Do not underestimate the power of this task, Luke.

I pulled the relay from under the passenger seat and I replaced it with a new one that I purchased from Pelican.

I do not have CO2 hooked up and it was running fine without it.

I eliminated te CAT and installed M&K pre-muffler

They all leak........
 

nicfranc,

If you could start and run the engine anytime you want it, that should not stop you from driving the car around. They (CIS engines) all leak!!!! It is just a question of how much leak you have in the system. Some leak are negligible, some are tolerable, and others that affect the mixture give us trouble.

The key to your question is, what's the probability of you not being able to start the car again after parking. If the car starts right away and the driveability is not compromised, drive it. Just bring your cell phone with you.

BTW, by late September and early August, watch this forum for people having CIS problems. Posts after posts asking about cold starts. Keep us posted.

Tony

NicFranc,

After you fix the vacuum leaks I would serious consider changing all the fuel lines. At 300,000 miles it would be prudent You didnt say how long you have owned it or if you knew the history but I would drop the engine now and replace all the hoses I could. I did that on my 73 CIS and it made a world of difference. It is a good way to get to learn your car. It could be a good winter project.

I had a similar problem when I upgraded my motor. I did the Reverse Vacuume Cleaner test and found the airbox cracked at the seam! When I replaced the airbox I put all new gaskets, vacuume lines, injector seals and the rubber tubes for the intake runners! I retested with the soapy water and found that even the new injector seals still leaked a small amount so I lubed them with some lithium grease and the car fires up and runs great now!

CIS is all about pressue & vacuum leaks
 

2nd the check for leaks. CIS is all about pressure & temperature. For a Pressure Gage Set, an old biker once old me "good food ain't cheap & cheap food ain't good". If you are in it for the long term get a nice Pressure Gage Set. Good tools last a lifetime & then some generations. Pressure lines & seals wear out so 2nd on checking them too. Best of luck.

Well put.

Yep - I screwed up. I do remember you posted that.

Difficult initial start…no problem starting after warmed up
 

When I start the car for the first each day I have to keep my foot on the accelerator or it will stall.
Once it is warmed up and I drive it there is no problem shutting it down and restarting.
I could shut it down for and an hour or more and it will start right back up.

It runs fine wide open but boggs down below 3000 rpm.
Bucks and coughs in 1st & 2nd if I don't keep the Revs up.

Runs great doing 80 mph….you would never know there was a problem.

I purchased the car in December from a friend who was the original owner.

The car is all original except for the deleted CAT and M&K exhaust that I installed.
300,000 on unopened engine with no broken head studs, no pop-up valve and no pressure fed chain tensioners.

Car was running great till this real hot spell up here in the North East.
When I spray Carburetor Cleaner around injectors the engine evens out and runs much better.

The more i drive it the better it runs.
Can the heat of the engine close up vacuum leaks ?

Last night I Met a local Pelican named John with a 1979 Targa 911sc at Cruise Night in Oyster Bay, NY.. He gave me some guidance and hopefully with the collective brain storming of this community I will sort out my CIS issues.

We saw two cool 911 track cars at Oyster Bay Cruise Night: a lime green 1973 & a Red 1974. Unfortunately I forgot to take some photos. If they are there next week I will definitely get some Pics.

My 1980sc Petrol Blue Metallic (300,000 Miles)
http://forums.pelicanparts.com/uploa...1375314329.jpg
John's 1979schttp://forums.pelicanparts.com/uploa...1375314579.jpg

You have sprayed carb cleaner and it smooths it out but repairs have not been addressed.

Have you put a wrench on the intake runners to see if they are loose?

I tightened up the sleeves that I can reach but I have not tried tightened down the runners to the heads. I have some swivel sockets and will try to tighten what i can reach.

If I can't fix the leaks by what I can reach I will do a partial drop and install the parts I ordered from Pelican which are on their way.

Simple solution.......
 

nicfranc,

At this point, you need to do 2 things:
1). Fuel pressure test.
2). Air/vacuum leak test.

Forget partial drop at the moment, you might not even need it. I would bet my money on item #2 as your prime suspect/culprit. And if you happened to find the air leaks by the injector o-rings/seals/sleeves, I have a simple solution for this problem. But you need to initiate the tests first. If the air leak is coming from the air box or some where else, that would be a different 'prescription'.

