Engine cuts out in the topend

[ho1ywars]

i can rev the power band perfectly from 600 to 7000 through third gear. In fourth gear, the engine cuts out around 5800, and 5500 in fifth gear. when it cuts out is just goes like limp for a few a few seconds. no jolts or anything, just goes. I don't have any sensor on my transmission hooked up, so there is no telling the ecu what gear it is in, so first gear and fifth gear should be reving the same right? the only thing i can think of is that there is more load on the engine in fifth gear, requiring more fuel, so its cutting out because of lack of fuel? i have a walbro 255 pump, no fpr, no tune. Any questions, suggestions? motor is stock except for fmic and 3in back. boost seems to jump around in between seven and eleven, my wastegate is ****ed up lol.

[ho1ywars]

comon, no one else has this problem? Somone without a tune please go out and romp on it in fifth and tell me when your engine stops listening to you!

[SpeedRacer1]

You dont even have your speedo working? This happens on my car at exactly the same rpm's. Its an ECU limiter.

[VigVoodoo]

It happens at around 5800 in 4th, so that's about 110MPH/180KPH right? It's the speed limiter in the stock ECU. It's normal for a stock ECU.

[silverarrow27]

I've never had a speed cut in 5th gear no matter what rpm I'm at on stock ecu. 4th gear seems about right for the speed cut which I always have as well, I just shift before it cuts hehe...

[ho1ywars]

how would it know what gear im in if i dont have any sensors hooked up to my transmission?

[DrifterProdigy85]

Speed limiter for the SR is 120-125mph. Youll relize if you hit it too. Its like a sudden stop.

[DrifterProdigy85]

Might be cutting out from too much fuel. Walbro fuel pump with stock FPR makes fuel pressure go up to 50-55psi from the added flow over the stock pump. Fuel pressure should be down around 43-45psi.

[DuckyD]

I have the same issue. I can accelerate through the gears and my car dies in 4th gear around 110mph (6000rpm'ish), I shift to 5th and can continue to accelerate to 125mph (approx 200kph) and hit the speed governor.

It has happened on several different ECU's (both automatic and manual SR ecu's) so it isn't the tuning.

I will look into the fuel pressure issue.