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Greg
Greg, Technician
Category: VW
Satisfied Customers: 6997
Experience:  17 years Shop Owner /Technician. 27 years experience,
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My 78 vw van has a now and then problem, runs great and for

Customer Question

My 78 vw van has a now and then problem, runs great and for some unknown reason seems to drop a cylinder and has little power..have done all spark related things,,Darrel
JA: What is the model of your '78 VW?
Customer: Campervan
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Yes plugs, points coil wires air filter ck for vacum leaks
JA: How old are the hoses? And what driving conditions do you most often encounter?
Customer: many of the hoses are new, seem under any condition because of the problem it doesn't get far from home.
JA: Anything else you want the mechanic to know before I connect you?
Customer: problem seems to fix itself only to reappear later
Submitted: 4 months ago.
Category: VW
Expert:  Greg replied 4 months ago.

Hi, I'm Greg (Indy-Tech).
Welcome to JustAnswer. I'm reviewing your question now, and will post back with your reply ASAP.
Rgds Greg.

Expert:  Greg replied 4 months ago.

Did you replace the distributor cap and rotor .

These two are the most common issue if the plug wires have been replaced .

When you are having the problem lift the engine cover and (best at night0 and look at the

engine wiring harness coil ,plug wires and distributor for arcing sparks

this will show you where you are losing HT voltage and dropping cylinders .

Need further assistance with this issue then please get back to me with the reply box below .
After rating there is no further cost for any other question relating this issue .
Kind regards Greg

Customer: replied 4 months ago.
I have changed the cap rotor and condenser and see no sparking in engine compartment. The vw will go up hill like new. Maybe the next day hardly make the hill. I work on it , maybe it goes fine maybe not, but the problem always seems to return ,Darrel
Expert:  Greg replied 4 months ago.

Which engine do you have fitted .

The original air cooled 2.0L Germany or Brazil.

Greg

Customer: replied 4 months ago.
Orginal 2,0l Germany
Expert:  Greg replied 4 months ago.

Check the Coil to distributor to plug HT wires that they are routed good and not shorting out on the engine .

Only bosch W8CC should be used .

See this one time due to a cheap china made condenser, was this replaced for a bosch part.

Greg

Customer: replied 4 months ago.
I'll have to check, but I'm sure it a Bosch.,Darrel
Customer: replied 4 months ago.
I'll have to check, but I believe that they are bqsch
Expert:  Greg replied 4 months ago.

Do a leak down test on each cylinder with a hot engine, may have a valve issue

Also possible is a weak valve spring .

Greg