Won't pull past 16psi

C

cjg454ss

Member
I have a built motor with a stock turbo.Timing is 10 degrees, fast ecu on e85. Plugs are gapped tight 0.018", wires are msd and test at 110 ohms. Hvc2 coil with msd 6a. Not sure what to do. New injectors and regulator, stock intercooler. Tried methonal injection on and off. Pulls great to 3500prm, Cam is a comp 412 with the recommend valve springs. Intake temps are 80 degrees. Tdc and timing is set correctly. New plugs. Msd cap and rotor are new. I tried all kinds of air fuel ratios from 10.2 to 12.5, leaner seems better one day then it will break up and I



Found a bad spark plug
 
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H

HAMMERHEAD

Member
Re: Won't pull past 16psi

That plug gap seems too tight. Try opening them up to about 0.025 and see if that helps. Might help to start with a fresh set of plugs too. The MSD unit could also be causing the problem. You could try disconnecting it and putting a stock coil on to see if that is the problem.
 
Peter

Peter

my Ty and me 25+ years
Re: Won't pull past 16psi

Sounds almost certainly like ignition, most likely something in the secondary side. This includes the coil wire, cap, rotor, plug wires and plugs. Last time your symptoms happened to me, I found a cracked distributor cap, and it only happened when it was wet outside. A couple of times over the years, it was worn out plugs, too large gap (>.030). I now use .025. At least once it was bad plug wires.
You are correct to play with the fuel ratio, also. Too rich will cause misfire that can fool a knock sensor and cause enough KR to kill your power.
However, playing with the fuel ratio may be just masking a degraded ignition component.
BTW, with E85, I ran closer to 20 degrees advance at 17 to 20 psi boost. 10 seems really small.
 
autoaddictions

autoaddictions

Active member
Re: Won't pull past 16psi

I would check your timing !! Make sure what's being commanded by your FAST is what you actually have with a timing lite. Plug gap way to tight and AFR on the gas scale should be 11.5 WOT. Try a 7 NGK plug. Add some timing I run 28*
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Won't pull past 16psi

What kind of plugs are you running? What size injector are you using?

I am not familiar with a fast ecu, but I assume it has a knock sensor. From you description it sounds like you are diagnosing knock audibly. Is it logging knock? when does the knock start?
 
C

cjg454ss

Member
Re: Won't pull past 16psi

Walbro pump, I don't have a knock sensor. I read the timing mark on the plugs. If I turn it down to 10psimit pulls clean and I have 28 degrees timing in it. Injectors are 60lbs from Eric. Regulator is from Eric too.

it will be good at 15psi and 26* timing and 3500rpm. After 2-3 seconds. It's high gear pulls so it stays in the same cell sometimes. Also if I go wot it will sound like knock at 3500 to redline, then it shifts and misfires a little. It will clear up if I stay in it.
 
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Aeroking

Aeroking

e.i.
Re: Won't pull past 16psi

A single Walbro should max out around 350hp on E85. I'm not sure how built your motor is, but you may be out of pump.
 
RealFastV6

RealFastV6

@jb_and_his_coffee
What injectors and what's your duty cycle at WOT? Also if you have a program and log post them along with what version of fast you're on.


Sent from my iPhone using Tapatalk.
 
RealFastV6

RealFastV6

@jb_and_his_coffee
Re: Won't pull past 16psi

Also I don't know shit about tuning E85 yet but you seem to be running AFRs that are 10.2-12, which for gas would be the ballpark, but isn't that super lean for E85 or am I all messed up?
 
C

cjg454ss

Member
Re: Won't pull past 16psi

RealFastV6 said:
Also I don't know shit about tuning E85 yet but you seem to be running AFRs that are 10.2-12, which for gas would be the ballpark, but isn't that super lean for E85 or am I all messed up?
Click to expand...

Yea the gauge only measures lambda. 11.8 is very safe for e85. I believe I had a bad plug. I swapped them out and now it pulls clean. Still believe I'm going to do a ls9 swap. All factory go parts with a 6l80 trans. Should make 800hp and be more reliable.
 
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