Why am I burning up electic fuel pumps?

I've got a 365" Caddy with an Edelbrock 4 duece intake which doesn't offer me much room for a stock mechanical pump. My second electric fuel pump quit and left me stranded this evening. I just installed a new AC Delco electric (diesel) inline fuel pump this morning. They put out approx. 15 psi. I have a fuel filter then pump then a low pressure Holley regulator set at 4.5 psi.
I drove it to a local cruise 10 miles away. When I got there I had NO fuel pressure even though the fuel pump was running. The tank is mounted at carburetor heigth so the fuel level was even with the float bowls given a full tank which I had. A fellow cruiser ran home and got his voltage meter and I had 14 volts at the pump with the engine running. I have a marine flip top gas cap ***embly welded to the top of my tank which is supposed to be self venting but realzed it is not. I took out the rubber seal and spring off of the cap so the tank could vent. From the cruise I stopped at a friend's house 5 miles away and had 4.5 psi when I arrived. Leaving my buddy's house halfway home I checked the pressure at a light and it showed 4.5 psi. 1/4 mile from my house I was left stranded with NO fuel pressure because my pump died and still had 12 volts going to the pump with the engine not riunning.
I ***ume that my first pump died because the fuel tank wasn't vented and it pumped till it got hot and burned out. Now on my second pump it just quite with adequate voltage going to it and with a vented tank.
WTF I'm very frustrated. I've had the identical setup in 2 other cars with 0 problems using the same pump and regulator?

Any help is appreciated.

 

Well, it looks like the new production AC pumps can't take the reduction of pressure from 15 to 4.5 for long, can they?

Welcome to the wonderful world of "Made in Communist China" quality.

 

Maybe try running a return line so the pump doesn't deadhead. Constantly flowing the fuel through the system should help the pump run cooler. Maybe?

 

My thoughts exactly

 

figured i'd add , use a relay with the pump as well.... brandon

 

Where is the pump mounted?

 

I use to work for chrysler corperation when carburated vehicles were sold,on the rwd 5th ave 318 police cars they used a fuel filter that had line with a fixed orificebuilt in that blead press to the tank.A return as stated before but a metered one.They had a y that put a 1/4 inch line to the side of the filter and ran it back to the tank.I just ran into a simular situation and im going to try this approach but instead of running a line back to the tank im going to tee it behind the electric fuel pump inlet.This should also take any pressure left on the needle and seat when the car is shut off.Hot soak drivability problem,fuel with high ethonol has a real low boiling point.Good luck,let us know how you make out.....Gary

 

Make sure you have a good filter between the fuel tank and the pump.

Make sure you hve a good ground for the pump. Electric pumps need a good ground as much or more than supply voltage for long life. Poor grounds can make the electric motor run very hot and fail in a short time-usually not as quick as you are experiencing though.

Where are you able to check the pressure? At the pump or by the carbs? If you have good pressure at the pump but not at the carbs, youhave some sort of blockage in the lines somewhere. It could even be something that floats and only blocks the line sometimes. I had a similar problem when I tried sealer in my fuel tank. The sealer did not stick to the tank and would float around a block the filter inlet sometimes but not always.

Lastly (or first) I would make sure the diesel pump is infact compatable with gasoline. I think diesel fuel has a bit more of a lubrication property to it than gasoline?

 

You may try a Holley Blue pump. They have 7 psi pump and a low GPM 4.5 pressure pump. As with carb selection...More is never better.

V

 

I still have my mechanical fuel pump on my caddy with 4 X 2 's but on my sbc with 3 X 2 's I had the same problem. I quit buying the higher priced elect fuel pumps and bought one of those cheap ones and never had another problem. Do you have it grounded really good ? S****e the paint off really well where its mounted and grounded.

 

A good bet (probably same filter) to look up at the parts store is the '82 Dodge Omni 2.2L carb'd model's filter, has the same setup and is easy to find.

I also wonder if the diesel pump doesn't get enough lubrication from gasoline? Carter makes excellent electric rotary vane pumps, I'd look there.

 

If you check the plumbing on most "new" fuel systems w/ electric pumps, they all have a return line to the tank. Yes, these are high pressure applications - however, the same principal applies. A deadheaded electric pump is a recipe for problems...seen it many, many times. Guys and gals, IMHO, unless there is no other solution, electric pumps should be avoided to minimize being parked on the side of the road. Latest incident for me...had to lay on the side of the interstate at GG Columbus and work on my buddy's "show car" w/ electric pump ... nice thing about it... I love to poke fun at him every time that fancy trailer queen breaks

Re the Holley "blue" pump - both the blue and red Holleys are racing application pumps - no help for you there... seen my share of those puppies fail too.

 

I run a Holley Blue pump and use a good Holley regulator (the kind with the allen set screw for adjustment) and have had really good luck with it. The pump is noisy, but other than that it works perfectly regulated down for use with 4 Strombergs.

If you're not married to the AC pump, you might try switching to a Holley. I'm going to try a Holley Red pump on the car I'm building now....should still have plenty of volume. And the return line may not be a bad idea either.

