HELP! Fuel Problems!, Fuel problem Troubleshooting Options

[clay914]

Hello all, I'm Clay in Loveland, CO. I just bought my first 914 on the 5th (IMG:style_emoticons/default/biggrin.gif) . It's a 1972 1.7 FI with 91K on the odometer. The previous owner had bought it 2 years ago and had only put about 2 thousand miles on it. My Father and I are familiar with general mechanics having done quite a few restorations on other vehicles, plus my father owned a 914/6 before he had me...bummer I know. I digress....back to the car.

The body is straight, with very little rust (some in typical places but easily fixed), the motor seems to be a bit cold blooded and wants to surge a bit when it is cold but after about 5-10 mins it evens out and runs well. I have noticed that it seems a little weak in the 2000-3000 RPM range.

Now the problem......

After owning and enjoying my new car for 24 hours (no joke) my baby wouldn't start. (IMG:style_emoticons/default/sad.gif) Having removed the oil bath filter and using starter fluid proved that I didn't have an ignition problem but a fuel problem. I removed the plug in one of the fuel rails ,turned the key and no fuel and the same before and after the fuel filter in the engine bay. After thinking that over for 10 seconds I realized that when the pump was moved from the engine compartment to the front that whom ever made the adjustment didn't move the filter between the tank and the pump, I will fix this. Having done this troubleshooting I can only believe that the problem lies with the fuel pump located in the front. It hums for a second once the key is turned then nothing which tells me it is on but not pumping. Is there anything else that I can check? Is there a way to test the pump? Please help.

[Spoke]

(IMG:style_emoticons/default/welcome.png)

The fuel pump running for 1 second when the key is turned on is normal to prime the system.

Once you turn the key to start the car, as the engine is turned by the starter, contacts in the lower part of the distributor tell the fuel injection (FI) brain which cylinders to fire their injectors.

These contacts in the distributor also tell the FI brain that the engine is turning and the FI brain will run the fuel pump. This is done in case of accident where the engine stops so the fuel pump will also stop.

That being said, you can test the fuel pump by grounding pin III of the FI brain connector on the relay board. The relay board is positioned behind the driver in the engine compartment. Below is a link to a pic of the board. The FI brain connector is in the bottom left corner and has pin designations I, II, III, and IV.

Relay Board on Pelican Parts

Remove the connector and ground pin III. This will cause the fuel pump to run continuously when the ignition is turned on and you can test your fuel pump this way.

If the fuel pump is not turning on when the engine is being started, check the contacts and connector on the distributor. You don't have to remove the distributor cap to see the connector. The connector comes out of the bottom of the distributor.

[swl]

So you are getting 'hum' for the one second but no fuel movement?

I'm wondering if the pump is 'stuck'. Kinda hard to explain sounds but does that 'hum' sound like the pump is turning or just labouring.

Is this a 3 port plug or 2 port?

I think I would do some really basic tests.
Lift the supply line - any gas there? (sediment in tank blocking the strainer)
If there is gas coming to the pump is anything coming out the delivery line? (Tap with hammer and try again)
If a three port is gas coming out the return line. (stuck bypass valve)

[Rotary'14]

You should verify that you have fuel. This can be done really easily with a flashlight (not a match!) and looking into the filler of the fuel tank. You might even see if there is crud in your tank,, which can plug a fuel filter pretty easily.

-Robert

[avidfanjpl]

Might be a really clogged filter. We all have had that happen. Be careful that a line is not kinked as well. Change the filter AFTER clamping the fuel lines into and out of the filter. If there is rust in the tank, and the fuel sock is torn or missing, you will have rust that has to be removed, and that typically mean pulling the tank and getting it cleaned or doing POR15 tank treatment yourself.

If there is no fuel to the rail, either the pump is bad, especially if it is a 3 port, or you have plugged lines.

If you are getting the pump to work when you turn the key but don't start it, then you have a plugged hose.

Or the pump has a bad valve in it.

Go back and see if you can get fuel into a can with someone turning the key for just a split second. The hose off a 3 port is supply to the engine will answer the question (I think it is the port near the aluminum adjuster cap, but check, because I forget without looking, but BE CAREFUL.

GAS work should be done OUTSIDE, not in a garage with a gas pilot water heater.

POR 15 is amazing stuff, but some here dislike it for anything but fuel tanks.

Good luck,

John

[914 shifter]

disconnect fuel line at the pump.one is a return line the other provides fuel.i pinched mine with some hemostats disconnect then open line fuel should flow from tank if not you have no fuel or clogged line. (IMG:style_emoticons/default/cheer.gif)

[clay914]

(IMG:style_emoticons/default/welcome.png)

The fuel pump running for 1 second when the key is turned on is normal to prime the system.

