The Resurrection: 94 Firebird Formula

[Injuneer]

Still using the -6AN fuel feed line from the pump to the rails? Are the rails run in parallel or in series?

[SSlowBoat]

Still using the -6AN fuel feed line from the pump to the rails? Are the rails run in parallel or in series?

yes 6an with a 255 and series. it was fine for a year.

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[SSlowBoat]

well boys, im at a major loss. I have smoke tested compression tested leakdown tested everything to no avail.

I REPLACED all the coils to new truck coils, coil harnesses, plugs/wires, crank sensor, o2's, map sensor, took out fuel in tune, readjusted tb, replaced fuel pressure regulator entirely for all new.

the last thing we noticed acting up was the fpr, I double checked with another gauge and fp tool that the regulator when adjusted wouldn't increase until you keyed off then on. seemed like it was sticking. with the new regulator thats no longer an issue.

yesterday it sounded like we got somewhere, car sounded rowdy rowdy again. took the car for a 20 minute ride on the na tune, felt rowdy felt good, AS SOON as I pull in the driveway, it wants to idle low and almost die 3 times. it was perfectly fine at multiple stop signs/traffic lights.

when it acted up kat ripped the hood open to check fp was OK, which it was. didn't go stupid lean before it happened either, actually both o2 were reading rich.

I dont get it. im burnt out and frustrated. last part is cam sensor, then harness and pcm are suspect.

seems like it only does it once heatsoaked. it revs snappy snappy again, but I dont get the idle issues suddenly

atleast it looks cool

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[Injuneer]

Do you think it might need a heat shield around the FPR and lines? Is the fuel supply line still far enough from the exhaust to avoid heat problems?

[SSlowBoat]

Do you think it might need a heat shield around the FPR and lines? Is the fuel supply line still far enough from the exhaust to avoid heat problems?

I dont think it should, it saw plenty of street miles last year layed out this way and was a non-issue. when it acted up the data shows both banks rich and the pcm cutting fuel, kat ripped the hood open and the fuel pressure was fine. I think it would act up much more often if it was heat related to the fuel system.

at any rate, racetronix is gonna send me a new pump under warranty. im also gonna run it open loop and see if it stops being dumb at idle.

one note, I must have fixed some part of the issue. wot now in that same log when the car felt great it was commanding 76% duty cycle on 42lb injectors N/A and maintaining 12.8 afr.

I am also going to do a write entire file to the pcm to rule out a bugged os flash

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[SSlowBoat]

sooo sorry guys, life's been crazy. we did go to the track on the 8th, after I threw the parts cannon at it with coils/coil harnesses/wires/map/tps/iac/crank sensor/o2 sensors.


seemed bettererer, until it was not bettererer.

went sunday, da was garbage above 2400ft, water grains over 100, not a good day for a nitrous car besides being able to throw timing at it to tune around the weather.

off the trailer with a 35-100% ramp/28 degrees of timing it was lazy and went a 1.500 60ft, only ran it to the eighth. checked plugs and threw 2 more degrees in it, and said screw it lets see how the suspension does, no ramp 100% spray at 3k rpm. was rewarded with a better 60ft and 10.15 pass.

adjusted tire pressure as it got too low and chattered on that one, went back to 17.5psig and back to left lane. also took 1psi of flowing fuel pressure out of the nitrous system from 7 to 6psig and it went a 1.378 and a 10.12 no spinning.

last pass fresh bottle took a little more out of nitrous fuel to 5psig to get the afr in the 12's, 31 degrees of timing 17.5psig and went 10.04 with a 1.361 60ft and a 6.39 eighth

da converted to cecil same day would have been a 9.85-9.90 pass. car decided to do its bullshit stall thing on way back to pits when turning over the bridge coasting at 20mph again.

overall happy but frustrated. dont know why it keeps randomly stalling. one thing I feel like we have definitely confirmed is the super victor 2 is WAY too big for the combo. the car is lazy in the middle even spraying all of it. data shows the car bogging, where it would have normally with the LT4 or Vic Efi would have wheelied or spun.

I have a tapered 1" 4 hole spacer on the way to try to see if it helps before i possibly swap back to the old intake. I talked to a few serious engine builders and porters, namely Chad speier and also Lloyd, and they both said the cubes/cam probably is not enough for the intake.

Chad told me to download the engine simulator pro from performance trends, enter everything and do it first with the "typical street single plane intake" which he said is close to a victor jr fully ported (which is the same as my fully ported victor efi) based on his data, which on the virtual dyno matched up to 750hp on 200 of nitrous and made power from 4000-7500. this maths out based on my good fast passes and car race weight

when changing the intake to Chad's actual measurements of port dimension/plenum volume and runner dimensions of a out of the box 2892 (my new intake) power actually DECREASED by 15hp peak on 200, and was down up to 50lbft and 40hp in lower rpms, just plateud later and didnt fall off as fast.

when putting the nitrous to 250hp in the program, the old intake actually makes 65hp more, the new only makes 33hp more.

talked to Abel racing as well and he said check the map value wot, if it starts dipping and the afr walks rich the intake is probably too big/velocity too slow and fuel on the nitrous is falling out of suspension. data shows it walking really rich from 6000-7500 even after leaning it out.

atleast it looks pretty.

frustrated. took the car for a ride tonight and it felt good, went to a local cruise night. came home and it definitely isnt idling right hot. meh. at this point it may get a carb and a LS ignition box


https://youtu.be/W8dVGmdFk7M?si=Z1vTZH84tS9pfE0K


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[shownomercy]

Its 2025, there should be no reason what so ever to run a carb.

[SSlowBoat]

Its 2025, there should be no reason what so ever to run a carb.

I was kidding. just frustrated. the setup looks awesome, but isnt performing. I guess the combo just liked being the ugly duckling under hood

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[shownomercy]

I bet the intake would work well on a 440ci, AFR 220 headed LT1 tho

[SSlowBoat]

did take it to a cruise night last night. felt fine again until i got home then the idle just sounded "off".

do i swap the intake manifold @Injuneer @JOATMON

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