I have a 383 stroker with Trick flow LT1 head,LT,LT4 hot cam,52mm TB,msd opti,and a Aeromotive FPR.Ive always had a miss at 5500rpms so I had 42lb injectors installed because I thought I may have been running out of fuel up top.After the 42lb were installed it was better but still missed about half as bad as before.Yesterday I turned up my FPR to 46psi and the car actually hit 6000rpm clean which hasnt happened since Ive had the car.I checked my FPR to see if it is leaking down after I shut off the car and the gauge goes INSTANTLY to zero after showing 46lbs.I know this is not correct but Im not sure whats going on????I have a Racetronix F/P kit installed on the car also.THANKS FOR THE HELP

 

Normally when the pressure drops like this you have an injector leaking down. How is the car doing when you start it up after the pressure bleeds off?

Do you smell fuel?

Willcox Inc.

 

There are three places fuel pressure can bleed off to without making a mess on the floor and smelling up the place; the fuel supply line, the fuel return line, or one or more fuel injectors. Once you trouble shoot to see where it's going, it will be easy to fix. Otherwise, anything you do is just throwing money at it with your fingers crossed.

RACE ON!!!

 

You should also know that you shouldn't just change injector sizes like you would carb jets. Each time a different size injector is installed, the PCM should be re-programmed so it'll know what size injector is installed.

You didn't mention that you had the PCM re-programmed, so I'm assuming that it wasn't. Based on what you're running, it should be. Give PCMFORLESS a call because the fuel and ignition tables need modification if your PCM programming is still stock.

Based on what you posted, you have a leak which, absent any sign of an external leak, has to be either in the fuel tank/pump or at the engine. Pressure should hold for a while after the engine is shut down. The actual time varies, based on the times that I've seen posted on this and other Forums.

The best way I know of to check for a leaking injector is to remove the fuel rails with the injectors still installed in them and energize the fuel pump while watching the injector tips for any sign of leakage.

Your missing problem could be a caused by number of different things; valve train float (lifter pump up/weak valve springs/lifter preload set too tight), improperly programmed PCM, fuel delivery (partially clogged fuel filter, internally leaking regulator), ignition circuit (fouled/bad/improperly gapped spark plugs, plug wires, Opti, module or coil).

This'll probably end up being a process of elimination; checking each possible source one at a time. I'd begin by solving the fuel pressure drop-off problem, have the PCM programming addressed, then move to the other, easiest to check areas.

Jake

 

My car with an Aeromotive regulator bleeds off instantly.

I called Aeromotive about this and they said it is completely normal for their regulator to do this - I don't remember the exact explanation they gave me but they said it's normal.

Make a run with the fuel pressure gage attached (be careful) and see what happens when you hit the gas.

 

The heads are brand new Trick flow LT1s from Summit.The brain has been retuned by PCMsforless.Brand new MSD opti,How do I check the fuel leak in the lines/pump?Maybe the lifters are adjusted wrong?

 

Sounds to me like the aeromotive fpr is a POS

 

Don't know - what I vaguely remember them saying is that by eliminating the factory regulator's check valve (or something like that) it allows the regulator to meter fuel more precisely.

Aeromotive is known to have good stuff so I'll give them the benefit of the doubt.