unless you have changed your chip, the spark advance data is not reported in the data stream. What you are seeing is the O2 cross counts. That is where the patch puts the spark advance data.
unless you have changed your chip, the spark advance data is not reported in the data stream. What you are seeing is the O2 cross counts. That is where the patch puts the spark advance data.
Square body stepsides forever!!!
Ok, I see. Someday I would like to change the chip and be able to see the timing on there but I guess it's not that critical. So I will drive the truck to work tomorrow and log when I get there. Thanks again for the help! Hopefully I will gain an understanding of how all this works sooner than later.
Last edited by georgeb; 06-15-2015 at 06:11 PM.
Ok, I drove the beast to work today and idled in the lot for a few minuets before recording this log. I goes into closed loop while I am driving or off idle but goes back open at idle. It also cools down a bit when idling......
It also seems rich at idle. The exhaust is rather strong smelling and makes my eyes water if I idle in the shop for any amount of time. I don't have cats on the truck if that makes a difference. The doors are open of course.
Last edited by georgeb; 06-16-2015 at 04:56 AM.
Okay, I see a couple of things. First, your IAC at warmed up idle is 0 steps. That usually means that you either have a vacuum leak, or you need to close the throttle blades a 1/4 turn. the second thing I notice is that yes you are in open loop, and your factory bin might be an open loop idle bin. Nothing really wrong with that, it just makes tuning idle a little difficult. In open loop, we can't see what fuel corrections are needed, because the BLM's and INT's are essentially locked. try to get your IAC steps into the 10 to 20 range then relog.
Square body stepsides forever!!!
OK, I closed the throttle plates about 1/3 of a turn on the stop screw to get to the IAC counts I have. I may need to re-bush my throttle shaft at some point because I know the plates are almost to the point they want to stick in the bore and I have some noticeable play in the shaft. I also noticed the plates seem to have corroded along the lower edge (the side that travels down as the throttle is opened). This poor thing was really neglected by the previous owner.
Again, thanks so much for your help! I have learned a great deal already!
ok, the next thing you may want to do is see what your fuel pressure is. Because you are rich at idle, it may be okay, but you should still test it. Then do a log warmed up and driving normally. That will give a good indication of what is going on
Square body stepsides forever!!!
I know I let this thread go dead for a bit but I have switched gears to working on the body of the truck. I picked up a southern cab and am in the process of prepping it for paint. Wont get it done before the snow flies tho. Anyway after running this truck with the initial timing at zero degrees since my last post I have become convinced that it runs like crap set there so I put it up at eight degrees. WOW, it runs so much better there. Pretty sure it's masking the issue but I'm good with it for now. Not sure what it did for my elusive surge during warmup that goes away at operating temperature. But I will run it in the drivway to see. I currently have no idea what to look at to locate the problem but I suspect the map sensor may be flaky. I need to try and diagnose it before I up and replace it. Well for now I am on body work and will most likely return to the drivability issues this fall. I need to replace the engine because of a bad block casting but would like to know if I can get the TBI to work properly before I make the change. Partly because I am inclined to ditch the TBI for a carb if I can't get it to run correctly. Thanks to all who helped! I will be back to pick up on this in the fall.
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