[T3] FI Normal Wear Items

[Jim Adney]

On 23 Jan 2014 at 6:47, Adam Douglass wrote:

> As far as I can tell with a short glance, everything was there as it
> should. What I am wondering is what are the normal wear items on a 70
> Square FI system? I know the pump. I would probably go with one of the
> Ranger fuel pumps just to have something more modern and more
> available. What else do I need to look for? What all am I getting
> myself into? 

There are only a few things that tend to need service on the FI: the 
hoses, the overflow hose, and the voltage regulator. On '70-1s, the 
pressure sensor (MAP sensor) sometimes fails because only those years 
have the diaphram that sometimes cracks; most of those are still 
fine, but failures occasionally happen. The voltage regulators need 
to be replaced when they wear out, because low system voltage makes 
the FI system run excessively rich.

The pumps will last forever as long as the gas is clean. The main 
cause of pump failure is a cracked overflow hose, which will let in 
dirt and water from wheelspray.

> My car does still have the wiring from when it was FI. I think it
> would be an easy swap, and I would love to get my car back to being a
> true FI Squareback. 

I think it's worth doing, but there are probably more parts to the 
system than you are aware of. If you're not familiar with the system, 
it can be challenging. I'm not trying to talk you out of it, I'll 
help as much as I can, but you'll want the donor car to be side by 
side with your car until you get the transplant finished.

> Along those lines, do the FI cars get better mileage? Once tuned and
> running, how dependable are they? 

Some do, some don't. In general, if you have an earlier OG Solex 
system, it will get better gas mileage if it is complete and properly 
set up, including the correct distributor. Aftermarket carbs will 
probably do worse, mostly because they will be set up for performance 
rather than economy or low emissions. The FI will do better at 
emissions than any carb setup.

Once set up and tuned properly, the FI is extremely reliable. Most of 
my cars are still running on all their OG FI parts, except for the 
hoses, overflow hose, and voltage regulator.
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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