Detonation at idle on new install
So I just installed an FITech Go Efi 4 600hp unit on my mild 355 in a 92 Firebird. The car has a TPI pump in it from a previous owner. I am getting massive detonation at idle, no matter where my timing is set at. I am running a locked out HEI and using the FITech to control timing. My fuel pressure is a little lower than it probably should be, around 45 max running at the supply line measured with a good inline gauge. Would this cause this huge detonation issue, it seems to be running really lean. I don't want to leave it running for the unit to learn anything because the detonation is so bad.
Fuel pressure needs to be 58psi for FITech throttle bodies ( doesn't it ?)
45 is a long way under and I doubt it will self tune its way out of that.
So, I suppose it could be fault of the pump - what pressure does it achieve dead ended ?
or the pressure regulator in the throttle body is faulty,
or, fuel pump pulse width modulation setting is set wrong.
in Fuel Pump Control ( main menu> pro tuning> initial setup > fuel pump control )
PWM low flow should be set to 75 ........ for a fuel delivery set-up with a return line to tank (which I think you have).
any number lower than 75 will mean reduced voltage to the pump at low fuel demands, ok for dead end systems but not returns
It is at 50-52ish at initial prime. I have PWM set to 74.9. I'll change that to 75 and see what happens.
I also realized that my timing was set totally out of whack and probably causing all kinds of issues. I think. I bought the car back after selling it like 10 years ago and I am undoing a lot of haxorage.
74.9 is what 75 entered will end up as , so that is correct.
I don't reckon your pump psi is high enough
I'm betting that is the problem. Upgrading to a new in-tank pump isn't a huge deal. Probably good insurance anyway.
Also checked my engine for TDC with a whistle, endoscope and my son's thumb. Found out that the factory notch on the damper is at 0 deg. There was a black mark that someone had set the timing off of on the car that looks to be about 18-20deg off. So my timing was WAAAAY off and that could be a big part of the issue too. I'm not even sure how the car ran with like 32deg of initial timing.
Detonation issue figured out, it was that timing issue. It runs good now. I probably still need to upgrade the pump but at least now I know what the knock issue was.