71 911T 2.2 Lt.

[dan3035]

I have a 1971 911T with a 2.2lt engine.(71000 m) When i start the car (cold) the engine pops and farts for approx. 2 min. Is this a timming issue.?? Thanx in advance D. from the great white north.

[ttweed]

This sounds like a fuel enrichment problem, not a timing issue. When the engine is cold, it needs a much richer A/F mixture to run smoothly. As it warms up (after your 2 minute "popping and farting" period), a leaner mixture works fine.

TT

[quattro]

dan3035, my '71 T does the same... I think the Zeniths might need a bit of freshening.
My plan is to adjust the valves, do a complete tune up, and then finally play with the carbs...
If all else fails a set of Webbers should fix the problem...

BTW one of these days we should organise a country drive with few other early cars in the area... I think you might have e-mailed me, if not we should talk...

Cheers
Martin

[ttweed]

Originally posted by quattro
If all else fails a set of Webbers should fix the problem...

The Webers I have do the same thing on cold starts. There is no provision for a "choke" on IDA40s or 46s, or PMOs for that matter, so fuel enrichment on cold starts is left up to the accelerator pumps. A few pumps of the gas pedal before turning the engine over helps by injecting some fuel into the barrels to get the motor to start, but until the combustion chamber and intake manifolds warm up enough to help atomize the fuel/air mixture properly, they always run rough for the first minute or two.

"False air" from intake leaks can help make the condition worse, so maybe rebuilding your carbs might help, but I would try just making sure your float levels are correct and your accelerator pumps are putting out to spec. Increasing the idle jet size a bit may help. Using an 02 meter or a gas analyzer to really see what it's doing as far as mixture during these varying conditions would help you tune it, otherwise it's just trial and error experimentation.

TT

[pwd72s]

I would STRONGLY suggest that you check to be sure the original 2.2 T "cold start" system has been unhooked. It consisted of tubes, stuck up in the plastic air cleaner assembly, with a little hole drilled to feed each carb. throat. What happens if this STUPNAGLE ENGINEERING system fails? You don't want to know...and I don't want to tell you how I know, since my old '70 T was sold soon after such a malfunction.