2.7 CIS cold start issue???

[bubbasev]

Hey guys, need some help. Feel certain that my 74 911 won't start due to flooding. Can cold start valve stick open? If so, would disconnecting wires perhaps yield temp fix? Where EXACTLY is this thing on my motor!! Feel certain that motor is flooding due to gurgles, pops, immediate start for a second or two and then dying...??? Thanks, Keith in Boise

[T77911S]

if it is stuck due to a mechanical failure, removing the electrical connection will not matter. i suppose if the TTS is bad it could keep the CSV on.
you can pull the connector off the CSV, it is located behind the throttle body (TB). make sure you get the one on the CSV and not the one on the air flow meter (AFM). the CSV has a fuel line connected to it. you could also remove the 2 wires on the thermo time sswitch (TTS) located on the front left timiing cover. i say 2 becuase one comes from the CSV and the other has 12v and i do not know which one is the CSV.
not sure what gurgles are.
popping usually goes along with lean. you need to check cold control pressures (CP). the screen in the warm up reg. (WUR) could be clogged.
if you do not have a popoff valve and it has backfired, you may have a cracked air box. that would make it run lean, pop and cut off.

[Paulporsche]

Is this car new to you? Did this condition recently come on w/ cold weather? Where are you located? Do you have a hand throttle and are you operating it correctly?

As T77911S said, usually cold start problems are associated w/ a too lean condition and there can be many causes of this.

If you give us more info, we will try to help.

Welcome. Post pics of the car when you can.

[bubbasev]

To those that took the time to help...thanks! In an effort to better explain history/problem here goes...The car is new to me and I don't know how to use hand throttle or even it's purpose! The car was running great until cold weather hit. Started up in cold and I did not let it warm up enough and stalled it. After that....It will start and rev up with no throttle applied and run for one second and shut off. In looking at the inside of airbox (see attached pic) it appears damaged as shown, but no evidence of plastic loose anywhere. I know I sound like idiot but presently own two 911's and two 914's and have not crossed this problem before. Help appreciated. Keith

[Walter_Middie]

The hole is where your pop-off valve goes - I can see it sitting in the back of the air filter housing. Stick it back in the hole and the car should start like it did before. The permanent solution is to properly seal the valve to the air box.

The hand throttle between the seats should be raised just about any time you start the car - unless you have just shut it off and the engine is hot. After the car starts, the hand throttle is just that - a manual throttle used to keep the revs up a little until the engine gets warm.

[Craig]

+1 on the pop off valve. Put it back in place and your problem should clear up.

Correct me if I am wrong, but I don't think 2.7's have a hand throttle.
I have a '77, and there is no hand throttle. Could be they had one in '74, but I don't think so.


YMMV,
Craig

[Walter_Middie]

The 74s and 75s have a hand throttle - the 77 was the first year where this was more automatic.

[Cipotifoso]

The hand throttle existed through 1975 for CIS. It was eliminated in 1976 when the Auxiliary Air Regulator and the Auxiliary Air Valve were introduced. I've got an extremely late 1975, which is equipped with the hand throttle.

[Craig]

I did not know that about the hand throttle.
This is why I spend so much time on this board, little tidbits like this.

Hope your starting problems are solved as well!

Craig

[don gilbert]

the pop valve will not just pop back in, there is a lot of prep work to be done. ive put many on and have had the best results by grinding the fins all the way down until the base of the valve is flush with the very bottom of the box. sand and clean both areas to be glued with mineral spirts, then use black urathane (not rtv) and make apprx 1\4 inch bead around the base of the valve, gently twist and press in place. ive use jb weld and lots of others and have had some come loose, which will leave you standed. have not had one come loose using urathane and it makes for a nice tight seal.

[bubbasev]

Glued back in pop off valve properly and again runs like a champ. Thanks to the folks that were patient enough to point out the problem without making me feel any more stupid than I am....Happy Holidays