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tylogans 22
08-07-2010, 08:05 PM
I'm fine tunning my 502 procharged 22 classic, I have a new issue it's building crankcase pressure once in a while it spews out the valve cover vent tube. Timing is set at 27-28, fuel pressure is at 30lbs at idle. Any idea's will be appreciated.

The Hedgehog
08-07-2010, 11:52 PM
I'm fine tunning my 502 procharged 22 classic, I have a new issue it's building crankcase pressure once in a while it spews out the valve cover vent tube. Timing is set at 27-28, fuel pressure is at 30lbs at idle. Any idea's will be appreciated.

Once and a while is ok. Lot's is bad.

Base fuel pressure sounds low but I will have to check my notes. I seem to remember 38 as a base but don't quote me on that.

I went to a puke tank to deal with that. My ventilation was driven largely but massive oil pressure and a loose tolerance to deal with the cold water temps I run. A stock engine should not vent that much.

I drop a couple oz of fluid a year so it is not too bad,

mrfixxall
08-08-2010, 12:20 AM
38 lbs of fuel pressure,then 1 extra lb for every lb of boost..you now need to do a cylinder leak down test,the 30 lbs of fuel pressure could have leined out the motor and scuffed a piston or pealed a ring land..also when you did a compression test what were the numbers(with the throttle body open and the huffer hose off?)

tylogans 22
08-08-2010, 08:37 AM
38 lbs of fuel pressure,then 1 extra lb for every lb of boost..you now need to do a cylinder leak down test,the 30 lbs of fuel pressure could have leined out the motor and scuffed a piston or pealed a ring land..also when you did a compression test what were the numbers(with the throttle body open and the huffer hose off?)

Thanks for yours and Hedgehog's feedback just to confirm my fuel pressure should be set at 43lbs at idle? (base 38lbs plus 5lbs to cover the boost.)

BUIZILLA
08-08-2010, 09:48 AM
fuel pressure should be 43# wioth the vacuum line OFF, it will be 38# with it on... then do your delta-P additions...

The Hedgehog
08-09-2010, 01:20 PM
Where are you checking the pressure? I got different numbers on the rail vs the regulator.

blackhawk
08-09-2010, 01:29 PM
Won't the amount of fuel pressure depend on the size of the injectors and the ECM program???

mrfixxall
08-09-2010, 02:25 PM
Won't the amount of fuel pressure depend on the size of the injectors and the ECM program???

the older 502's only use a vacuum line on top of the regulator to regulate the fuel pressure..their should be a boost referenced fuel regulator on his set up..the ecm program deals with timing and injector pulse width's and firing time on the injectors..

blackhawk
08-09-2010, 03:23 PM
the older 502's only use a vacuum line on top of the regulator to regulate the fuel pressure..their should be a boost referenced fuel regulator on his set up..the ecm program deals with timing and injector pulse width's and firing time on the injectors..

So, if you are running larger injectors and/or wider pulse width you would need less fuel pressure than someone still using stock injectors and/or stock pulse width, correct? That's the way I have always understood it.

The Hedgehog
08-09-2010, 04:24 PM
So, if you are running larger injectors and/or wider pulse width you would need less fuel pressure than someone still using stock injectors and/or stock pulse width, correct? That's the way I have always understood it.

Basically but the ECM would need to be tuned accordingly. As Fixx sort of said, they all go hand in hand. You can't just put in bigger injectors and then arbitrarily drop the fuel pressure.

I guess it would be possible to correlate pressure and pulse width from stock to bigger injectors but you would be risking a bunch of melted pistons if you got it wrong.

The Hedgehog
08-09-2010, 04:27 PM
the older 502's only use a vacuum line on top of the regulator to regulate the fuel pressure..their should be a boost referenced fuel regulator on his set up..the ecm program deals with timing and injector pulse width's and firing time on the injectors..

That is pretty much what mine did too.

The Hedgehog
08-09-2010, 04:28 PM
fuel pressure should be 43# wioth the vacuum line OFF, it will be 38# with it on... then do your delta-P additions...

Yep.

Man, that brings back memories. How do you remember that? It has been years since I have fooled around with tuning a stock procharged engine and I forgot that step with the vacuum line. The delta-p additions I do remember.

tylogans 22
08-09-2010, 04:44 PM
Yep.

Man, that brings back memories. How do you remember that? It has been years since I have fooled around with tuning a stock procharged engine and I forgot that step with the vacuum line. The delta-p additions I do remember.

I want to thank everyone for your input, I'm making arrangements to take my boat to an engine builder in Michigan (Tyler Crockett marine engines). I will report back once the problem has been fixed. I hope my kids won't mind if I use there college money!!

blackhawk
08-09-2010, 06:55 PM
Basically but the ECM would need to be tuned accordingly. As Fixx sort of said, they all go hand in hand. You can't just put in bigger injectors and then arbitrarily drop the fuel pressure.

That's what I am saying/asking, doesn't seem like there would be black and white "correct" fuel pressure numbers without knowing what he has done such as bigger injectors, reprogrammed ECM, etc.

blackhawk
08-09-2010, 06:57 PM
I want to thank everyone for your input, I'm making arrangements to take my boat to an engine builder in Michigan (Tyler Crockett marine engines). I will report back once the problem has been fixed. I hope my kids won't mind if I use there college money!!

That's a great move! Tyler definitely knows his chit. If you want to spend more money you can put an O2 sensor in the exhaust and he can dial in your ECM. :yes:

The Hedgehog
08-09-2010, 08:00 PM
I have not had any personal dealings with Tyler but hear that he knows his stuff.

Probably a good move.