Fuel cut or Backfire

[Migzz]

Ive searched this topic many times and its been pretty much beaten to death,but i havent really gotten the answer im looking for.So here it goes, at exactly 5k my car backfires out the exhaust and gets that "brick wall feeling".But heres the kicker it only does it when its below 60 degrees outside (ambient temp.).ive got my a/f ratio dialed in at 11.1 via the wideband ive replaced my ignition wires,spark plugs gapped to .28,checked the ohm resistance on both igntion coils,and ive done hundreds of boost leak tests.And it also does it no matter what my boost is set at.Does this make any sense?I really dont see how the temp could be causing this, im extremely pissed and im hoping someone can help me out here.....

 

[tbonitz301]

I remember when i was on the t-25 i would hit fuelcut in the winter time. I may be wrong, but the low temps(denser charge) may have something to do with it. I'll leave that to someone else

 

[98spydereugene]

Is it when you hit full boost?

 

[Migzz]

Yes i usually hiy full boost by 3500 rpm's.And i forgot to mention it does it in every gear except for 1st it just sux its like my car physicaly wont let me go above 5k its kinda like hitting a rev limiter except with the violent bucking

 

[Migzz]

I guess nobody has dealt with this?........

 

[N1balla16]

How much boost are you running?

 

[Migzz]

20 psi

 

[91talon27]

What are you tuning with? My car did that when I hooked up the stutter box into the switch that kicks off cruise instead of the clutch switch. It was like I was hitting a wall and I couldn't go over 5000 rpm. When it does it is the wideband fluctuating at all?

 

[Project2G]

I'm looking at your mod list and you have a walbro 255 with no AFPR. My car back fires because I have the same. Perhaps this is why.

 

[Migzz]

My wideband is steady at 11.1 when it happens and im not positive if i have have a 255 fuel pump it had a few things done to the car when i bought it and that is what i was told i re-did the whole car except for the fuel pump....

 

[Staytuned]

Sounds like fuel cut based on high airflow numbers due to the cool dense air.....possibly made worse by a small boost leak.

 

[turbotalawd]

I duno if this applies to you guys, but the same thing happened to me when my timing was not set at TDC. Whats your timing when that happens?

 

[webconnect]

Confirmed, on my t25 it does this in cold weather because the air is denser.

 

[N1balla16]

Sounds like fuel cut to me and you should really get a AFPR with the mods you have on your profile. That should help if not look into a fuel cut defender as long as your A/F ratio is good.

 

[Migzz]

My logger shows 5 degrees of timing at idle and about 30 degrees at its peak (dunno why its so high this is another issue all together) but anyway ill be getting dsmlink soon and that should hopefully solve my problems. and o yea to the high air flow numbers caused by denser air comment I was under the impression the stock 2 g maf was good for higher air flow and it is pretty hard to over run, i could be wrong but either way how would this be corrected without the use of lets say dsmlink