CIS Problems - Test Gauge recommendations - 1980sc running rough
 

Time for me to climb the CIS learning curve.
Have read Jim's CIS Primer, CIS for Dummies (tirwin) and also have read Tony's (boyt911sc) threads. Thanks guys for posting so much content.

Question:
Is there a CIS Gauge Testing Set that anyone can recommend or prefers ?

My US 1980sc has been running great until this week.
My car has its Original unopened Engine with 300,000 miles

I left it out in the heat and did not drive it for a 8 days.
When I started it this weekend it ran very rough and coughed through the exhaust at low revs.
It barely idles without stalling and now when I remove the oil cap it stalls completely which it never did before.

The car runs well at high revs and at high speed but it is bogging down in first and second.
Unfortunately I can't be driving around town doing 80 all the time ;-)

My first task will be to eliminate potential vacuum leaks as you all recommend. I am prepared to do a partial engine drop to replace as many hoses as I can reach. I would like to put off pulling the Engine till the winter.

Rotor, cap, plugs are new and Valves are adjusted distributor has been timed 5 Deg. BTC
No broken head studs.
Air Box is good and there is no Pop-Off Valve
Cat has been deleted and there is no O2 sensor
Relay under passenger seat has been replaced.
Original Engine with 300,000 miles

I have not inspected WUR (need Gauges)
I have a new fuel filter from Pelican that I can install but was wondering if I should replace the screen on the bottom of the gas tank first.





Noticed this kinked breather hose.
But I do not think it is the cause of the rough running.
http://forums.pelicanparts.com/uploa...1375104639.jpg

Consider buying Charles Probst's Bosch fuel injection book. It goes into theory deeper than the other sources but still is geared towards the laymen.

Buy the set from Pelican. It's a (very) few more dollars than the Harbor Freight kit but from threads I have read it is of better quality.

Did you do any work before the eight day rest? Just getting at sometimes the last things you do can have created problems. Hose bumped off, etc.

O2 sensor is pretty important. Cat is not. No O2 sensor sensor will not allow the frequency valve to operate in closed loop mode. You are running in open loop now and you will not derive all the benefits (e.g., fuel economy) the system provides.

As a starting point for assurance, make sure your O2system/Lambda fuse is not fried. If it is toast, the function of the Lambda relay that was replaced will be negated. If that system has no power, it will operate in "loopy" loop mode which means horrible. Very poor throttle response. You can limp the car around but it is more of a "gimp" than a limp.

A favor please. The kinked breather hose. Where does it connect? On my 81 there is a hose like that which connects to the charcoal canister. It connects to the side that has the small hose exiting the canister which is closer to the firewall and not the rear bumper side. Any way you can post a pic of where the end connects? You may have it on the wrong port but can't tell from pic.

CIS Guidance…..
 

Thank you Bob for the advice.
I will order the Book and the Gauges today.

I took some more photos of the braided hose.
I have a replacement that I purchased from Pelican and I believe it connects from the Engine breather port to the lower hose connection going to the the oil tank by the filler tube.

I can't see how I can replace it without an engine drop or at least a partial drop.
It looks like someone spliced this braided hose which now has the kink in it. Perhaps it was his way of replacing half of the hose without removing the engine.

I also have discovered there is no restricter in the top tube that connects to the Oil Filler tube.

The charcoal canister does not have a hose in the rear facing the Oil Filler Tube.
It does have two braided hoses in the front of the canister. One is larger than the other.

Nick

Braided hose connected to oil tank.
http://forums.pelicanparts.com/uploa...1375118338.jpghttp://forums.pelicanparts.com/uploa...1375118495.jpg

Update- vacuum leaks
 

I sprayed Carb Cleaner around the intake manifold area on both the left and right side of the engine and it smoothed right out and began to run perfectly.

Could the car sitting out in the hot sun for a week caused the intake gaskets to loosen and no longer seal ?

Is there a way to isolate where the leak is.
Right now it seams like there are multiple leaks.

How sweet it is. You are halfway home.

Did it smooth out when you sprayed the air box side or the cylinder head side?

Breather hose is do-able with partial drop - pure hell but worth the scrapes. Been a while since I did it.

Your charcoal/carbon canister hook ups are ok. Thanks for that. The skinny line runs to the left front fender where you expansion tank for fuel overflow/vapor. The fat line runs behind engine and then to the driver's side of the air-box. 77 was the last year for the hose off the bumper side that plugged into the fan shroud over by # 1 cylinder. However, boyt911SC has this hose on his 78 so there may have been some leftover parts bleed over into the SC model.

[QUOTE=Bob Kontak;7574927]How sweet it is. You are halfway home.

Did it smooth out when you sprayed the air box side or the cylinder head side?

I am trying to narrow down the source of the leaks.
I am going to try using a propane torch to see if I can pin it down.

I noticed that the injectors wiggle a bit from side to side and they are a source of some of the leaks.

This is the first time I have left the car out so what might have happened the 33 year old materials expanded in the really hot weather we have been experiencing up here in Oyster Bay.

[QUOTE=nicfranc;7574996] Direct spray of the carb cleaner/starting fluid is pretty effective om a particular spot.

You will find it. Your o-rings are probably hard as rocks.

How hot was the car when you last drove it? Any oddball things that would have caused the engine temp to spike?

Vacuum leak search......
 

