View Single Post
Porschepetter Porschepetter is offline
Petrolhead
 
Porschepetter's Avatar
 
Join Date: Jun 2025
Location: Fredrikstad, Norway
Posts: 16
Garage
Quote:
Originally Posted by smadsen View Post
My CDI box failed. After a 30-minute heat soak the motor would start to splatter and quit. Found a Porsche shop with a known good CDI for back to back test. Sent the old box out to a guy who fixes them. I believe he just touches all the solder joints and replaces whatever fiddly little gizmos on the circuit board that have failed. All in, a couple hundred dollars.
Hey smadsen,

Thanks for sharing your experience – that actually sounds a lot like what I’m seeing.
The “runs fine for 30 minutes, then starts to splutter and quit” description is pretty much spot on for my issue.

Good to know a bad CDI can behave that way after a heat soak. I might try to source a known good one for a swap test like you did – seems like a quick way to confirm. Also good tip about getting the old one repaired instead of buying new. A couple hundred dollars is way better than the price of a brand new unit!

I’m also going to try the things Bob suggested – checking the points gap and making sure the CDI is getting stable 12V – just to rule those out before I swap the box.

By the way, do you remember who you sent your CDI to for repair? Always good to have a trusted contact if it comes to that.

Thanks again for the insight – really helpful to hear from someone who’s been through the same thing.
__________________
1976 Porsche 911 S, Coupe
1978 Porsche 911 SC, Targa
1983 Porsche 911 SC, Coupe
1983 Porsche 944 Coupe
Old 08-05-2025, 04:32 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)