Jatkat
Newbie
Howdy fellers. I'm about to drag up a very tired subject, so be prepared
My K2500 (1995, TBI, 7.4) Has been giving me some very frustrating issues as of late. Seemingly without warning, it'll shut itself off. Can happen at an idle, or when I'm coasting to a stop, or even under light throttle. I slapped a jumper into the ALDL connector, threw a code 54. Typically a 54 would indicate a bad relay, or a bad oil pressure sensor. Replaced both, no change. Cleaned up and redid the fuel pump ground, same story. I thought I had it figured after cleaning up the pump ground, but it went back to doing it today. No code 54 this time. At the same time, I've been chasing a high idle.
I borrowed one of those swanky scanners from a local mechanic that can actually talk to these old trucks. Everything seemed fairly normal, temp sender was communicating properly, and the IAC was adjusting the idle right. (I had earlier done a re-learn along with turning down the forbidden screw a little bit). Today, I still had the scanner with me, and after one of it's shutdowns, I plugged it in and looked at the data. The truck was calling for an idle of 975, but the actual was waay up at 1300. I noticed the IAC count had dropped to zero (all the way open). I limped it down the road, and let it idle for a while. Gave it a hoof full of gas, and the idle re-adjusted, and the IAC count jumped up to 65 or so.
Am I looking at a bad IAC here? Would that be enough to kill the truck if it snapped shut when it wasn't supposed to?
As far as I'm aware, the ECM is acting as it should, though I know they can be hard to track when they do start to malfunction.
Sorry for the extremely wordy post, but I've been pulling my hair out at this one. I just want my truck to be safe enough for us to drive without dying in the middle of an intersection!
My K2500 (1995, TBI, 7.4) Has been giving me some very frustrating issues as of late. Seemingly without warning, it'll shut itself off. Can happen at an idle, or when I'm coasting to a stop, or even under light throttle. I slapped a jumper into the ALDL connector, threw a code 54. Typically a 54 would indicate a bad relay, or a bad oil pressure sensor. Replaced both, no change. Cleaned up and redid the fuel pump ground, same story. I thought I had it figured after cleaning up the pump ground, but it went back to doing it today. No code 54 this time. At the same time, I've been chasing a high idle.
I borrowed one of those swanky scanners from a local mechanic that can actually talk to these old trucks. Everything seemed fairly normal, temp sender was communicating properly, and the IAC was adjusting the idle right. (I had earlier done a re-learn along with turning down the forbidden screw a little bit). Today, I still had the scanner with me, and after one of it's shutdowns, I plugged it in and looked at the data. The truck was calling for an idle of 975, but the actual was waay up at 1300. I noticed the IAC count had dropped to zero (all the way open). I limped it down the road, and let it idle for a while. Gave it a hoof full of gas, and the idle re-adjusted, and the IAC count jumped up to 65 or so.
Am I looking at a bad IAC here? Would that be enough to kill the truck if it snapped shut when it wasn't supposed to?
As far as I'm aware, the ECM is acting as it should, though I know they can be hard to track when they do start to malfunction.
Sorry for the extremely wordy post, but I've been pulling my hair out at this one. I just want my truck to be safe enough for us to drive without dying in the middle of an intersection!