Last night a beat a stock vr4 and lost to a modded camaro ss by like 2 cars. In 4th gear I hit what felt like a fuel cut at I wanna say 6-6.5k rpms. My boost was creeping but I didnt see exactly how high, maybe up to like 11. I have a STOCK fuel system. I know Im askin for it, Im gonna port the wastegate and get a walboro fuel pump soon. Anyways what could this be? It felt like two fuel cuts like one right after another. My fcd cant be bad can it? b/c it has never cut before and I know ive hit about 9psi. Help me fix this so I can go kick that camaros *** once and for all!

 

O yeah, my ecu is spittin out a faulty boost sensor reading....

 

do you have cats?

 

nope

 

maybe u were hitting psi over what your car actually cuts fuel at... it cuts at like 8 or 9 psi stock right and the FCD cuts it at like 12ish right.. were u over that?

 

Put your digital meter on the output of the boost/pressure senors brown/red wire (with it connected up). Now put your hand operated pressure gauge on the nipple of the boost/pressure sensor. Pump the pressure and note where the voltage stops rising.

The voltage should stop rising b/t 3.6 and 3.7 volts(3.7volts is I believe where fuel cut happens or there abouts). If your voltage rises above 3.7volts on the brown/red wire, then you are not clamping the voltage with the fcd properly. Adjust the fcd's pot to max out around 3.6 volts. Comprende????

Or, I guess you should make sure the fcd is installed right first with no broken connections.

 

you can't hit fuel cut twice one after the other while on the gas....

probably detonating / pulling back timming on you...

 

Ya I'm gunna go with scott on this one. What kind of FCD do you have anyways? And the code for a faulty boost sensor...hmm. Not sure if you should get that since your tricking the ecu about your boost levels or you should not get it since you tricking the ecu that your running at stock levels.

 

Second hand rp fcd that worked good for the previous owner supposedly. I was under the impression that the fcd eliminated fuel cut, not just raised it. Im guessin I probably went over 12 psi. God damn it. Im gonna have to port the wastegate soon and quit racing in the mean time. I dont think i hit fuel cut twice just had 2 real bad hesitations at almost the same time. and i didnt hear any pingin so if there was detonation it must have only been mild.

 

We've got a shop here with a 9 second FC and they recommend the HKS FCD over the RP or RB (same?) due to it's higher range.

If I were you I'd at least get a Walbro in ASAP! It could be the FCD or you're reaching max duty cycle on your injectors - either way, do something about your fuel b4 it costs you.

 

I agree, probably detontion, but have you tried it since last night? Just curious. if your still encountering a problem under heavy acceleration.

 

The FCD circuit clamps the output voltage at the preset threshold. You cannot hit fuelcut if you have a properly installed and working FCD.

Now that this is out of the way, check the obvious: if the FCD is working as it should (no short-circuits, no fried components, get a variable source and check if the FCD clamps where it should i.e just under 3.7V), and if the FCD is installed properly (if it came with a fixed connector, then there is very little chance of it being wrongly installed, but check anyway). If the FCD is fried, or clamping at the wrong voltage, or improperly installed, then you can hit fuelcut.

But, by the sound of it (double "fuelcut" feel), you were probably detonating. I dont think that it was retarding....

 

is does get rid of it.

yes it would have been mild. if you heard it the engine would be toast now if you hit fuel cut. it remains cut untill you remove your foot from the pedal. then then press down again. if you held the pedal down, and it did it for a sec, but then keep going. it wasn't fuel cut

 

well i let off the throttle real quick and shifted to 5th. no other problems.

 

Well......you might have very well have tested your knock sensor! Sounds plausible, more so than the fcd going out of range.

 

I will warn you now - get an upgrade fuel pump, or you're going to blow the engine up, period, if it hasn't been hurt by now.

You've got no business running that kinda boost and still running stock fuel.&nbsp At least rewire the stock fuel pump power wire...


-Ted

 

I got a walboro on the way and the stock pump is rewired. Im gonna port the wg as soon as it warms up a little here. Then set the boost to like 9 psi.