L.J.,

Here are my test results on the relay socket, ignition in run(dash lights on) probe clip to ground.
86- light on
87a- light on
87- light OFF

Test with probe clip to positive on 85- light is on

I printed off a schematic and will run continuity on the ignition switch and report back- hopefully yet this evening.

Thanks,
Rutager

Ignition switch continuity tests- new switch 964.613.012.00. Old switch-no number

One clip on 30

Off: continuity to p

First position: continuity to X and R

Second position(run?)continuity X,R and 15

Start position continuity R, 15 and 50

I looked at the schematic and can't understand what positions relate to which wire, anybody know?

Thanks,
Rutager

Okay, let's take a step back and confirm some things.

Your test, above, confirms that the relay is wired correctly and, most important, the circuit to the starter from the ignition switch is correct up to the relay--it is powered only when the ignition is in the start position. Remember, this wire to the relay is a branch of the wire that feeds the starter solenoid from the ignition switch. Also, the relay appears to be correctly grounded by the air flow sensor (socket 85), which has influence on the running of the fuel pump with the engine not running.

However, your earlier post indicates your have power at the solenoid with the ignition in the "run" position. Am I correct on this? If so, this creates a puzzle. If the branch of the yellow wire that goes to the starter is somehow getting an electrical feedback along its path, it would show up at the socket of the relay unless the solenoid wire has been completely disconnected from its correct path back to the ignition switch (think 14-pin connector.)

An alternative is the relay itself is somehow connecting terminal 87 (starter) with 86 or 87a, internally. Have you tried replacing the relay with a known good one? If not, please do so and see if you get a change in the symptoms.

One other simple test you can run, using your test light at the relay socket. Run the test for a ground at socket 85 one more time, and this time lift the plunger inside the intake. Does the test light go out? (Run the test with the ignition off as there is no need for the fuel pump to run.) If the light goes out, then your plunger and air flow sensor switch are operating correctly.

In your testing the heater blower switch is off right? They do some load reduction by using the starter solenoid coil as a ground.

Rick, yes the blower is off.

L.j.,

When I did the tests to the relay socket, I had the yellow wire off of the solenoid, otherwise the starter would have been running. I double checked the 14 pin and it sure appears to be properly lined up and seated.

Should I hook it back up and redo the relay socket tests?

Can anyone confirm that the ignition switches are switching the correct loads?

Thanks,
Rutager

Having the yellow wire disconnected from the solenoid tells you two things:

1) The relay socket (87) from the start circuit of ignition switch is not getting power from the ignition switch in the "run" position, which is normal.

2) There is no electrical feedback into the yellow wire along its path to the solenoid either, otherwise you'd get a light on during your test and you didn't.

I'm beginning to suspect the relay itself for two reasons. First, you posted that the fuel pump runs with the ignition in the on position and the engine is not running. Second, you posted that the starter motor also runs as soon as you turn on the ignition.

Try the following tests. Leave the solenoid disconnected and put in the fuel pump relay. Turn on the ignition to run.

1) Does the relay "click" every time you turn the switch on and off?

2). Does the fuel pump come on as well?

Reconnect the wire to the solenoid and remove the relay. Turn on the ignition.--nothing should happen with regard to the fuel pump or the starter. Now, turn the switch to the "start" position. Does the starter begin to crank and does it stop when the switch returns to "run?" It should.

Reinstall the relay and repeat the test. If the pump and starter both come on as soon as you put the switch into the "on" position, your relay is faulty as that's the only variable left that allows power to the solenoid. Replace the relay with a known good one (or even swap in a black one for a test ) and see if that solves the issue.

L.J.,

Thanks for the next set of tests, between work, walking the dog and mowing the lawn, I didn't get to the car tonight- I have tomorrow off, so I'll try all of these and report back.

Rutager

I edited the tests as you posted. Please check the post again before running the tests.

It is possible to get a bad new part. Test with one you know is good.

L.J.,

BRAVO and THANK YOU!!

Indeed it was a bad relay; I replaced the red one(only a few years old and made in China) with the black one for the horn and before I reconnected the yellow wire to the solenoid, I turned the ignition to run and no noise from the pump/injectors, then hooked up the yellow and it started only when I turned it to start!

Thanks again for taking the time to walk me through the tests and increasing my and others knowledge.

Sincerely,
Rutager

My pleasure, but the most important thing is that you solved your problem and also let others know how your odd symptoms led to a faulty relay. Good luck on all your endeavors--911-wise and otherwise:D.

BTW, be sure to get a new red relay for the fuel pump asap.

L.J.,

Red relay was ordered from our host minutes after I got the problem solved.

Thanks again,
Rutager

Hi Rutager,
My 77 911S is showing the same problems. Do you have a part number for the red relay you replaced? Thanks...

911.615.108.01