gregrob

iTrader: (8)

First off I finally got around to putting in the Walbro I've had and it seems like the car is running rich.

Have any of you guys noticed a spike in fuel pressure or had to retune because of adding a pump?

My old one was really noisy, so I'm assuming it was fairly weak.

Second, I now am picking up around 4 degrees of knock retard at WOT.

Wondering if the added fuel (if it really is way richer) could be cause knock retard. I know that sounds backwards, but I've seen it several times tuning LS engines. When they're way too rich they wont take any timing without seeing KR, then when you get the AFR close to where it wants to be, the car will take more timing.

Car definitely feels weaker and I want to get this lined out.

I beat up on a cam, stalled, nitrous (150 shot) CTS V tonight, and a stalled, bolt on, 150 shot G8 GXP. I got a fast *** truck to race tomorrow night and want to get it running a little better.

Thanks

gregrob

iTrader: (8)

Also wondering if I could have gotten some bad gas at the pumps tonight to cause the KR.

Too bad I cant get any race fuel tomorrow to throw in and try.

SS RRR

iTrader: (2)

Your air/fuel mixture should be no different with the added pump unless your FPR is failing.

ThreeHonks

iTrader: (10)

If his old,stock pump was only capable of pushing lets say 30psi and he tuned it with that going on and now he has a new pump, the regulator would still allow it to bump up to 43. psi, which would add extra fuel.

I think it is possible to cause some problems to the tune. I would hook up a wideband and go from there

blown94

iTrader: (1)

very good point. pretty sharp for this early in the a.m. Im still half asleep, but id agree 100%

gregrob

iTrader: (8)

That's what I'm thinking, if the old pump was never pushing the limit of the regulator and this one is now. IDK

Cant figure out why I picked up KR either, this is the only thing that has changed. Well besides a clutch.

Maybe the new clutch is loading the engine harder. IDK

ThreeHonks

iTrader: (10)

could have something to do with the tuning. Fix your AFR and see if the KR goes away, I bet it does

gregrob

iTrader: (8)

Kr is gone! I leaned it out a little and pulled 1 degree.

95z28onjuice

iTrader: (-2)

glad it worked out

ThreeHonks

iTrader: (10)

good to hear!