Stumped, motor won't fire on #1 Options

[Rusty]

We're stumped. I even caved and took it to my local VW expert for help.

Background: The car had been stored for 7-8 years. Before storage, it had been worked on by a third party (including replacing the distrubutor, IIRC). When the car was stored, it was running poorly.

Symptom: Car won't fire on cylinder #1, but fires fine on 2 thru 4. (Was it firing on #1 prior to storage... I dunno. I stored it out of frustration.)

Motor: 1973 1.7L, dual Weber carbs, Pertronix points replacement in 009 distributor.

Details: Car has air, fuel, and spark.

Air: Valves are adjusted correctly (.006) and timing is on. Compression on all cylinders is 90-95 pounds. Heat exchanger removed and checked for obstruction. Covering/blocking the air intake on #1 has no effect to the motor running.

Fuel: Carb on cylinders 1/2 has been cleaned and adjusted. We can watch fuel go into the cylinder. Some of it ends up as white smoke going out the exhaust. There is an oil leak on the drivers side of the motor and the oil smells faintly of fuel.

Spark: Plug wires are routed correctly. Taking a plug out and laying it on engine tin, spark is strong. Wires, cap, rotor, and plugs have all been swapped out. Pulling the plug wire on #1 at any RPM results in no change.



I talked to my guy today... he's very well regarded in the area. He's as stumped as I am.

Any thoughts?

[Rusty]

I do appreciate all the replies. I'm taking notes.

maybe the fuel isn't fully atomizing? Try switching the jet stacks and see if the problem follows...

That's an interesting idea. As part of the troubleshooting process, he tore down the carb and cleaned it. I can try swapping the jet stacks though.

Depending on the linkage, swapping the full carb from one side to the other could be a big deal. I'd def start with the jet stacks on the same side. It shouldn't take more than a couple minutes to switch 1 to 2. Hopefully the problem will follow and all that will be needed is a good jet cleaning.

More work, but it would certainly be a good test.

intake valve not opening, bent pushrod or something?

TDC on number one feels right. Valve adjustment went okay.

Also check the idle jets and mixture screw port for obstruction

Roger.

Goes back to my compression check question. He said his mechanic tested. Rusty, do you trust said mechanic's answers? We know it isn't timing, so it has to be fuel or compression. (Assuming the plug you tested for spark was actually the one pulled from that cylinder.)

Yeah, I do. But a second look at the compression on #1 might not be a bad thing. Yes, the plug I tested was the one pulled from that cylinder. Got the same result with the replacement plug.

Weber carbs run on the idle circuit about half way thru their range. A clogged idle jet or idle passage will cause this. It is much more common than you would think. Pull the idle jet and check it for infinitesimal debris and blow it out. If that does not cure it, pull the carb and clean the idle circuit with carb clean. Install a new inline fuel filter. Clean fuel is the key to Weber’s.

Charlie

Thank you. I'll double check his work if all else fails.

Dirty plug? Pull the plug and wire wheel off the carbon?

Zach

One of the first things I did when I pulled the car out was clean the plugs. I've since replaced them with another set. (IMG:style_emoticons/default/smile.gif)


I'll pick up the car tomorrow.