Hey guys, I'm back. Well, something seems to go wrong when I WOT after a certain amount of time. I think that I am getting a fuel cut, But let me tell u guys how it happened... So, I start racing a fixed up WRX and a stock M3 roadster, and as soon as I shifted into 4th gear, my car just stopped like if I had a fuel cut. It reminded me of how my car used to have the fuel cut before I had the Hobbs switch Mod. What could have caused this? The weather was really cold, like around 27-30 degrees. We took off from the line so I was using all of 1st, 2nd,3rd, and once I shifted into 4th the engine just stopped. Well, if anyone can give me some advice on what to do or what could be happening, I'd appreciate it very much. Thanx again guys! BTW, I killed the WRX and was 1/2 a car ahead of the M3 roadster before my car had that fuel cut.

~AC

 

you have not said what rpm or speed you estimate you were goin at the time....


if it is just under WOT everytime not at a specific speed or rpm, I would suggest checking for a vaccuum leak...it will have similar symptoms....good luck!

 

I was going at about 90 mph and rpm's should be about the 4-4500 mark. IT only happens if I keep WOT from 1st gear to 4th and then BAMM ... fuel cut. AM I not having enough fuel pressure? I have a 3.125 pulley with greddy catback exhaust and a 8:1 FMU disk. Should I get rid of my vortech FPR and install a walbro 255 l/h high press. fuel pump instead? Isn't there enough fuel with the vortech FPR? I am still not sure what is wrong. Maybe it could be something else?


~AC

 

if I can ask a couple ???

you have the stock fuel pump
you have the Vortech Fuel Pressure regulator

Are you using the inline Auxiliary fuel pump?
Are you using the Vortech Fuel Management unit?

just trying to understand the items you actually have...

 

Yes, I have both, the stock fuel pump and the vortech fuel pressure regulator with the aux. fuel pump. And I also have the Hobbs switch mod. This has never happened until recently so I am clueless of what it could be.

~AC

 

How much gas was in your tank? If you are lower than about 1/8 tank you can starve the pickup during hard acceleration, I've done this in a car with alot less power (less weight transfer) than an SCd max.

 

This exact same instance happened to me just last night. I was cruising at 80 when I saw this black vr6 golf 2 door approaching. He moved over in front off me and I proceeded behing him into the left lane then as moved back right one lane I followed and I downshifted to 3rd and punched it I quickly redlined at ~100mph then I shifted to 4th and nothing happened. I am not sure what rpm I was at but the car just stopped accelerating. It happened so fast and the VW just pulled away and I shifted to 5th and it started pulling again of course not that hard. I had over 1/4 tank of gas so I don't think the fuel shifting would have starved the pickup and I have a 255lph pump. I thought something bad had happened and I have only been boosted for 1 week. Please shed some light on this as I think there is something in common here and I don't think its low fuel related more like a fuel cut like maxboost00 was saying.

 

AllGo: U say u have a 255l/h pump? Is it a Walbro high pressure fuel pump? I was thinking of installing a walbro cuz I seem to be getting these fuel cuts more often whenever I WOT after a certain amount of time. Has anyone else had these same problems and found out what was wrong? AND yes we have done the Hobbs switch mod. Thanx.

~AC

 

Yes I have the Walbro gss342 255lph High Pressure but I dont have any hobbs switch mod? I think that is the one for the pump in the stillen kit. I did have above a 1/4 tank of gas but the momentum shift from getting off the throttle in 5th, to getting behind that VW and coasting/waiting a second to get out from behind a slower car in the fast lane and change back to the next right lane while downshifting to 3rd was ok. I redline 3rd which I guess shifted the fuel from the front to the back of the tank and then hammered 4th and the starvation must have occured. It was very brief, maybe 1-2 seconds but thats all it took at 100+mph for the car to show a dramatic difference. Like I said I have been boosted for 10 days and this was my first highway encounter. Needless to say it wasn't a fun experience and that dam Vr6 just left me like I was standing still. Let me know what the circumstances are when this happens to you.

 

BIG Problem now guys!! I raced a camaro z28 and then a new mustang GT and something went terribly wrong after my last race. I got that same fuel cut during my last race but this time after a about 2 minutes I noticed my car was idling bad and was misfiring. So, I go home and a check engine light goes on. I was like DAMN! What the hell could it be?! I was hella stressin cuz I don't know if I blew something internally or if it was something minor. I was lucky that my friend was not asleep yet so that he can come to my house and see what was wrong using his diagnostic computer. It said that my #6 cylinder was having problems. So then we check all of the spark plugs and I see that the #6 spark plug gap was 0! Somehow something must have caused the gap to close all the way. All of the other plugs were okay except for that one. Well, we gap them all again, put everything back on and turn on the car. It ran smooth again. I was glad that it wasn't anything bad internally. Then I take it for a spin and after 5 minutes of driving, it starts to idle bad again. And what's worse this time is that I hear like a knocking sound to it. I usually mix 100 octane with my 91 octane with a 3:1 ratio. What could be happening? Has my cylinder gone bad? I only have 10K miles on my car.I need help quick. If anyone has any info of what can be happening , please let me know. Thanx.

~AC

ps. BTW, I killed both cars

 

Oh yeah, I am trying to post up the vids so u guys can see my kills if u want. But if u guys can, let me know what could be wrong with my car cuz I changed my #6 plug again this morning to the stock one and the car was idling bad again. When I drive it, it runs okay. It's when I leave it idling, that the engine and exhaust shakes abnormally and also my exhaust sounds different as well. if u guys can help me out, it'll be greaty appreciated. Thanx again.

~AC

 

That would scare me to death if I saw that. Maybe something came loose somewhere in your intake tract, wound up in the #6 cylinder and hit the spark plug before exiting the cylinder. Or maybe a chunk of aluminum breaking loose from the top of your piston. Sorry for the scary scenarios, but it's hard to imagine what could have closed a spark plug gap like that. I would do a compression check on that cylinder right away.

 

What would be an accurate reading of a compression test in our cylinders? thanx again.

~AC

 

Well, normal compression readings are supposed to range from 170 or 180 psi up to about 210 psi, but don't quote me on that. I'll have to look in the FSM to be sure. What matters more in your case is that the one cylinder with the problem is not reading significantly lower than the other five, so be sure and check all six.