89luderSi

iTrader: (1)

I have a B20 vtec that i am running with E85. ive done some searching around and haven't really found the info im looking for.

So my problem is, after im hard on the throttle for idk maybe 15 seconds and at high rpm (7500ish) i let off the gas and decel for about 3 seconds ish and rpm down to about 6k i go to get back on the gas and i have no power and it just chugs for a while like 15 seconds while im trying to give it gas, then all the sudden it picks up and goes again then it starts all over. I do race this on a dirt oval track. i can go great with no issues for 3 laps then when i go in the corner and decel for a bit and get back on it to come out of the corner thats when i have no acceleration and the engine chugs, not running rough like a misfire, its like literaly no power. all the way down the straights it pulls hard and air fuel ratio is right at what its suppose to be.

The engine is a B20 block bored to 85mm with forged pistons, gsr head, delta regrind cams, 12.0 compression and a skunk 2 first gen intake. the car is tuned for e85 and runs great when it doesnt act up. i put a walbro 190lph pump in and rc high impedance injectors 370cc i believe (i did check the part number when i bought them to make sure). i know my fuel pressure isnt dropping or changing because i had a guage hooked when i experience the issue to make sure thats not the problem, it doesnt ever drop below 40psi. i did remove the vacuum line to the fuel regulator to make sure it wasnt sucking fuel in the intake when i decel so i know thats not it. possible vapor lock? maybe my chip or ecu is bad? my air fuel ratio doesnt go way lean or go rich when it happens. it does lean out a little when it chugs but thats probably just a side affect of the real issue. may my rc injectors are getting hot and being sluggish? maybe the e85 just does like the setup and tune? idk. any thoughts or ideas would be great.

Things ive ruled out
-fuel pressure regulator
-crank case vent system
-fuel tank level (keeping it at full)
-spark plugs
-ignition coil
-fuel filter

Sorry for such a long post. i just want to be thorough and give u all the info.

Katman

Pretty late reply back but it sounds to me like possibly ignition and/or a TPS problem(s).
Here's a few questions:

Are you running an oem ignition setup or anything aftermarket?
If oem, take a look inside your distributor and see if the rotor screw is loose or fell out. Check contacts on dizzy cap. Swap igniter and/or coil separately to see if either of those could be suspect. To save some $$$, you can use an igniter and coil from a donor D-series dizzy if you have access to one. D/B dizzy's use these same parts. Also check each spark plugs, perhaps one or a couple are loose or water corrosion build up has occurred on them somehow.

Running a stock, chipped, or engine management ecu? Any loose wires at the ecu or in engine bay that were tampered with?

Check the TPS sensor? original TPS or aftermarket?

Whats your oil pressure at during those decel issues?

Is your oil topped off?