Extreme rich condition

[Bradjon]

I had something like this happen and it was a o 2 sensor wire had burned on the exhaust

[Perry Mitchell]

I have a fuel pressure gauge installed where the Schrader valve was. It reads about 45 psi which I think is a little low. It bleeds down slowly. How long should it take to bleed to zero?

[Paul Workman]

Originally Posted by Bradjon

I had something like this happen and it was a o 2 sensor wire had burned on the exhaust

YES! (beat me toit!) A shorted O2 sensor will signal LEAN to which the ECM responds with increasing the injector dwell time, flooding that side with fuel.

In my case, the O2 voltage would intermittently short to ZERO, resulting in a lot of my hair pulled out before I bought a scanner and caught it in the act while driving. Making matters worse, the situation did not always throw a code. But, after smoking some time, I'd get an SES light. (This experience was on a 95 LT1 base car).

The question I have is, are the plugs on BOTH sides showing rich?

[Perry Mitchell]

I will pull the plugs this morning and inspect them. I am sure they need to be cleaned anyway. I suspect all cylinders to be rich. Don't the 02 sensors need to be heated up before they come into play. The sensor wires are definitely not burnt and the sensors are new but probably sooted up as well. I really appreciate the help.

[Perry Mitchell]

Just as I suspected, all 8 plugs were carboned up. Something is causing too much fuel to be introduced to the new FIC injectors. The FPR is also new and the prom properly calibrated. It has to be a malfunctioning sensor but I do not know how to test them. Maybe the MAP sensor?

[Paul Workman]

The fuel pressure (on mine) reads 45 psi after turning the intention switch to ON and the rail primes (normally). The pressure remains constant to within a pound (psi) over 30 minutes. If your pressure bleeds off by 3 or more or drops to zero in 30 minutes, it is an indication of a injector or check valve leaking.

If you tape the pressure gauge to the windshield and go for a drive, the pressure with light throttle should be ~45ish. But, at WOT, the pressure should jump to ~!53-55 psi range and hold there as long as at WOT.

Hope this helps...

P.

[Perry Mitchell]

Thanks Paul. This information gives me something to watch and tomorrow I will time the pressure drop on the gauge. Is there a check valve somewhere in the system other than the fuel pressure regulator? Maybe at the pump? However, I don't see how a pressure drop, when the key is off, has any effect on the rich condition I have.

[LGAFF]

How old is the gas? What is the gas color?

[Perry Mitchell]

Originally Posted by LGAFF

How old is the gas? What is the gas color?

Thanks for the suggestion but the gas is fairly recent and is non-ethanol 87 octane which is the highest non E gas I can get in my area. Marc has compensated for that when he re-calibrated the prom.

[LGAFF]

I chased an issue after a car sat for the winter super rich fouled plugs, drained the tank it was yellow and once I swapped for fresh car ran fine...