Going to electric pump

[siteunseen]

I hardly ever drive my 240 but when the weather is so nice I can't stay inside, and "all work and no play makes Jack a dull boy".

So I've driven it some but after sitting so long I think the mechanical pump must have dried up and cracked the diaphram or whatever makes it work. Anyhow it died on me yesterday. Lucky me has a good neighbor because he has such a good neighbor. I called him up and told him where and what to bring me so I could get the car off the side of the road. An old low pressure pump I've had for years to transfer gas from here to there and my tool bag. Oh yeah my best testing tool, about 15ft of speaker wire with alligator clips on both ends. Didn't take long to hook it up and get it home. Now I'm researching trying to decide if it's possible to have both mechanical and electric. Pretty sure it is, I'll figure it out.

Long story short...my thinking is the mechanical pumps don't like being left alone for very long. 

[texasz]

It is possible to have both electric and mechanical fuel pumps on a 240Z.  There is even wiring already in place for the electric pump in the rear near the fuel pick up/sending unit.  My 240Z had both when I bought it.  I'm making several updates to things and replacing many old items including the electric fuel pump (the one that was there was not wired using the stock wiring and what was run was attached with a twist and some electrical tape...can you say fire hazard!).

 

To select your electric fuel pump there are some threads on here that discuss different pumps...the largest complaint seems to be that some are loud.  To help with the noise, no matter what one you get, use rubber isolators when mounting.  😉

[Racer X]

16 minutes ago, siteunseen said:

I hardly ever drive my 240 but when the weather is so nice I can't stay inside, and "all work and no play makes Jack a dull boy".

So I've driven it some but after sitting so long I think the mechanical pump must have dried up and cracked the diaphram or whatever makes it work. Anyhow it died on me yesterday. Lucky me has a good neighbor because he has such a good neighbor. I called him up and told him where and what to bring me so I could get the car off the side of the road. An old low pressure pump I've had for years to transfer gas from here to there and my tool bag. Oh yeah my best testing tool, about 15ft of speaker wire with alligator clips on both ends. Didn't take long to hook it up and get it home. Now I'm researching trying to decide if it's possible to have both mechanical and electric. Pretty sure it is, I'll figure it out.

Long story short...my thinking is the mechanical pumps don't like being left alone for very long. 

My race Z has not had a mechanical fuel pump since I bought it in 1989. That was the first thing to go way back when.

The only trouble I have ever had was when one pump (the car has a fuel cell with two sumps and two pumps, not something needed for street driving) died during a race. The engine ran lean while cornering and detonation caused the crankshaft to break.

So go for it Cliff.

Ditch the mechanical pump and all the troubles they have.

 

 

[siteunseen]

My only unanswered question that I can't find definitive answer to is run the electric pump out of the tank then through the mechanical like OE with no regulator or safety switches. Seems like if I flipped the car over the mechanical pump would be the dead end but it runs off the cam so no safety switch needed.

More reading to do.

[Racer X]

36 minutes ago, siteunseen said:

My only unanswered question that I can't find definitive answer to is run the electric pump out of the tank then through the mechanical like OE with no regulator or safety switches. Seems like if I flipped the car over the mechanical pump would be the dead end but it runs off the cam so no safety switch needed.

More reading to do.

I use an oil pressure switch to operate a relay on the race Z. If the engine is shut off, the fuel pumps stop. 
 

The fuel pumps get power when the key is in the cranking position, then continue running  once the engine fires up and oil pressure is present.

[SteveJ]

12 minutes ago, Racer X said:

I use an oil pressure switch to operate a relay on the race Z. If the engine is shut off, the fuel pumps stop. 
 

The fuel pumps get power when the key is in the cranking position, then continue running  once the engine fires up and oil pressure is present.

A 78 oil pressure sender can be adapted for this: https://www.rockauto.com/en/moreinfo.php?pk=488596&cc=1209260&pt=4588&jsn=830

You can get the female T connector from Vintage connections and wire the gauge connection to a female bullet to connect to the engine harness.

According to the 78 wiring diagram, the horizontal pin is for the gauge, and the vertical pin would be your switch.

You can also install an inertia switch like this and put it under the dash. https://www.amazon.com/gp/product/B07RBK4873

The trick with the one in the link is that you need to swap one of the wires from the normally open to the normally closed position. I helped a friend install one of these in his track car, and he has not experienced accidental activation of the inertia switch.

 

[Racer X]

10 minutes ago, SteveJ said:

A 78 oil pressure sender can be adapted for this: https://www.rockauto.com/en/moreinfo.php?pk=488596&cc=1209260&pt=4588&jsn=830

You can get the female T connector from Vintage connections and wire the gauge connection to a female bullet to connect to the engine harness.

According to the 78 wiring diagram, the horizontal pin is for the gauge, and the vertical pin would be your switch.