Nicfranc,

It would take only a minute to do the engine vacuum leak tests with soapy water. Apply a continuous flow of air (low pressure). I had posted some pictures in a couple old posts. With the engine installed, you can't see the whole airbox specially the backside and underneath it. But with a good light source and a small mechanic mirror you would be able to peek at it.

With the system (engine) under air pressure (1-2 psi) just enough to inflate a latex glove would reveal all these hidden or unknown spots where leaks are presence. An air compressor even the portable ones could be used to inject air into the engine and plug the exit orifices/holes to keep the pressure positive. You'll be surprised how much air leak could be there even with a decent running CIS engines have at anytime.

PM me if you need further assistance. Test and confirm.

Tony

[QUOTE=Bob Kontak;7575053] I had the car out in the direct sun and it was brutally hot and when I opened the engine compartment I noticed all the my wires were really flexible.
Before they were a bit stiff as the sheathing was brittle and dried out.

I started tightening up the leaks I could reach and am putting together an order for Pelican.

I got the car to run better but it is taking awhile to warm up and run without breaking
up. After ten minutes it was revving nicely. I put some techron in and will see if that helps.
Thanks for checking in.

[QUOTE=nicfranc;7575697] I was going to suggest to "burp it" as Joe Bob says with a can of BG44K but the Techron is probably just fine. (FWIW: I decided to start using the BG44K after reading a lot about it on here. I've got no personal data that says it's better or worse than Techron.)

Listen to Tony. The starting fluid trick is only great for macro leaks.

If you take the time to do the reverse leak test - the correct test - you pressurize your system - not too much - and spray soapy water on the suspect areas and they bubble out where the leaks are. Literally get kids bubble soap.

Now, the minute Tony speaks of is a "Tony minute" Give yourself an hour or two as you have to figure out what to seal off, etc. It's worth every second.

nicfranc -

I just finished replacing the airbox in my 82 and have been researching CIS fuel pressure gauge kits. The kit from our host is listed as on backorder, so I may have to source one elsewhere. Just make sure whatever kit you get is CIS specific so that you get the correct fuel line fittings.

There's no way I could have tackled my project without invaluable help from the forum and especially Tony. (boyt911sc) I was on the phone with him just this past Saturday as he helped walk me through startup for the first time since getting everything back together. Thanks Tony! SmileWavy

That kinked braided breather hose connects to the breather cap (a.k.a. the "Trinity") on top of the engine directly beneath the airbox. The swivel fitting you see with the hose clamps is the correct factory setup. On my car, the hoses are smooth rubber, not braided. Sounds like you're well on your way to fixing some intake leaks. Assuming you replace your injector seats (2 o-rings and the plastic holder) you might clean your injectors while you have them out. There's a great DIY on how to do it yourself by billjam. Good luck!

http://forums.pelicanparts.com/uploa...1375152698.jpg

http://forums.pelicanparts.com/uploa...1375154133.jpg
http://forums.pelicanparts.com/uploa...1375154176.jpg

Words are so overrated.

Nice.

+1

vacuum leaks
 

I ordered from Pelican injector sleeves and O rings and also ordered manifold gaskets and
intake rubber runner sleeves.
I am also replacing some breather hoses to the oil tank.

Are there any other common sources for vacuum leaks that I should check out ?

Interesting thing I have noticed is as the car heats up the vacuum leaks seam to dissipate a great deal. Is that the a common occurrence ?

Should I not be driving the car while I have these vacuum leaks ?

I think you can drive it without damage but others may know better.

Note how tight the nuts are on the intake runners where they bolt to the heads when you replace the gaskets.. If they are loose, it's a good source for leaks. #6 piston nuts are a bear to get to. 1/4" drive ratchet and some fancy swivel toys will help.

I remember putting grease on the injector o-rings. Not silicone based but something else. Also, HC based is no good either. I may have used lithium grease and I am not even sure that is correct.

The hose that runs from the drivers side of the engine to the vacuum booster for the brake master cylinder can cause fits. There are probably several ways to check it. John Walker has seen these hoses fail underneath the car.

My brass pipe that runs into the back of the throttle body (I think this ties into the brake booster hose) came loose from the back of the TB. I had to JB weld it back in and subsequently found I did not have the support bracket bolted down which was the root cause of the issue.

Anywhere on the airbox past the sensor plate.

I have seen the hose on the aux air valve slide off the snoot if the clamp is not reefed down enough.

The bubble test might be a good one BEFORE you disassemble. You can even use a shop vac in reverse if you do not have an air compressor.

Your breather access should be way easier with #3 and #6 intake runners removed.

May help to take the small blower fan and it's base off as well for breather access as well.

#6 intake runner nuts will be the biggest PITA of the job.

Nice work, BTW. Keep us posted.

Bubble test….
 

Thanks Bob,

I have both big and small Compressors and Vacs.
I will give the bubble test a shot

The sudden onset of my engine running poorly makes be wonder if a hose came loose.
I will check for vacuum leaks where you recommended.

Nick

Sudden onset could be the O2 system blowing a fuse or the O2 relay going belly up.

Find the O2 system fuse and pull it while the car is idling. If there is a big "honkin" reduction in how it runs, put it back right away. :-)

If no change, gotta get into the O2 relay and pull that while idling.

Suspect it's not the issue and forgive me if this is a repeat.

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