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PAC part throttle problems??

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norbs

Classic fast, XFI, SPortsman & MS3 programming
Joined
May 25, 2001
Messages
6,202
I am running into a problem of surging and pulsating hard at part throttle with the alky on. The problem is i can come up on boost fast to 15-20 psi only with about 40% throttle. This means that the alky is not getting past the throttlebody in full volume and maybe causing a problem. The PAC controller only knows boost, but doesn;t know where the throttle blade is at, also i could be at 15 psi boost at 4000 rpm or 6000 rpm, and the PAC controller doesn;t trigger off rpm either. I may have to put a switch on my tps not to inject alky until a certain %TPS.

Also thinking about using a solenoid, but since the alky pump will dead head thats another problem. Who makes a bypass regulator to work with the surflo pump? I don;t like the idea of alky on at 5psi aboostnd ramping up slowing then filling the lines. The pressure should be instant on demand and not come on below 15 psi slowing the car down. Or am thinking the worng way?
 
Just for you.. since you have a DFI, program an output to switch a relay "on" to ground the violet wire on the controller at your command. This reduces alky volume to 1/3.

FWIW, I dont have this issue.. you may have compressor surge.. Which happens at part throttle on bigger turbo cars ;)

Another thing is interference.. which happens like on cars with MAF's using translators or on turbolink.. then the fix is hot-wiring the PAC or translator to fix the issue..
 
Interesting, i could try that, but it worked fine before, the pump was sitting all winter, i wonder if its gone bad?
 
norbs said:
Interesting, i could try that, but it worked fine before, the pump was sitting all winter, i wonder if its gone bad?

If the pump went bad, you'd have zero alky. It either works or doesnt, let alone your wide band readings will tell where the air fuel is. If they increase then your leaning out.. if your leaning out.. the you have a fueling issue whether it be alky or fuel.

But a pump never increases in pressure if its going bad, all pump go down in pressure if there is any issue.. so your air fuel will tell you.

BTW.. bout time you took the car out :)
 
Well, i am just to busy really, with everyone else's problems. I am going to put back the same program i had in , and switch back to 83s instead of 55's. THe a/f readings don't look that bad, making it harder to determine whats happening.
 
Maybe switching to a FAST may help your problems :eek: :D :eek:
 
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