 

have you looked into the new walbro on demand pumps? they have applications that can flow plenty of fuel,and at the pressure you need. the on demand pump only run when you need fuel. remember the old time AC pumps? thats who used to make them. they have gotten rid of the old problematic breaker points and made them solid state now too. i'll see if i can find my link.

 

ok go to this link, http://www.autoperformanceengineering.com/ now click on the new fr series in the side bar and scroll down to the frb and the frd series. they are the same but one can flow more fuel then the other. i don't know which one you need.

 

And a note to add to this on the regulator. Holly makes 2 types Low pressure 1-4psi and a higher pressure one that is 4.5-9psi........Rochester and Strombers dont need that much pressure! The lower psi reg. is fine with multiple carbs.

 

yes i run one on my little 86 excellent regulator for carb use. the 1-4 psi have had no problems and it's rebuildable. the only difference i know of between it and the higher pressure one is the spring.

 

I'm measuring the pressure at my firewall just before the distribution block. The pump is mounted beside the frame rail under the driver's seat.
The regulator is a low pressure Holley unit. I ran an identical setup for 2 years on a stock flathead with a single carb. Same pump, regulator, filter, fuel tank ets. with 0 problems. I just sold a 38' Willys pick up with a 350 sbc single 4 bbl Holley that had the same identical setup for 10 years and had 0 problems with it. Perhaps I just lucked out on those 2 applications? I am by no means married to the AC Delco pump so I think I'm gonna try a different manufacturer and see what happens.

 

Aren't electric fuel pumps set up to "push", and not to "pull" fuel??? Maybe mounting that far forward isn't helping either...

 

yup!!

And the blue holley is a street pump, red is low end race pump.

Put the pump as close to the tank as possible, and as low as possible, I would run a full loop byp*** type regulator if you are trying to lose that much pressure. Holley pumps will put out 14-16 psi, regulate that down to 3-4 psi and the pump is seeing a load of 10-11 psi constantly. With full loop byp*** the pump sees no load, the excess pressure is return to the tank and everything will live a long time.

 

I work on attempting to get space for a good old mech pump. I got tired of being dead on the road with electric pumps. Mech, no problems.

 

The line of Carter electric pumps are the best pumps for a street application.

They're not only quiet but they last forever too.

You'll burn up a lot of Holley pumps before your Carter pump ever gives up.

 

try a company called racepumps mechanical but excelent design

 

I just got back from driving around all day after installing a Mr. Gasket 4-7 psi electric pump from Autozone. I completely understand the return line thing on the AC pumps that I tried. Its just that I've had the same setup on 2 other vehicles which worked really well, for 10 yrs. on 1 car before selling it.
All the help is greatly appreciated

 

I was glad to see the truck show up at my house, and maintaining fuel pressure. Kirk has had all the luck with this build, and I dont mean good luck either. If it could go wrong, it did.

Time to drive the hell out of it now.

Here is a pic from a cruising friend Mike, from the Saturday evening cruise in Grand Blanc Michigan. The first truck is mine, the one behind it, is Kirk's '34, and then Mike's cool little Allstate (Henry J).

 

I'll jump on the band wagon, you need a by-p*** regulator and a return line.

 

Are you running a relay? It would still read 12v but if you are getting the power from a bad line not enough amps, you'll burn up the pump or the place your getting the power from.

 

As everyone said.

1) Filter close to tank fuel pump right after it.
2) Filter after pump to regulator and byp*** return off to tank.
3) Use proper sized line to deliver fuel and return it. If in doubt oversize it. To small does not help.
4) Use the very best quality parts and pieces you can find not the best you can afford. (this has been proven time over in lost cars to fires.) If you have to cheap out do it in the interior or radio.
5) Power and ground sources must be as perfect as you can make them.
6) Secure everything like it was going to be used to hoist the car. Use hold downs and proper routings. (like away from exhaust!)
7) Just think 10 feet tall and bullet proof. Plan it out.

I know it sounds like overkill and it may not lend to "traditional" but you cannot get the best out of the system using 5/16 line (with much smaller fittings) and running a deadhead pump system to a 3-400 Hp motor and expect top performance of the motor or the system.

There are good diagrams from every manufacturer but look at what the folks who do fuel delivery for a living to see the ideal set-ups.

 

Listen to the pump, solinoid/diapham pumps are designed to deadhead at a pressure determined by the spring they put in them. They have to be mounted lower than the pickup in the tank. Then they should pump rapidly untill preset pressure is reached in the line, then pumping will slow to 1 pulse every 20 seconds or so. If it keeps running fast, 1 Float stuck in carb and your filling the engine with gas. 2. Fuel is running on the ground. Or 3. You have an air leak from the pickup to the pump and it is ****ing air. Hoses on barb fittings without clamps, split hoses, cracked filters, loose threads. If these pumps get the least little bit of air in them, they run like nuts untill it mixes with the fuel going out. They called it Vapor Lock. If it don't stop pumping, something ain't right. I don't think a byp*** will help, unless it flushes the air out of the pump.

buflochp

Oh Yea, it can also happen if pump is to close to the exhaust pipe and causes gas to vaporize in the pump.

Good Luck