need help with MS6

[_MSprotegy]

so ive had my car for year or so now and i am pretty much fully bolted. now that the temps are climing my car has been running weird. at idle and at normal cruising speeds my car runs like a champ, but a soon as i go WOT it will start to bog out and backfire. i guess the problem is fuel cut or maybe even boost cut. now i know what each of the two are because i have also owned an MSP and i have gone through all of the "cuts". i checked for boost leaks yesterday and everything came out fine. i doubt i blew an injector seal because i'm not making too much power for them to give out.

if anyone out there has any idea of what i should try next or look for please post up.

 

[batou079]

wahts your AFR @ WOT?
i would first take a day in the weekend to go through all the possible checkpoints.
check spark plugs, all intake joints/clamps, bpv, fuel pressure, graph a run of WOT/Cruise, monitor boost spike, boost hold @ WOT, all air temps from intake, to after turbo, to ambient, to coolant, etc etc etc.

hard to know offhand, if it feels like a cut you have experienced before, chances are it may be that.

 

[_MSprotegy]

yeah i checked the plugs and they look normal, AFR's i havent really checked, IATs are usually 10 degrees lower than the BATs. fuel pressure is 1750psi-1650psi at WOT.

it did it once today while i was leaving work but didnt do it again on the ride home.

 

[batou079]

BTW!!! are you sure it isnt just a slight lug when you go WOT, cause thats just the AWD drivetrain adjusting TQ via the ECU control.

i assumed... but do you have a dashhawk? or AP?
if so, i highly recommend running a few data logs...
record, pull & save for a couple days, under various driving conditions.
using multiple data sets.

then compare em, see if any obvious drops are shown.
If nothing is apparant, then... uh *shrug* mechanic time?

 

[_MSprotegy]

yeah i know for sure its not the AWD kicking. it back fires a few times before i get off the throttle. ive also got a dash hawk and i will be data logging tomorrow.

 

[batou079]

ah ok let us know!

 

[Eyedea23]

Your idle is fine correct? Cause I was going to say check the 02 sensor... but if it is idling fine then I doubt that is it. Only other thing I could say would to be check the MAF sensor, or running a bottle of seafoam through the gas tank to try and clean the injectors... Neither would hurt and could only really help.

 

[Mistersix]

what engine management are you using? if ap, what map?

has anything changed since the car last ran well.

 

[_MSprotegy]

Eyedea23- i ran a bottle of octane booster not to long ago just to see if my afr's would be affected much. i might need to run some seafoam to get them (injectors) clean now.

Mistersix- i'm running a SB. it hasn't been tuned properly yet. i did a little adjusting but not very much.

i was driving the other day and i laid into the throttle and i noticed that it started bucking. so i take a look at the fuel pressure and that thing jumped up to 2100 PSI! i was like WTF and let off. i laid into it again, both times was from about 3500 RPMs, and as soon as it would reach about 4700 RPMs it would start to buck again.

IDK whats going on but it does it when it feels like it, not all the time.