Good deal Jeremy. I'm following this one closely as I have yet to finalize my return system. Right now it's just an air burper quasi dead ender using the stock return. Looking to improve it. I will be bumping up my pressure soon.

 

OK I have to back off my more pressure stance a wee bit: It now looks like the fuel increase DOES appear to improve some portions of the injector operations. I am still unsure as to exactly why.

side note: How does the ICP sensor on the fuel log work? studying the FORD manual seem to indicate that it provides fuel pressure status to the pcm which affects pulse width.

 

The ICP sensor detects the pressure of the high pressure oil system. Not fuel.

 

I've seen plenty of fuel pressure diaphram failures on gas engines. And yes it fills the intake with gasoline and floods it out. Even to the point of hydrolocking the engine. If you do end up with a broken diaphram it will pump a LOT of fuel into your intake. I know it's fun to have this hooked up like that, but I am one of those guys that would never do this. Perhaps someone could figure out an electronic interface and do away with the physical line between the pressure regulator and the intake manifold.

 

I had the stock pressure regulator diaphram fail on my Bronco once, it let a lot of fuel through a pretty small hole and it operates at a lot less pressure than these engines. Had a bugger of a time figuring out why my engine was running so rich.
It also wouldn't take a lot of fuel to create some very serious problems IMO.

 

OK you party poopers. I would tend to agree that any failure could be catastrophic. Anyone know of the Aeromotive failing? In the interim, what would be a good fix? I'm gonna put some of the few brain cells I have left to work on this one.

On edit: ya gotta pay to play.

 

I agree... but a runnaway truck?... I just wish I had the money to do it with!

 

Yeah, I cannot afford it either. As always, Dan's words remain in the back of my mind. The voice of reason and experience. I thought of a seperate pump cut-off switch but that would only stop the situation after it has begun and is percieved. Maybe too late.

Safety is no accident! A runaway truck is unacceptable. Things can be replaced, people cannot.

So far the best I can come up with is to agree with Scott,(another one of those voices). A mechanical check valve will stop that situation in it's tracks. Then, I believe the situation would be evident by an unresponsive fuel pressure gauge as the regulator will no longer increase PSI as boost climbs.

 

A check valve would work, except how would it let boost bleed back out of the regulator and allow fuel pressure to come back down, when the boost comes back down? Wouldn't a check valve that prevents fuel from flowing through it and into the manifold also stop air pressure?

 

Darn Jeremy, I guess I was one brain cell short, well at least one. That is a serious problem too. Gonna drive around at the highest pressure attained like that. Hmmmmm Back to the drawing board. Maybe I'll eat some fish today.

 

how about in addition to the check walve plumbing a orifice in paralelling the check valve. say perhaps a # 80 or smaller hole. get fuel but not a lot on diaphram rupture but would slowly bleed down to ambient.

 

That's an idea. Now we're talking. I've got some small orifice valves I could use as well, left over from plumbing my externally regulted system. Let me see if I can work up a diagram of what I'm thinking.

 

Ok here's a diagram of what I've got in mind. Check valve would allow pressure to build quickly. The small orifice would allow air to easily pass through to bleed down boost pressure rather quickly, but the small hole wouldn't allow fuel to flow through very quickly. But, it would flow enough fuel to indicate a problem because the truck would run differently, but not enough fuel that the truck could run away.

 

Yuppa that be it. Teensy hole on the orifice like what is on the cheapo propane adapter on my wallyworld BBQ. I am thinking you'll lose only a bit of signal when you get off the boost, BUT immediate response when you get back on boost.

Idle would probably go to 2500 with a leak on the diaphram since it don't take a lot of fuel to idle. Lotta smoke and pinging also. Might want to test that scenario before getting carried away at the stoplight.

I aslo think that this is a short term experiment?? Better hardware solutions Should be available long term

 

Yes, this would be good. The tiniest of orifaces would be sufficient. Air passes through an oriface much easier than a liquid so the response would be nice and quick, where if you suddenly sprung a leak the flow rate for the fuel would be a lot less.
But you already knew that.