Turns off when in neutral or engaged clutch

[boonebeau]

I have an ‘83 911SC 3.0 that suddenly wouldn’t start. Identifies a problem being the pop off valve came out so I got a replacement, cleaned up the hole, and installed the new valve. I was then able to get it to start but now it won’t start on unless I’m pressing the gas pedal. If I put it into neutral or engage the clutch it turns off. The exhaust smells a little like gas so guessing it’s running too rich. I’m wondering if I still have a leak or need to adjust something? Any help is appreciated.

[pmax]

So the toilet seat leaked and ejected itself, nice. Can't it simply be cleaned up and reinstalled ?

As to the running problems, chances are someone tuned it to compensate for the leaks caused by the valve. Now that it is sealed again, for who knows how long that will hold up, the engine runs rich.

In a pinch, you could adjust the AFR using the 3mm allen, remember lean out but be incremental about it by small amounts each time, no massive changes.

Fun read starts here ...
CIS pop off valve

[boonebeau]

Originally Posted by pmax

In a pinch, you could adjust the AFR using the 3mm allen, remember lean out but be incremental about it by small amounts each time, no massive changes.

Fun read starts here ...
CIS pop off valve

AFR? Where is that adjusted at?

[emac]

Originally Posted by boonebeau

AFR? Where is that adjusted at?

If you don’t know where or how to adjust your mixture PLEASE DONT TRY!! take it to a Porsche mechanic. And buy the Bentley Service Manual.

Emac. 81SC

[stownsen914]

Being that this is a DIY forum and all, it seems appropriate to offer guidance

Try searching CIS mixture adjustment here on the forum, there will be many threads on the topic. Here's one: https://forums.pelicanparts.com/porsche-911-technical-forum/383956-adjusting-cis-fuel-mixture.html

[EC900]

Smelling gas in the exhaust leads me to believe a fuel dump at the injector(s). Is there plenty of black smoke with rough idle?
Was there any backfire before the pop-off valve was damaged/replaced ?
Hard cold start that’s requiring you to press gas pedal before it starts, and same when warm start up? What’s the current idle speed when running now?

[targa80]

In order to blow your pop off valve out of its glued in position you must have had one heck of a back fire. More than likely you have also blown the air box and now you have a major vacuum leak. Below if my write up on repairing the air box.


https://forums.pelicanparts.com/porsche-911-technical-forum/1081238-blown-air-box-repair-upgrade-spider.html?highlight=Blown+air+box

[walt]

Agree, you may want to double check the airbox for cracks. A couple of good posts here on setting the CO.

https://forums.pelicanparts.com/porsche-911-technical-forum/217176-setting-mixture-without-gas-tester.html

[boonebeau]

Originally Posted by EC900

Smelling gas in the exhaust leads me to believe a fuel dump at the injector(s). Is there plenty of black smoke with rough idle?
Was there any backfire before the pop-off valve was damaged/replaced ?
Hard cold start that’s requiring you to press gas pedal before it starts, and same when warm start up? What’s the current idle speed when running now?

It does not idle. That’s my problem. As soon as I let off the accelerator it dies.

[boonebeau]

So it’s been a bit because I got a knee replacement and have been laid up. I was looking at Things and found out the problem of the gas smell. There was a loose connection on the warm up regulator. I tightened it and now no more gas leak or smell. However, I still can’t get it to idle without dying.

[boonebeau]

Originally Posted by targa80

In order to blow your pop off valve out of its glued in position you must have had one heck of a back fire. More than likely you have also blown the air box and now you have a major vacuum leak. Below if my write up on repairing the air box.


https://forums.pelicanparts.com/porsche-911-technical-forum/1081238-blown-air-box-repair-upgrade-spider.html?highlight=Blown+air+box

I’m feeling like this might be my problem. Was hoping not to have to get a new one. The shop quoted my about $2k for the job. It feels steep but then they can turn everything else with it.