You can also install an inertia switch like this and put it under the dash. https://www.amazon.com/gp/product/B07RBK4873

The trick with the one in the link is that you need to swap one of the wires from the normally open to the normally closed position. I helped a friend install one of these in his track car, and he has not experienced accidental activation of the inertia switch.

 

I considered the Ford inertia switch, but never implemented it. Good idea though, especially if running fuel injection, given the higher pressure and flow rate.

[qz16]

I think I understand the benefits and the desire to run either an electric fuel pump with or without a mechanical pump. 

In your original post you mention that you don't run your 240z frequently and that you thought the diaphragm may have dried up and caused the pump to fail or not perform as it should.  Sorry if this is off topic.  During the restore of our car there have been long periods where the car has not been started.  I am running a mechanical pump without the benefit of an electric.  I have a fuel filter before the pump.  I too was having issues starting after the car sat for a while.  After sitting for a period of time the fuel filter bowl was always empty.  At first I did not think much of this, but that changed with time and effort.  Since the car is in the process of being restored most of its parts are new or restored.  New fuel pump, new hoses and clamps, restored fuel tank, restored SUs, restored plumbing from the pump to the SUs., ... etc.  I read that many of the cardone fuel pumps had issues so I purchased another pump, but it too was not able to suck fuel from the tank.  I got to be an expert at filling fuel bowls by hand, to get the car started.  I was thinking that my fuel pump was not strong enough to pull the fuel the distance from the tank while it was cranking and that it was taking too long to crank the car to fill all the lines and the fuel bowls. A friend suggested that there was an air leak that was causing the system to lose its vacuum, and that the tell tale was the fuel filter bowl being empty after the car sat for a while.  He talked me into checking to make sure that the right size (diameter) hoses were everywhere.  Sure enough I did have some that were a bit larger than they were originally.  While I never really proved that the diameter of the hoses and clamps was the issue, the fuel filter bowl now is able to stay full even after the car sits for months.  I believe if I checked the fuel pump that there would be fuel in the pump keeping the diaphragm wet.  Anyway, I was considering going to an electric pump but forgot about it after my issue was resolved.  Don't get me wrong electric fuel pumps are great, a little noisy sometimes, but pushing fuel at a constant rate is beneficial.  Really like Racer X's and Steve J's safety solution.

Edited October 11, 2021 by qz16

[siteunseen]

My car used to take awhile to crank but my floats were way shallow. Now that they're right the filters stay full and it cranks on the 3rd try everytime after sitting for a month or 2.

I've got to find out if the mechanical pump allows fuel to pass through when it's not operating. Seems like it would so I need a safety someting or another. I need to figure the cost and effort of the oil sender vs inertia switch.

I'm thinking there may be away to have both pumps and only use the electric one when the other one goes out but then why even waste money on another mechanical pump. I've got a couple of block off plates and my car is not stock anyway.

OR...go down the road and spend $35 for a new mechanical pump. The one I have now just went out after 6 years.

 

Edited October 11, 2021 by siteunseen

[Racer X]

1 hour ago, siteunseen said:

My car used to take awhile to crank but my floats were way shallow. Now that they're right the filters stay full and it cranks on the 3rd try everytime after sitting for a month or 2.

I've got to find out if the mechanical pump allows fuel to pass through when it's not operating. Seems like it would so I need a safety someting or another. I need to figure the cost and effort of the oil sender vs inertia switch.

I'm thinking there may be away to have both pumps and only use the electric one when the other one goes out but then why even waste money on another mechanical pump. I've got a couple of block off plates and my car is not stock anyway.

OR...go down the road and spend $35 for a new mechanical pump. The one I have now just went out after 6 years.

 

You may also want to change the oil. When mechanical fuel pump diaphragms fail the fuel can get passed the broken diaphragm and go into the crankcase.

[siteunseen]

Thank you Racer! It needs changing too.

I'd forgotten how much that car means to me, all the time and money to get it where it's at now. Then I was scared to drive it with these idiots around here. So it sat under cover for 5 years, only driven about 1,000 miles.

I can't stand it when something doesn't work so I took the chicken $^!# route and drove across town and bought another $35 mechanical pump. Started right up!

I've got to my affairs in better shape before I do the switch to electricity. End of the year, property taxes, homeowners ins. then Christmas presents.

I will drive it more now for sure. I've got a great Hagerty's policy on both of them.

It's like a kid I guess, can't keep them inside forever.

Thanks for the replies. I know what to do now.

Cliff

[SteveJ]

If you trust it enough for a 3 hour drive up this, I can help you with installing an electric fuel pump, Cliff. I have a lift and all of the tools to do the job right.

Heck, you could bring the dog, too. The wife and I like 4 legged guests. Our old girl might ignore your dog, though. She's pretty much to the resting most of the day stage in her life.