FAST 90mm: going to redo idle tuning, tips and tricks welcome
04-01-2013, 08:33 AM
#21
There seems to be a little confusion...I have plugged the hole that was drilled in it.
I did discover a huge mistake on my part. When I was running wiring through the firewall to install my new gauges, I had pulled the pcv hose out of the way *facepalm*. I left it unplugged from the valve cover...surprised the car was running as good as it was.
So I fixed that. Here are the couple things that remain now:
1) Car was cold starting and staying running now, but might not if it's cold outside since it was rough running for a few seconds
2) On any start up, the car revs high, falls to ~1400rpms, revs up to ~2000rpms, then falls slowly to a normal idle. Is this a sign the car still has too much airflow and the IAC takes that long to correct it?
3) Every so often the RPMs fall a little too much coming to a stop, might need to tweak the followers to correct I am assuming?
4) Twice (out of about 20 drives) the car was trying to idle at 1400 and cruise a little. The first time I turned it off at a light and let it sit for a few seconds and it was fine on restart. The other time that didn't work. It seems to be if I start the car and put it in gear before it finishes all the crap from #2 above it hangs but if I let it settle down first it works.
So I think I can fix most of it with another try on the cold cold start and fix the dip/surge with the follower. So if anyone has any ideas about the #2 issue I think I will be golden.
Still enjoying driving the car a lot more than before though, so I think that's progress.
I did discover a huge mistake on my part. When I was running wiring through the firewall to install my new gauges, I had pulled the pcv hose out of the way *facepalm*. I left it unplugged from the valve cover...surprised the car was running as good as it was.
So I fixed that. Here are the couple things that remain now:
1) Car was cold starting and staying running now, but might not if it's cold outside since it was rough running for a few seconds
2) On any start up, the car revs high, falls to ~1400rpms, revs up to ~2000rpms, then falls slowly to a normal idle. Is this a sign the car still has too much airflow and the IAC takes that long to correct it?
3) Every so often the RPMs fall a little too much coming to a stop, might need to tweak the followers to correct I am assuming?
4) Twice (out of about 20 drives) the car was trying to idle at 1400 and cruise a little. The first time I turned it off at a light and let it sit for a few seconds and it was fine on restart. The other time that didn't work. It seems to be if I start the car and put it in gear before it finishes all the crap from #2 above it hangs but if I let it settle down first it works.
So I think I can fix most of it with another try on the cold cold start and fix the dip/surge with the follower. So if anyone has any ideas about the #2 issue I think I will be golden.
Still enjoying driving the car a lot more than before though, so I think that's progress.
04-01-2013, 11:32 AM
#22
Actually, I would now hit that RAF table as Exidous had suggested earlier. May find your fix there for issue #2.... you have left the new injector data in as well right and working from those values now?
04-01-2013, 11:48 AM
#23
I intend to load your IFR table but didn't have time to retune the rest so I held off.
Also one you sent me was something along the lines of "fuel to wall" and I wasn't sure if I have that or what it's called in EFI live.
04-03-2013, 10:24 AM
#24
Yes, MAF and VE will need tuning with the change. Ill see if I can get into a EFI set and find the fuel to wall table for you. I'm not sure if you have it either right now, but is an important one for idle as well
04-08-2013, 08:41 AM
#26
Been sick for about a week but I did discover a good cause of the problems. The brake booster has been leaking for who knows how long, finally started hissing at me. I just replaced it in winter 2010. Not sure how long it's been leaking since then, but the car's brakes aren't stellar so the lack of assist is hard to notice since it always fades gradually...hard to diagnose until the hiss shows up when you turn the car off and it bleeds vacuum.
I'll get it replaced before I start tuning again. It never ends.
I'll get it replaced before I start tuning again. It never ends.
05-01-2013, 09:28 AM
#27
New booster is on and seems to be working fine again.
When I was in OK at my parents the car kept trying to idle too low and surge. Drove back up to NW AR (~1300ft higher elevation) and it ran perfect a few times then was idling high and cruise controlling and then went back to running right.
Really thinking about trying to find a different TB to try on it. Hopefully it doesn't rain this evening and I can tinker with it some more. Going to try resetting the blade set screw and then work on the base airflow table.
Might try unplugging the hole the previous owner drilled in the blade and tinker with the tune that way too under a different file name so I can easily revert back. I hate this Fast tb so much...tuning a car with a stock TB and ls6 is so much easier.
When I was in OK at my parents the car kept trying to idle too low and surge. Drove back up to NW AR (~1300ft higher elevation) and it ran perfect a few times then was idling high and cruise controlling and then went back to running right.
Really thinking about trying to find a different TB to try on it. Hopefully it doesn't rain this evening and I can tinker with it some more. Going to try resetting the blade set screw and then work on the base airflow table.
Might try unplugging the hole the previous owner drilled in the blade and tinker with the tune that way too under a different file name so I can easily revert back. I hate this Fast tb so much...tuning a car with a stock TB and ls6 is so much easier.
05-08-2013, 09:18 AM
#28
Hooked up the laptop to get a cold start idle log...and for the first time since the swap it fired right off, ran rough for just a second or 2 then rumbled away at 1000rpm cold then dropped to 850 warm. IAC counts were in the 60s-70s and it never flared. *SMACKS HEAD INTO WALL*
So I let it warm up and go for a drive and it's running idling perfect. IAC counts are now in the high 30s to mid 40s.
I start stopping and starting hoping it will go to hell so I can get a log. Closest I get is on start up once the car did it's "rev up then idle thing". During this the IAC was up around 140.
I have these logs and they were set to monitor as many airflow/IAC PIDs as I could if they will help anyone take a look at this with me.
In the mean time should I do something to get the IAC counts up a tad so they are in the 60s-70s warm or is it fine low? Should I adjust the throttle blade screw or the tune itself?
What could cause this to be so intermittent with no changes to the car? The only thing I can think of is that the battery is kinda shot and while it starts fine and holds fine running, it fails a load test hardcore. I really don't think it's related since it's been such an ongoing issue but is it worth looking into?
Any other ideas?
So I let it warm up and go for a drive and it's running idling perfect. IAC counts are now in the high 30s to mid 40s.
I start stopping and starting hoping it will go to hell so I can get a log. Closest I get is on start up once the car did it's "rev up then idle thing". During this the IAC was up around 140.
I have these logs and they were set to monitor as many airflow/IAC PIDs as I could if they will help anyone take a look at this with me.
In the mean time should I do something to get the IAC counts up a tad so they are in the 60s-70s warm or is it fine low? Should I adjust the throttle blade screw or the tune itself?
What could cause this to be so intermittent with no changes to the car? The only thing I can think of is that the battery is kinda shot and while it starts fine and holds fine running, it fails a load test hardcore. I really don't think it's related since it's been such an ongoing issue but is it worth looking into?
Any other ideas?
