Car won’t fire when using starter but pushing starts it

[cm0435152]

On July 4th, I purchased my 1975 1.8 ltr Porsche 914. While I knew there were some flaws with the machine, it is just the right color to take to the football games on Saturdays in the fall and there is plenty of room for the tailgating stuff.

Jerry who is my mechanic is a former VW and Porsche guy, and after I got the car, he completed a thorough tune up (about $700) and it runs like a dream. I also have a 1973 Karmann Ghia and you can imagine my delight stepping from the Ghia to the Porsche. However, there remains one major problem.
About every two weeks, it will decide not to start. When that happens, the engine will fire and then die with no possibility of starting again using the key and starter. I do have roadside assistance through my insurance company but they are getting tired of getting behind the Porsche and pushing me so I can “pop the clutch”. Also, the balloon of smoke in which they are engulfed has made them a little reluctant to take the service call. There is no question that the engine becomes flooded when this happens, as the smell of fuel is prominent.

This “push start” process has always worked and after it has been started that way, I am good for a key start for another two or three weeks. I have tried finding parking places on a hill but sometimes those are not available.
In addition to the tune-up (new plugs, wires, clean the injectors, set the timing, new points) my latest effort to fix this has included a rebuilt starter and a voltage regulator since Jerry thought the old starter might have been drawing too many amps. However, the day after the rebuilt starter was installed, I came out of the office and you guessed it. It fired then died and then my call to the towing company. They pushed and we started again.
I wonder if anyone else has had this problem and can help identify what next to replace or investigate. I have discussed replacement spark plugs but Jerry isn’t confident that hotter spark plugs will help either.

I am confident that Jerry has checked all of the normal culprits in his troubleshooting but surely there is a simple reason for this. It seems like a math problem where we are forgetting to carry the one.

Any ideas?

Chucke1

[RandyLok]

When it dies and won't start again.... Does if fail to crank, or does it crank and just not fire?

Either way, the first thing I would check is the ignition switch. The plastic insert in these things tends to crack and cause problems like this.

-Rand

[914GT]

I'd check your battery terminals, cables, and battery condition first. When cranking you're pulling a large load on the battery and if too much voltage drop, you won't have enough to energize the coil. Push starting eliminates the starter draw and more hence voltage at the coil.

[Dave at Pelican Parts]

Flooding, though. That might not be poor voltage...

Try unplugging the CSV (cold-start valve) that is attached to the inake manifold. Just unplug the wires and see if that helps. The CSV should not be active or needed at all below about 40F (or lower, depending on who you ask). However, if one of the wires going to it gets shorted to ground, the CSV will spray the whole time the starter is engaged. (Guess how I know that?)

That's the first thing that pops into my head for intermittent flooding when trying to start.

--DD

[914GT]

True, but it's always good to check the simple things first and make sure you've got a good stiff voltage source for the starter, ignition and other electrical loads.

[cm0435152]

Thanks for the ideas.

We have checked the battery, the terminals, the cables, and that is why a replacement starter was added. Plenty of voltage from the coil but not enough sparkplug to ignite all of that fuel.

Last night was my latest encounter with not starting and while it will crank fine, it will not fire.

I came back the next day with pick-up and tow rope in hand and we needed to pull it about 50 ft and when it started - the exhaust smoke was massive. In fact, some folks walking by thought things were destroyed. After it cleared out and would idle smoothly, I drove it home without any more problems. Starts fine today but next week will be another story.

[hardflex]

Make sure there is spark when it won't start too. But it sounds like flooding. Pull a plug when it's not starting to see if they are wet.

[hardflex]

and remember to park on a hill if you can... :-/