Well, it's been awhile since I started this thread about my fuel problem. Finally found (made) the time to install the fuel pressure gauge into the fuel line from the Stage 1 pump to the Quadrajet. (The Corona Virus didn't help any either) I'll do some testing later today as we've had rain almost all week so far. I cut about 6 inches out of the stock fuel line and installed a tap to which is connected the Summit gauge and braided steel line going to the windshield. I did have to put a small flair into the steel lines to hold the rubber fuel hose. Here's the setup in case anyone is interested.
Well, road test performed today and the expected results are in. It's fuel pressure, not the carb. On cold start-up and at cruising speed warmed up, fuel pressure is only about 3 psi. On medium acceleration pressure drops steadily to less than 2 psi. If I accelerate any harder, pressure drops to 1 psi or less and if I go all the way, pressure drops to zero and car noses over and almost stalls unless I get off the throttle. Now, the question is, is there a way to determine if there is a blockage from the pump back to the gas tank or, should I just replace the Stage 1 pump and hope that cures it? Any thoughts? An additional question is, should the fuel pressure hold at the idle reading when the motor is turned off? Mine stays at 3 psi (actually goes to 4 psi when fuel is heated by engine being turned off) for a good hour or more. By the way, the Summit liquid filled pressure gauge works great and is steady as a rock with no jitter at all.
Inspect the line all the way back to the tank, look for kinks or other damage to the metal line, and look at the rubber line near the tank. Any dry rot? Have you ever dropped the tank and looked at the sock?
This sounds like a very familiar problem, thank you for doing some testing. You definitely figured out you have a problem, and now I'm certain I do too.
Haven't dropped the tank yet and there is some dripping in front of the tank (on the driver's side) onto the garage floor. Guess the next step is to drop the tank and replace the rubber lines back there. I'm just wondering if it would be worth it to try a new pump just to see if that's bad too? If it's OK, I can sell the one I removed on the forum as a good used one. What's the source for the fuel sock and a new pump? The auto parts places I've checked with all show out of stock.
Seems to me at your power level, you might as well upgrade. https://www.robbmcperformance.com/products/1069_gmsend.html I use the above sender/pick up. It has no sock, I use a billet inline filter under the driver's door.
Rockauto seems to have stock senders, https://www.rockauto.com/en/catalog...+v8,1379774,fuel+&+air,fuel+sending+unit,4436 and pump, https://www.rockauto.com/en/catalog...l+455cid+v8,1379774,fuel+&+air,fuel+pump,6256 info says 6.5-8 psi for the Airtex, https://www.rockauto.com/en/moreinfo.php?pk=58814&cc=1379774&jsn=429
