[T3] 1972 VW Type #3 Fuel injected engine

[Jim Adney]

On 12 Mar 2012 at 9:26, BilDylJ at aol.com wrote:

> I found a used distributor with a set of trigger  points in it. I have
> a local guy working on the trike. The engine was  running pretty good
> but after it warmed up when I held  the throttle at a steady speed. {
> 30 mph  } it would backfire  through the mufflers. If I  didn't
> accelerate it would get worse and  louder until I did accelerate. My
> local guy admits he don't remember much  about the old type 3 engines.
> He said  he thought it was the lower Trigger points, I thought it was
> a  fuel injector because It would always backfire from  the same left
> side muffler.

FI trigger points don't wear like ignition points. The only wear 
would be to the rubbing block. To minimize this wear, clean off the 
cam every time you have the trigger points out, and apply a thin 
smear of clean grease to it. I can reset used trigger points, but 
there's no way for you to do that.

A couple more things to check:

Verify that the hose from the pressure sensor is connected at each 
end and hasn't fallen off. Also suck on the pressure sensor port to 
make sure it still holds vacuum.

Measure the battery voltage at medium rpm. It should be 14.1 - 14.4 
V. If it is below 13.5 V, replace the voltage regulator with a Bosch 
30-019. Low system voltage makes the FI run rich, which will produce 
some of the symptoms you describe.


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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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