ok i think its just fuel pressure problems because i run 116 octane and i cant smell it burning! But it does burn the eyes if your in the back of the car. On my drive back from the exhaust shop it died at every stoplight. I have a accel gauge hooked up and its pegged to 65 psi I know thats not good so i am just gonna put my old regulator back on this aeremotive thing sucks i bought it last year during my parts gathering months i am running 36lbs injectors do you think the stock regulator will be fine? it is tuned by pcmforless.com. p.s what is the stock regulator set at

 

i think stock is 43.5 and if your running 60 psi i bet it does stall out at a stop because thers so much fuel. you could run that pressure but you would have to retune the injector costants

 

so then stock should be fine? i tell you what though it still moves pretty good but i need to fix it thank you

 

Every post I have ever read about the Aeromotive AFPR has been about how it won't adjust the pressure..... it just stays at 65+psi. Appears the Aeromotive is a total POS, based on the large numbers of problems.

If you told your tuner that you were running 36# injectors at 43.5psi, you are pouring 22+% extra fuel into the cylinders. The PCM can not correct for that much excess. You may be washing the lubrication off the cylinder walls, risking serious damage. I'd get it fixed before you hurt anything.

Why would you run $7/gallon racing fuel anywhere other than the track?

 

Must be a recent problem...mine has no problem adjusting pressure.

 

MIne has no problem either, Turn it down dude! Have you tried adjusting it?

 

wouldnt it just run past the injectors into the return line if it had to much PSI? I could be wrong. The injectors can only handle so much fuel.

 

The computer has the inj. constant setup with 43.5psi in mind, so when it calculates how long to keep the injector open, it is based upon the flowrate of the injector at the given pressure. So if the injector opens for 1 second (exaggerated) and it thinks it flows 36lb/hr @ 43.5psi. However, with the higher fuel pressure the injectors are acting like 54lb/hr's. This will show its affects at WOT, but typically the computer will adjust based upon O2 sensor readings during closed loop.

Someone correct me if I am wrong.

 

Your concept is right, its the math that you screwed up. The injector is simply an "orifice" that controls the flow rate of fuel. The flow through the injector can be calculated using the orifice equation. Essentially, flow through the injector is proportional to the square root of the pressure ratio.

Appears you figured:

65 / 43.5 = 1.494

1.494 X 36 = 53.8#/Hr.

The correct calculation is:

65 / 43.5 = 1.494

1.494 ^ 0.5 = 1.222

1.222 X 36 = 44.0#/Hr.

As I stated in my post, the 65psi fuel pressure is causing the injectors to deliver 22+% extra fuel with each pulse. The long term fuel corrections can only pull about 15% before they "bottom out".... 108 / 128 = 0.844. So there is no way the PCM can prevent the system from running rich in closed loop (except for setting super low INT's), .... and when you go into PE mode at WOT, since it was "reducing" fuel in closed loop, the BLM's will default to 128, and you will be pouring in 22.2% extra fuel. A properly set A/F ratio of 13.0:1 (for example) will be producing a 10.6:1 A/F ratio because of the extra fuel through the injectors.

A

 

If it's really running as rich as it appears you better fix it, pronto. Once you start getting into the 10:1 range you not only are going to foul your plugs but you may wash the cylinder walls clean of lubricant (oil) and cause major wear problems down the road.

It may be even worse than Fred's calculations suggest if the tune is for stock injectors, though you do indicate that it's a custom tune.

Rich Krause

 

Good work Fred! Thanks for the insight!

 

When I grow up, I wanna be a teacher.