1979 VW Convertible will start but immediately dies

[Sickies Garage]

I have a stock VW with fuel injection…car will start but immediately dies. I bought the car this way and the prior owner had no luck finding the issue. I have gone through the double relay and all tests check out. I have three double relays, checked them all and tried starting with each one…no luck. Fuel pump turns on when in start mode and when I hold the flap open in the air sensor, as it should. The brown wire is connected to the battery I have a good ground at the computer and relay. I don’t see any vacuum leaks. I don’t know what else to look for. Car starts right up when bumping the key and sounds strong.

[busdaddy]

Any big vacuum leaks you might have missed?, done a smoke test?

Have you done a fuel pressure test?, does the pressure remain up when it's quitting?

Maybe connect a test light piggyback onto the fuel pump terminals to see if power to it quits when you let goo of the key. If the pump makes enough noise a helper can listen for it as an alternative. That'll narrow things down a little.
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[Sickies Garage]

I can’t determine any vacuum leaks. Fuel pressure is good but I didn’t do a pressure test test. (Unplugged a fuel line to injectors and turned key… good flow) I did put a test light on the double relay and saw the light turn on while cranking and running, then turned off when engine died,.

I’ll see what the smoke test is and do one of those.

One thing I have noticed in other 79’s is that the MAF plugs in from the side facing you in the engine compartment, mine plugs into the backside

[volksworld]

its starting off the cold start valve but the 4 injectors arent working...theres a single wire(as in all by itself from the firewall grommet) in the FI harness that goes to the points side of the coil ...it tells the computer to fire the injectors when the points close...it may be hooked to the wrong thing....iirc bad or disconnected head temp sensor can be a problem too...look into all the injection harness plugs...the wire terminals can pop out of the plastic plug and not make contact with the pins on the component they are plugged into...also over zealous trouble shooters tend to cram the point of a test light into the plug terminals so deep that they spread the contacts so far apart they'll no longer make contact...get the numbers off the black cover on the air flow sensor...maybe someone stuffed something on off a bus or digifant water cooled car?(or not even vw?)or its upside down?...the plug should be facing you just above the oil filler cap

[wimkever]

Run a wire off the + 12 volt at the alternator to the + side of the coil (terminal 15) and start the car. If it keeps running you're dealing with a bad ignition switch.
Don't forget to remove that wire afterwards.
_________________
a beetle is like a cocker spaniel, always funny but sometimes not listening

[Sickies Garage]

Thank you for the suggestions…I will check out all of your ideas. Stuff I haven’t checked yet. I didn’t mention that the car had electronic ignition when I got it and I put the original one back in it. (Points)

[Sickies Garage]

So I was checking voltages and grounds and found that pin 16 on the ecu connector is not testing as a good ground to the engine block. This wire apparently should be grounded under the left side air intake on the engine block along with pins 5 and 17. I can not find any of these grounds to the block, even though the other 2 pins test good. Can I just cut a block ground into pin 16 under the connector cover?

[busdaddy]

It would be better if they had their own wires, all those grounds terminate in a couple of ring terminals that screw to the top of the alternator between the D+ terminal and the fan shroud.
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[Sickies Garage]

Thx…I’ll check it out

[Sickies Garage]

[Sickies Garage]

[Sickies Garage]

[busdaddy]

Probe for power at 88b on the DR (key on), if yes then it's time to have a good look at the resistor block.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[VW_Jimbo]

[Sickies Garage]

Voltage at 88B is good with the key on.
Car will start without the screwdriver holding the flap open. (I hear the pump run with ignition on when I have the screwdriver holding the flap open so I know the pump is good)

Checked the resistor block and have 12v at each injector.

[Sickies Garage]

Voltage at 88B is good with the key on.
Car will start without the screwdriver holding the flap open. (I hear the pump run with ignition on when I have the screwdriver holding the flap open so I know the pump is good)

Checked the resistor block and have 12v at each injector.

[Sickies Garage]

I’d like to test the coil wire that fires the injectors for continuity….Does the other end of that wire land at the ecu connector or the double relay?

[Lost69Convertible]

Sickies - If you start the car with the screwdriver holding the AFM flap open, does the engine keep running or stall?
(keep the screwdriver in place, don’t remove it)
_________________
1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible

[busdaddy]

[Lost69Convertible]

I’m wondering if the fuel pump power switch contacts inside the AFM have been monkeyed with. And the air flap has to be opened a lot to power the fuel pump.
_________________
1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible