1980 SC engine turns, doesn't start

[Wout_RS]

Hi guys,

I've removed the alarm system that was sitting in my car. I didn't had any key to (de)activate it, so I removed it as it's dead weight to me



Since I removed it my engine won't start.
The engine turns when cranking but won't start.
I hear the fuel pump turning, and it's sparks.

I've measured the battery: open circuit 12,49V, loaded 10,09V.
So it isn't due to a low battery.

When I crank there's a red light in the gauge of the oil.
What does this mean? I can't find it really out in the bentley.


Only thing I need to remove from the alarm is one wire that is running under the gear lever and parking brake. But i need to remove all the carpet to see were it's running to. But the actually wire is cut of from the fuse box and actually alarm wiring.
Maybe this one wire can block all of the functions?

Anyone has some suggestions were to search further?

[Flat6pac]

Lift the airflow sensor under the air filter with the key in on position for a couple seconds. This should run the pump to charge the fuel system. If you have spark, you should get momentary ignition.
You pulled the factory alarm? Or just an aftermarket?
Does the weight reduction make you a better driver or the car handle better?
Bruce

[Wout_RS]

Hi Flat6pac,

did already remove the air filter and lifted the airflow sensor.
But this didn't help.

I removed the aftermarket alarm, because it looked like a real mess in the trunk.
And I didn't receive the keys to activate it.

[Srwilliams]

Originally Posted by Flat6pac

Lift the airflow sensor under the air filter with the key in on position for a couple seconds. This should run the pump to charge the fuel system. If you have spark, you should get momentary ignition.
You pulled the factory alarm? Or just an aftermarket?
Does the weight reduction make you a better driver or the car handle better?
Bruce

Is this the Bruce that use to be up here in the Delaware/Baltimore/DC area before moving to North Carolina. If so, this is your old friend Charlester in DC. Just saying hello and getting ready to move to North Carolina

[Wout_RS]

Anyone?

Our should I start looking at the injection system?

[CCM911]

Did you check the fusebox up front in the frunk? A lot of these alarms had wiring that ran to the fuse for the fuel pump, which disabled it to prevent the car from being started. Also, did you have to resolder any wires on the ignition switch? We'll need some more info here.

[CCM911]

Originally Posted by Flat6pac

Does the weight reduction make you a better driver or the car handle better?
Bruce

Those are not reasons for removal. Rermoving an aftermarket alarm system is done to limit things that may go wrong in the future. Very wise of the OP to do so.

[Wout_RS]

That's a good hint CCM911.

I had to remove some wires that were running true the fuse box. I will check the one from the fuel pump.
I removed one wire that was running from the ignition switch. This was layed around the wires from the originals. So I needed only to disentangle them. Also the car ran after these were removed.

[Wout_RS]

Just checked the fuel pump relay circuit.

There was no battery voltage at terminal 87a and terminal 86 in the relay socket when the key was switched to position ON.
So I checked fuse 16 and was realizing that there was a wire missing.

I must have removed it in a hurry and never rechecked it, if something was missing in the fusebox.



Guess I have to start with laying a new wire

[Wout_RS]

I'm looking at the wiring diagram as a complete layman in my bentley Porsche SC manual.



Correct me if i'm wrong:
One side should leave a red wire to the relay. The other side should have a black wire running to ignition starter switch?

So I have to check if the red wire goes to the relay? And then check if it's the black wire that's missing and lay it to the ignition starter switch?

[MotoSook]

In your original post, you indicated that you can hear the fuel pump. Is it really the fuel pump? You are on the right path. There appears to be a relay in your first picture which would have been the fuel pump interrupt relay, activated by the alarm.

Remove the fuel relay, jumper the terminals and see if the pump will run. If the pump doesn't run, then there is a disconnect you have to find. If the pump runs, try cranking the starter and it should fire if you have spark as you say.

[boyt911sc]

Wout_RS,

A few years ago, I mailed a WUR while I was in Paris to a Pelican parts member from Belgium. Was that you? An anti-theft device is usually designed to interrupt the fuel pump or the ignition or both. Most likely yours deals with the FP relay. Test the FP relay socket for NC (normally closed) and NO (normally open) terminals. Read DKLever48's post about FP relay testing. Everything you need to know about testing the FP relay is well discussed in that thread. Keep us posted.

Tony

[Wout_RS]

@ Motosook: I thought it was the fuel pump. But on closer inspection it's the whine of the CDI module I hear from the engine compartment.

@boyt911sc: That must be another BE member, I have the car for a year now, directly bought from the US.

The testing I have done yesterday, weren't that the NC and NO terminals I have tested? Can they give normal results with a wire missing from the fuse?
Indeed I've read the post from DKLever48's about FP relay testing, but that's seems far-fetched as there is no voltage with the key in position ON? Not?
I'm also a real beginner in all these kind of works.

