Any hidden trick when installing new Fuel Pump?

[estevaf]

Hi there!

Firstly, Merry Xmas to you all.
I was thinking about my MII today and about the new fuel pump I have to install.

The thing is. This is going to be the third new pump I am installing.

When I bought the car, it had an adapted fuel pump.
Then, I bought a new one on ebay. Run nicelly but insisted on stopping after an hour or so of driving (maybe overheating).
Then, I bought a second one, this time at Rockauto. Even worse.
I ran for a couple of hours in three days and broke.

I was wondering, before I install the third one, if I am doing something wrong or if is just bad luck.

I am taking the pumps and bolting them on. After that, just start the car and it seems to work fine. That's is all.

Any clue? Any special procedure that I should pay attention to?

 

[eaglecap]

I would check out the other possibilities. Float sticking, plugged line or filter, etc. I assume this is the standard mechanical fuel pump.

 

[LILCBRA]

Also check the routing of the fuel lines, could be vapor lock. Good luck!!

 

[estevaf]

Yep. This is the standard mechanical pump (old fashioned, isn't it?)
I tryu to keep the II as original as possible.

The previous pump was working but it used to stop working after getting hot...

I installed the new pump with the new carb. It ran OK for a while and then, not start again.
I checked the fuel and there was no gasoline coming into the carb (before the filter)

I then removed the pump and checked it. It was blocked. It seems that the internal valves were defective. I even tried to put compreessed air on it but it did not went through...

Weel, I am waiting the new pump to arrive. I hope it will work now.

I am thinking about filling it with gasoline before installing so that I can avoid the extra stress on the pump when I install it...

Do you guys happen to know if there is any need to install a spacer between the pump and the engine?

Thanks guys!

 

[Vegas Stang]

I have no idea what the cause is but I had the same problem of burning up pumps. I switched to Holley High performance mechanical and have not had a problem since. Been about 8 months now. I still have fuel starvation problems but at least do not burn up the pumps. I will be dropping my tank this winter and checking / replacing pickup.

 

[eaglecap]

The last fuel pump I replaced was during a rebuild of my 75 that had set for several years. Before I pulled the engine I tried to start it, no fuel getting to carb. I thought I had a plugged fuel line and put compressed air in at the tank end. Dumb!!! That resulted in blowing out the diaphragm in the fuel pump so I had to replace it. (Turned out to be a plugged filter) I would not use compressed air on the fuel pump.

The new pump had a spacer and a different size actuator/plunger. I did not use either. Installed the new pump with the old plunger and it worked just fine. I think this pump was designed to use on several different cars.

 

[estevaf]

I have no idea what the cause is but I had the same problem of burning up pumps. I switched to Holley High performance mechanical and have not had a problem since. Been about 8 months now. I still have fuel starvation problems but at least do not burn up the pumps. I will be dropping my tank this winter and checking / replacing pickup.

My engine is a stock V6 (no v8s in 74). Any idea if I would be to find those hi performance pumps for the V6 171cid...

 

[estevaf]

New Pump Installed

Hi, I have just installed the new pump, and the engine is running ok (despite some trouble with the choke adjustment in my new carb).
When I got it I realized that it was slightly different from the other I had bought in the past. I believe that it is the model for the '76 on, where the inlet and outlet are in opposite sides.

Let's see if it will last.

Thanks for all the inputs.

 

[Wart]

That resulted in blowing out the diaphragm in the fuel pump

Lucky you didn't rupture the fuel tank.


If the car stops running I would first check the fuel pick up in the tank, the screens tend to disintegrate allowing the passage of contaminants, and scuzz tends to plug intact screens.

 

[Dano78]

For some stupid reason the V6 fuel pumps have problems. I've pulled engines before that were running and re-installed them and suddenly the pump doesn't work. I would replace it and it'd be fine. The last couple of V6s I changed out, same problem again, I decided to prime the pump or pour fuel into the inlet and outlets of the pump. I know that sounds stupid and shouldn't have made a difference, but it sure did. It worked. I did this at least 2 other times just to make sure I wasn't crazy or seeing things. So there is something weird going on with the V6 pumps anyways. I can't explain it.

In your case though, you may have other problems looming. I'd definately look over the rest of the fuel system. Any pinhole in any steel or rubber piece or connection may not be enough of a hole to cause a noticable leak (because gas vaporizes so quickly) could also cause loss of prime to the fuel pump. Had this happen on my brother's V8 Maverick.

Seen improper gas caps stop pumps from drawing fuel from the tank. Plugged vents/charcoal canisters etc.. not allowing the tank to vent are known culprits too.

 

[a351Must2]

Man, I'm really late to this post, but thought I'd share that one of my worst/first mechanic experiences in my life was replacing the fuel pump on my '74 V6 Mustang II right before work ... ... ... ...