You can not fix the problem/s unless you are able to identify the culprit/s causing the symptom you are having now. The fact that you are depressing the gas pedal during start is a sure sign of trouble. Stop guessing and do a systematic diagnosis of the problem. You need to use the right tools and the proper procedure to get to the bottom of your problem/s.

Tony

Down 'n Dirty CIS
 

You can not fix the problem/s unless you are able to identify the culprit/s causing the symptom you are having now. The fact that you are depressing the gas pedal during start is a sure sign of trouble. Stop guessing and do a systematic diagnosis of the problem. You need to use the right tools and the proper procedure to get to the bottom of your problem/s.

Tony[/QUOTE]

Gauges are on their way from Pelican.

I am a Porsche Rookie but no stranger to simple internal combustion engines.
I grew up rebuilding VW's, a 66 Mustang and a 56 Chevy and so on…...

Longing for simpler days…...
I am curious if there is a minimal amount of vacuum hoses and peripheral bolt-ons that you need to run these CIS engines ?

Let's say for arguments sake that the car would only be used in 50* F or above.
and let's say emissions were not an issue (I know, I know)

Is there a stripped down CIS set up that works ?
What can be eliminated or capped off ?
Or is the short answer you have to ditch the CIS and go with carburetors ?

Thanks for all the help…..I will now put on my hard hat and get ready to duck.

CIS engines........
 

Gauges are on their way from Pelican.

I am a Porsche Rookie but no stranger to simple internal combustion engines.
I grew up rebuilding VW's, a 66 Mustang and a 56 Chevy and so on…...

Longing for simpler days…...
I am curious if there is a minimal amount of vacuum hoses and peripheral bolt-ons that you need to run these CIS engines ?

Let's say for arguments sake that the car would only be used in 50* F or above.
and let's say emissions were not an issue (I know, I know)

Is there a stripped down CIS set up that works ?
What can be eliminated or capped off ?
Or is the short answer you have to ditch the CIS and go with carburetors ?

Thanks for all the help…..I will now put on my hard hat and get ready to duck.[/QUOTE]


Nicfranc,

There is really nothing difficult about running a CIS engine any time of the year, regardless of weather. Like someone mentioned earlier, it is all about fuel pressures and vacuum and with decent compression and ignition sparks the engine would run. The biggest problem about CIS troubleshooting is the lack of basic understanding how the system works. You need to test and verify to solve the problem/s.

Switching to carburator system is not a solution your current CIS problem/s. Your engine has some unknown problem/s and these could be checked easily without guessing by simply doing the appropriate test/s. Any DIY'er like you or me could easily and conveniently do these tests at home using conventional or home-made tools.

http://forums.pelicanparts.com/uploa...1375372338.jpg

I have yet to find a 911 CIS engine that could not be diagnosed correctly by guys like us.......BTW, I would be interested in buying your CIS unit in case you decide to go to a different system. Keep us posted.

Tony

When I installed my 3.0L sc motor into my 914-6 I didn't have to worry about smog so I removed the decel valve and a bunch of other stuff!

Here is a photo of the motor before I put it in!
http://forums.pelicanparts.com/uploa...1375374227.jpg

The CIS system will never look as sleek as a high butterfly injection setup but it is still easy to look at in this configuration and at this angle.

Nice job.

Wur ID
 

Does this WUR look right for a 1980sc ?
I can't see the numbers put i thought maybe someone could ID it by inspection.
Plus I found an orphaned loose plug (lower right) that was tucked under the WUR.

http://forums.pelicanparts.com/uploa...1375378459.jpg

So the Decel Valve can be deleted.
anything else ?

If you look at the photo and your motor you can see all the stuff that is removed! That whole vacuume diaphram mount and assorted vacuume lines that go to it!

Thanks!

http://forums.pelicanparts.com/uploa...1375381008.jpg

Here it is mounted in the 914-6!
http://forums.pelicanparts.com/uploa...1375381261.jpg

Wrong WUR ?
 

I can't see the number on my 1980 WUR but it appears it might be the wrong one.

http://forums.pelicanparts.com/uploa...1375400093.jpg
http://forums.pelicanparts.com/uploa...1375400112.jpg