Alan

OK I was responding to an email from Mark on this

I now see more context of the failure...

For others benefit - most of these fuses on an '85/'86 are after the switches for the equipment they control - hence they are never powered except when active. I think they are probably mostly working correctly.

For a 1986 model: (inputs are at the top)

Fuses 1-5 inputs are the X-Bus (X) direct from the ignition switch
Fuses 6-13 inputs are the Ignition Bus (15) inputs direct from the ignition switch
Fuses 14-15 inputs are the retained power bus from the power window relay (similar to 15)
Fuse 16 input is unswitched direct individual battery feed (30) for the ABS (low noise supply)
Fuses 17-29 inputs are unswitched battery feeds (30) to the whole CE panel from the Jump Post/Alternator
Fuse 30 input is from the fog light relay (fog switch & X-Bus)
Fuses 31-32 inputs are from the light relay (light switch pos'n II & High Beam and X-Bus)
Fuse 33 inputs are from the light relay (light switch pos'n II & High Beam and X-Bus)
Fuses 34-37 inputs are from the Turn Signals (Ignition pos'n II & L-R Switch & 15 & Flash=Active)
Fuses 38-39 inputs are from the light relay (light switch pos'n II & Low Beam and X-Bus)
Fuse 40 input is from the light switch pos'n I/II OR the Turn Signal L & Light switch Pos 0
Fuse 41 input is from the light switch pos'n I/II OR the Turn Signal R & Light switch Pos 0
Fuse 42 input is from the ignition relay controlled by the ECU (~15 & engine running)
Fuses 43-44 inputs are from the light switch pos'n I/II
Fuse 45 input (NB Euro only) is from the rear fog lamp switch & front fog lamp switch (~X)

As you can see most of those 30-45 are indirect X-Bus controlled power and /or are normally off - unless a switch or combination of switches are activated - test some of these to verify...

However Fuse 29 input should be live battery (30) feed though - check?

Anyway - you seem to presume that the fuse power is your problem - I'm pretty sure it actually is not... probably there is a single-point failure affecting whatever doesn't work on the car...

For the no start condition it may well be related to the aftermarket alarm:
particularly since it has been flakey before...

The after-market alarm may use the stock disable mechanism or may have invented its own. I think the aftermarket alarm needs to be excised forthwith!

1) Is the wiring modified in any obvious non-stock way as a result of the alarm install?
- e.g. they could have come up with an alternate disable mechanism?

2) If the stock connections are used the disable ignition can be defeated by linking (jumper) Pins F25 & B23 on the bottom of
the CE panel (Pin F25 is the top right terminal on Plug F, Pin B23 is the middle right terminal on Plug B. Just link them
temporarily with a wire into the back of the plug - (connect the F25 end first)
OR
if you like you can just test that with Ignition in Position II you get 12V on pin F25 - if you do not - the car will not start because power to the ECU's is disabled - this is how the factory alarm disables the ignition.

3) Its possible they left the stock alarm in place and its still able to disable the EZF...?

4) If this seems OK or the jumper makes no difference - It is also possible you just have a failed relay. The most critical to engine start are the EZF (XVI), Fuel Pump (XX) & LH (XXV)

Any one of these may be a type with a fuse tester built in (most likely the EZF) but all are otherwise standard types and all can be replaced with the horn relay (XII) to test...try swapping each of them in turn to test.

You said you have changed them all recently - what did you use? Posche branded, Bosch branded? something else...

Be aware that all relays are not all created equal - off brands or incorrect types may have lower contact ratings - have different pinouts/functions (in odd cases) or have incompatible diode protection built in...

5) You didn't disconnect any other wires at the battery did you...? the ECU's have a seperate feeder direct from the battery...

Alan

For reference (my terminology):

Ignition Switch:
Position 0 - off
Position I - Accessory X-Bus (X) only is on)
Position II - Run - Ignition (15) & X-bus (X) are on
Position III - Start - Ignition (15) and starter (51) are on, X-Bus (X) is off

Light Switch:
Position 0 - off
Position I - Marker Lights only on
Position II - Marker Lights & Headlights on

Tampa 928s

For Alan

For what I am gathering power to these fuses will not be apparent until the device is switched on.
Would it be Ok to enable the relays relating to the LH to aquire a voltage on the connector?

Be aware that all relays are not all created equal - off brands or incorrect types may have lower contact ratings - have different pinouts/functions (in odd cases) or have incompatible diode protection built in...
They were not Porsche brand but did have the 53 stamped on them I belive a VW replacment called for the horn relay via Auto Zone information.

5) You didn't disconnect any other wires at the battery did you...? the ECU's have a seperate feeder direct from the battery...
Yes added an new post it has a 6AWG along with the started feed cable.

The alarm:
The wire color coding on the alarm:
BRN TO BLUE GLASS BREAKAGE
RED
ORG/WHITE STRIP CUT OFF
ORG TO RED GLASS BREAKAGE
GRAY
YELL
GREEN
BLUE TO BLACK GLASS BREAKAGE
I NEED TO HAVE SOME LIGHT AND SEE WHAT THE FACTORY WIRES COLORS ARE CONNECTED, TOO WAY UP IN THE DASH!
The alarm led has never worked and the bypass switch in the glove box does not seem to change anything.

