I have a 1970 Volkswagen Squareback. It has fuel injection and has a problem keeping the RPMs up enough to keep it from stalling. I also notice a fuel smell. It will run well when its at a speed of 30 mps or higher. Any suggestions for a do it your selfer?
This fuel injection system is a nightmare to work with.
First off, check the rubber intake runner seals at the plenum for signs of wear or rot. I suspect you have a vacuum leak somewhere. You should be able to find replacements at a VW shop. Also check to make sure the intake gaskets at the heads are not leaking. Spraying carb cleaner down here while keeping the engine idling is how I normally do it. If the engine levels out, you found a leak.
Next, since you smell gas, is to check all the fuel hoses for signs of leaking. I’d be inclined to simply replace all the rubber hoses with new. Remember to get fuel line rated for fuel injection. Regular fuel/emissions hose is inadequate for the high pressure of the fuel injection set-up. If I remember correctly, the rubber hoses on this system are all clamped down, no fittings to worry about, and simply require cut-to-fit hoses you can buy in bulk.
I was 18 or so when these cars started comming in the independant VW shop I worked at, and would start sweating as soon as I heard it was here for a drivability issue.
Like Knuckles said problems are too numerous to list. I think this car could be considered a “forced to diysefer”, as most would refuse to work on it,OK maybe you would find some kind of eccentric old fart wanting one last chance to fix one.
One thing that does mess these cars up is the Fuel Injection harness grounds to a tab near each head, if that ground shows high resistance nothing works right.