Oct 19, 2005 at 11:59 AM
88 Bronco, 5.0, AOD
Okay, here's my problem and a not so brief description of what I've done to diagnose/correct it thus far. And yes, I've searched, and I've been to the fordfuelinjection website several times.
I've owned this truck for about 2 years, and the check engine light has always been on (p.o. removed the bulb, I put it back). Code 31 has always been the biggie. I initially changed the EGR valve (it was stuck), then the EVP (the resistance was way jacked up) but that didn't fix it. I then realized that most of my vacuum and/or emission lines were broken, missing, or otherwise inop. So I left it for awhile.
I finally got off my butt, went to the boneyard, and got a new vacuum harness for it (all the hard lines bundled as from the factory). The truck now runs much better. I erased the codes, and started over. Did a KOEO test with my scanner, got a 31 again.
So....I checked the EGR valve (it moves with vaccum applied from a pump).
I checked the resistance reading on the EVP (4400 ohms closed to 330 ohms with 10in vacuum). According to my books, this is in range.
I next tested the voltage at the EVP harness connector (4.6 volts) again, in range.
Then, I checked the resistance between the harness connector at EVP signal to socket 27 on the connector to the EEC PCM (0 ohms) once again, exactly what it should be.
I then checked the resistance between the harness connector at EVP signal to ground. I got that the circuit was open. Good, no short to ground.
Next, I checked the harness connector for stray voltage at EVP signal (none found). Good, no short to power.
Now I'm stumped.
I want to clear this KOEO code, so that I can proceed with whatever else may turn up when I do the KOER test. I'm trying to be methodical, sytematic, and not throw parts at it until I know what's wrong. ANY ideas/suggestions would be greatly appreciated.
SOMEBODY SAVE ME!!!
Will
Okay, here's my problem and a not so brief description of what I've done to diagnose/correct it thus far. And yes, I've searched, and I've been to the fordfuelinjection website several times.
I've owned this truck for about 2 years, and the check engine light has always been on (p.o. removed the bulb, I put it back). Code 31 has always been the biggie. I initially changed the EGR valve (it was stuck), then the EVP (the resistance was way jacked up) but that didn't fix it. I then realized that most of my vacuum and/or emission lines were broken, missing, or otherwise inop. So I left it for awhile.
I finally got off my butt, went to the boneyard, and got a new vacuum harness for it (all the hard lines bundled as from the factory). The truck now runs much better. I erased the codes, and started over. Did a KOEO test with my scanner, got a 31 again.
So....I checked the EGR valve (it moves with vaccum applied from a pump).
I checked the resistance reading on the EVP (4400 ohms closed to 330 ohms with 10in vacuum). According to my books, this is in range.
I next tested the voltage at the EVP harness connector (4.6 volts) again, in range.
Then, I checked the resistance between the harness connector at EVP signal to socket 27 on the connector to the EEC PCM (0 ohms) once again, exactly what it should be.
I then checked the resistance between the harness connector at EVP signal to ground. I got that the circuit was open. Good, no short to ground.
Next, I checked the harness connector for stray voltage at EVP signal (none found). Good, no short to power.
Now I'm stumped.
I want to clear this KOEO code, so that I can proceed with whatever else may turn up when I do the KOER test. I'm trying to be methodical, sytematic, and not throw parts at it until I know what's wrong. ANY ideas/suggestions would be greatly appreciated.
SOMEBODY SAVE ME!!!
Will