I have a holley in tank fuel pump 255 lph (part #HLY-12-914 at summit) which was installed 14 months ago and a holley fuel pressure regulator. I recently started driving a route lasting ~90 minutes for work but at about the 70 minute mark my engine stops running when ambient temperature is hot. I say this because the car runs fine when I commute at night but dies every time when I commute during the afternoon. During one stalling episode I happened to pull into a gas station and fill the tank up, the car then started and ran fine (as opposed to the other times when I had to let it sit for 2-3 hours before it would start and run fine). All these facts together made me assume the fuel pump was overheating for some reason and then failing to maintain adequate fuel pressure causing the stall. I checked my fuel pressure the following morning (cold engine/fuel system) and the pressure was 47 (with the engine off) which is where I had set it. I then managed to check the pressure during a stall episode. The car barely started, was running ~32 psi then would die when the pressure fell to 28. Three hours later the pressure was back to 47 and the car ran fine. This leads me to a few questions. Has anyone ever had this happen to them? Are holley fuel pumps bad in general or do I have a lemon? I have seen that many people recommend the Walbro fuel pump, but my understanding is that it is the same as the holley unit. Any thoughts on this matter would be appreciated as the only solution that I have right now is to replace the pump and since that is a pain in the @%% I would like to put a reliable pump in. By the way the engine is a 383 with 24 lb injectors which is why I didn't run a stock pump in the first place.

 

I just had the exact same thing happen to my car. In the morning the car runs great, but when the ambient temperature is high, the car won't run at all. When the car won't run, the fuel pressure is around 20 psi. Also, filling up the gas tank does temporarily solve the problem. I assume its because the fresh gas cools off the pump. I'm in the middle of changing out the fuel pump right now, but it won't be done before Saturday. After I dropped the tank I noticed that the solder joint on the tank was cracked. Whoever owned it before me tried to fix it with some epoxy. Didn't work. So, I have to wait for a new gas tank to arrive. When I get it back together I'll let you know if that fixes the problem. BTW, dropping the gas tank is a real pain.

 

Holley AFPR's for TPI often have leaky diphragm probelms, which will cause fuel pressure problems. If you pull the vacuum line off of the AFPR while the engine is running, you will see fuel leak out of the vacuum port on the AFPR if it is leaking past the diaphragm.

 

I have checked the fuel pressure regulator and have not seen any fuel in the vacuum tube, thanks for the suggestion.

 

I'm having a problem at cold start up. I've replaced the filter and relay, my FP is 35 @ start up and remains between 35 and 38. Once you shut it off the pressure bump to 38 and holds but bleed down below 20 psi after 10 mins or so.

So before I replace the dreaded pump is there anythig else I can check or replace to solve my problem??

The car will finally start if you quickly turn the key on. so what does the great minds of 3rd gen members have to say

 

If your pump is fairly new and is having pressure issues - here's one of many articles on fuel pumps. http://www.carterfueldelivery.com/fu...rt/TEC1620.pdf

 

I solved this problem and decided I should post my finding in case this happens to anyone else. I replaced the pump and found that the nipple where the pump meets the rubber fuel hose had dislodged from the pump and travelled about 1/4 inch up the hose and was twisted so that the hose lumen was about 80-90% occluded. I assume that the problem was that the pump had to work very hard to move adequate quantities of fuel past this occlusion and so overheated after running for a certain amount of time. I am not sure if I dislodged the nipple while installing the pump initially or if it somehow came off on its own but that was the problem. If you look at the attached picture the silver deal on the end of the black tube is the piece that was dislodged.

 

Huh, that's interesting. I wonder if Walbro redesigned their pumps at one point in time, or if yours is just a different model. It's been a while since I put my Walbro in, but I honestly don't remember it having that silver nipple at the top. In fact, mine didn't even have a bulge or flare at the outlet. It was just smooth and tapered. I tightened the worm gear clamp down pretty tight since there wasn't any kind of flare. Just went out in the garage and grabbed the box mine came in, and the model# is GCA758-2. Of course I didn't buy it directly from Walbro, so who knows if that number means anything, but I think it cross-references to the GSS-340M. Sucks that you had to drop the tank again, but it's cool that you figured out the problem!