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TOPIC: 14 pin connector

14 pin connector 11 Sep 2013 20:31 #15911


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Hi All,

I'm so fed up with my car and need help. I'm ready to throw the towel with all the issue's I'm having.
I've had gremlins getting my car to run. I was wondering if their a test to the 14 pin engine harness that I perform to figure out if the harness is my issue on MY87?

Thanks in advance.
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14 pin connector 12 Sep 2013 07:55 #15921


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There really isn't a test for the 14-pin connector - nor is it the most likely cause for problems.

My only suggestion is to post here, with very complete and detailed problems and symptoms. General complaints ("My car won't start.") are totally useless. Specific problems and symptoms ("When I turn the key to the start position, the starter spins the engine at a normal speed, but there is no attempt to run.") will get knowledgeable guesses and suggestions. Giving complete info on the car is essential.
Wally Plumley
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www.928gt.com
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14 pin connector 16 Sep 2013 15:21 #15950


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I apologize in advance writing this long response but you wanted me to give you an idea what has happened to my car.
Three years ago I replaced my motor mount and oil pan gasket I've had the following problem.

After doing the work the car started and idle fine but after driving the car for a few miles the car would hesitate and shut down. It was difficult to get the car back to run but once it ran it had erratic idle and hesitation during the drive back to the garage.
My friend and I got it back and went through the work we did find the ground strap mounted to engine and to the body was not connected. After connecting the ground it problem still persist.
I got the car home with this issue from Kentucky to Chicago and didn't use it for 6 weeks. I decided to drive the car to Wisconsin to Tim Murphy 928 gathering and Dyno day. It drove without any issue. While running the car on the Dyno it appears the car was running lean and we decide to stop the Dyno. After the Dyno car idle poorly and hesitates excessively. By the way before the Dyno Andrew Olson swap the ECU chips with his tuning chips and right after we stop the dyno he returned my stock chips. I was lucky enough I got the car home even with rough idle and hesitation. I since stored the car for the winter.
The following year I got the car of out storage the car run but with high idle around 12-13 k when operating temperature. When cold it idles around 900 to 1K . So I had a 30 yrs. Porsche dealer master technician work on it during the summer. His diagnostics that I have intake leak and these cars are known for this problem. So he removed the intake manifold and replaced all the gaskets. When I got the car back still high idle after I paid him (stupid mistake). None of the issues was fixed. He promised he would get this figured out before the summer was over.

The technician finally found time to work on it again in the fall and check the following. I drove the car to his place of work and had him work on it for 2 months. He did the following not in this order.
All the ground check out ok. He wanted to replace the EZK because he said the car does not have spark. So I got a loaner and did not fix the problem. He checked the crank sensor that was ok.
He found the wiring on the Hal sensor broken so he fix the wiring but that did not fix the problem.
I told him there was a crack on the 14 pin engine harness connector but he said that would not cause all the issue's I was having. He finally recommended that I needed an engine harness since he couldn’t get the car to run anymore. I told him I wasn't going to invest on an engine harness unless he can guarantee that this would fix my car. Since he couldn't for sure tell me this was the problem I decided to get the car back. At this time the car will no longer run. I had the car towed back home and left it for the winter.

This year I worked on the car and decided to replace the Hal sensor since the mechanic did a poor job fixing the wiring. The car still would not run. I inspected the 14 connector and found the crack on the housing was so bad the pins looked like they could fall off. I had Roger from 928Rus send a 14 pin connector. After replacing the pin connector for the engine harness my car finally run. The car run but it idles at 11-12k once the car warms up.

For 5 weeks the car run every day then one day all my problems are back. I'd be driving down the road and the car would just shut down. I tried to restart the car multiple times but it won’t run. I'd check the 14 pin connector and try to start car it would run again. This happened multiple times and I was lucky to get back home. Every time this happen I know I have fuel because I can see it on the fuel gauge mounted on the fuel rail.

It's been 2 months since the last time the car ran. The car does not run anymore it just starts. I notice 3 weeks ago that there is no fuel on the gauge installed on the fuel rail. So I replaced the relay and still the car will not run. I recently I jump power from the battery to the fuel pump to see if the pump will run and it does. The gauge under the hood shows pressure.

So far this is what I have done not in specific order.
Check Compression = OK
Check and swap temp 2 sensor
Replace spark plug.
Install a fuel gauge to see if we have fuel.
Replaced LH
Replace EZK
Replace the MAF
Replace Hal sensor
Replace 14 pin connector
Replace fuel pump relay
Check all the ground points and wiring on the car
Check timing
Check the timing belt
Trouble shoot running issues using the WSM all of the symptoms jumping pins in the ECU’s.

Thanks in advance,
Ariel
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14 pin connector 22 Sep 2013 10:06 #15980


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First, we need to see if you have fuel and fire. Have an assistant spin the engine while you watch the fuel pressure gauge. Do you have fuel pressure?

If you have fuel pressure, get a mechanic's stethoscope (cheap at an auto parts store) or a four-foot piece of rubber or plastic tubing, and use one of these to listen to the injectors as the assistant spins the engine. There should be a regular clicking (one for every other revolution) from the injectors. Do you have this regular click?

If you have fuel pressure and injection, get one of your old spark plugs. Pull a plug wire from one of the cylinders fed by the left coil, and install the plug in that connector. WARNING! The 928 ignition system can hurt you and even kill you! Never ever do anything that can result in ignition voltage (coil wire or plug wire voltage) passing thru any part of your body! Put the plug on the metal of the engine, making sure that it is nowhere near any wiring harness. Have an assistant spin the engine while you watch the plug gap. You should have a hot, snapping blue spark as the engine turns. Do you have such a spark? Repeat on a plug wire fed by the right coil. Do you have such a spark?

