Fuel Pressure

[TR6]

Anyone know what my stock fuel pressure should be? Car is currently dead stock. It is running about 25# at the rail. This seems low to me, but I have also heard that according to the manual that is the stock pressure. I thought the throttle-bodied GMs of the 90s were running like 35#, so 25 seems low.

Also, there is not much change at WOT. Shouldn't pressure go up at WOT? Any ideas would be great. If this is normal, all the better.

I am looking to upgrade pump, injectors, regulator, and possibly chip, but would like a good baseline and to know if anything is out of whack first. Any input would be great.

 

[garyk1970]

should be 35-40? psi for a fuel injection system. should see an extra lb of fuel press for every extra lb of boost.
heres a link to help. HTH, Gary

Fuel System Check Up

 

[SS/GNX]

Anyone know what my stock fuel pressure should be? Car is currently dead stock. It is running about 25# at the rail. This seems low to me, but I have also heard that according to the manual that is the stock pressure. I thought the throttle-bodied GMs of the 90s were running like 35#, so 25 seems low.

Also, there is not much change at WOT. Shouldn't pressure go up at WOT? Any ideas would be great. If this is normal, all the better.

I am looking to upgrade pump, injectors, regulator, and possibly chip, but would like a good baseline and to know if anything is out of whack first. Any input would be great.

Ya, that sounds real LOW, and it SHOULD change at WOT! Sounds like you need a fuel pump, hotwire kit, new fuel filter, and an adjustable fuel pressure regulator!

That will wake it up!

 

[TR6]

Thanks guys. I thought it sounded low as well. Funny thing is I have a full 13.5 volts at the pump, even at WOT, no hot wire. I do have a fuel pump to put in, and I have changed the filter already, but I wanted to get a better idea what I was looking at before changing too many things. I had someone tell me that the service manual shows that fuel pressure should be 25 #s, but I don't have a manual to verify it with, and that still seems low to me for a fuel injected car, especially multiport.

Any other ideas? Anyone have an ajustable regulator for sale at a good deal? I also need injectors if anyone has a set of fairly mild ones on the cheap in good shape.

 

[granatl]

I'll venture a guess to say that it's the fuel pump or sock on the fuel pump. If you still have the stock one, I'm surprised that it lasted that long.

 

[TR6]

I believe it is the stock pump. The tank was replaced before I got the car, but he didn't think the pump had been. I already bought a pump thinking the same thing, not to mention that the stocker is inadequate for any kind of extra power anyway. Money is tight so I am kind of building as I go, so I have not put the pump in yet as I still need a regulator and injectors too.

 

[SS/GNX]

Put a post in the "parts wanted" section on these boards. There are some really good deals out there, dont take the first one offered, some guys on here like to make a little too much money on their old stuff.

I need injectors too and found someone will sell me 30# injectors for $55!
Not very big, but all I need for now just to get me by until I can afford bigger ones.

Anyway dont worry, this board will take care of you.