to wonder if you don't just have a bad computer. I hate wiring/electronic issues. Good luck.
Ok. Well, I can at least check that one off the list.No. The 02 that was used utilised a 4th wire our cars don't have. It would just not heat up as its supposed to and give a bad signal back to the ecu.
Thanks so much! I'm not quite as sick today so I'll try to work through these paths. I'll note the findings and relay them here.Codes 31 & 63 have this in common; the are both caused by low or missing +5 VREF voltage.
It is time to do some resistance measurements between the +5 VREF wiring between the engine mounted sensors that use +5 VREF and the 10 pin connector . Use the code31 & 63 test paths as a guide to finding the missing voltage or bad connection. Since you didn't get a code 22 (map/baro sensor fault). you have +5 VREF coming from the computer.
CODE: 31 (KOEO) - EVP circuit below minimum voltage. Vref (5 volt reference voltage supplied by the computer) missing or broken wire or bad connection in circuit. Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or MAP sensor located on the firewall near the center of the car. Use the black/white wire for the ground for the DVM.
With the sensor removed from the EGR and still connected, press the plunger and watch the voltage change on the brown/lt green wire. Pull the passenger side kick panel and measure the voltage at the computer. You will need to remove the plastic cover over the wires and probe them from the backside. A safety pin may prove very useful for this task. Use pin 27, EVR input (brown/lt green wire) and pin 46, signal ground (black/white wire) to measure the voltage. The orange/white wire is Vref and should always be 5 volts -/+ .25 volt. Be sure to measure Vref at the EGR sensor to rule out any broken wires or bad connections.
Measuring the voltage at the computer helps you spot broken wiring and intermittent connections.
See the graphic for the 10 pin connector circuit layout.
Code 63 - Throttle Position Sensor (TPS) signal too low.
Revised 02-Jul-2009 to update TPS setting procedure & add 10 pin connector layout.
Vref missing (5 volt reference voltage supplied by the computer), bad connections or damaged wiring, TPS sensor failed, TPS sensor way out of adjustment. Use a DVM to check for 5 volts on the Orange wire. If it is missing, look for +5 volts at the Orange wire on the EGR or MAP/Baro sensor located on the firewall near the center of the car. If there is +5 volts on the MAP/Baro sensor, but not on the EGR, clean the #2 & #5 pin on the white 10 pin connector. If there is +5 volts on the EGR but not on the TPS, look for bad wiring inside the engine fuel injector harness.
See the graphic for the 10 pin connector circuit layout.
Setting the TPS voltage
You'll need a Digital Voltmeter (DVM) to do the job.
Wire colors & functions:
Orange/white = 5 volt VREF from the computer
Dark Green/lt green = TPS output to computer
Black/white = Signal ground from computer
Always use the Dark Green/lt green & Black/white wires to set the TPS base voltage.
Do the test with the ignition switch in the Run position without the engine running.
Use the Orange/white & Black white wires to verify the TPS has the correct 5 volts source from the computer.
Setting the TPS: you'll need a good Digital Voltmeter (DVM) to do the job. Set the TPS voltage at .5- 1.1 range. Because of the variables involved with the tolerances of both computer and DVM, I would shoot for somewhere between .6 and 1.0 volts. Unless you have a Fluke or other high grade DVM, the second digit past the decimal point on cheap DVM’s is probably fantasy.
Since the computer zeros out the TPS voltage every time it powers up, playing with the settings isn't an effective aid to performance or drivability. The main purpose of checking the TPS is to make sure it isn't way out of range and causing problems.
The Orange/White wire is the VREF 5 volts from the computer. You use the Dark Green/Lt green wire (TPS signal) and the Black/White wire (TPS ground) to set the TPS. Use a pair of safety pins to probe the TPS connector from the rear of the connector. You may find it a little difficult to make a good connection, but keep trying. Put the safety pins in the Dark Green/Lt green wire and Black/White wire. Make sure the ignition switch is in the Run position but the engine isn't running.
Always adjust the TPS and Idle with the engine at operating temp. Dive it around for a bit if you can and get it nice and warm.
When you probe the leads of the TPS, do not use an engine ground, put the ground probe into the lead of the TPS. You should be connecting both meter probes to the TPS and not one to the TPS and the other to ground.
The TPS is a variable resistor, much like the volume control knob on a cheap radio. We have all heard them crackle and pop when the volume is adjusted. The TPS sensor has the same problem: wear on the resistor element makes places that create electrical noise. This electrical noise confuses the computer, because it expects to see a smooth increase or decrease as the throttle is opened or closed.
TPS testing: most of the time a failed TPS will set code 23 or 63, but not always. Use either an analog meter or a DVM with an analog bar graph and connect the leads as instructed above. Turn the ignition switch to the Run position, but do not start the engine. Note the voltage with the throttle closed. Slowly open the throttle and watch the voltage increase smoothly, slowly close the throttle and watch the voltage decrease smoothly. If the voltage jumps around and isn’t smooth, the TPS has some worn places in the resistor element. When the throttle is closed, make sure that the voltage is the same as what it was when you started. If it varies more than 10%, the TPS is suspect of being worn in the idle range of its travel.[/b]
I currently have no other ECUs. It will take 4-6 weeks to get another one and $150.can you swap out EEC's to test?
I currently have no other ECUs. It will take 4-6 weeks to get another one and $150.
Good idea. However, that's what I'm referring to. They don't stock them anymore. They either rebuild yours or switch it out. Either way it will take 4-6 weeks. Trust me. I went through this already. Summit gives an undetermined amount of time for a fox ECU replacement.check your local oreilly, advanced auto, or autozone... they used to stock and sell them
Thank you. I'll check that wire for voltage. As far as the test paths, I actually copy/paste onto a Word doc, then broke down the paragraphs into numbered steps and substeps. I really only had a few questions pertaining to which wire you were indicating.The orange/white wire connects to both the TPS & the EGR sensor and pin #2 of the white 10 pin connector. The picture you posted shows a white wire with a red stripe, which is not standard for 5.0 Mustangs. But by looking at the other 2 wires, I would guess that it is the +5 VREF.
Go back and slowly read the Code 31 & 63 test paths; everything you need should be in there. You may want to print them off and highlight the steps describing the test and measurement parts of the test path.
Thanks for the reply. This info is truly helpful, you have no idea. My TPS is adjustable. I have a summit 70mm TB and it has an adjuster plate onto which the TPS attaches. I just turn the plate either way to adjust. I'll look to put the TPS more in the middle of the .600-1.1 range.The TPS voltage is a little high, I recommend that you try turning the sensor and see of you can get it to decrease a little bit.
Other than that, you seem to be on track. I don't have an upper voltage on the EGR, but I suspect that once you have resolved any +5 VREF questions that it will be OK.
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