Please report the results of each of these tests.
Wally Plumley
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14 pin connector 23 Sep 2013 11:43 #15989


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Wally I don't have fuel but if I jump relay 30 and 87 terminal I have pressure and can hear the pump running. I've replace the relay with a new relay and also use the horn relay just to be sure but I dont have pressure.
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14 pin connector 24 Sep 2013 13:33 #15993


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Ariel,

The fuel pump relay is triggered by the LH ECU based upon a signal from the EZK ECU. The EZK ECU is triggered by a signal from the Crank Position Sensor (also called the RPM Sensor in the wiring diagram on Page 97-275 in the Factory Workshop Manual). If there is a fault in the CPS or its wiring, there will be no RPM pulse to the EZK ECU, thus no trigger signal to the LH ECU, thus no Fuel Pump Relay activation.

You can check for the relay activation:
- Remove Relay XX, the Fuel Pump Relay. Using the diagram on the relay, identify the four connections in the relay socket.
- Check for 12 vdc on terminal 86 when the ignition switch is on.
- Check for continuity to chassis ground while the starter is spinning the engine.
If there is not continuity to ground, a CPS fault is one likely cause.

If there is no movement of the tach needle when the starter is spinning the engine, that is another indication of a possible CPS fault.
Wally Plumley
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www.928gt.com
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14 pin connector 24 Sep 2013 14:00 #15994


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Wally I'm not that great of mechanic so I'll have to ask a dumb question. How do I check for continuity to chassis ground while the starter is spinning the engine?
Thanks,
Ariel
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14 pin connector 25 Sep 2013 22:12 #15997


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Set the multimeter or Ohmmeter on the lowest resistance range. When you touch the probes together, you should get very close to zero Ohms resistance, showing that you have continuity between the two probes/leads.

Put one probe on the ground connection above the Central Electric Panel - this will be a bolt to the body/chassis with a bunch of brown (ground) wires attached. This puts one lead of the Ohmmeter at ground.

With Relay XX (Fuel Pump Relay) out of the socket, look at the diagram on the relay, and identify for certain terminal 86 in the relay socket. Recheck to be sure that you know which terminal (female 1/4" electrical socket) is 86.

Put the other probe on terminal 86 - there should be no continuity - the meter should read max resistance, often shown as infinity (signified by the "sideways-8 symbol). Have an assistant spin the starter. When the Crank Position Sensor sends pulses to the EZK ECU showing the crankshaft position, the EZK ECU will send pulses to the LH ECU. This will cause the LH ECU to ground the wire going to the 86 terminal in the relay socket. Since there is battery voltage on terminal 85, which is the other side of the relay coil, the coil will be energized, which will pull the relay contacts closed, which will energize the fuel pump.

The reason for all of this is so that the Fuel Pump Relay will not be energized except when the engine is turning. This kills the fuel pump in a crash situation...
Wally Plumley
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www.928gt.com
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14 pin connector 25 Sep 2013 23:52 #15998


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Or hook a test light to power, put the pointy end in 86 and reach up and crank it and it should turn the test light on.

By the way, I would not use a test light on new car electronics (Wally's is the correct method) but I believe the EZK is robust enough to turn the test light on since its a relay circuit.
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14 pin connector 27 Sep 2013 13:16 #16005


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Here's my results in Red following Wally's instructions. - Remove Relay XX, the Fuel Pump Relay. Using the diagram on the relay, identify the four connections in the relay socket.
- Check for 12 vdc on terminal 86 when the ignition switch is on = 11.9 volts- Check for continuity to chassis ground while the starter is spinning the engine.
Positive probe to pin 86 and neg probe to ground. Volts = 0.00 Ohms .79
There is movement of the tach needle when the starter is spinning the engine.

Ariel Trajano
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14 pin connector 28 Sep 2013 09:41 #16009


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My apologies - I screwed up!

Terminal 86 should have battery voltage when the ignition switch is on. Terminal 85 should be grounded while the engine is spinning. Look closely at the meter, and be sure that you know how how to read voltage, and how to read resistance (Ohms).

Set the multimeter or Ohmmeter on the lowest resistance range. When you touch the probes together, you should get very close to zero Ohms resistance, showing that you have continuity between the two probes/leads.

Put one probe on the ground connection above the Central Electric Panel - this will be a bolt to the body/chassis with a bunch of brown (ground) wires attached. This puts one lead of the Ohmmeter at ground.

With Relay XX (Fuel Pump Relay) out of the socket, look at the diagram on the relay, and identify for certain terminal 85 in the relay socket. Recheck to be sure that you know which terminal (female 1/4" electrical socket) is 85.

Put the other probe on terminal 85 - there should be no continuity - the meter should read max resistance, often shown as infinity (signified by the "sideways-8 symbol). Have an assistant spin the starter. When the Crank Position Sensor sends pulses to the EZK ECU showing the crankshaft position, the EZK ECU will send pulses to the LH ECU. This will cause the LH ECU to ground the wire going to the 85 terminal in the relay socket. Since there is battery voltage on terminal 86, which is the other side of the relay coil, the coil will be energized, which will pull the relay contacts closed, which will energize the fuel pump.

The reason for all of this is so that the Fuel Pump Relay will not be energized except when the engine is turning. This kills the fuel pump in a crash situation...
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14 pin connector 06 Feb 2014 11:58 #16764


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Just to follow up. Finally took it to a shop and Dave Zaprev figured out the issue. He replaced Crank sensor. I still have a high idle but it's running. I'll probably have to do another intake refresh to get the idle sorted out.
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