'86 930 CIS Ignition Issues Seemed To Start When Alarm Issues Started

[Jonny H]

If you get no signal between 7 and 31d with the plug out, it suggests that the shield wire is broken. The signal looks fine with the plug in so it is finding a ground somewhere else. It might not be the cause of your problems but it isn’t right.

[spoke]

Originally Posted by Jonny H

^. Where are you measuring this ‘considerable resistance’?

I assumed the 2 volt drop I see is due to resistance to the battery/alternator. You may have a better feel for what the characteristic input resistance is in these cars.

[spoke]

Originally Posted by Jonny H

If you get no signal between 7 and 31d with the plug out, it suggests that the shield wire is broken. The signal looks fine with the plug in so it is finding a ground somewhere else. It might not be the cause of your problems but it isn’t right.

I tried moving the wires around to see if there's some change. Right now at the CDI connector w/o the CDI I measure 675 ohm from pin 7 to 31/d. When jostling the wires near the CDI on purpose, I've seen it go to infinity then back down to a much lower resistance but it doesn't stay there.

I've also seen the resistance change when I touch or move the wire near the distributor. Next step will be to remove the distributor and inspect and test the pickup wires. If the wire is suspect, can I get a replacement wire or is this stuff just simply shielded cable?

[Jonny H]

Originally Posted by spoke

I tried moving the wires around to see if there's some change. Right now at the CDI connector w/o the CDI I measure 675 ohm from pin 7 to 31/d. When jostling the wires near the CDI on purpose, I've seen it go to infinity then back down to a much lower resistance but it doesn't stay there.

I've also seen the resistance change when I touch or move the wire near the distributor. Next step will be to remove the distributor and inspect and test the pickup wires. If the wire is suspect, can I get a replacement wire or is this stuff just simply shielded cable?

Yep, coil resistance is about 600 ohms. it's a shielded cable but the connector at the distributor end is molded on. Some cars have a two part wire with a junior timer connector, others don't and wire is one piece.

[spoke]

I think I've found out why I'm losing the distributor pulses. The wire at the distributor connector is shorting out. Both wires are bare right by the connector. Looks like I'll need a new wire and connector.

I see a couple of wires here but they are 5 inches long then have some connector on the other side. Is there a longer wire to be purchased somewhere?

[spoke]

It is hard to see the break in the inside conductor's insulation. Definitely shorting out at times.

[Bucketlist]

Originally Posted by spoke

It is hard to see the break in the inside conductor's insulation. Definitely shorting out at times.

Is that Pink Shag? ^^^^
I havn't messed with this on mine but most of the wires advertised are really short. If I needed one it would have to be longer since my CDIs are under the seat.
I saw this, if it will help....
https://www.amazon.com/Porsche-78-84-Ignition-Distributor-Green/dp/B00AHIU1W2
Check this post:
Ignition distributer wire ( Green Wire)

[spoke]

Originally Posted by Hot Euro

Is that Pink Shag? ^^^^

Not quite. It is a purple towel just shown really close.

The longer distributor wire looks better however it still has a connector on the other side. Now I would need the opposite connector or cut it off and splice into a similar shielded cable.

To test out if this shorting wire is the problem, I cut off a bit of the connector then used JB Weld to freeze the wires away from each other. The break in the inner conductor's insulator was only at the plug. I also applied some liquid insulator to protect the shield wire where the outer insulator had hardened and broke off.

I want to get the car running before I purchase anything.

[Rich76_911s]

There is a guy up in Oregon that sold me the connector to put the new green wire into the car. His name on pelican is timmy2. I think it was somewhere around $15-20 shipped.

Here’s his contact

http://forums.pelicanparts.com/members/101896.html

Rich

[spoke]

Been driving the 930 all weekend. Seems to be running well. Had it WOT several times and runs well.

The broken turbo hose, shorting distributor wire, and leaky vacuum advance all contributed to the engine not running and not running good.

I still need to find a solution for the distributor vacuum advance not working. If these cans are NLA, then maybe an MSD 6AL-2 with mapped advance would help.

One more question: How do I check the timing of the engine? I've pulled the distributor a couple of times and it's close to where it was but I need to check. Is there a write-up somewhere of how to time the 930?

[flightlead404]

I got the green wire for the 928 which is a bit longer.

