why my car does not run good in high rpm

[gmc9sqm]

ok so i'm kinda new to the dsm world but anyways i cannot figure out why my car does not run good in high rpm. i have a logger i am using the MMCD program and this is what it is telling me......at 3843rpm i'm getting a (o2-r .68v) (tima 39 degrees)(fuel pressure 78.2)... i'm not sure if this looks like it's suppost to be doing any help will be great

 

[Avionixx]

You have to be a little more specific here; describe in great detail how the car is running. 3843RPM is not exactly high RPM either and MMCD or the ECU does not log fuel pressure so I'm not sure what you were looking at.

 

[gmc9sqm]

ok so when i hit about 4500 rpm it cuts out really bad. i have the boost turned down to 11psi. it acts like it is getting to much air but my mbc is turned down all the way and it still cuts out. it has the stock injectors, and i put a 255 fuel pump in. . . . . .i just downloaded the mmcd version 1.8 and it has more things that it will watch but i'm not exactly sure.

 

[Defiant]

Plugs and wires. NGK BPR6ES at .028"

 

[gmc9sqm]

i just replaced both of them and i still have the same problem. is their some thing that controls the fuel pressure according to how much boost you are getting?

 

[BrokenTsi]

The fuel pressure regulator itself does that job. Maybe it needs to be replaced. If at 3800 rpms you're at WOT, thats way too much timing.

 

[gmc9sqm]

so if i get a new regulator will that fix the timing advance too?

 

[assault187]

so if i get a new regulator will that fix the timing advance too?

No....Check timing with a timing light

Im some cases with certain boost controllers, turning the knob all the way down will actually turn the boost all the way up.

 

[gmc9sqm]

my base idle timing is at 5' and i have tried turnning my boost controller knob both ways so i know that it is turned all the way down.

 

[BrokenTsi]

A bad ecu, or maybe even a bad CAS can cause that whacky timing advance. Try to find a friends ecu to switch out with and give it a shot.

 

[-TunedDSM-]

Do you have an AFPR? If you are running a Walbro 255 with the stock FPR you are likely overruning the FPR and drowning the engine with fuel. A boost leak test would be a good idea as well.

 

[gmc9sqm]

ok thanks i will have to try that. do you think that that would also help on the start up ### it is very hard to start you have to keep cranking it and sometimes it wont start till you roll start it?what is a good pressure to set the regulator at?

 

[-TunedDSM-]

1g stock base fuel pressure is 36-37psi with the vacuum line disconnected.