I'm definitely not hearing anything when I lift the plate.

spark
 

Hi Anthony , me again from link 4 , thats why i ask you re about your Distributor
even though you dont have pertronix ignition, the modul or inside points what ever you have is critical ,hope you get her right soon regards,.

CIS troubleshooting........
 

Anthony,

Avoid doing guess-work and you will find the problem with your car. You need a fuel pressure gauge to begin with. Without one, you will be wasting a lot of your valuable time. The FP maybe running but you don't know if the FP delivers the correct pressure or volume. At this point, you don't know the status of your FP (?).

Second, you have to verify and test the presence of ignition sparks. An inductive timing light does a good job of demonstrating the presence of ignition signals. Doing it in a dark work area or at night gives a good visual effect.

Spraying starting fluid or carb cleaner liquid to locate vacuum leak/s work only with a running motor. I prefer to use a continuous supply of low pressure air into the system and spray bubbled water into suspected areas. If the air box is cracked underneath it, it is almost impossible to detect the leak with the engine installed.

You could perform all the above suggested tests under 15 mins. and in your case I will give you another 15 mins. I have a remote starter but I seldom use it and could perform these test procedures conveniently by myself with no assistance. Do what ever you could do and keep us posted.

BTW, what is the resistance reading (Ohms) of the WUR when cold?

Tony

I wish I could do all that in 15! It takes me 20 minutes of research just to figure out how to test at each step. I'm ready to test spark as soon as I can get a friend to turn the key. Getting fuel pressure gauges would be a half day project for me. (Researching what to get and then figuring out each test, etc.)

It seems that my number one symptom right now is that when I lift the plate on the air flow meter (key is on), I get zilch. I hear no injectors or fuel pump working. So what is the next logical step following that test?

The problem seem binary. The car either starts and runs great or doesn't start at all. It makes me think that one connection or component is going on/off.

Overcome your anxiety.......
 

Anthony,

There are several ways to skin a cat. Other people have a different ways or methods of approaching the problem/s particularly about fuel injection (CIS). There is nothing difficult about CIS troubleshooting and I have not encountered a CIS problem that a typical DIYer like you or me could not diagnose correctly. The key to a successful troubleshooting is to eliminate or reduce the variables for a given problem. How do you do it? Test and confirm. Refrain from relying on luck on your problem solving.

Examples:

Fuel pressures...........use a pressure gauge.
Ignition......................use an inductive timing light, spark plug, etc.
Vacuum leak..............for a non-running motor, starter fluid or carb cleaner won't work. Perform a pressure test similar to finding a pin hole leak on your tires.
Electrical....................loose connection or open circuit could be tested.

Use a known good working part as a substitute for ECU, relay, and other electronic or electrical components unless you know how to evaluate them. Hands on experience has no substitute. You could read all the manuals and literature about the subject and you won't gain any experience or know-how until you put it into practice.

Tony

I've done a lot of DIY wrenching but I've been so lucky with this 911 that I really haven't had to learn much about CIS, fuel, spark, etc.

I think I'm getting closer. Things are leading towards the fuel pump or the power to it. I tested voltages at fuel pump relay socket and get:

30 - zero
85 - 12.35v
87a - .05
87 - 12.35
85 - zero

Next I tried to jumper the fuel pump relay (key on). I jumpered 87a and 30 and the fuel pump is silent.

Next step is to get at the fuel pump, check connections, test directly with 12v, etc.

Ok, I don't think it's the fuel pump. I jumpered incorrectly before. Direct 12v on the fuel pump makes it run and also jumpering 87a to 30 makes the pump run.

I'm sort of back to where I was above. (Key on, and lift air flow meter plate and fuel pump does not run.

So, with the fuel pump jumpered and running, nothing happens when you raise the plate?

What you should get is some sound, which is indicative of fuel running out of the injectors.
You can confirm this by pulling an injector out and sticking it into a bottle (plastic water or the like works well, as transparent) and seeing if you get a flow. You don't want to do this too long, because you don't want the other five to squirt too much fuel into the system.

As you have figured out, there is an interlock connector on the back of the base part of the fuel distributor side of things. Normally, if you pull this connector with the ignition key turned to run, the fuel pump will run without any air flowing to raise the plate. Similarly, in this configuration the FP will run (you can usually hear it) as soon as you turn the key on.

When the plate is in its rest position, as long as the system is set up right, a running fuel pump will not send any fuel through the injectors. This is because at the rest position the internal plunger is situated so that no fuel can come from the center barrel out into the any of the six fuel lines. So you won't get any of the buzzing sound which appears when air flow (even just from cranking the starter) doesn't lift the plate, and thus the plunger in the FD.

If this doesn't happen, chances are good that fuel under adequate pressure isn't reaching your FD. And that you need to check the fuel pressure to confirm this before messing with anything else. A CIS system and warm up regulator (better called control pressure regulator) is indicated. You can get them for less than $100 from JCWhitney or Harbor Freight. My JCW one from years ago came with enough adapters to allow its use on metric CIS fittings, and I suspect the HF one does too.

