Ok, rotory gods...This one's for you guys. I recently installed the
Power FC, and am experiencing a nasty fuel cut at about 4000rpm's. I've played with the duty cycles since then, checked all the vaccuum hoses, but still, I get this annoying fuel cut. Plus to top it all off, because of this, (and you guys are gonna hate me for this), I lost a street race to a mildly modified integra. It was a
very humbling experience that I'm am not used to. PLEASE!
I pray to you...HELP ME!!!

 

What are your boost pressure values set at?

 

Wouldn't hurt to check the rev limit as well.

Alan

 

If you boost over .25 more than what the PFC is set for it will fuel cut or if you hit the rev limiter or if your down around empty on the gas and you gun it you'll get the ultimate fuel cut...

 

No, actually I'm barely hitting about 7 or 8 lbs of boost. It doesn't actually cut off the fuel completely. Something wierd though, the other day I really pushed it, and it hit around 11.5 psi, at about 5,500rpms but it wasn't plling hard at all. And that should be right in the kick *** part of the powerband. This is just really depressing me. My mechanic is mind boggled as well. Does anyone know of any good PFC programmers in the So.California area, with a dyno hopefully? Thanks so far.

 

I went 2 months with a problem like that before I finaly found out what it was... I had a hole burnt threw a coil wire boot where it plugs in to the bottom tower of the leading coil, it was arcing to the 10mm bolt on the oil filler neak next to it... It really pissed me off, check it out..

Chris

 

I am having the same problem. I have had this for about 2 months now. I have replaced every thing just shy of the engine and the igniter. I have put on coils, wires, fuel filter, fuel pump, all injectors, plugs, fuel pressure regulator, made ground straps every where, and no dice. If you step on it from a stop or a slow roll it will pull hard to about 4000 and fall on its face, if you stay in to it and run it up through the gears at about 5500-6000 it feels like it just isn't pulling and you can fell a faint bucking. I am still lost. My datalogit will be here this week and I am going to see if my maps are just to rich. I have no idea, also I get outragous knock readings, I have had them as high as 180 but usually 120'ish this is why I am even scared to drive it! I just work on it drive it to see if I fixed it, then park it in the garage untill more parts arrive and repeat. One day I hope to have a working car again.

 

A friend had a similar problem but at the point where vacuum went to boost, 0 psi. He had used the wrong injetcor to housing seals for the primary injectors. The early manuals show the same type of cushion seals for both primary and secondary injectors. But the primary injectors has seals that fit at the top of the center housing, not ones that go down on top of the deflectors like for the secondaries.

Thus when he hit boost where only the primaries are still working, the pressure was blowing the fuel out around the injector holder. This made the engine go flat.


Maybe something similar is having to you-all.

 

Yep, It sound like your having problems during the secondary injector transition.. My first guess would be that your experiancing a drop in fuel pressure as they start to fire up, causes could be clogged fuel filter, fuel pump is not switching over to 12V when it is supposed to, bad fuel pressure regulator... I would check these items first, this goes for the guy who started this thread as well..

 

Thats the funny thing I have done all of that already. The first thing I did was replace the fuel filter. And I have also shorted across the fuel pump speed relay to give the fuel pump 12 volts all the time ( also checked with a meter to make sure of this). And just this week I put an aftermarket fuel pressure regulator on. The fuel pressure gauge I have for setting the pressure will not feed up under the hood to check the pressure while on a wot run but I have even tried setting it at 40psi at an idle to see if it helped (normal I think is 28-32). It seemed as though the fuel pressure regulator helped but did not fix. I was going to check and make sure all of the injector settings were right in the PFC I bought it brand new tuned from SR motorsports. And Chuck the only reason I don't think that it is the o-rings, because it started the one of the problems ( the low end stumble )when I still had the factory computer and injectors, and the wierd part was it started doing it only under a 1/4 tank of gas. When it was full no problem, so i assumed it had to be a problem in the tank. I have replaced the pickup and the pump, with better nippondenso pump, in the tank. Still had the problem then it got worse, now it does it under a 1/2 tank. So I bought a power fc ran great for a few days then developed the high rpm stumble/loss of power. So I thought that since I was seeing high 90's on the injector duty I sent all (primary and secondary) injectors to SR to clean and inspect and enlarge the secondaries to 1300cc. The only reason I have not written it off as a blown engine is because the car still idles fine and pulls hard up to that point. I am at a loss. I have asked many times on this board and everyone says plugs, wires, fuel filter, and I have done all of that. Basically everything besides the engine and ignition ( i did replace the coils) is new. If it is a blown engine I will just replace it but I would like to know that it is definately the problem so I don't risk having the same problem with a new motor.
Nick

 

Have you replaced the ignition coil pack harness. I had a 6800rpm misfire that would occur as soon as boost went above 11psi. Everything I tried did not work until the coil harness was replaced.


Also check the wiring from thre ecu to the injectors. Measure the resistance and manually applly voltage to each injector from the ecu connector. An assistant should be able to hear each injector click as voltage is quickly applied and relmoved. Before doing this type of test, depressurized the fuel system and have the fuel relay removed. You do not want to flood the engine.


When I rebuilt my engine last year, I took a different route. All new engine harnesses, injectors, and PFC.
Checked all solenoids while they were out.

 

I've got a good coil sub-harness if you want to swap it out to see if it helps.

Alan

 

Thanks I'll give all that a try, and let you all know. I just dreaded playing that game with the wireing. But I will do what I have to do to get my car running properly again. Thanks
Nick

 

New idea... pull the injectors and see if any of the diffusers are broken... I've had this problem also... doesn't let the fuel atomise all the way... My car sucked 2 of them threw the engine w/o damaging anything and It tool me forever to figure out that's what it was...

Chris