cutting out?

[spoolinawd91]

Ok I'm trying to figure out what could cause this. I can boost great until 4200 in 2nd-5th. Everytime its gets near that rpm (4200-4300) under wot it cuts-out kind of it's like hiting a rev limiter in a way. but if I part-throttle it I can go to redline. Any ideas on what could cause something like this?

 

[weith1111]

Sounds like fuel cut. Search, there are a million threads and topics for dealing with it.

 

[spoolinawd91]

I have no fuel cut via my dsmchip

 

[weith1111]

What airflow are you seeing at these RPM's? Now that I see your injectors I'm wondering how you can only have an AFC. Most people struggle with 750's on just an AFC.

 

[weith1111]

I have no fuel cut via my dsmchip

Figured you were going to say that. Do you have a log to post?

It's funny, I'm seeing a similar problem but up around 5800. We have one thing in common = supra pump.

On a wideband my AFR goes from 11:1 to 13:1 in a heartbeat. I wonder if you are getting the same thing.

Do you have a wideband or EGT?

 

[spoolinawd91]

well my dsmchip is also setup for my injectors so tuning isn't that hard. the airflow is 1100-1300hz depending on what gear I'm in the higher the gear the more airflow I see

 

[spoolinawd91]

yea I get 11.2 all the way until it cuts-out it isn't leaning out or knocking

 

[weith1111]

Does it cut out completely or studder?

If it's cutting out completely it has to be spark related, as the fuel and air are still flowing I'm sure.

If it's studdering it could be your pump, injectors, filter, plugs, coil pack, wires, etc.

Do you not have an AFPR? Your FP is way to high if you don't.

 

[spoolinawd91]

cuts out completely

 

[flytalon93]

I am also having that same issue. Right around 5-5.5k+ she acts like someone is turning the ignition switch on and off. It was really bad when I had the boost set at 17-19psi but I turned it down to 15psi., before it used to do it earlier on in the rpm ranges. I read on another board that it could be spark plug related. It isn't fuel cut because folks that have had fuel cut stated its like hitting a brick wall and mine isn't doing that. Its just hicupping at wot at the high rpm range. My AFC states I am pulling 1900-2100hz at 15psi. The plug/gap issue sounds logical because so much forced air is pushed through that the spark could be blowing out (any suggestions on this logic?). What plugs are you using and how old are they?

Steve

 

[GriffZero]

I have to bring this back up. I'm having the exact same problem. I'm running 15psi of boost. I have my MBC set as low as I can get it. When I first was testing the MBC everything was fine. Just recently I starting getting the same problem you guys are discussing. It only happens when the boost gets up to 15psi. I figured it was fuel cut, but it's not like hitting a brick wall, it's more like a stutter.

Anyone find out what this was?

 

[highboostintsi]

its gotta be some sort of fuel cut. even tho ## car is tuned on a dsmchip.