Blackhawk8

I have a 2000 Firehawk, that I installed a set of LT Kooks race headers, slp lid and had the car tuned. The car ran great before I installed the headers, now the car seems sluggish, and my A/F ratio is contantly changing. I have HP tuners and a dynojet wideband 2, when I make a pull my A/F is at 12.5, then make another pull 10 min later and my A/F will be 13.5. Any ideas to what could be causing the problem? Bad fuel filter? Issue with Headers?

Thanks

Adam

BLK02WS6

iTrader: (2)

Are you logging it during the pulls? What are the LTFTs doing during the pull - going to zero, or adding fuel? Did you completely tune the VE and MAF tables from idle on up with the wideband in open loop? If not, that is probably your problem - if it is lean at part throttle, and the LTFTs are adding fuel - when you go to WOT, the LTFTs will be added on top of PE. This can cause inconsistent fueling because it will do it sometimes and not other times (depending on what LTFTs are when you go into WOT)...

This is exactly what happens when a car is only tuned on the dyno for WOT, and not given a complete tune...

Blackhawk8

Yes I'm logging the car during the pulls, LTFTs are reading zero throughout the pull. I'm sending my logs to a tuner and his making the changes, and yes I'm pretty sure he completely tuned the VE and MAF tables from idle on up with the wideband in open loop.The tuner is looking for a stock tune now to make sure his not missing something. He cant figure out what's going wrong. I'm going to change out the fuel filter and see what happens.

SMOKINV8

iTrader: (6)

I was going to mention the same thing until you said your FT's are 0 through the pull. Fuel pump, fuel level, or fuel filter could all be the issue. Although the filter would cause issues all the time, it wouldn't fluctuate. Hook up a fuel pressure gauge and see if pressure is holding a steady 58psi through the pull. If it is, compare the fuel pressure to your AFR's on multiple pulls and see if there's a relationship there.

Ed Wright

iTrader: (1)

Could be going into cat cool down mode during the rich runs.

BLK02WS6

iTrader: (2)

X2 - check cat overtemp... also check fuel pressure...

salemetro

iTrader: (5)

Adders in the heatsoak tables?

SMOKINV8

iTrader: (6)

Cat overtemp? That would mean his tuner set it up to run 13.5 outside of cat overtemp... Surely not.

Ed Wright

iTrader: (1)

Do you not know which would be the rich run? 13.5-1 is LEANER than 12.5-1. Not richer.

SMOKINV8

iTrader: (6)

I'm with you, but if cat overtemp was kicking in on the owner, that would mean the tuner set it up to run 13.5afr. Or are you suggesting the tuner set fueling while it was hitting cat overtemp?

BLK02WS6

iTrader: (2)

Maybe... depends on how he tunes... Did he ask you to log commanded fuel? He should have you logging commanded fuel, which would tell him it is going into cat overtemp and commanding rich... The correct way to tune fueling is to set commanded fueling to what you desire, then bring actual fueling (using the wideband readings) into line with commanded by tuning the VE and MAF tables. Without seeing logs and knowing how he tunes, no way to tell for sure what is going on...

Ed Wright

iTrader: (1)

I'm wondering why some of you think the 13-1 pass would be the COT pass, not the 12-1?

salemetro

iTrader: (5)

Op.....please post the tune file.....and a log file if possible.

Blackhawk8

I'll post a log and tune later today when I get home from work.

SMOKINV8

iTrader: (6)

Think you're referring to me, but I don't think that, I'm agreeing with you. My English sucks.

Blackhawk8

Hey guys sorry it took so long, but heres the lastest tune and log I have for the car. I changed the fuel filter since this log. Should have a new one tomorrow as its raining here today.

joecar

Hi Ed,

SMOKINV8 said this:
i.e. he is saying that the plain run (non-COT) is at 13.5.

Ed Wright

iTrader: (1)

Sorry. I evidently mis-read that. That's lean, but I've seen that before. Some try to make the biggest dyno numbers, instead of what goes down the track quickest. Seldom the same.

Blackhawk8

Hey guys anyone take a look at the logs and or tune?

Thanks

Adam

salemetro

iTrader: (5)

Looks like PE was not raped (good thing), and COT is disabled. Still looking at it....

EDIT: Spark tables all look reasonable, Main VE looks good too as far as I can tell. PE is set to 12.9.

You're seeing 2+ degrees of knock retard at 2400rpm when going WOT....with a AFR @ 15.1 (17% lean). Even once fueling a catches up, you're logging 13.5afr @ wot. PE delay is set to zero. DFCO looks to be active, I'd disable that.

You said that this car ran great after the dyno tune? No known knock retard?

How is your fuel pressure?