Itinerant Air-Cooled

Hello all. I tried searching around before posting. I have had this 3x white 1979 Fuel Inected Beetle for a while and has always run perfect (except for brittle vacuum lines from time to time) or easy fix stuff. A week ago I went to my son's baseball game - dropped him off, ran to 7-11 to get him some Gatorade thought while I'm here I'll get some gas. Got about 5-6 gallons, started up, went down the street about 1000 yard, went to shift and when I pushed the clutch the engine died.

Being that I was already rolling, I popped the clutch and she sprung back into gear - although not much power. After the game I nursed the car back home (about 4 miles) and here she sits. I can start it up but she runs really rough and there is a lot of exhaust - just regular exhaust but runs like crap and if I don't feather the pedal it will die.

At first I thought maybe water in the gas but I drained it and no water - it's running very rich - I can smell the gas. I changed out the TS2 thinking it may be that but no luck. Only other thing I can think of is the cold start valve sticking open (or other injectors for that matter) or the double relay being bad. Usually when I see the relay go bad you don't get gas because it controls the fuel pump.

I'm thinking about getting a new relay but wanted to reach out and see what I may be missing.

Thoughts?

Good start on suspecting the Cold Start Valve (CSV). It may also be the Thermo-Time Switch (TTS), which controls the opening of the CSV.

If the TTS has failed and is providing voltage to the CSV full-time, then you can test that by disconnecting the electrical connection from the CSV. The CSV should then not open at all. You can doubly confirm the TTS as a culprit by measuring the voltage across the terminals in the CSV harness plug.

If instead the CSV has failed mechanically and is stuck open, then you can test by removing the fuel feed to it (and plugging the hose and the CSV inlet with appropriate fittings to prevent fuel leakage). Then the CSV can't possibly deliver any fuel into your intake.

Good luck

SlowLane wrote:Good start on suspecting the Cold Start Valve (CSV). It may also be the Thermo-Time Switch (TTS), which controls the opening of the CSV.

If the TTS has failed and is providing voltage to the CSV full-time, then you can test that by disconnecting the electrical connection from the CSV. The CSV should then not open at all. You can doubly confirm the TTS as a culprit by measuring the voltage across the terminals in the CSV harness plug.

If instead the CSV has failed mechanically and is stuck open, then you can test by removing the fuel feed to it (and plugging the hose and the CSV inlet with appropriate fittings to prevent fuel leakage). Then the CSV can't possibly deliver any fuel into your intake.

Good luck

The cold start circuit is electrically dead the instant you release the key upon starting. The TTS does not provide voltage to the CSV, the starter does. The TTS merely grounds the circuit that is only juiced during starter operation.

Remove the air filter/AFM and see if the flap is binding, check the vacuum hose to the fuel pressure regulator, and if you can run the engine just long enough, you might spot the potentially leaking injector by means of plug color/wetness.
Colin

Amskeptic wrote:The cold start circuit is electrically dead the instant you release the key upon starting. The TTS does not provide voltage to the CSV, the starter does. The TTS merely grounds the circuit that is only juiced during starter operation.

As usual, Colin is correct. I hadn't sussed that the cold start enrichment is only active while the starter is energized. My new lesson for the day.

The test I suggested for a CSV which is leaking because of mechanical failure is still valid, though.

SlowLane wrote:

Amskeptic wrote:The cold start circuit is electrically dead the instant you release the key upon starting. The TTS does not provide voltage to the CSV, the starter does. The TTS merely grounds the circuit that is only juiced during starter operation.

As usual, Colin is correct. I hadn't sussed that the cold start enrichment is only active while the starter is energized. My new lesson for the day.

The test I suggested for a CSV which is leaking because of mechanical failure is still valid, though.

Yes it is. The testing on Beetle L-Jet is a bit more challenging due to its haphazard parts placements adorning the engine. And the double relay is in the interior, so harness checking gets a bit difficult.
Colin

Add then, that neglected convertible tops begin to leak right onto the double relay...... It's gets fun real quick..

Fortunately this baby is garage kept all year long for preservation. It's pretty original and just past 50k miles. The FI has (had) been working like a champ. Without getting too crazy, and assuming I'm on point to replace the CSV, my plan is to cut the line to the CSV, stick a plug (likely a bolt) in there and a clamp it so I don't spring a leak. Sound like a plan or am I headed for trouble?

Just throwing this out there but could this be a bad coil? Couldn't be that easy could it?

Please don't use a bolt to plug your FI hose. Even with a clamp on the hose, 30 psi of gasoline will find its way past the bolt threads. Find something solidly cylindrical with a smooth surface and about 7.5 mm in diameter.

re: the coil. Can't say for certain, but I've found that an effective troubleshooting strategy is to make sure that the electrical/ignition systems are functioning well before moving on to blaming the fuel system.

RESOLVED!!! Finall. Ended up being a combination of the ECM and the AFM. Replaced the ECM with a known working one (after about a year and a half) and started right up and ran. The AFMhas a seal leak at the top. Sealed and runs a champ.

Thanks all!!!

Wow. Great perseverance there. Glad you were able to get it going. Pity that it's just in time to park it in the garage for the winter and that you missed out on two summers of going topless.