inconsistantly consistant

[Jeremiah P]

I acquired my first 914 about four months ago. She's had been treating me well during these first months. I am now having a bit of a problem. She's a 73 that has been converted to a single double barrel carb, a permatune ignition module, still has points though, but no condenser that I can locate?, and a 12 volt, solid state, in-line fuel pump. The can basically shuts down when it feels like it and given any where from ten seconds to ten minutes to start back up. The rpms just drop to zero, no sputtering, no warning. I took it to a Porsche Only mechanic and he said it wasn't getting fuel. He moved the fuel pump so it would gravity feed but didn't replace it and charged me 300 bucks, no change, yucky yuck. I then replaced the old fuel pump myself. I also noticed some arcing in between the SS plug wires I had., so I replaced them as well, still no change. I have also played with the key a bit by wiggling it when the car is running. This doesn't make the car stall. Could it be the ignition switch in the steering column, bad coil, carberation, ignition module? I fear there is a short, or the arcing in the old plug wire did damage to another component.

Any thoughts or suggestions on replacement parts would be greatly appreciated

Jeremiah
miahmoon@hotmail.com
480 824 8222

[Dave at Pelican Parts]

Does the tach drop to zero before the engine does? If you're driving down the road in gear, will the tach just drop while you're coasting? If so, that indicates a problem with the ignition system--the points/condensor and likely the permatune thing as well. You might try going back to a stock points/condensor/coil setup to troubleshoot, bypassing the CD box.

--DD

[Jeremiah P]

Yup, RPM's just drop to Zero even while coasting. I' ll try bypassing the CD unit. Would you recommend a particular replacement CD unit, Or should I convert back to the points/condesnsor set-up.

Jeremiah

[Dave at Pelican Parts]

Try going back to points & condensor, at least for testing.

Most four-banger 914s work reasonably well without a CDI. I think MSD is probably the most popular one.

--DD

[Jeremiah P]

Dave, I bought a condenser so that I could bypass the CDI unit but I am unsure of which wired to connect and/or disconnect. There are a total of six wires coming from the CDI. Green And Black go to the Coil, Yellow to the Points, White goes to the relay board, Purple to the what I believe to be power, since it is in parallel with the power lead to the fuel pump and a Brown one that is grounded to the coil mount.

Any info would be appreciated since I do not have the manual on the CDI unit.

Thanks
Jeremiah

[Dave at Pelican Parts]

Stock wiring:

Black/red from relay board to coil (+) terminal; this powers the coil and has +12V when the key is on.
Black/purple from relay board to coil (-) terminal; this is the tach signal wire.
Green from points (by way of the condensor) to the coil (-) terminal; this is the points signal wire.

The red stripe and purple stripe fade over the years, so they can be hard to tell apart. The power wire is thicker than the tach signal wire, though.

Your fuel pump may or may not be hooked up to the coil power terminal, depends on how the person who did the conversion wanted to do the work.

--DD

[Jeremiah P]

Thanks for the info Dave, however the wiring isn't stock. I had found the ID number for the CDI and located some specs online at permatune.com. They have detailed tech support for each model CDI unit with before and after hook-up diagrams, which was very helpful. If others have permatune problems I would lead them inthat direction for now on. In the end I found the the coil mount had been faulty and the coil had melted and grounded out which was causing the CDI to malfunction. I replaced the coil and mount and installed the condenser thus by-passing the CDI. It seems to be running with no problems as of yet. Thanks for you guidence. I know have a much better understanding of my car's ignition system now. I may just stay stock, but I can tell a slight difference in the performance. Thanks again.

Jeremiah