FPR problem!!! I think??

[95gstnotwalkin]

so heres the deal, i installed my 255 3 weeks ago and it ran great for about 300 miles.. then, it started to run insanely rich and missin like crazy.. when i pulled the plugss the three at the feed side looked good but the one closest to the regulator was black as the ace of spades. so i assumed that it was just overrunnin the stock fpr and forcin all the extra fuel out of that injector. am i right?? anyway, today i installed my aeromotive fpr and now it wont even fire. i know its gettin spark cause it shocked the hell out of me but i have no clue why its not gettin fuel.... any ideas please.. im dyin here.. thanks
matt

 

[95gstnotwalkin]

anyone???

 

[oldman]

If the car ran before the afpr install then it's almost certain that it's related to it. Check your work against this SX install then follow the direction using the fuel pump check valve to check for fuel pump failure, leaks and set your base pressure to 44psi with the vacuum hose off. http://www.vfaq.com/mods/FPR.html God luck.

 

[mirkoelek]

how many psi would vacum hose suppose to take down pressure on the idle
mine is about 3psi
it that normal

 

[oldman]

how many psi would vacum hose suppose to take down pressure on the idle
mine is about 3psi
it that normal

You have Web cams, what is your vacuum reading at idle? Do you have an afpr? 1:1 intake pressure to fuel pressure ratio.

 

[mirkoelek]

You have Web cams, what is your vacuum reading at idle? Do you have an afpr? 1:1 intake pressure to fuel pressure ratio.

i have afpr, and waht is diff about web cams

 

[Big Woo]

First off, if the fuel pressure was too high, all of the injectors would have been injecting more fuel per unit of time. This would happen because the flow rate through the injectors would increase due to an increase in the pressure drop. For example say the fuel pressure is 40 psi at six pounds of boost (positive pressure in the intake manifold) that would mean that the working pressure or the amount of pressure driving fuel into the intake track would be 34 psi. If your fuel pressure increases and the boost setting stays the same then your driving pressure into the injectors would increase, but they would all increase by the same amount, not just one of them.

In the past I have seen one injector fail, or start to leak, which can cause an overly rich condition to occur within one cylinder, it can even get so bad that the cylinder will no longer fire, because of excessive fuel. Additionally I have seem the ECU in DSM's fail, causing all four injectors to basically turn on and stay on. This causes fuel to flood into the all cylinders, and should be easy to recognize.

Also check what you have the fuel pressure set to with the Aeromotive regulator. If you have changed the regulator and the problem still ex hists, then the regulator was not the problem, or was not the only problem.

 

[oldman]

i have afpr, and waht is diff about web cams

After market cams have different specs than stock therefore have different vacuum readings. Again, what is your vacuum reading at idle?

 

[mirkoelek]

After market cams have different specs than stock therefore have different vacuum readings. Again, what is your vacuum reading at idle?

about -15psi

 

[oldman]

about -15psi

That would be -15HG = approximately -7.5psi which sounds about right for an aftermarket cams. Did you double check the afpr install? Check for fuel leaks? Base pressure setting?