Engine shuts down

Capt Bob · Capt Bob's Garage

To all - I have read through some of the posts on 930's randomly shutting down and now its happening to me. My 930 is a 1982 with some updates with 82,000 miles. See attached photos. This weekend it died on me backing out of the driveway. Just shut down. I attempted to start and I could hear the fuel pumps running but definitely no ignition...not even a pop. I cranked it over 3 or 4 more times and nothing. Then I went in had lunch came back out 30 min or so later and it fired up like nothing happened.

I noticed last weekend while on the highway and running along at a steady clip that the tachometer started acting up, dropping to zero then back but no actual drop in RPM with the engine.

Let me know where to start to find this electronic gremlin.

Thanks!

356911930 · 356911930's Garage

First I would check the ground wires, clean and tighten. One from transmission to rear tunnel area where transmission attaches to shift "tube". I think there is also a ground in the engine compartment at the fuse panel.

Also check the green wire from the distributor to CDI. When you start the engine shake it around to see if it is broken inside the plastic housing. If broken it will shut down the engine or make it run very rough.

Rahl

icemann427 · 09-24-2018, 10:17 PM

Check the two fuses in your first picture. Mine would do the same thing as you are experiencing. I would take out the fuses, put them back in, and spin them. And somehow it would start...Bad connection, me thinks.

Capt Bob · Capt Bob's Garage

Thanks for the responses. I will start there.

T77911S · 09-25-2018, 04:28 AM

I would just replace that permaDOOM with an MSD and coil.
you can adjust the rev limit with the MSD and run a solid rotor.

another advantage to the MSD is that is has an LED that shows you are getting the signal from your dist so if it dies you can eliminate that easily.

Capt Bob · Capt Bob's Garage

Thanks for the recommendation regarding the MSD, coil and solid rotor. I will need to do some research on this. Found this MSD on Pelican parts: MSD 6201 Digital 6A Ignition Control. Any mounting issues between the two different systems?

smurfbus · 09-25-2018, 09:37 PM

I think even the newer MSD unit will be bigger that your current one. Size L x W x H: 18 cm x 10 cm x 5 cm

T77911S · 09-26-2018, 04:03 AM

i used the 6AL in mine.
check advance for price too.

I relocated mine to above the relay panel but had to move some relays. no big deal.
I also bought a connector that plugged directly into the factory harness that goes to the engine.
I have my bosch unit but carry it a a spare. if needed I can just plug it back in.
you have to swap the 2 wires (+ and -) coming from the dist that goto the MSD but do it on the new MSD connector.
I also mounted my coil upright in the original location. I have clewett wires. I called him and had him make a special coil wire that was longer and the coil end had a 90 degree fitting on it.

T77911S · 09-26-2018, 04:05 AM

notice the 2 relays on their side

Capt Bob · Capt Bob's Garage

Looks nice....now its time to figure out when to swap it out.

Capt Bob · Capt Bob's Garage

And to move the relays as well.

Capt Bob · Capt Bob's Garage

Cleaned the transmission ground strap, battery ground, engine started right up, idled smoothly, engine warmed up, weather was perfect - 78 sunny and dry. Went for a drive, and again for no reason the car shut down about 2 miles down the road. It didn't miss fire, stall, or anything just immediate loss of ignition. tack to zero. Tried cranking, fuel pumps running, and nothing...walked away for approximately 15 min then turned the key and magic, she fired right up. Ran perfectly back to my garage.

356911930 · 356911930's Garage

It sounds like the CDI needs to be rebuilt. They get hot and shut down. You can try to put some ice on the CDI next time it shuts down and see if it recovers faster.

Rahl

timc · 05:57 PM

when it shuts down, and will not start, just turn the key on soy have power (don't turn far enough to engage starter) walk back to the engine and see if you hear the whine from the CD, if you don't, that is your problem. Also, just for added info, when you turn the key on (again, don't try and start the car) you should also hear the fuel pumps run for a split second then stop.

Just an FYI, The other day, I went to lunch then the car would not start when leaving. I turned the key on, walked back to engine, I could hear the whine from the CD, so then I turned the key off and back on to see if the pumps ran for the split second, they did not. I reseated all the relays, then spun the fuses, went back turned the key on, pumps ran as relays energized, turned back off then back on and started the car and went for a nice drive....

Capt Bob · Capt Bob's Garage

Strange thing....I tried the turn the ignition (not far enough to engage the starter), didn't hear any whine, did hear the fuel pumps run, however they do not shut off. So I cranked the engine and she fired right up. Tried it again and same thing, fuel pumps run and do not shut off, crank the engine and she fires right up.

mark houghton · 10-01-2018, 06:09 PM

It's a safety feature....the fuel pumps aren't supposed to run but for a scant second (if at all) when you turn the key to ON. The usual culprit is that the connection to the air flow metering arm micro switch is disconnected, which will cause your pumps to run as soon as you turn on the key. Ordinarily, the pumps won't run until enough air is drawn in during cranking/running to deflect the metering arm and trip the switch.

For your issue, don't even focus on that. Are you certain you're hearing the pumps running, or could it just be the Lambda frequency valve buzzing (assuming you're running with an emissions Lambda circuit and oxygen sensor? Just need to be 100% certain it is indeed ignition related, and not fuel.

T77911S · 10-02-2018, 04:28 AM

you should verify no spark when it dies.
I would also verify power to the CD unit

the relays are not hard to move.

Capt Bob · Capt Bob's Garage

Well this morning I went out to fire up the 930 and go for a spin...the engine would not start. So I checked for spark and pulled the Nr 5 cylinder plug had my wife crank the car over and no spark at all. So I cleaned up the plug (Bosch Platinum RO 942's which wasn't bad at all) put everything back together and cranked again and it fired up. So I took the same plug out again and checked for spark. Obviously had a decent spark, the engine rumbled briefly to life, less the Nr 5 cylinder, until I yelled to the wife shut it off...

Anyhow, I verified this is a completely random ignition issue. Went for a quick ride and the 930 ran perfectly. So I'm back to the plan to install an MSD ignition.

Capt Bob · Capt Bob's Garage

Now to figure out when to get started with the MSD ignition...I need to get back to driving this 930 and to not worry about it randomly stranding me on the road. Fall is a great time for these air cooled super cars!

Capt Bob · Capt Bob's Garage

Does anyone have a solid rotor part number that I can reference to work in conjunction with the 6AL MSD.