IcemanG17

your aftermarket alarm very well may be the culprit...which makes it impossible for any of us who can't physically see it figure it out....some of those alarms end up being serious hack jobs

Try this

there should be voltage on pin 30 (ground 87) of the EZK-LH-Fuel pump relay all the time...regardless of ignition...as this is the constant power source..... jumper all three (I would do the fuel pump last).....then see if the car starts.....it "should".....of course it won't turn off until you pull a jumper either....

If this doesn't help......I like the alarm...or a dying LH brain.....my no start-run ended up being a dying fuel pump....or at least thats what I think it is...will find out tomorrow for sure!

Mike Frye

Alan,

That is some great stuff. I just copied and pasted your whole post into my troubleshooting notes. Thanks a million!

TAREK

There are two connectors in the spare wheel well. Disconnect them and clean them good. Reconnect and crank her up again. One of the wires is the ground for the factory alarm. Also, have you replaced/removed the battery lately? If so, make sure all wires to and from the battery are indeed intact. This caused me to leave my car behind in VA on the way back from SITM to NY one year. Good luck!

Tampa 928s

In the spair well there is a four pin connector behind a cover what does that do ?

I did not see any modification to the panel the odd part is the after market alarm never indicated that it was armed the led never turned on. I do not have a remote but the alarm has been set by locking doors and a few times it would blow the horn unless I locked and unlocked the door the horn would stay on.

I do remember having power to the Lh with switch on before this problem appeared.

I used the manual to trouble shoot the LH relay, said to place meter on Pins 5 & 9 of connector and ground to W-21 voltage appeared with power off; this checked out OK

The Ezf seems to indicate a problem: Test states connect meter to W 25 and 12 turn on switch should show battery voltage, none is present. If this fails the next test is to connect meter to W14 and ground turn on switch this works power is present. The problem is it does not explain what to look for on the failed test. I’m sure the Ezf is not getting power!
My thoughts at this point that if I substituted one relay at a time with a modified relay; in the closed position I may find the culprit; what do you think?

I contacted Crimestopper and here is a copy of there E-mail:

Crimestopper has never made any product with the part number RS-100.

It may be made by some other manufacturer.

Good Luck with your search.

Best Regards,

Ralph Turner
Crimestopper Security Products Inc.
www.Crimestopper.com

----- Original Message -----

I called for a manual of an Rs-100 and have not received it as of yet! I have an 86 Porsche 928s and it will turn over and not start power to the computers and several fuses are missing. Can you provide a manual to trouble shoot this?



Thanks for your input

Fabio421

Does it look like this?

http://209.85.165.104/search?q=cache...lnk&cd=1&gl=us

Tampa 928s

Fabio
No my is so old same size no remotes for it plus mine is a 5-speed!

Tampa 928s

I placed an open relay to observe its operation with key on:
Iv ignition relay closes
Xvi Ezf relay closes
Xx Fuel pump relay closes when starting
Xxvi relay closes

Alan

Mark - the operation you describe appears correct - the LH will not enable the fuel pump except when starting until it detects the engine is actually running..

It appears the relays work - not sure exactly what you are testing on the EZF ECU but I think that is a possible suspect anyway...

No Run conditions are basically:

No starter spin - you are OK there
No fuel - you have initial fuel pumping & pressure - only leaves injectors:
- if you smell any raw fuel in the exhaust or can pull a plug and see if its wet after cranking thats prob OK
No Spark - if you have a spare extra spark plug you can test it... (BUT BE VERY CAREFUL!! - ground the plug and don't touch it - the 928 IGNITION SPARK SYSTEM CAN KILL YOU!)
Insufficient air... (not likely to affect starting)

I think you may have an issue with EZF or LH operation - EZF is easiest to quickly test - do you have a noid light to test the injector drivers for the LH?

Either one of these ECU's could be working fine but lacking a valid sensor input...

I will send you a doc to help you debug.

Alan

Tampa 928s

I put a scope on the pins 7 & 19 of the EZF the signal was present I grounded pin 20 signal still present. Crank sensor is working
With Exf connected Lh pin 1 I recived a control signal. Control signal working

I can smell fuel

I had a sub Lh I just sent back it was not the issue no Ezk spair.

The alarm shows a voltage on the orange wire with key on no other voltages present on other wires. I locked the car with window open unlocked it via the inside **** alarm sounded.

Tampa 928s

Noid lamp are you talking about a 12v test lamp with a ground wire, yes I have one.

Tampa 928s

By the way to test inj on an 86 I will have to completly remove the intake and rails. I have new Injs and connectors a short would cause this but I had this issue before and it corrected itself.

Tampa 928s

Getting spark pulled one plug looks dry, I am getting fuel pressure This leaves the Ezf or inj are shorted!

WICruiser

The correcting itself note should be a clue, things rarely are fixed in this way, they just wait until a more inconvenient time to reappear.

I seem to recall the previous thread about the injectors and potential wiring concerns.

Can you identify what may have been done about the time of the previous "repair" ? It might lead you to where to look for the actual problem.