94 Yukon 350 Idle issues and Loss of power.

[AllStrobedUp]

First Guess: 650--700 IN GEAR is too high.

Put a smaller pulley on the alternator. Hope you don't have problems when the trans kicks-down and engine RPM goes up.

No, the alternator makes output at a little under 600.

I will check what called idle is, if it's low I'll try to find someone to program the prom.

 

[AllStrobedUp]

Also to add, when the truck is at warm idle it doesn't move with your foot off the brake. I think the idle is too low and never knew it because it always idled high and rough because of a bad pick-up coil.

 

[Road Trip]

I don't think the knock sensor is supposed to look like that. Not sure if it's part of the problem, but definitely not part of the solution.

You must be registered for see images attach

Greetings AllStrobedUp,

Congrats on persevering with the troubleshooting and not giving up on the fix.
I was happy to see this thread pop back up with you sharing the solution instead of it just ending
last November with no update.

Re-reading the thread, though, I remember seeing your photo of the janky Knock Sensor, but there's
no mention of it's replacement afterwards? Did you get that swapped out as part of the recovery process,
or is the one in the photo still installed? A bad Knock Sensor can make a real difference in both driving and
gas mileage. (A lot of times when they go bad they become too sensitive, causing the computer to pull timing
when it shouldn't.) EDIT: If you still have the original KS in there, is it possible that it's reacting to some
extraneous engine/accessory noise & pulling timing at idle to where the idle is now slightly too low? (Stranger
things have happened.)

Again, thanks for coming back and sharing the wealth regarding what you found & what fixed it. This benefits
everyone.

UPDATE

Huge thanks to @scott2093 we have been remotely and in person troubleshooting this truck for a few weeks now. He has lent me his hands, his parts, his scan tools and manuals and we have finally tracked it down.

It was the distributor pick-up. We swapped in a spare distributor which was timed perfectly I might add and she came right to life on the first bump of the key.

I have his backup in the truck and will be ordering a replacement.

@scott2093, now that's the way to make big deposits into your karma savings account!

Very, very cool to read about someone stepping up and doing the right thing. After
the steady stream of bad actors humans in the news, it's so refreshing to read about someone
who leads by example on how to be an exceptional GMT400 forum neighbor.

Nice.

 

[AllStrobedUp]

Greetings AllStrobedUp,

Congrats on persevering with the troubleshooting and not giving up on the fix.
I was happy to see this thread pop back up with you sharing the solution instead of it just ending
last November with no update.

Re-reading the thread, though, I remember seeing your photo of the janky Knock Sensor, but there's
no mention of it's replacement afterwards? Did you get that swapped out as part of the recovery process,
or is the one in the photo still installed? A bad Knock Sensor can make a real difference in both driving and
gas mileage. (A lot of times when they go bad they become too sensitive, causing the computer to pull timing
when it shouldn't.) EDIT: If you still have the original KS in there, is it possible that it's reacting to some
extraneous engine/accessory noise & pulling timing at idle to where the idle is now slightly too low? (Stranger
things have happened.)

Again, thanks for coming back and sharing the wealth regarding what you found & what fixed it. This benefits
everyone.





@scott2093, now that's the way to make big deposits into your karma savings account!

Very, very cool to read about someone stepping up and doing the right thing. After
the steady stream of bad actors humans in the news, it's so refreshing to read about someone
who leads by example on how to be an exceptional GMT400 forum neighbor.

Nice.

I still have the original knock sensor, I do however have a replacement but after checking it with the scan tool it is working ~properly~. I will be replacing it and the head temp sender when time allows.