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Reviving non-driven 928 (12 years in Garage)

 
Old 07-04-2019, 12:20 AM
  #16  
dr bob
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Don't just throw parts at it and hope. Like the ignition switch.

The starter relay demands a ground via the gear indicator switch on the transmission. Cycle the gear lever though the gear positions manual, and try to crank in both neutral and park positions.

The fuel pump is intended to work for a second or two at key-on, then shuts off and waits for tach pulses to tell it the engine is spinning. From your description it's doing the first part of that OK.

----

Drain --all-- the old fuel from that tank before you run the pump. Pull the tank sender cover in the boot, and look in the tank to see how much dirt and varnish have accumulated. The old gas will contaminate the CIS bits. CIS loves to be driven regularly because of its sensitivity to dirt and contamination. You will likely end up dropping the tank and cleaning it if it isn't really clean inside. Do This Before You Contaminate The Whole Fuel System by running the pump with a cruddy tank.
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Old 07-04-2019, 12:45 AM
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Once you can crank the engine, the CIS is going to be your Big Job. The CIS runs exclusively by pressures. Having the right pressures is about 80% of the Big Job. The other parts, are good fuel pressure, and clean injectors. Technically, the injectors can't be cleaned, and must be replaced. There are jigs that are used to test and clean them, but most of the 'cleaning' is of questionable value. If you choose not to replace, at the minimum you would be wise to pull them and setup the jig to test. When working correct, the injector will buzz or hum a bit as it is a vibrating pin that allows the fuel to be properly atomized(vaporized?) at the nozzle. Google 'CIS spray pattern' and follow a couple links, some from MB, some from Porsche and they will guide you.

Having the pressure test kit for CIS is almost a requirement. This is the starting point, and all the CIS links will refer to pressures. Many guys use injector cleaner like Ventil Sauber, or Techron, or other varnish remover. Again, questionable value, but maybe worth a try. When the CIS is setup right, and driven regularly, it's an adequate mechanical FI system. If it is not setup right, or is not driven often, it will begin to give trouble.

CIS pressure gauges
CIS new injectors - or
CIS test and cleaning jig
CIS dist rebuild kit(avail from ebay)
Cleaning fluid of your choice.

Read the links, and set it up right from the beginning.
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Old 07-04-2019, 06:15 AM
  #18  
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@dr bob, I have removed the starter assembly from the car and connected a fully charged battery directly to the starter motor -> works. When connecting to the solenoid 12V and start switch connection -> nothing. Thats why I am planning to replace the solenoid, since it seems to have gone bad. Similarly for the ignition switch, it does not turn back to the "run" position on its own and shows error lights all over the dash. Assuming I wont be able to fix the spring in the switch itself, I am planning to replace it as well. Would you disagree?

I have emptied the tank completely and flushed all lines up to the fuel distributor with fresh fuel. Once it cranks, I hope the distributor will clear itself with a little help of injector cleaning solution. Can I connect 12V to the fuel pump directly to try and test the distributor and injectors before actually cranking the engine?
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Old 07-04-2019, 05:42 PM
  #19  
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One thing to remember:

When you initially turn the key to "On", all of the warning lights on the dash are supposed to light up.
It's a bulb check feature.

While Dr Bob has a good point about 'throwing parts and hoping', you do have some of the 'classic' ignition switch failure symptoms.
They are known to go bad over time.
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Old 07-05-2019, 01:25 AM
  #20  
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Originally Posted by Dr.Digga View Post
Once it cranks, I hope the distributor will clear itself with a little help of injector cleaning solution. Can I connect 12V to the fuel pump directly to try and test the distributor and injectors before actually cranking the engine?
OK, here's the deal. People have done the 12V to the pump thing before, and filled a cylinder with fuel, then hydrolocking the engine. This is a bad thing. Many have also tried buckets of injector cleaner, and made things even worse. Advice and step-wise procedure has been provided, and ignored. You are already taking shortcuts, so this is the point where I bid adieu and wish you all the best in your continued mis-adventures.
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Old 07-05-2019, 11:01 AM
  #21  
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Originally Posted by Dr.Digga View Post
I have emptied the tank completely and flushed all lines up to the fuel distributor with fresh fuel. Once it cranks, I hope the distributor will clear itself with a little help of injector cleaning solution. Can I connect 12V to the fuel pump directly to try and test the distributor and injectors before actually cranking the engine?
I would strongly suggest against this idea.
It will likely make things worse, not better.

The fuel distributor is very sensitive to dirt & crud. There isn't a 'cleaning solution' out there that will get it right (I don't care what the label says).

There's a basic but good video in the "New Visitor" sticky thread that explains the basics of how CIS works.

The 928 Classics website also has some good info on how it works and getting it running right.

After sitting as long as it has, you will likely need to take it all apart, clean it properly, get it back together and gt it dialed in (you need the pressure gauges for this).
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Old 07-11-2019, 11:04 AM
  #22  
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In my experience, techron really, really helps to clear things up. Also, there are alot of micro-ports in the FD, but it's often the orings that dry up from non-use. If you want to run the fuel pump, jumper from the CE panel. This is safer as you don't want any sparks near the fuel pump...
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Old 07-12-2019, 04:10 AM
  #23  
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Alright, I am back with the car.
I replaced the starter solenoid and the engine now turns over, when I jump the starter with the yellow cable on the jumper terminal in the engine bay.
However, it does not turn when jumping the starter relay and I do not have continouity between terminals 87/30 and the starter pin at the female side of the 14 pin connector. (sorry in this sounds a bit weird - english is not my first language).
Do you guys have any idea how to go from here?

Last edited by Dr.Digga; 07-12-2019 at 04:52 AM.
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Old 07-12-2019, 08:01 AM
  #24  
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Another problem arose: The oil connector lines to the radiator are loose/not connected. The previous owner seems to have removed the old radiator without transferring the oil hose fittings.
Does anyone know the replacement number? I have only found the engine side connector 90091500302 ( RosePassion P12448), but not the radiator side.

Last edited by Dr.Digga; 07-13-2019 at 12:17 PM.
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Old 07-17-2019, 05:21 AM
  #25  
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A quick follow-up if anyone else will have a similar problem.
The thread size of the side tanks of the radiator are M20x1.5 and require an adapter to M26x1,5 for the engine oil hose. The engine side adapters cannot be used, since they have a thread size of M22x1.5 to M26x1.5.
I am not 100% sure, but believe that the transmission oil hoses use the same diameter and requires a radiator side adapter of M20x1.5 to M26x1.5 as well. The adapters are currently not available from Porsche and extremely hard to find in general. Therefore I have opted to use M20x1.5 to AN-10 connectors and to replace the oil lines altogether.
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Old 07-17-2019, 11:21 PM
  #26  
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you mentioned cleaning the grounds, as far as you have found them. do you know which you were able to find? personally, i would start there....make sure you get them all.

also, get a can of deoxit spray and make it a habit to pull every connection apart while you are working in any given area of the car and give it a squirt. i can't tell you how many things have started working again in my car as I have done that...
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