Fuel Pressure on a 99 Silverado

[Kyle F]

I am working on my borthers 99 Silverado with a 5.3L in it. (LS1 style injection). Currently we are getting a code that is sayign that it is running rich. We have checked a few things and found the fuel pressure to be out of spec. We are getting 52 and spec sayes 56-62.

So, is this low fuel pressure our culprit? Is the poor spray pattern causing incomplete burns and showing that we are falsly rich?


Any ideas?

 

[squeeze87]

Not sure if this may be of some help or not, but my 2000 silverado developed a hot start overly rich condition which turned out to be a ruptured fp regulator diaphragm, luckily still under warranty The mechanic said that its a fairly common problem with these trucks. maybe worth looking into?

 

[Kyle F]

Everything runs fine but we are just crusing down the road and the code pops up. The truck seems to run perfect. Thanks so much and keep the ideas coming.

 

[Nashty]

Is the throttle blade sticking also?

Try a good thorough de-carbonizing with some carb cleaner. That helped mine quite a bit. The service tech said that it also may be a ruptured FPR but you can tell that by pulling the vacuum line off and watching for gasoline coming from the port.

 

[Kyle F]

Thanks for the info.. will try. Keep the ideas coming

 

[John Larkin]

I've been hearing recently of codes being set due to a loose gas cap. I think they are more toward the emissions end of things but maybe it's a culprit.

 

[Kyle F]

This has been going on through many tanks of gas. So, I would think the gas cap is tight, unless it is some how borken. Will check to make sure.