Volkswagen: Fuel Injection 79 VW Superbeetle, air flow meter, fuel injection system

Question
QUESTION: Our Superbeetle was running on only 3 cylinders and a VW expert said it needed a new cylinder head.  We replaced both cylinder heads, gaskets and 8 push rod tubes.  Then it started but only stayed on for a few seconds.  Our mechanic (who knows VW's but is not an expert) replaced the temperature sensor on the 3rd cylinder head, the condensor, and now the air flow meter box.  He got it to start and stay on for 5 minutes, but it still died.  While it was on for 5 minutes it back-fired a few times.  Now it starts but only stays on a few seconds again. We think it's fuel injection related and researched past advice you have provided but don't know what to do next.  We know we want to keep the fuel injection system which is what you recommend and not change to carburetor, but we're getting tired of having to deal with this.  Any suggestions?
Thank you!
Darcelle

ANSWER: Hi Darcelle,
There is something called the 'auxillary air valve'.  It is in the front of the engine, and you can identify it with a book.  It provides extra air to a cold engine so it runs until it's heated and than turns off.

If you get a VW shop book (try e-bay) it has all the do-it yourself tests in order to troubleshoot it.

Don't be afraid of the fuel injection!!  It really is simple if you take some time to study it.  There are more mechanical parts than electronic, and you should be able to troubleshoot it with little-to-no problems.

Best of luck!

Ron

---------- FOLLOW-UP ----------

QUESTION: Hi Ron,
Well, we replaced the auxiliary air valve.... That didn't fix the problem.  I am wondering if I should replace the ECU?  We replaced it about 6 months ago with a used ECU which I think was just used - not rebuilt.  Do you think we should replace the ECU or is there something else we are missing?  Your advise is very much appreciated!
Darcelle

Answer
Hi Darcelle,

I never heard of the ECU causing this type of problem.  (although it may be possible).

I would remove the cold start injector and have someone turn the car over.   See if it is working -- just aim the spray into a coffee can.

Let me know what you find out.

Ron