My car has been running fine, albeit a little rich, so I took it to the guy who installed the FAST ecm in the car, and he said it was way rich at cruise and light acceleration. I drove while he tuned on the laptop. He pulled alot of fuel out of the ve table. I then dyno'd the car, and put it back on the trailer. It kinda seemed like it might have been missing a little, but not bad. I got home and finally got to drive it a little. It seems to cut out randomly at idle, cruise, and light throttle application. Not neccessarily a "miss" per se, but you can be cruising at 2000 rpms, and its fine, then all of a sudden it hiccups and resumes. It barely stumbles at idle, but just off idle, if you lightly accelerate, it "putts", between 1000 and 2000 rpm. If you give it more throttle, it clears out, but still has that little cut out. if you give it more than half throttle, its fine. I've gone over the ignition, and can't find a problem. it didn't do this until he tuned it, so maybe theres a problem. I hooked up my laptop, and watched the A/F as I drove, and it seemed OK, ranging from 13:1 to 15:1. I didn't like the 15:1, so I added a little fuel till it came down into the 14's. Any thoughts? Sorry for the long post, thanks for your time.
Fighting a missing problem, FAST related?
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correction%%??
Drive it in closed loop and check to see what the O2 correction is.. that should tell you if he has fubared the VE table /vs the commanded A/F table.
Did he log the run that shows the rich condition??
Could be other parameters are out of whack??
Drive it in closed loop and check to see what the O2 correction is.. that should tell you if he has fubared the VE table /vs the commanded A/F table.
Did he log the run that shows the rich condition??
Could be other parameters are out of whack??
It seems better today, I decided to drive it to thanksgiving dinner at my dads to play with it, but it drove fine. The only thing I can think of is I over octaned it. Last night after my initial drive I added 5 gallons of pump gas to the 6 or 7 gallons of about 107 I had in there, but it still acted up. Maybe the gas didn't get a chance to mix last night? I added it and only drove for a few minutes before giving up due to rain. I did add some fuel last night in a couple spots, but it didn't seem to help last night.
I can't see where the octane would cause that problem. I have never experienced a miss due to fuel and I run 114 on spray and 93 pump gas on the motor.
Anyway, just some thoughts here and my experience. I fought this issue for a week or two a while back. Just started to miss on the hwy and had to richen the A/F's up to kind of cover it up. I played with the programming until I really had it messed up and it of course didn't run for crap. Well I went back to the basics and checked plugs and wires. Changed plugs and a bit better, had one boot on a plug wire that was burned, changed that, it was better. Ohmed all the wires and compared them to the new wires, twice the resistance so I replaced all of them. Problem solved. I can run 15:1 at cruise with no problems, like I used to be able to do.
Other situations of poor operating running conditions have also let me down the road of screwing with my VE's to try and correct it only to end up worse off than I was before. A classic was when I had a miss early in the spring and totally fouled up my VE's only to find out I had a lifter going bad. Again, cause I am poor at saving my programming before making changes, I had to reformat my VE table.
So, my moral to the story is whenever I have a bit of an issue with a running condition I think back to the basics. Since your tuneup is quite a bit leaner and a leaner mixture is harder to fire I would simply verify that all is up to snuff on the ignition side of things.
Anyway, just some thoughts here and my experience. I fought this issue for a week or two a while back. Just started to miss on the hwy and had to richen the A/F's up to kind of cover it up. I played with the programming until I really had it messed up and it of course didn't run for crap. Well I went back to the basics and checked plugs and wires. Changed plugs and a bit better, had one boot on a plug wire that was burned, changed that, it was better. Ohmed all the wires and compared them to the new wires, twice the resistance so I replaced all of them. Problem solved. I can run 15:1 at cruise with no problems, like I used to be able to do.
Other situations of poor operating running conditions have also let me down the road of screwing with my VE's to try and correct it only to end up worse off than I was before. A classic was when I had a miss early in the spring and totally fouled up my VE's only to find out I had a lifter going bad. Again, cause I am poor at saving my programming before making changes, I had to reformat my VE table.
So, my moral to the story is whenever I have a bit of an issue with a running condition I think back to the basics. Since your tuneup is quite a bit leaner and a leaner mixture is harder to fire I would simply verify that all is up to snuff on the ignition side of things.
I can't see where the octane would cause that problem. I have never experienced a miss due to fuel and I run 114 on spray and 93 pump gas on the motor.
Anyway, just some thoughts here and my experience. I fought this issue for a week or two a while back. Just started to miss on the hwy and had to richen the A/F's up to kind of cover it up. I played with the programming until I really had it messed up and it of course didn't run for crap. Well I went back to the basics and checked plugs and wires. Changed plugs and a bit better, had one boot on a plug wire that was burned, changed that, it was better. Ohmed all the wires and compared them to the new wires, twice the resistance so I replaced all of them. Problem solved. I can run 15:1 at cruise with no problems, like I used to be able to do.
Other situations of poor operating running conditions have also let me down the road of screwing with my VE's to try and correct it only to end up worse off than I was before. A classic was when I had a miss early in the spring and totally fouled up my VE's only to find out I had a lifter going bad. Again, cause I am poor at saving my programming before making changes, I had to reformat my VE table.
So, my moral to the story is whenever I have a bit of an issue with a running condition I think back to the basics. Since your tuneup is quite a bit leaner and a leaner mixture is harder to fire I would simply verify that all is up to snuff on the ignition side of things. The other thing I would just verify is the IAC is clean as well. A little O2 safe carb cleaner sprayed into the IAC hole can help smooth out an idle alot of times.
Anyway, just some thoughts here and my experience. I fought this issue for a week or two a while back. Just started to miss on the hwy and had to richen the A/F's up to kind of cover it up. I played with the programming until I really had it messed up and it of course didn't run for crap. Well I went back to the basics and checked plugs and wires. Changed plugs and a bit better, had one boot on a plug wire that was burned, changed that, it was better. Ohmed all the wires and compared them to the new wires, twice the resistance so I replaced all of them. Problem solved. I can run 15:1 at cruise with no problems, like I used to be able to do.
Other situations of poor operating running conditions have also let me down the road of screwing with my VE's to try and correct it only to end up worse off than I was before. A classic was when I had a miss early in the spring and totally fouled up my VE's only to find out I had a lifter going bad. Again, cause I am poor at saving my programming before making changes, I had to reformat my VE table.
So, my moral to the story is whenever I have a bit of an issue with a running condition I think back to the basics. Since your tuneup is quite a bit leaner and a leaner mixture is harder to fire I would simply verify that all is up to snuff on the ignition side of things. The other thing I would just verify is the IAC is clean as well. A little O2 safe carb cleaner sprayed into the IAC hole can help smooth out an idle alot of times.
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