[T3] Fwd: Engine Backfire
BilDylJ at aol.com
BilDylJ at aol.com
Wed Jul 18 07:40:05 PDT 2012
Thanks Jim
I appreciate the help.
My engine ran good for about 4 yr's. I had to leave it outside
(covered} for about 2 mo. and it wouldn't start after. I had it checked by
2 { Certified } VW mechanic's they got it running but it has been
backfiring on the left side 3 & 4 cylinders ever since. They can't stop it
from backfiring. I thought maybe the rubber rings on one of the injectors
were leaking air. There are no fuel leaks from the injectors or the hoses.
The engine starts and run's pretty good But it still starts backfiring
every time you let off on the throttle and hold it at a steady speed. {approx.
30 mph}
The engine is in a Trike motorcycle and no one wants to mess with it.
It must have been set up alright originally it ran good for 4 yr's.
Thanks Again !
Billy D
In a message dated 7/16/2012 5:40:58 P.M. Eastern Daylight Time,
jadney at vwtype3.org writes:
On 16 Jul 2012 at 16:48, BilDylJ at aol.com wrote:
> Can anyone out there tell me how to change the fuel injectors on a 1972
> type 3 engine.
I would not suspect injector problems as the source of engine
backfire, unless you have some non-Bosch injectors there. Non-Bosch
injectors can usually be easily identified by the fact that they
don't have the nicely rounded corners around the electrical
connector.
If you're having problems not related to leaking gas, I suggest you
go to the bottom of this message and check the tightness of all 2
push on electrical connectors.
There is very seldom any need to replace all 4 injectors, unless
you're talking about an engine that has not run in decades. If the
problem is gas leaking from failed original hoses crimped onto the
injectors, the crimp can be cut off and that short piece of hose
replaced. However, you still have to remove the injectors to do this.
Removing the injectors is a mid level job, neither easy nor really
hard, but it is cramped, especially working on the LHS.
Start on the right. Remove the air cleaner.
Unplug the electrical connectors from the injectors. Don't pull on
the wires, pull on the connector body. (You can feel the body thru
the rubber boot.)
Loosen the clamps that attach the multiple port "Tee" to the 2
injectors.
Rock the Tee back and forth while pulling it out of the injectors.
When it comes out gas will spill. Do this outside or with good
ventilation. No smoking.
Find a combination of 10 mm socket and short extension that will let
you get to the nuts in the center of the injector mount. Remove both
nuts and washers.
Pull both injectors outwards, along with the mounting hardware. Each
injector will have a large and small rubber ring. The small ring may
stay in the socket when you pull the injector out. The small rings
are still okay as long as they are plyable and not broken all the way
thru. The large rings are okay as long as they will still fit in the
phenolic retainer.
Note that there should be a small metal sleeve surrounding each
mounting stud. They may stick inside the phenolic mounting plate.
They are necessary to keep from breaking the plate.
The phenolic plate may be broken if the injector has been leaking. If
this is the case, you will also need to replace that rubber ring,
because it will be swollen too large to fit back in the plate. I just
swap these and let the gas slowly evaporate from the rubber and use
them again in a few months.
Installation is the reverse of removal. Repeat on the LHS.
I have all the parts and I can replace the hose ends on the injectors
if that's a problem for you.
I have had poor results with non-Bosch injectors. That's about the
only time I ever replace an injector. I have new Bosch injectors,
too, but I never recommend replacing injectors unless there's some
good reason to. They do NOT seem to wear out, but they sometimes
develop leaks that can't be fixed. Small thru leaks can be ignored.
If you are having injector problems, you should also check that the
electrical connectors are tight on the injectors. Bosch made a major
mistake at some point in their production: They reduced the thickness
of the material used to make the injector pins. This causes huge
problems with poor connectons there. To fix this, you must remove
each pin from it's connector body and very carefully squeeze it down
until it is snug on the injector pin. Then snap it back into the
connector body. This is actually more work than removing the
injectors.
--
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************
_______________________________________________
VWType3.Org mailing list - type3 at vwtype3.org
http://lists.vwtype3.org/listinfo.cgi/type3-vwtype3.org
Contact gregm at vwtype3.org if you need help with the list.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.vwtype3.org/private.cgi/type3-vwtype3.org/attachments/20120718/1fa39027/attachment.htm>
More information about the type3-vwtype3.org
mailing list