Carbon canister

[Teacherman]

I bought a 79 Spitfire 1500 about six weeks ago, and have been slowly working out various kinks left behind by the previous owner. My latest is puzzling, and I found it by accident. The PO removed the catalytic converter (left the EGR) to make room for high-performance headers. The carbon canisters are still in place. One is connected to via number of hoses, the other isn't connect at all.

I installed a hose to connect the two canisters because I saw that's was listed in a Victoria British catalog (I was replacing worm water choke and heater hoses at the time), and the car wouldn't start. It would crank, turn over, but not catch. Took off the connector hose, everything worked fine.

Then, I briefly covered up the connector hose line to the canister which was linked to the engine and the car died. By briefly, I mean a few seconds. I started it back up and covered up the hole; it died again. This, to me, seems like something is seriously wrong or something is misconnected. I haven't played with these lines, but it looks like I might have to.

As a side note, the car does have timing and carb issues. The timing is set to 0 degrees BTDC. It should be 10 degrees. If we set it to 10 degrees it idles around 1600 and won't come down. Idle adjustments on the carb do not help. Could these problems be related?

John

 

[TR3driver]

I started it back up and covered up the hole; it died again. This, to me, seems like something is seriously wrong or something is misconnected. I haven't played with these lines, but it looks like I might have to.

Does the connected carbon canister have an anti-runon solenoid on the bottom of it? If so, it might be that the ARS is getting power all the time. It is supposed to only get power when the ignition switch is off but the engine has oil pressure; which is accomplished with special connections to the OP switch and ignition switch.

Or it might be that the canister itself is clogged up, causing the same effect. They were supposed to be replaced every 50,000 miles or so, but no one ever does. Early ones could be disassembled for cleaning, but the later ones were welded together.

Not sure if this applies to a 79, but on earlier cars there was a valve built into the carb that switched the float bowl vent between the carbon canister (with the throttle closed) and a line directly to the air intake with the throttle open. The linkage to that valve can sometimes prop the throttle open and cause fast idle.

There should also be a bypass valve somewhere, designed to admit more air to the engine during overrun, that may be opening at idle. On some cars it's right in the throttle butterfly, on others it's a wart on the side of the carb.

 

[Norton47]

See the WIKI on Triumphs for the Buckeye articles.
There is a very good carb article that includes theory of operation for all these functions. Is written for TR6 but the concepts hold true and the testing can be adapted.
FWIW