Need ideas on rich startup problem
Need ideas on rich startup problem My buddy's '01 TA: Mods are patriot ls6 heads/comp cam (dunno specs, he bought the car modded) k&n fipk, slp maf, bbk 80mm throttle body, longtubes/loudmouth, 3500 stall, moser 9".
Problem: The tune the car came with has it running perfectly except for initial startup. The car will turn over and fire, but will die almost immediately if you don't give it gas, and while it attempts to run in open loop you can't let off the gas or it'll die. Meanwhile it's spitting/coughing and bellowing black smoke out the exhaust, so I know open loop has to be rich as hell. Once close loop kicks in the idle stabilizes and settles right at the commanded 900rpm. I've tried scaling afterstart enrichment by 50% and more with no luck. Also tried setting OLFA table to 1.00, no luck. I haven't had the car for more than 5 mins at a time, so I haven't been able to scan to see what commanded afr is at startup, hopefully I can do that one night this week. I figured leaning out startup enrichment would fix him right up! Any ideas? Thanks guys!
Problem: The tune the car came with has it running perfectly except for initial startup. The car will turn over and fire, but will die almost immediately if you don't give it gas, and while it attempts to run in open loop you can't let off the gas or it'll die. Meanwhile it's spitting/coughing and bellowing black smoke out the exhaust, so I know open loop has to be rich as hell. Once close loop kicks in the idle stabilizes and settles right at the commanded 900rpm. I've tried scaling afterstart enrichment by 50% and more with no luck. Also tried setting OLFA table to 1.00, no luck. I haven't had the car for more than 5 mins at a time, so I haven't been able to scan to see what commanded afr is at startup, hopefully I can do that one night this week. I figured leaning out startup enrichment would fix him right up! Any ideas? Thanks guys!
If the fueling is where it should be, check the RAF table.
Also scan his IAC counts, I think I read something a while back about the BBK's not having a hole in the TB from the manufacturer.
Also scan his IAC counts, I think I read something a while back about the BBK's not having a hole in the TB from the manufacturer.
Originally Posted by Billiumss
Did you adjust your VE table yet? If not, lower the first 3 columns of the VE table by: 60%, 75%, 80%. That should help a lot till you WB 02 tune the VE table
If the VE is not close (tuned right) at low RPM's and/or you injectors not scaled right, you will have your current problem.
Do your first 3 columns in your VE table match a stock file, compare them, they should be a lot different.
Do your first 3 columns in your VE table match a stock file, compare them, they should be a lot different.
Originally Posted by Billiumss
If the VE is not close (tuned right) at low RPM's and/or you injectors not scaled right, you will have your current problem.
Do your first 3 columns in your VE table match a stock file, compare them, they should be a lot different.
Do your first 3 columns in your VE table match a stock file, compare them, they should be a lot different.
Originally Posted by SSpdDmon
Exactly. Check injector scaling (should be stock unless he has aftermarket injectors), VE around idle, and MAF around idle. I quick hint to idle issues that disappear when the car hits closed loop is to check the LTFT's and STFT's. I bet they go way negative once he hits closed loop. If I'm right, you need to make sure the injectors are scaled right, dial in the VE and recalibrate the MAF for his setup. The good news about it is this can all be done with the stock O2's. Just make sure they're ok first....and beware of the Bosch replacements. I've seen quite a few issues with those sensors, whereas the factory ACDelco's - not so many issues.
Good ideas, I'll check it out tonight if I can get ahold of the car. I wish he had more info about the mods from the PO. I don't think the injectors were replaced but I haven't checked the IFR table yet either.
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Forgot about this thread, thought I'd update. I finally got ahold of this guy's car for a weekend, and it ended up throwing a MAF code right when I got it. I promptly unplugged that paperweight slp maf and voila, horrible rich startup problem gone. Convinced the owner to go ahead with a speed density tune and toss the maf. Got his VE table dialed in and the car is running perfectly. Moral of story, slp maf = 
MAF table had been modified to '01-'02 calibration too, still ran like hell.
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