tr4guy

Ok guys, I need some help. My 76 911 that I bought last year has some problems and I'm looking for advice. It just hasn't run as good even in warm weather as I think it should, but right now in the winter cold I like to start my cars at least to keep the battery charged and oil circulated but my 911 just refuses to start snce October. It will start and run really crappy with a lot of coaxing and then it dies and refuses to start at all after that. I addition I'm getting some backfires that I'm reading may be caused by either air leaks in the air box or loose seals on the injectors. Has anyone had these problems???? Any suggestions where to start would be a great help. I'm thinking the cold start valve has problems????

Edgy01

From your question alone I would have to guess that you don't stay on top of air leaks. The CIS injection system has a lot of hoses throughout the system so you have a chore going through them all. As you noted, you could also have a problem at the injector seals, themselves.

Do you have a pop-off valve within the air box? I hope so!

tr4guy

I'm new to Porsches but I'm learning. I just read an article about the pop off valve but havn't been able to get a decent day to check and see if one is installed. That's on the top of my list as soon as the temp gets up to where I can get some time in my unheated garage.

theiceman

first of all if you put your car away put your car away .. don't go in their to keep starting it thinking your doing the car a favor .. your not .. unless you are getting it out and driving it up to operating temp all your doing is inducing combustion moisture... Once it's put away put some stabil in and leave it .

As far as your other issues go ...
if your back firing your running lean . too lean a mixture will combust in the intake runners or airbox causing a back fire.

Your issue may be in the cold start valve or the thermo time switch but that is only to start the thing. i would say if you still have issues after starting look elsewhere. If you do get it started and warmed up your gonna need a CO checker as this is the baseline as to where to start. This has to be bang on perfect to start in cold conditions.

As Dan points out the only thing saving your butt right now could be the pop off valve .. but also keep in mind this could be causing your condition if it is leaxking air into the air box and is not sealing properly.

There could be many many issues but if i were you I would take some time and pull the whole air box out , inspect for damage and replace all the rubber sleeves from the box to the runners and all the gaskets from the runners to the head. Put it back together make sure the thermo switch and cold start injector work and also check the WUR if that model has one .

Your gonna need some type of Bentley for sure to help you along this road

RoninLB

the car may have had a tune=up before you bought it?

if so that usually means new points

new points "break in"

the points close as the rubbing block sets in and need to be re-set

all this assumes that you had a good running car when you bought it