Fuel Pump Getting Weak?

[nocooler]

What is the wideband saying Brad?

[Scoobum]

Won't calibrate. I assume the sensor is fukd.

[Steve Wood]

for the moment, to heck with the O2 numbers.  Does the pressure match the boost?

[Scoobum]

1 for 1. I have a million PL files with the 02's around 820 on 20-22 PSI on default high gear fuel. All of a sudden it's 770-780. I swapped in another 02 sensor at the track. No difference.

[Steve Wood]

Okay, so you fixed O2s at idle, you fixed fuel pressure at a given boost, and you have searched for air leaks (including exhaust leaks?)

At wide open throttle, to my knowledge anyway, the maf is ignored.

Remaining possibilities that I can think of are maybe ecm (kinda doubt it), dirty injectors, and higher air density.

Given that the nb O2 is not linear and we have no idea what the actual difference may be, I agree this is time that a wb could be useful.

[Scoobum]

I'm gonna look at more PL files...but here's some info. I'm getting huge 02 dropouts at idle...and spoolup. I watched the 02's today when idling at the trailer. They stayed in the 760's for a couple of minutes and fattened up to 850's. Let's see what the MAF is doing during these dropouts.

Humidity was 32 percent today. NA cars were running 2 to 3 tenths quicker...the air was THAT good. That could be leaning it out. Temp was 78 degrees.

Injectors are new.

[Scoobum]

MAF appears normal. Huge 02 dropouts coming off the line about 6-10 miles per hour...and spoolup.

[Scoobum]

The only time I've seen this engine run leaner is in the fall air. low 50's for temp and low 30's for humidity. That's the only time I've had to add fuel. Steve is there anywhere to find out how 'clean' the air was at Shannonville Ontario today? It was 78 degrees...and when the sun went in it damn near felt cold.

[nocooler]

http://www.dragtimes.com/da-density-altitude-calculator.php

Don't know if they have your track. How did the mph stack up?

[Steve Wood]

it's about 66 F right now, humidity is pretty high in the 60 something percent  range now

here is the hourly  https://www.accuweather.com/en/ca/shannonville/k0k/hourly-weather-forecast/2290923

[Scoobum]

I was tracking temp and humidity this morning and it was 78F and 32 percent humidity. Jeremy...no idea. I waited till it got into high gear...and then matted it for about 2 seconds. I wanted get a look at the high gear fueling...and not blow it up. I wanted to go back out with high gear fuel added...but the fukn SM took a dump...so I couldn't adjust fuel/timing. I'm not having any luck.

[Scoobum]

I use a small spade connector in the front of the ALDL port for the SM. It came out at the track. Tried plugging it back in...but nothing from the SM. I'll try hard wiring it in the rear of the ALDL tomorrow.

[good2win22]

Is your chip a 5.7 version?  If so you can adjust fueling via the laptop using PL. way easier than the throttle stomp method.

[earlbrown]

it's about 66 F right now, humidity is pretty high in the 60 something percent  range now

LOL    Low in GA is 100 percent

[Scoobum]

This is where we're at. New fuel pump. new injectors, new fuel filter. Hot wire fuel pump harness is inspected and fine. Racetronix fuel injector hot wire kit. Caspers volt booster.
 
On the first run yesterday I matted it well into high gear and at 20 psi the fuel pressure was 60.

I went back out with the boost turned to 23 and the fuel pressure went to 63...so the boost and fuel pressure are 1 to 1.

I swapped in another 02 sensor...no change.

LAST week I bumped the high gear fuel to 142. The car went 98 mph through the traps on 20 psi with the 02's checking in at 802. I had a spotter watch the exhaust at the 330 foot mark and it was clean...so the 02's appear to be correct.

The ECM runs the whole show...so we'll swap it out and retry Friday nite. If it pushed a head gasket towards the intake side I would expect to see the idle BLM's jump up...but they remain at 118.

I'm open to suggestions as to what's wrong.

02's on this car are always around 820 at 20 to 22 psi on default. I always have to pull fuel...not add it.