Hi all,
Last year, my '87 Suburban V20 was having issues where on the highway it would randomly seem to throttle itself up hard for about half a second then start running rough. The Service Engine Light would come on when this happened. I was getting a code 42. I changed the ignition module and it seemed to clear this problem up but a few weeks later it happened again.
Shortly after this, the engine developed rod-knock so it's been parked for about a year.
I just bought a re-manufactured long-block for it and want to make sure I have any other issues sorted out before I put it all back together.
I was just testing my throttle position sensor following the document here on the forum (
http://forum.73-87chevytrucks.com/smforum/index.php?topic=29996.msg251278#msg251278)) using the chart "Test Sheet TP 6".
Here's the readings I got:
A to B:
At rest = 1.75k
Rotated = 5.40k
C to B:
At rest = 5.61k
Rotated = 1.94k
Now these readings are quite a bit off from what the chart says they should be at.
I noticed my sensor doesn't look the same as the one in the chart, so I was going off the assumption that the left-most pin is "A", the center pin is "B", and the right-most pin would be "C".
Also, I had my selector on the multimeter set to "20k".
Knowing all this, is it safe to say the throttle position sensor is bad?
I also took and analog meter and watched the needle as I rotated the throttle all the way through it's range. The needle moved very smoothly and wasn't jumpy at all. Just something to note.
I don't necessarily think this is the cause or solution to the code 42 issue, just wanted to add that info in there in case that would be helpful.
Thanks!