So where is the electrical connection to the air flow meter? I don't see anything obvious. I push the plate and my fuel pump doesn't go. I'd like to trace that electrical connection or at least check the connections.

I also found this connector unconnected:
http://forums.pelicanparts.com/uploa...1435783171.jpg

Thanks Walt and Tony and everybody else for your patience.

I must be confused about the raise plate test. I thought I've read that you turn the key to on, go to the back and raise the plate and that should energize the fuel pump.

Do I have to jumper it in addition to that?

Ok, I'm getting somewhere. These last few posts were inspiring. I jumpered the relay, and with the fuel pump going, moved the plate and yet I hear the injectors working.

There came my inspiration. I jumpered the fuel pump and then started the car. The car fired up and ran perfectly.

So I know the problem is fuel pump relay / socket / wiring. (I did try every relay I have and none worked.)

Let's start from square one...........
 

Anthony,

Search for DKlever48's post about FP relay. Read it again and again until it makes sense to you. If you have any question, don't hesitate to ask. Post here or sent PM to anyone that could help you.

Once you get a feel of how the fuel pump relay operates, the rest would be easy to digest. Right now you are following instructions blindly and have no concept why and what you were doing specially with AFM (air flow meter) switch which is actually terminal #85 in the FP relay socket.

Do you have a reference shop manual like Bentley or the factory wiring diagram? It would help a lot if you start visualizing by making sketches and diagrams of the FP circuit.

Everything you need to know about FP relay testing are more or less discussed in that particular thread by DKLever48. Let us know your next question/s.

Tony

Believe me, I'm not trying to fly blind. I've been reading, and reading, and reading. I will search for DKlever48's post. Thanks.

I do have a Bentley manual.

Wow, DKLever48 has exactly the same symptoms.....reading that topic now!

The connector you picture is not part of the CIS fuel system.

If you look at a picture of the front of the engine (the side closest to the front of the car), or a CIS system diagram, you will see that there is one of those funny Bosch rectangular colored plastic connectors for the frequency valve (on the left looking toward the front of the car), and another similar one on the right. There is also one on the right side of the intake manifolds by the auxiliary air slide - and easy to see there. The one in question is reachable by sticking your hand around the front of the motor from the left side. This is easiest to do with the hot air blower removed, though I recall it can be done with that in place.

It should be plugged in because it is a safety feature which shuts off the fuel pump if the engine stops. It works backward - when it is plugged in, it works, and you need air flow for it to allow the fuel pump (controlled by the hard to understand fuel pump relay circuitry) to run. Except for when the key is in the start position, which bypasses all this. When it is unplugged, turning the key to run will make the fuel pump run - assuming the relay and so on are all in order.

That two wire plug is for the cruise control, I think, and I bet your car doesn't have CC. Porsche made the same wire loom whether you had CC or not. I've got one of those on my SC as well.

So good to know the engine starts and runs fine with some jumpering of the relay. You might try one of the other relays, and see if that works without the jumper. The red fuel pump relay differs from the horn relay, for instance, only by the addition of a diode, which is intended to prevent reverse voltage spikes. Just how important that is is unclear to me. But this could be diagnostic on whether your red relay is working right or not.

I went through DKlever48's thread and did a bunch of the tests. The results Tony's first round of tests jumps out (testing at the FP relay socket):

test #1
Key off
all voltages zero

Test #2
Relay removed
Key turned to on position
86 --- 12v
87 --- .05v (should be zero)
87a --- 12v
85 --- zero
30 --- zero

Test #3
Relay installed
key turned to on position
86 --- 12v
87 --- .03v (should be zero)
87a --- 12v
85 --- .14v
30 --- .02v

On this last test I wasn't sure how to perform it. I pulled out the relay a little bit and touched the probe on the exposed relay terminal.

For test #2, I see .05 volts for terminal 87 when it should be zero. .05 is not a lot but I'm guessing that it should be a point of concern. Any comments?

I also tested the ground path from 85 to AFS per Tony's procedure. When I lift the plunger the ground breaks.

The connector in your photo is unused after 1979 in the US/CAN engine harness. Still included up to '83 harness for Euro CIS version.
It runs the thermo vacuum switch in '78/79 CIS.

I don't have a CIS car but doesn't the brown wire (ground that energizes the fuel pump relay coil) go to the D- terminal on the alternator? It looks like it runs from the air flow sensor directly to the alternator where it picks up ground.

EDIT: It also looks like the fuel pump is directly powered (yellow wire, normally closed relay contact) when the key is in start.

Suggestions........
 

Anthony,

Use a simple test light for the tests in analyzing the FP relay and socket. It is good to have a multi-tester but for this kind of work, a TL works well. Please repeat your tests using a TL and post the results. Thanks.

Tony