Fuel Pump Blues

Blittleton · #1 (**permalink**) 08-07-2004, 05:47 PM

Boudy, or anyone. Why will my fuel pump quit or lock up when driving my BDR. It is fine when I'm driving normal, but if I'm on it on the highway, say 80mph for a couple miles, it seems to get a vapor lock or something of that sort. I'm using a Holley w/ a regulator? Any help in this area would be appreciated.

Bill

Boudy · #2 (**permalink**) 08-07-2004, 09:23 PM

Sounds like it's starving for fuel. Check routing into and out of the pump and then into and out of the regulator. Avoid sharp bends or 90 degree elbows. These tend to restrict flow.

Also, make sure you have a good, clean, free flowing filter that's not restricting flow. A good fuel log to keep ample supply handy is not a bad idea either.

What engine/carb are you running. You may need to upgrade the entire fuel run from front to rear if you're running one of those monster setups that drinks gas at the rate of methanol.

What is the fuel pressure idle?

Keep in touch.

Boudy

Blittleton · #3 (**permalink**) 08-08-2004, 04:28 AM

I don't have any bad bends in my fuel lines. I'm getting 5.5 psi at idle. When the fuel pump quits or locks up, it takes 5-10 min. to return to normal. I felt the fuel pump when it quits, it isn't hot. I also don't have a good fuel filter, I'll change that.

I'm running a demon 750 carb and engine is a 351w.

Ron61 · #4 (**permalink**) 08-08-2004, 06:24 AM

Bill,

Which Holly do you have, the blue or red one? Also when you rev the engine while just setting watch your pressure gauge and see what it reads. I had a similiar problem with the Holly Blue pump and talked to a Holly tech about it and he told me the problem as soon as I toldhim what it was doing. That was about 6 years ago and I have never had a problem since. In fact I may put it back as when I get on it the darn thing almost sucks the tank into the engine.

Ron

MrMagoo · #5 (**permalink**) 08-08-2004, 07:54 AM

I had a similar problem. It ended up being my fuel mixture... the symptom feels like fuel cutting off.

I run the Holley Blue. I think for the 750 carbs, thats what you need.

Now that I have the carb tuned, all is well with the Holley Blue.

Boudy · #6 (**permalink**) 08-10-2004, 08:47 AM

Ron: What was the problem?

Boudy

Blittleton · #7 (**permalink**) 08-10-2004, 11:25 AM

Boudy, I replaced the fuel filter and I couldn't get it to duplicate the problem. Sounds like I work on aircraft or something. I hope I found my problem.

Blittleton · #8 (**permalink**) 08-23-2004, 06:42 PM

Still having the problem, found out that the blue fuel pump has systematic problems of my kind. I was told to use a carter fuel pump instead.

Blittleton · #9 (**permalink**) 08-23-2004, 06:43 PM

Still having the problem, found out that the blue fuel pump has systematic problems of my kind. I was told to use a carter fuel pump instead.

Blittleton · #10 (**permalink**) 08-29-2004, 04:24 AM

I emailed Ron61, he told me that Holley suggested that he removed the fuel filter between the tank and the pump, since the fuel pump has a screen it shouldn't be a problem. I removed the filter and went on 10-15 mile scat and no problems as of yet. I'll update soon to let everyone who is interested my findings.

Ron61 · #11 (**permalink**) 08-29-2004, 09:17 AM

Boudy,

Sorry that I never answered your post, but I haven't looked at this thread since I posted on it. Then when I received Blittleton's e-mail it made me think of it. I used the fuel filter that they sent and had it between the tank and pump like I have always did in the past. The first thing the Holly tech I talked to asked me was if I had a filter between the pump and tank. When I told him yes, I used the one they sent, he told me to take it out and throw it away. I asked him about using a different one and he said they have one that is about $7 dollars and it won't screen out anything that the filter screen in the pump intake won't. So I just left that filter out and it has worked great for over 2 years now. I did have to re-adjust my pressure reguator as with the filter it was putting out 7 pounds at idleand as soon as I opened it up the pressure dropped to about 1 pound and it would stumble. After removing that filter and using the pump screen and an inline filter before the carb, I had 14 pounds at my regulator so I had to re-set it to cut the pressure down to the 5 - 8 pounds Holly recommended. I think I set mine at about 7 pounds or just on the high side of that. I have never had a problem with the stumble or seeming to run out of gas since and I have my pump mounted so it is easy to remove the hose from the tank and look at the screen once in a while to see if it is getting any stuff on it.

Ron

moneymanager · #12 (**permalink**) 09-05-2004, 12:51 PM

Boy all this sounds so familiar to me. I just bought my BDR Cobra and withinb the first 100 miles it did the same thing. Just stopped running. The fuel pump simply shut down. After a little while it started and ran again.

I removed the filter between the tank and fuel pump and put a new (different style) filter in after the pump befor going into the mian feed line heading foreward and haven't had a problem since.

I had a guy tell me that it may also be the way Backdraft wired the car without a RELAY on the fuel line circuit. So I am also having a relay installed on the fule pump circuit to prevent any over heating of that power line feed.

"Doc"
in Mesa, AZ

Dennis Kelley · #13 (**permalink**) 09-05-2004, 05:10 PM

Carter Mechanical. Never a problem.

moneymanager · #14 (**permalink**) 09-15-2004, 09:17 PM

Mine stopped again, even after removing the filter and inserting a new one after the pump before the line goes forward.

It appears that mine is vapor locking inside the TANK itself.

I called Reg at Backdraft and he said that since my BDR #13 being an early car has the plastic fuel cel in it which does NOT have a tank vent. This causes some of them to vapor lock.

He said one did it to him onetime and he popped open the gas cap and drove it home. He suggested drilling a hole in the top of the tank and inserting a vent line, routed into the filler neck somewhere.

I personally have ordered a new stainless fuel cel from Backdraft with a vent! I don't like the plastic tank anyway.

I have also noticed that the fuel line up front runs very close to the headers and then in front of the engine.
I am in the process of rerouting the fuel line to the rear of the engine, mounted to the firewall instead. Supplying the fuel to the back of the carb instead of the front of the carb as BDR had it routed. This too should help eliminate vapor locking if that in fact is the problem.

NOTE: the only 2 times mine vapor locked and stopped was while I was ruinning very slow in heavy HOT traffic. It has never stopped while I am running at highway speeds or anytime the whole car is cool with plenty of air movement, even on a 112 degree day here in Phoenix.

Doc