No Fuel Pressure

[avocadotom]

I'm new to my 914 and I'm trying to debug my fuel system. 1972, stock FI AFAICT.

Symptom: fuel at the pump, rail isn't getting pressurized at startup.

I hear the fuel pump start up for a second when I turn the key to the on position, so it may work, but I'm not sure. I've been trying to open the air-flow meter flap, which I've read that I need to do to activate the pump, but I'm not sure I'm moving the right thing. Is this it:
https://m.flickr.com/#/photos/avocado_tom/14472480113/

I'm guessing my next step is to remove the outlet line from the fuel pump to see if anything comes out when I initially turn the key, but I'm looking for debugging guidance...

[TheCabinetmaker]

confusion here. a 1972 car should have D- jet injection, the airflow meter is not in a D-let car, only on L-jet cars. So what do you have for an injection system, D-jet or L-jet?

Certainly check the pump for flow, do not run the pump for long if it is not flowing, gas flow helps keep it cool.

the pump could be hooked up wrong, re-check all connections, make sure tank outlet is not clogged, there is an internal wire mesh filter inside the tank, replaceable by removing the outlet fitting. also of course check the inline filter that is right before the pump, mounted on the lower forward engine fire wall (access near pump).

PS what is AFAICT?

[avocadotom]

Thanks for responding! I honestly don't know what FI system I have. I picked this up as a project that someone else had mostly put back together and I was told that it was the stock engine. I thought I had read that to test the fuel system in the '72 I should toggle the AFM, but I must've gotten mixed up and been looking at the wrong FI manual.

I do know that the pump is getting fuel because I drained the tank (and line) and refilled it and I can see fuel in the line at the pump. I think I replaced the filter already with a new one, but I'll verify.

I know that the pump is hooked up correctly insofar as I hear it power up when the key is first turned on, but I'll verify the hoses are hooked up to the right ports. I'll verify the wires are connected to the right spades too, but I'm pretty sure they are. Are there other things I should check?

And, AFAICT is "As Far As I Can Tell".

[beatnavy]

As mentioned, it seems like you may be confusing D-Jet and L-Jet concepts. If you have a stock '72 FI, it's D-Jet, and the "air flow meter flap" is not a factor. D-Jet fuel pump is primed when ignition is one and you should have fuel at the rail. A couple of questions:

1. Can you take and post a picture of your engine? That may help settle it.

2. Has the car been sitting for some length of time? Residual fuel in tank and lines may have gone to sludge. Your pump may operate, but it's not going to pump tar. May want to disconnect line at fuel filter and see what comes out (if anything).

Good luck!

[avocadotom]

Hi beatnavy,

Several engine photos can be seen here: https://m.flickr.com/#/photos/avocado_tom/sets/72157640042666674/

The engine has been sitting for a while, so one of the first things I did was drain the tank and lines. So I know the new fuel is good. I also know fuel is getting past the filter, as I can see it in the line. Looks like the next thing to check is whether anything comes out of the pump when I turn the key...

Thanks!

[Dave at Pelican Parts]

The component you show in your picture:



is the throttle body.

The D-jet does not have an air flow meter. The D-jet bible can be found here: Brad's '70 914 2.0L . Read and understand it to understand your fuel system better.

Is it possible you hooked up the hoses wrong? The pump should be labeled S, D, and R. The S goes to the fuel filter and then the tank, and is the feed from the tank to the pump. The D is the pressure connection, and it goes to the right-side fuel rail. The R is the return, and it goes to a Y connector that goes to the fuel pressure regulator and also back to the tank.

Is it possible that you hooked up the wires backwards? They shouldn't, if you kept them in the body of the plug, but if they are just plugged in as wires then you can switch them.

--DD

[avocadotom]

DD,

I will check all of the above this weekend when I'm home. (Currently out of town for work) Thanks!!

[avocadotom]

Ok, it looks like the hoses were set up right and that there's flow through the filter. I'm guessing the pump is the issue ... It's not firing up when I turn the key on anymore and the wires are still in their plug, so they should be in right.

[porschetub]

Blocked filter,yep you may have changed it but it may be blocked with old cr#p,your pump should run smooth and make little noise,it not it is worn out or is trying to suck thru a bad filter.