Once you turn the key to start the car, as the engine is turned by the starter, contacts in the lower part of the distributor tell the fuel injection (FI) brain which cylinders to fire their injectors.

These contacts in the distributor also tell the FI brain that the engine is turning and the FI brain will run the fuel pump. This is done in case of accident where the engine stops so the fuel pump will also stop.

That being said, you can test the fuel pump by grounding pin III of the FI brain connector on the relay board. The relay board is positioned behind the driver in the engine compartment. Below is a link to a pic of the board. The FI brain connector is in the bottom left corner and has pin designations I, II, III, and IV.

Relay Board on Pelican Parts

Remove the connector and ground pin III. This will cause the fuel pump to run continuously when the ignition is turned on and you can test your fuel pump this way.

If the fuel pump is not turning on when the engine is being started, check the contacts and connector on the distributor. You don't have to remove the distributor cap to see the connector. The connector comes out of the bottom of the distributor.

Jerry,
Thanks, Jumped the III and pump ran as it should. disconnected line down stream and no fuel. Plenty of fuel to pump. My guess bad pump. I have ordered a reman from pelican but it is back ordered. Any suggestions for alternate source of this expensive beauty?

Thanks

[clay914]

So you are getting 'hum' for the one second but no fuel movement?

I'm wondering if the pump is 'stuck'. Kinda hard to explain sounds but does that 'hum' sound like the pump is turning or just labouring.

Is this a 3 port plug or 2 port?

I think I would do some really basic tests.
Lift the supply line - any gas there? (sediment in tank blocking the strainer)
If there is gas coming to the pump is anything coming out the delivery line? (Tap with hammer and try again)
If a three port is gas coming out the return line. (stuck bypass valve)

Thanks,

Diagnosed bad pump since no fuel downstream. Plenty of fuel to pump. Pump is out of car but if it is just a stuck valve can it be corrected by me? somehow?

Don't really want to spend for a reman but probably should since I am this far.

[clay914]

disconnect fuel line at the pump.one is a return line the other provides fuel.i pinched mine with some hemostats disconnect then open line fuel should flow from tank if not you have no fuel or clogged line. (IMG:style_emoticons/default/cheer.gif)

Shifter, Thanks. I think I have a bad pump.

[clay914]

You should verify that you have fuel. This can be done really easily with a flashlight (not a match!) and looking into the filler of the fuel tank. You might even see if there is crud in your tank,, which can plug a fuel filter pretty easily.

-Robert

Robert, Thanks. I had fuel no out put so I have ordered a new pump.

Thanks

[clay914]

Might be a really clogged filter. We all have had that happen. Be careful that a line is not kinked as well. Change the filter AFTER clamping the fuel lines into and out of the filter. If there is rust in the tank, and the fuel sock is torn or missing, you will have rust that has to be removed, and that typically mean pulling the tank and getting it cleaned or doing POR15 tank treatment yourself.

If there is no fuel to the rail, either the pump is bad, especially if it is a 3 port, or you have plugged lines.

If you are getting the pump to work when you turn the key but don't start it, then you have a plugged hose.

Or the pump has a bad valve in it.

Go back and see if you can get fuel into a can with someone turning the key for just a split second. The hose off a 3 port is supply to the engine will answer the question (I think it is the port near the aluminum adjuster cap, but check, because I forget without looking, but BE CAREFUL.





GAS work should be done OUTSIDE, not in a garage with a gas pilot water heater.

POR 15 is amazing stuff, but some here dislike it for anything but fuel tanks.

Good luck,

John

John, Thanks.

From all the great help I am pretty sure the problem is the pump. Great time to pull the tank and replace some lines while I wait for the back ordered pump.

[clay914]

Thanks to everyone that has responded to my question. This is great I hope I can help someone when I am more knowledgeable.

Clay

[swl]

The 2 port pumps used in the later cars are much less expensive than the 3 ports. They work just fine in a front location.

[TheCabinetmaker]

The 2 port pumps used in the later cars are much less expensive than the 3 ports. They work just fine in a front location.

(IMG:style_emoticons/default/agree.gif)

[clay914]

The 2 port pumps used in the later cars are much less expensive than the 3 ports. They work just fine in a front location.

Thanks, I thought of a 2 port but what is done with the return? Just connect direct to tank? If so this would be the way to go.

[swl]

Yup.

Near as I can figure out the R port is used to bleed off air during priming so it doesn't go down the fuel rails. In normal operation it is closed. With the pump up front and at the bottom of the tank air is not a problem.

It also has a second stage that that seems to bleed off overpressure but again a bit of over engineering.