Engine misses & cuts out under load.

[edhughes]

First, I have searched the forums for a couple hours now to no avail so I decided to post my problem.

71 fastback fuel injected. Just got it a coupe months ago.

brought it home on a trailer for a couple of reasons, brakes among them, today was the first time I tried driving it on the road.

While I was working on the front brakes I cleaned the fuel pump and put on a new filter. I cleaned & gaped the plugs. Compression is around 120 on all cylinders. Electronic ignition upgrade so no points. The engine starts easily and runs and idles fine sitting in the driveway. When it's sitting still I can rev the engine up and it sounds smooth, no misses or coughing. Take it out on the road and accelerate and it misses, coughs and cuts out really bad.

Any suggestions or direction to posts on the topic I've missed?

[Bobnotch]

When you converted the distributor to electronic points, did you add 3 drops of oil to the felt pad under the rotor? Just asking, as those drops of oil lubricate the mechanical advance mechanism, and that's what your problem sounds like...no advance.

Another possibility is you have a coil getting ready to die, and the way you descibe it is exactly how it was when mine died (carbs and points). Granted I spent 3 days chasing every part of the engine (but the engine) to find it.
Just a couple of places to look.
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Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120

[sjbartnik]

Missing/stumbling under load is a classic symptom of timing set incorrectly (too retarded) so you might want to check that first.
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1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[Donnie strickland]

It can also be a sign of bad plugs/wires. Watch your wires at night and see if they're glowing blue.
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71 Elm Green FI A/T Squareback

[KTPhil]

I'd check timing and then check out the TVS with a VOM and adjust it.

[edhughes]

[edhughes]

OK Checked the timing, it's right on at 0 degrees which, according to the book, is correct for a "U" engine. Swapped in a different coil and nothing changed. Advance appears to be working OK.

At this point I'm pretty sure it's not ignition related. I put a vacuum gauge on the port that feeds the distributor There's almost no vacuum at idle, when revved the vacuum goes up to maybe 15 inches but fluctuates quite bit.

So. probably a vacuum leak somewhere. Maybe at the injector seals? I'm thinking that if it's starving for fuel when under load that may produce the symptoms I'm seeing? I guess the only way to know for sure is to take out the injectors and replace the seals Any other likely places for vacuum leaks?

I'll start searching the forum for info on how to test and adjust the TVS. Seems to me though that if it were the TVS I'd see symptoms when just revving the engine in the driveway?

[ddare]