$100 Prize for the Guru that solves my Itermittent long cranks problem!

[mysocal911]

Originally Posted by gomezoneill

That is some mighty sloppy solder work there.

Yes, what a waste of rare Bosch CDI unit to incorporate a Mickey_Mouse aftermarket design.
Those Bosch eight pin 8 CDIs, i.e. used on the early 930s & BMW race cars which rarely if ever fail,
typically sell for $1,000 - $1500.

https://www.ebay.com/itm/Porsche-911-930-ICM-Ignition-Control-Module-BOSCH-0-227-300-003-19-C-402/153948638279?epid=110267163&hash=item23d80dcc47:g:KLoAAOSwnNZdjWsZ

[ivanuf]

Originally Posted by ClickClickBoom

4 dead CDIs? This would seem to indicate that something is killing them, my bet is the alternator is overvolting, killing the CDIs plenty of the caps in the electrical components are rated for 16V, not much headroom for overvolting. When my alternator was dying it took some electrical components with it.

Good point, it was repaired prior to engine install, but I will verify. Thanks

[ivanuf]

Originally Posted by 47silver

My 75 non turbo did the same thing. Sometimes it would start easily other times not so easy. Random. Had it towed twice thdn it started when back home. Checked everything. Pulllrd the distributor adjusted points etc. bought a pertronix ignitor. When i installed it i noticed that the black points wire in one section was bare from rubbing against the distributor cam lobe. It did not alasys touch but i assume would shrink or expand to cause a problem. Pertronix installed the problem was solved.

Very interesting discovery, since the distributor was bought new from the same supplier of the CDI I will pull it out and verify while I wait for the new CDI. I’ll keep you posted on this. Thanks
Ivan

[ivanuf]

Originally Posted by mysocal911

Yes, what a waste of rare Bosch CDI unit to incorporate a Mickey_Mouse aftermarket design.
Those Bosch eight pin 8 CDIs, i.e. used on the early 930s & BMW race cars which rarely if ever fail,
typically sell for $1,000 - $1500.

https://www.ebay.com/itm/Porsche-911-930-ICM-Ignition-Control-Module-BOSCH-0-227-300-003-19-C-402/153948638279?epid=110267163&hash=item23d80dcc47:g:KLoAAOSwnNZdjWsZ

Yes, I agree. At the time it seem like a good deal at $600 for a 8-pin distributor.
But now we know why.

[mysocal911]

Originally Posted by ivanuf

Very interesting discovery, since the distributor was bought new from the same supplier of the CDI I will pull it out and verify while I wait for the new CDI. I’ll keep you posted on this. Thanks
Ivan

Who is that supplier?

[spoke]

Originally Posted by gomezoneill

That is some mighty sloppy solder work there.

That PCB does not have solder mask on it. All the traces are open to the environment. Plus the PCB doesn't look like it was cleaned after final soldering. Is this a prototype board or a production board?

[kach22i]

Originally Posted by ivanuf

Very interesting discovery, since the distributor was bought new from the same supplier of the CDI I will pull it out and verify while I wait for the new CDI. I’ll keep you posted on this. Thanks
Ivan

Now I remember when I had a similar starting problem, and it would strand my vehicle.

The CDI went on my 2-stroke hovercraft, I probably messed it up by allowing the battery to die.

I eventually removed the electric starter and battery and just used the pull rope to start, but the intermittent problem persisted until I replaced the coil and CDI at the same time.

[mysocal911]

Originally Posted by spoke

That PCB does not have solder mask on it. All the traces are open to the environment. Plus the PCB doesn't look like it was cleaned after final soldering. Is this a prototype board or a production board?

What do you expect from a likely DIY project found on the internet?
Have to love the way the components are mounted for an automotive application/reliability, right?

[ClickClickBoom]

Originally Posted by ivanuf

Good point, it was repaired prior to engine install, but I will verify. Thanks

My alternator would provide 13.9-14.1 with German precision, then occasionally(once a month on a daily driver) would spike to 16-17v as per my installed voltmeter. My tach was the telltale, it spazzed out and the needle waved like a flag in a hurricane. Shortly there after my YellowBox speedo correction unit died followed by the speedo then the tach. 4 dead CDIs is a huge telltale, if they were infact dead.

[madkow]

Originally Posted by ivanuf

First let me clarify that this has been going on for a couple of years, and during that time I have read all topics on this forum of no-start, cold, warm, you name it I have read it.

The car:
1977 930 with 3.3 Pistons, and Ignition (counter-clockwise rotation, dual vac.) and all
The 77 CIS including 8-pin CDI with replaced internals with modern electronics by another vendor. Engine out all new top end service. The car runs great and it always starts.

Sometimes it will take just a touch of the key and it will start right up, cold or warm. Quick after a drive or after a couple of weeks parked it does not matter, if it in the mood it will start right up.

But 1 out of 3 it fells like it misses that sweet spot and you will have to crank it for several long no-start cranks until it starts. The amount of time it takes is completely random. It could be warm, or cold it does not matter.

What I have troubleshooted and replaced during the last 2 years.

1. Both fuel pumps and check valves.
2. Fuel Distributor and WUR set to Tony to repair and calibrate.
3. Removed MSD and replaced with CDI with modern internals.
4. New Distributor for 3.3 bottom end
5. New engine wire harness
5. Spark plugs and cables with proper OHM ends
4. New coil and coil wire proper OHM end
5. Ignition switch
6. Fuel Filter and New Fuel Accumulator
7. New high torque starter.

Ignition timing: I do not recall now, but we have verified several times and it is within specs.

Fuel Pressures: Also all values are in spec as per my WUR as per CIS Primer hand notes for Turbo Cars.


It is not a big deal because it always starts, but if really frustrating having this issue plus my SC starts right up every single time and it just feels good.

Any suggestions on what to try or test next, I ran out of options. The person that submits a suggestion or proper help to solve the problem will receive $100 via paypal as a token of my appreciation.


Merry Xmas!

Ivan

Hmmmmm....Sounds like the wires behind the
ignition switch. The spade connectors there
expand and contract over time and eventually loosen to cause intermittent starting issues. This happened to my best friend's 930 at a car show. The car started right up after wiggling the wires. Be sure to please disconnect the battery before attempting to tighten those wires.....

Unplug each spade and ever so slight with needle pliers squeeze
each connector, also be sure to clean the connectors with a little
sandpaper. Hope this helps...

[ivanuf]

Originally Posted by madkow

Hmmmmm....Sounds like the wires behind the
ignition switch. The spade connectors there
expand and contract over time and eventually loosen to cause intermittent starting issues. This happened to my best friend's 930 at a car show. The car started right up after wiggling the wires. Be sure to please disconnect the battery before attempting to tighten those wires.....

Unplug each spade and ever so slight with needle pliers squeeze
each connector, also be sure to clean the connectors with a little
sandpaper. Hope this helps...

Great idea, I will put this on my todo list while I wait for the CDI.

[fabregas]

Ivan, when your car have a puff puff sound or oscillation in the baffel plate when starting it’s fuel related. If your car have puff puff sound in the exhaust then is electrical related. Maybe fuel injectors issues.

[gomezoneill]

Originally Posted by fabregas

Ivan, when your car have a puff puff sound or oscillation in the baffel plate when starting it’s fuel related. If your car have puff puff sound in the exhaust then is electrical related. Maybe fuel injectors issues.

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[kltarga72]

CDI printed circuit board, looks like a couple components have been replaced along with trace repair. I would consider the circuit board suspect and most likely causing your intermittent problem. Cold solder joint issues.

[fabregas]

Your CDI must be bad or dead now but if your car have intermittent electrical issues in a CDI or in a ignition distributor your car will have back firing when starting or running.

[easyed8]

Concerning your 930 intermittent starting issue.
I would double check the plate height in the air flow housing and make sure it is set to the correct position. i believe that is - the plate even with the edge of the venturi. On cranking of the starter causes downward movement and activates the pumps. It is
important that the plate is in the correct position.. Perhaps also check the relay for the
air sensor and maybe the charge pressure switch in the intake.
best of luck with this, you deserve it!

Easy ED

PS: unplugging the safety switch is another option and quick check !

[ivanuf]

Originally Posted by kltarga72

CDI printed circuit board, looks like a couple components have been replaced along with trace repair. I would consider the circuit board suspect and most likely causing your intermittent problem. Cold solder joint issues.

Yes, the board has been sent back for repairs several times.

I will be changing to a Bosch 6-pin CDI.

I am thinking, how susceptible can these printed circuit boards be?
One thing that is way different from my SC on the 930 is that it runs HOT! Temperatures inside the engine bay are extreme!

Maybe this is the cause of all these circuit board CDI failures?

Anyway I order a 6-pin CDI from a fellow forum member, will update once I get the car running again with the new CDI box. I am also waiting for a new set of fuel gauges to post system pressures.

[ivanuf]

Originally Posted by easyed8

Concerning your 930 intermittent starting issue.
I would double check the plate height in the air flow housing and make sure it is set to the correct position. i believe that is - the plate even with the edge of the venturi. On cranking of the starter causes downward movement and activates the pumps. It is
important that the plate is in the correct position.. Perhaps also check the relay for the
air sensor and maybe the charge pressure switch in the intake.
best of luck with this, you deserve it!

Easy ED

PS: unplugging the safety switch is another option and quick check !

Thanks, will add to my to-do list and post findings after I try again with 6-pin CDI installed

[HarryD]

Still thinking CSV. You have reported the components appear to be functional.

As a test, you can pull the wire to the CSV, attach your voltmeter between the lead and ground and with the car cold, crank the engine and see if you have power to the CSV.

I would advise NOT messing with the CIS until you have ensured all other systems are functional.

OLD SAYING:
“There are 3 types of CIS Owners:
1) The guys with working CIS systems are probably out driving their cars so they won't reply.
2) The guys that tinker with their CIS systems and have them royally screwed up will keep you running in circles with suggestions.
3) The guys that have spent a fortune on Webers will tell you they're great to justify their expenditure to themselves.

Your choice.”

[bkreigsr]

Originally Posted by HarryD

OLD SAYING:
“There are 3 types of CIS Owners:
1) The guys with working CIS systems are probably out driving their cars so they won't reply.
2) The guys that tinker with their CIS systems and have them royally screwed up will keep you running in circles with suggestions.
3) The guys that have spent a fortune on Webers will tell you they're great to justify their expenditure to themselves.
Your choice.”

nice one Harry