I have tried everything I can think of, so any suggestions?

383, right at 14.1 static, single plane 4150 TB, solid cam

When I got to WOT or mash the throttle quick it pops back through the intake, like a lean pop. If I smash it slow it does not do it.

When you drive it......it does the same thing just worse.

I have tried everything with the tune....DFI, I went up and down in fuel and timing and no diff.

Possibly a mechanical issue? I checked and changed the following
Plugs, several different ranges racing, regular etc.
Plug wires
Coil and ICM
More fuel press.
Checked all sensors
Valve lash several times.

I can't think of anything else

 

mine was doing that, the coil wire was bad(stupid make-your-own taylor junk) and i am pretty sure it was arcing to the maf

 

Intake valve hanging open possibly?

 

pretty sure you would hear that at idle, load suggests secondary ignition imho

 

Pretty sure its not.

I have been over it several times.....



Its not a coil wire.....I got a new set of wires and checked resistance on all the were all good. The opti is new, I used it to test on another car before I installed it and it did fine.

For some reason I feel its in the tune......Its DFI also, could the timing be too low/too high?

 

Im glad someone else is having this problem. Mine does the exact same thing as you describe. I've been looking for a while and have yet to find the problem.

 

FWIW mine checked out fine too, and because of that i avoided it for a while and finally just started replacing things

when you replaced the wires was the coil wire also replaced?

 

yes, thats not it...I'm 100% sure its not the coil wire, I have had 2 brand new coil wires...no difference.


I added alot of timing in the low areas and got my vac to 75 kpa at idle.
The other issue when you give it throttle I'm thinking is fuel........I have added and added but no difference

 

Have you checked/changed your fuel filter? That was my next step on mine, just hadn't gotten around to doing it.

 

It is not the fuel filter. I have plenty of fuel pressure at all times

Someone told me to dissconect the rear 2 throttle blades. so I did that, it is not as bad now only has a little tiny pop when you go WOT around 4500 5000. Possibly still going lean? That would be 750 cfm with just the 2.

 

Its lean, jack the fuel presure WAY up and try it. I did that trying to get mine to idle, turned it down too far. I popped the throttle to clean it out and that bitch backfired-popped back through that WS6 filter...I was standing right over it....skeered me LOL.

You may have pressure, but your volume may be down. Sounds like you have a pump going t!ts up.

Load an old file in the ecm and see if it quits. Does it detonate, when you drive it.


David

 

David its a new set-up I haven't run it before. The pump is brand new...I have a -10 line into a Y then a -8 to each rail feed and 2 -6 going to a reg with a -6 return. I have a gauge on the reg and before the rail....I'm good on both sides. I'm @ 55 PSI now. I will try more fuel press next.

It does not detonate when driving.....I can't drive it much, it a race car..on slicks etc. so I can make a quick run down the street and back thats it. No tags either.

It does o.k. if you ease into it...but if you hit the gas quick or come off the converter WOT she starts popping....its even worse on the street.

 

Your gauge is on the pressure or return side? Should be on the return.


Can you datalog?

David

 

I have a gauge on both, Why would it be on the return? (its acctually in the regulator)

The other is on the rail in a Y fitting

 

You need the regulator and gauge on the return side.


David