Running Rich with Low Fuel Pressure

**F-Body Man** · 04-21-2010, 07:02 AM

As the title states, I have a 2001 WS-6 (M6). When I first bought the car in 06, the Fuel Pressure was around 58-60 PSI like it should. But over the years my Fuel Pressure has slowly gone down and also my Richness has gone up. My Fuel Pressure now sits around 48-50 PSI. I have changed the Fuel Filter every 15K miles, changed out my O2s a few months ago, I every Oil Change run a bottle of Lucas Fuel Cleaner, and I clean my K&N Filter when it needs to be cleaned. I am running pig rich, example I gun it, alot of smoke comes from the tail. Also after just a few days you can see the rear of the car getting small black deposites on it.

I have the Predator Programer and I have tried to lean out the Fuel mixture with it, but no luck. After all of that, the only other thing I can think of is it might be the injectors and I have a set of 30 lbs injectors I could swap in, to see if my Fuel Pressure goes back up. But I dont want to put them in if my Injectors aren't the issue. All mods are in the Sig below. Thanks.

**SOMbitch** · 04-21-2010, 12:47 PM

Don't change injectors unless you have your tune adjsted for it. Bigger will make you rich and wash down cylinders and smaller will make you lean.. Get somebody with HP tuners to look at your LTFT #'ers......

**JRENIGAR** · 04-21-2010, 01:47 PM

^^^ the predator will do that. Go to diagnostics and live data streaming. Use in fast mode not slow and no need to log it. LTFT should average a 2k rpm's between -2 and 0. You might have a vaccum leak too. Mine had an egr leak and run pig rich, would also stumble for a sec or two when I came to a stop.

**F-Body Man** · 04-21-2010, 04:46 PM

Well I went out for a drive and watched the LTFT and the Avg was around 5.47% both sides. I was driving around 40 MPH in 4th gear at 2K RPM. But again I am also concerned with the low Fuel Pressure. Any ideas?

**Cutlass** · 04-21-2010, 05:34 PM

That excessive amount of Lucas Fuel system cleaner you've been dumping in your gas tank probably ruined your fuel pump, (disclaimer: but thats purely speculation based on no facts whatsoever )
You may need a new fuel pump for your low fuel pressure problem

**F-Body Man** · 04-21-2010, 05:39 PM

Thats not excessive for the Fuel Treatment since its recommended every 3k miles. Also and if I have a Fuel pump issue why I am running so rich? If my fuel pump wasnt giving up enough fuel I would be running Lean. Thanks for the replies so far.

**Cutlass** · 04-21-2010, 05:57 PM

5% fuel trim isn't excessively rich.
excessively oiled K&N air filters are known to gum up the MAF sensor and skew its readings. You could try cleaning your MAF

**JRENIGAR** · 04-22-2010, 12:19 PM

subtract 6% in the fuel tables and run it again, should be close to zero. If the fuel press is low then that tells me the regulator is dirty or bad. Its the only thing that would cause the press to be high. Like you said if it was pump would be a low press prob. I think???

**Damian** · 04-22-2010, 09:16 PM

Handheld tuners have nothing to do with how much pressure you're seeing at the rail and trying to compensate with the tuner isn't going to get you anywhere. If you're 10-20psi low on fuel pressure, you're fuel pump is about to take a shit on you. Better to go ahead and change it before it leaves you stranded somewhere. Now's a good time for an in-tank upgrade.