I'm trying to adjust my IAB with a dwell meter and it's staying at 9 deg on the 6cyl scale. It won't budge a bit. Any ideas?

 

Your O2 sensor is telling the ECM that it's horribly lean, whether it actually is or not is another matter. The ECM is doing all it can to richen the mixture up.

Zero volts out of the sensor corresponds to max lean, about .9 volts sorresponds to max rich. Sounds to me like the O2 sensor is not generating its voltage, and either the wire is bad or disconnected or something, or the sensor itself is fornicated.

 

Once again RB, you're on the mark. I checked the O2 sensor and it's running around .220 volts.

This all started with starting up one morning and it felt like there was a vacuum leak. I had to keep my foot on the gas to keep it ideling. As soon as it went to closed loop them it would idle but was rough. There's a terrible bog too. I checked all over for a vacuum leak but am 100% confidant there's no leak. I'm getting about 18in on vacuum and ocasionally get a 1/2 in fluctuation towards 19in. I don't know why I tried it but when I unplugged the mixture control solenoid lead the tdle smoothed out just a tad.

I'm thinking I'm looking at a symptom of something else screwed up?

 

Any ideas???

 

Just checked out my tps. It's stuck at around 3.5 volts. Guess it's bad, huh?

 

Did you replace the O2 sensor?

 

Yeah, TPS shoud be around .75V at a curb ilde and about 4.5 at WOT (ceck it key-on, engine off once you replace it). Start there, but don't be surprised if you have multiple problems interacting with eachother here. I suspect you still have a REAL vacuum leak somewhere. And I've found them all over the old carbureted engines- places you'd never expect them- like the HVAC vacuum reservoir, the cruise control reservoir and the power brake booster line (worn through from rubbing on the intake manfiold).

 

The O2 sensor only has about 5K on it so I'm thinking it's good. I'll be blocking off all the vacuum ports tomorrow and double checking the vacuum thing. I'm with you Damon. I'm thinking multiple problems. You'd think that if I can figure out multiple problems on the F18 I should be able to figure this thing out. The airplane is easier...