Fuel Cut?
#3
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Yes, PFC as in power FC. Reason I am asking is that I installed my MP yesterday and once under WOT I got a slight hesitation, a couple of small momentary cut outs.
I thought it could be detonation, but I didn't hear any pinging. My PFC knock levels have always been a bit high even before the midpipe.
I didn't think that the 3rd gens with a PFC had fuel cut. My boost is about 11.4-12.0 psi.
I thought it could be detonation, but I didn't hear any pinging. My PFC knock levels have always been a bit high even before the midpipe.
I didn't think that the 3rd gens with a PFC had fuel cut. My boost is about 11.4-12.0 psi.
#4
Ex fd *****
12psi is not high enough to hit fuel cut on a STOCK ecu and a PFC doesn't have a 'cut' - you may be having an Ignition problem or a poor primary to secondary injector transition. does the hesitation happen around 3500rpm? - that should be the transition area.
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Originally posted by maxpesce
12psi is not high enough to hit fuel cut on a STOCK ecu and a PFC doesn't have a 'cut' - you may be having an Ignition problem or a poor primary to secondary injector transition. does the hesitation happen around 3500rpm? - that should be the transition area.
12psi is not high enough to hit fuel cut on a STOCK ecu and a PFC doesn't have a 'cut' - you may be having an Ignition problem or a poor primary to secondary injector transition. does the hesitation happen around 3500rpm? - that should be the transition area.
The power FC will give you a fuel cut if you boost .25 over what your target boost is. If I don't have my settings exactly right I will hit a fuel cut when drag racing right after shifting into 3rd (at transition)
Its a real pain in the ***, I got a profec b but I don't think I'm gonna use it. The way to tell if your fuel cut is due to power FC....When you hit the fuel cut based on over boost it you will not get power back until you shift again.
#6
Ex fd *****
You are correct the PFC will cut - But it is not at a FIXED level like the stock ECU. The description redbase gave of his prob. does not correspond to your description of the PFC fuel cut.
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Originally posted by maxpesce
You are correct the PFC will cut - But it is not at a FIXED level like the stock ECU. The description redbase gave of his prob. does not correspond to your description of the PFC fuel cut.
You are correct the PFC will cut - But it is not at a FIXED level like the stock ECU. The description redbase gave of his prob. does not correspond to your description of the PFC fuel cut.
david
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#8
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Actually the stock ECU isn't at a fixed level either. It can tolerate up to 13.3psi at the transition and 10.8 psi at 7krpm, sort of like a pyramid to account for spikes at the transition. Also, the ECU dumps a lot of fuel around transition for the same reason.
#9
Ex fd *****
BUT it is a fixed map vs rpm, ie at any given rpm it is always the same, unlike the PFC where it is a offset from the Target setting.
and I know about the extra fuel also - My car puffs a big black cloud out the exhaust during transition at wot. just like stomping the throttle on an old 4bbl carbed muscle car.
and I know about the extra fuel also - My car puffs a big black cloud out the exhaust during transition at wot. just like stomping the throttle on an old 4bbl carbed muscle car.
Last edited by maxpesce; 10-25-02 at 11:15 AM.
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Originally posted by redbase
The boost levels for my PFC is on the second setting: Primary .9 and Secondary .8.
The boost levels for my PFC is on the second setting: Primary .9 and Secondary .8.
.90 .68
.80 .62
Change your duty cycle like this
.90 .64
.80 .58
That should fix it, if you still get it, reduce the DC further. its all dependant on how cold it is, so you can run a setting at one point and be fine, but then 2 hours later hit a fuel cut on the same setting. Its a pain in the ***.
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It doesn't sound like a fuel cut problem. I've never experienced the fuel cut on the PFC, but with the stock ECU, when you hit the fuel cut you'll definetally know. The car will just fall flat on it's face. It sounds like more of an ignition problem to me.
#13
Ex fd *****
neevosh
I agree (see my first post)
on the stock ecu, hitting fuel cut is like driving into a lake, a very sharp decrease in power, not just a slight hesitation.
I agree (see my first post)
on the stock ecu, hitting fuel cut is like driving into a lake, a very sharp decrease in power, not just a slight hesitation.
#16
I just rebuilt w/ port and it has been damn cold in tampa Just to add some knowledge, the PFC does have fuel cut. I hit it a few times when it is cold outside. I am not 100% sure, but I believe the problem comes from boost spikes. The base boost is set @ .28 for break in and if I hit it at all it overboosts and cuts. I can see my injector duty cycle is not hitting 100% so it has to be the boost differential. I would not say it is a differential of .25 but seems to vary depending on quite a few conditions.
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Originally posted by jf4828
I just rebuilt w/ port and it has been damn cold in tampa Just to add some knowledge, the PFC does have fuel cut. I hit it a few times when it is cold outside. I am not 100% sure, but I believe the problem comes from boost spikes. The base boost is set @ .28 for break in and if I hit it at all it overboosts and cuts. I can see my injector duty cycle is not hitting 100% so it has to be the boost differential. I would not say it is a differential of .25 but seems to vary depending on quite a few conditions.
I just rebuilt w/ port and it has been damn cold in tampa Just to add some knowledge, the PFC does have fuel cut. I hit it a few times when it is cold outside. I am not 100% sure, but I believe the problem comes from boost spikes. The base boost is set @ .28 for break in and if I hit it at all it overboosts and cuts. I can see my injector duty cycle is not hitting 100% so it has to be the boost differential. I would not say it is a differential of .25 but seems to vary depending on quite a few conditions.
If I have these settings I will hit a fuel cut
85 78
85 68
If I do something like this....
85 68
90 54
or even this...
85 68
80 58
I will not hit it. It all depends on how cold it is, etc.
#18
Senior Member
fuel cut
Ditto the responses re fuel cut. Like going from full throttle acceleration to hitting the brakes. Anything less is probably some other problem, BTW it's real disconcerting if you happen to be passing on a two lane road with oncoming traffic when it happens.
Ron A.
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