Spark is bad? Never ending issues.

[bobswei]

I've been trying to trouble shoot this project for quite some time. Running rough, no power, black spark plugs. I've replaced THC, set fuel pressure, timming, points, replaced MPS with new rebuilt one with correct part number, swapped different plugs. No improvements. I decided to check all ignition wires with my timming light. I don't get a consistant flash. So, I recorded the spark plug while cranking and it seems the spark goes off to the side and back to the middle. Here's a screen shot of the video catching the spark on the side. What causes this? and could it be the issue?
Thanks...

[John Rogers]

Several things to check: Wait until it is dark with no lights around and run the engine and look for spark jumping from wires to a ground or the blue glow. See if you can find someone that can measure the voltage at the plug, compare it to Porsche's spec. Look at the inside of the distributor with strong light and magnifying glass to see if there is ant burning. Measure resistance of the plug wires, compare to specs. Look at boots inside to see if there is any oil, clean as necessary. If you have points, get rid of them.
John

[jess p]

Don’t throw your points away just yet. Solve your problem first which is a weak ignition. Adding another electrical parameter will just complicate the matter further. I have bought a pointless ignition setup that was bad from the factory.

[bobswei]

John, just came in from my dark garage. No signs of arching so tomorrow, I'll go to the other suggestion you had. Good idea about the lights out test. I recall checking continuity on 911 plug wires so should be easy. Measuring voltage at the plug maybe a more difficult find.
And Jess, yea I do want to make it run per the factory setup before modes. I have an MSD on a 911 and really like it. But not yet, for the 914.
Thanks for the responses....

[bobswei]

I've been holding off till I had an update. Well, I don't have an update. I did decide to order ignition wires since they may be a culprit and the current ones didn't match from side to side. One side was set for the little cap to be on the plug and the other needed just the threaded tip. I open the box of wires and this is what I got. Doesn't look correct to me. Thoughts?

[Dave at Pelican Parts]

Two long sockets for the front plugs, two short ones for the rear plugs. That's what I remember.

--DD

[bobswei]

Originally Posted by Dave at Pelican Parts

Two long sockets for the front plugs, two short ones for the rear plugs. That's what I remember.

--DD

OK, that makes sense, and you would know. All the old plug wires are the same length but I did notice the plug socket went a "little" further in, to reach the plug, on a couple of the cylinders. Maybe 1/2". So, I guess I'll install them.
Thanks!!

[John Rogers]

If you still have some of the money the Federal Government handed out, contact your friendly local Snapon tool person and buy their ignition voltage tester which can measure voltage with it's clamp on wire system. I had one for the 914-6 race car and with the MSD system and 9mm plug wires I made myself it told me I had 18K volts at the plug at idle. The voltage went up as RPMs did!

I had to make sure the plugs were clean and the wire boots were clean inside or there would be voltage leaks like crazy. I blew a couple engines and oil does get everywhere !
John

[bobswei]

I installed the new wires yesterday and now I can't get the car to idle. And when you give it gas, it takes a while for the engine to rev up. Anyway, the wires were not correct since they were too short and stretched at both ends so I returned them this morning.

Tried to find snap on voltage tester and only got this result:




Nothing that shows voltage. Also found this on another site:



I don't believe it shows voltage either. But I'm not an expert on things that shock you.
I'll order wires from a real Porsche after market place and continue the journey.
Thanks for the help.

[John Rogers]

When I bought mine, Mark the mechanic who built my racing engine said I had to go to one of the trucks as they are expensive! It looked something like the lower picture you posted. If I remember it hooked directly to the + and - battery terminals and clamped to the plug wire with the voltage in a little window.
John

[bobswei]

Well, I think I found some other voltage testers for in the $150 to $350 range. Not sure I want to keep spending with no result.
But, I did check resistance today. All the plug wires show 0.6 ohms. The coil wires shows 2.4 ohms, which I thought it should be the same as the plug wires. I may have a spare I will try in the next day or so. I was talking to my dad about it and he was a mechanic in the Airforce. He said, in Korea, ignition wires were hard to get so they would use bomb fuses. I may try that next.
Thanks again.

[joesh]

FWIW I had problems like this for a while and ended up buying a 123 distributor. Most all the problems went away. Poof! For me it was totally worth the price.

[bobswei]

Originally Posted by joesh

FWIW I had problems like this for a while and ended up buying a 123 distributor. Most all the problems went away. Poof! For me it was totally worth the price.

Joesh, Yea, I'm starting to think about replacing the ignition system. Just the other day, I added my last resort. A new distributor cap. It started up, ran terrible, wouldn't idle, died and could not start again. The more money and new parts I get, the worse it runs. I have a MSD in another car and works great. Maybe that or the dizzy you mentioned.
We're going on a vacation so when we get back, I'll take another stab at it.
Thanks for the input.

[Dave at Pelican Parts]

If you have another car available, try swapping parts to see if the problem follows the parts or not.

Where are you located in N CA?

--DD

[bobswei]

Dave,
No other 914 to trade parts with. I have replaced almost everything. MPS, points, dizzy cap, wires, CHT sensor, plugs, set timing, point gap, checked injectors (visual), compression, hum? what else did I do...
I'm in Fairfield, Solano Co. We used to autocross together back in the 90's. Are you suggesting, you have lighter fluid and a match?
Thanks,
Bob

[Dave at Pelican Parts]

Rats. It would be convenient to have another car to swap parts with for testing.

--DD