Wout

[boyt911sc]

Wout,

We don't know what you got from your initial troubleshooting. Until you share the details of your test results similar to what DK did, we could not be of any help to you. If you could post the test result for the following terminals 87, 87a, 86, 85, and 30 with the ignition switch @ on and off positions would be a good start.

If there is no power to terminals 87a and 86 with the ignition switch @ ON position (not start) this is where your problem lies. Trace the wire/s between ignition switch terminal #15 to S11 ~ S16 ~ 87a and 86. Until you get power to 87a/86, the FP will not run.

The big question you have to know or answer is why there is no power terminals 87a and 86 with the ignition switch @ ON position. Keep us posted.

Tony

[Wout_RS]

Hi guys,

Sorry for the late reaction, was on a short holiday to Luxembourg.

I measured everything again like you asked.

First I want to be sure if I'm measuring correct.
So I put my multimeter on the 2V measuring range.
I put the black cable against the body of the Porsche the measure the ground, the red one I stick in the different terminals?
Is this correct?

Measurement with switch @ OFF
87 ... 0V
87a ... 0V
86 ... 0V
85 ... 0V
30 ... 0V

Measurement with switch @ ON
87 ... 0V
87a ... 0V
86 ... 0V
85 ... 0V
30 ... 0V

You mentioned next that I should trace the wire from terminal #15, is this the same as fuse #15?

[Dr J]

Not 2v range but more like 20v range on the multimeter. In any event, whatever is the next setting over 12 as you are looking for about 12V.

[boyt911sc]

Originally Posted by Wout_RS

Hi guys,

Sorry for the late reaction, was on a short holiday to Luxembourg.

I measured everything again like you asked.

First I want to be sure if I'm measuring correct.
So I put my multimeter on the 2V measuring range.
I put the black cable against the body of the Porsche the measure the ground, the red one I stick in the different terminals?
Is this correct?

Measurement with switch @ OFF
87 ... 0V
87a ... 0V
86 ... 0V
85 ... 0V
30 ... 0V

Measurement with switch @ ON
87 ... 0V
87a ... 0V
86 ... 0V
85 ... 0V
30 ... 0V

You mentioned next that I should trace the wire from terminal #15, is this the same as fuse #15?

Wout,

I suggest you use a continuity tester or a test light (TL) for the FP relay socket test. It takes me a minute to test all five (5) terminals. This is how I do it:

a). For testing power or voltage...........connect one end of the TL to a good ground. And use the probe to test the terminal/s.

b). For testing ground contact.............connect one end of the TL to the positive (+) of the battery or to a power source (12v).

For example:
Using test (a) set-up with ignition @ ON (not start), these are the normal results;

87a................12 v (this is connected to ignition switch @ terminal #15).
87................. none (this is connected to the starter).
86.................12 v ( this is connected to ignition switch @ terminal #15).
85.................none (this is a ground contact).
30.................none (this is connected to the FP).

Note: The FP relay is removed to test the FP relay socket. The above procedure is for testing the FP relay socket. FP relay test is completely different.

Terminal #15 is the red/black wire from the ignition switch that goes to fuse 12 and fuse 11. From fuse 11 it comes out as RED wire to fuse 16 and finally to FP relay @ 87a. Do the tests (a) and (b) above with the ignition OFF and ON.

Keep us posted.

Tony

[Wout_RS]

boyt911sc,

Why is a TL better to use then a digital sensitive multimeter?
Not that I don't want to test it in this way.

But I tried to make a test light but it doesn't seem to work well.
When I connected the ends to my battery, the light went on,
then out, sometimes not, then burns more,... not realible in my opinion.
Or not wel built

The above results I gave were from the relay socket and not the relay itself

[boyt911sc]

Originally Posted by Wout_RS

boyt911sc,

Why is a TL better to use then a digital sensitive multimeter?
Not that I don't want to test it in this way.

But I tried to make a test light but it doesn't seem to work well.
When I connected the ends to my battery, the light went on,
then out, sometimes not, then burns more,... not realible in my opinion.
Or not wel built

The above results I gave were from the relay socket and not the relay itself

Wout,

Both multi-tester and TL would work for this kind of troubleshooting. Whatever method you choose is up to you but I find the TL more convenient. Why build a TL? They are available and very cheap. What you want to find out in this test is continuity from terminal to terminal and if you forgot to change the setting correctly for the multi tester, you blow the fuse.

Tony

[Wout_RS]

Thnx Boyt,

Let me give some time to accure one, I come back to the problem within a few days.

I've already followed the red wire from fuse 16, this one goes directly to the fuel pump relay.
But no wire is coming from fuse 11 to fuse 16.
Is it possible to lay a wire and try? Or is there a risk to damage the fuse box?