New 408", 1-2 sec into dyno pull, falls flat, shutsdown till you let off, cause?
11-11-2004, 12:23 PM
#21
Injectors
Originally Posted by C4VetteLS1
This is a really hard to describe problem...
Have a car that just put a 408" in. Car drives around fine, 1/2 throttle the car pulls really hard and well, and the A/F is fine, LTrims are fine as well.
Sometimes instantly, but usually 1-2 seconds into going WOT the car completely nose dives, not like power is falling off, but its almost like you ran out of fuel or the PCM shuts down completely.
The car doesnt miss or do anything odd until you cross the 50% throttle range and its never at the same rpm. I can take the car up to 5500 rpm, then floor it and it cuts out instantly. Or i can stomp it at 2000 rpm and same thing.
On the dyno the A/F will be nice at the part throttle pull the moment it hits you hit the gas and it shutsdown, A/F doesnt just head lean, it goes immediatly off the scale above 18:1 in a vertical fashion, Meaning the injectors shutoff completely. Duty cycle on the 28.8 injectors is approx 125% on the computer and im going to put 30# SVO's in tonight...but i dont think static injectors could cause this.
Anyone ever had this problem?
Have a car that just put a 408" in. Car drives around fine, 1/2 throttle the car pulls really hard and well, and the A/F is fine, LTrims are fine as well.
Sometimes instantly, but usually 1-2 seconds into going WOT the car completely nose dives, not like power is falling off, but its almost like you ran out of fuel or the PCM shuts down completely.
The car doesnt miss or do anything odd until you cross the 50% throttle range and its never at the same rpm. I can take the car up to 5500 rpm, then floor it and it cuts out instantly. Or i can stomp it at 2000 rpm and same thing.
On the dyno the A/F will be nice at the part throttle pull the moment it hits you hit the gas and it shutsdown, A/F doesnt just head lean, it goes immediatly off the scale above 18:1 in a vertical fashion, Meaning the injectors shutoff completely. Duty cycle on the 28.8 injectors is approx 125% on the computer and im going to put 30# SVO's in tonight...but i dont think static injectors could cause this.
Anyone ever had this problem?
You have answered your own question, 125 % duty cycle is what is causing it. Your injectors are locking up. I won't get into the theory about the Pecentage thing but I have seen duty cycles up to 140%. Don't waste your time on the 30# it will have very little change if any, go to at least 36#...
11-11-2004, 04:01 PM
#23
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Originally Posted by moehorsepower
You have answered your own question, 125 % duty cycle is what is causing it. Your injectors are locking up. I won't get into the theory about the Pecentage thing but I have seen duty cycles up to 140%. Don't waste your time on the 30# it will have very little change if any, go to at least 36#...
Well i hope it fixes it, ill know in a few days....... 30# svo's are 36lbs or so at 58 psi and will easily support 500-550 rwhp...
So i guess ill post results in a few days after the swap. I just never thought out of injector could cause this problem
11-11-2004, 07:12 PM
#25
Originally Posted by Chris ARE 385
are you running disc style or pintle style injectors?
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11-12-2004, 04:13 PM
#28
Originally Posted by C4VetteLS1
Well this is an ls1 conversion using a fbody computer. What is the 1514 table?
Just throwing idea's out to ya