I bought a weatherpack 2 pole m/f connector and opened up the brown covering for the harness. I found a lot of hardening and cracking of the insulation so I trimmed it back to a suitable place and spliced in the weatherpack connector. Trimmed the other end of the new green wire to length and installed the other connector, one pole for shield, one for conductor.

This way in 30 years it will be an easy replacement :-)

[flightlead404]

Originally Posted by spoke

Been driving the 930 all weekend. Seems to be running well. Had it WOT several times and runs well.

The broken turbo hose, shorting distributor wire, and leaky vacuum advance all contributed to the engine not running and not running good.

I still need to find a solution for the distributor vacuum advance not working. If these cans are NLA, then maybe an MSD 6AL-2 with mapped advance would help.

One more question: How do I check the timing of the engine? I've pulled the distributor a couple of times and it's close to where it was but I need to check. Is there a write-up somewhere of how to time the 930?

Timing of the engine? or the ignition? Engine timing, aka valve timing is set during cam installation and is checked with a dial gauge to measure valve lift at specific locations. I think you mean ignition timing.

Depending on your engine (US, RoW) and year there's various methods but you'll need an inductive timing light and a golf tee. Generally you hook the vac line, plug it, run the engine to a set rpm and check the timing. You loosen the 13mm nut on the distributor hold down and rotate the distributor to get the timing you want.

There s/b a sticker on the lip of the engine compartment that describes it for your car.

[spoke]

Originally Posted by itsme

Also " I sprayed a bit of starting fluid in the intake and the car started up and ran for several minutes" makes me wonder about it being ignition related. When it dies does it always start with starting fluid?

Every once in a while the engine will not start when cold. A shot of starting fluid and it fires right up and runs well.

When it won't start, on 1st start it will chug a bit then slowly die. Subsequent starts will yield just a bit of chugging then stall. I could do this 5+ times. One shot of starting fluid and it starts up and idles strong at 1400 RPM.

Could the fuel metering flap on the fuel distributor be sticking? At times when I've had the air cleaner off I've pushed on the flap and sometimes it sticks a bit then opens with a low level of rubbing sound.

[T77911S]

the metering plate should move freely when pumps are off, it will have resistance with pumps on and there should not be any free play before you feel resistance.

[spoke]

Originally Posted by T77911S

the metering plate should move freely when pumps are off, it will have resistance with pumps on and there should not be any free play before you feel resistance.

There is no free play in the metering plate. When initially pushing down on the plate with the engine off, there's a bit of resistance and a slight scraping sound coming from where the plate fulcrum is. The plate itself is not scraping the sides of the intake. Is it possible to put oil or other lubricant on the moving parts of the meter arm?

One other thing is I believe the engine is/has been running lean. I purchased the car in Colorado and the PO said the engine was set up to run at the higher altitude and I should adjust the AFR for PA altitudes. That was 10 years ago.

When investigating the sticking, I also pressed on the plate with the engine running. With just slight pressure, the engine idle increased dramatically. I turned the adjustment screw on the plate by 90 degrees and the idle increased from below 1k RPM to about 2.2k RPM.

I need to get an AFR meter. What is the best AFR meter to put on my car? TIA.

[Bucketlist]

I'm not sure what year and system your car is so this may not apply to you.
To set the timing:hold the rpms at 4000 rpm and line up the 26* before top dead center line on the engine pulley with the vertical line on the fan housing using a timing light on #1 spark plug wire. I have a full page on this if you need a pm.
The instructions are also on a sticker on the bottom right side of the engine lid and in the owners manual.
10 years with no adjustments? Wow Must have been well sorted.
A 90* turn of the idle mixture screw is a lot!
AFR is usually adjusted with the WUR. idle speed with the air screw on the throttle body and lastly idle mixture with the screw on the air flow meter.
Not sure what you are feeling with the metering plate. When the adjustment shaft is pushed down very slightly to where it deflects the arm it will enrich the mixture and your idle will change one way or the other. if rpm's go up, then you were too lean to start with, and if they go down you were too rich to start with and are now even richer.
I wouldn't mess with any this without knowing the afr and control pressures. I have the innovate lm2 meter which I used a lot when I was learning about the afr and boost. It is still hooked up but then I added an innovate afr gauge to the dash, I mainly use this. Innovate is ok but there are many others out there that some say are better.
I am not the expert but have stumbled thru the learning process like many others.