popping/backfire noise at 3200rpm

[evil12vcummins]

so i just installed 4000gsk kit and some full cut DV's in my 911 pump i just purchased. well the thing is is fine at all rpm's except when i reach between 3200 rpm and 3500 rpm. it starts to pop and sputter really loud. it sounds like its back fireing. any clues

 

[kalder]

Have you checked your timing or fuel pressure?

 

[lee01dg]

Free reving or driving when it pops/sputters. Do you aftermarket valve springs?

 

[evil12vcummins]

Have you checked your timing or fuel pressure?

well i have not checked fuel pressure, but when i installed the pump i made sure the crank/cam was TDC and the pump also with the timing pin on the side of the pump.

 

[evil12vcummins]

Free reving or driving when it pops/sputters. Do you aftermarket valve springs?

it will only do it when i am driving. and yes i do have 60# valve springs that were shimed so all have the same lift. i have a small fuel leak in the fuel return manifold. could it be sucking in air at a high rpm to create the pop

 

[evil12vcummins]

another thing, i do not have a FASS/AIRDOG could i be starving the injection pump with the stock lift pump.

 

[kalder]

I would double check your timing.

 

[chrleb1]

Your timing is too retarded. Advance it a couple of degrees and run it again.

 

[Cummins Driver]

You need more fuel volume. My stock lift pump would hold decent fuel pressure on my truck, but it would still pop and sputter somewhere between 2800 and 3200rpm under load. I put my 4601hp carter lift pump on it after trying lots of other things, and it pulls hard all the way up now. Go ahead with a fass or an air dog, or at least a carter or holley pusher pump and ill bet that will fix your problem. Apparently it is a volume issue, and not really a pressure issue.

Eric

 

[evil12vcummins]

i have double checked the timing its all back to 12.5 untill i solve this problem. and with my gt4202 i can only make 40psi of boost. it should be 55psi with the sticks and other fueling upgrades.

 

[Cummins Driver]

Listen to my truck around 21 seconds in this video:

Video - Eric's 94 dodge vs Keith's 06 dodge.. Just havin a little fun

Is that what yours sounds like? Im betting fuel pressure is your problem. I had a new stock lift pump, and clean filter on mine and it would still do it.

Eric

 

[evil12vcummins]

its more the sound of firecrackers going off in my exhaust pipe. this is just a reason to finally purchase a FASS. thanks for the help

 

[chrleb1]

i have double checked the timing its all back to 12.5 untill i solve this problem. and with my gt4202 i can only make 40psi of boost. it should be 55psi with the sticks and other fueling upgrades.

12.5* is way too low. You need to be above 16* at least. 12.5 is less that some stock motors.

 

[G-dubs]

yea i would bump up the timming

 

[TxDiesel007]

Your timing is too retarded. Advance it a couple of degrees and run it again.

100 percent agreement

 

[BlackSkyRacing]

Get a pusher pump, it will solve the popping... Then bump the timing to wake it up on top. :Cheer: