CIS injector seals
 

Folks (thanks in advance for the assistance - I always learn from these posts) I have checked through the threads for the last hour and got insight that pulling the injectors areca a real bear of a task. I have dismantled my CIS and I am trying to figure out if I need to replace the injector seals. My car was having the problem of misfiring only when the car warmed up so i went through everything and sumised it was a vacuum leak somewhere- (cold start fine etc) so I am resealing up the air box, installed the pop off valve, new intake runners, etc. My injectors seem fairly loose as I can turn them easily. I plan to dip soak them all in carb fluid to make sure they are clean. My question is - how can you tell if the injector seals are bad. IF one was bad how could you tell from the engines performance. Is there a way to check them while they are still in the induction runners. Thanks.

What year is your car?
If you drive a 1973.5 with CIS I can tell you all about those injector seals!

Regard
Bob
73.5T

Sorry about that - the car has a 77 2.7 CIS motor in it.

You mean the soft copper sealing rings? When mine leaked I went to my local autoparts store and bought a variety of soft copper brakeline seals (it's the same stuff for the same purpose). They were exact matches and sealed perfectly. I think they cost me $2 for a dozen or so.

Yeah but the question is how do you know when the seals are bad and need replacing?
My 79 911SC has the plastic lines from the CIS distributor to each intake runner and they are able to turn easily at the runner connection. Does this mean they are bad?

If the 77 CIS is the same as an 80 and 83, there are two orings. One for the injector which is smaller but thicker. When you pull the injector out, it will remain on the injector. Then there is a second oring around the injector receptor, sealing the gap between itself and the intake runner. Those you need to remove the intake runner to change because the are set in with a 3 point crimp. I may not have the terms right, but believe this is accurate.

When should you replace the orings? If you can wiggle the injector and see it moving in the receptor, it's time to replace them. You'll probably find they are rock hard by now. If you wiggle the injector and see the receptor moving, well then the receptor oring could use a changin' ... BTW, does anyone know of a good "temporary" sealnt to use on these?

Hope this helps.

Tony

Tony is right about there being two seals: I remember one thick O-ring to retain, and one smaller O-ring to seal. Bentley page 240-18 will help. I remember using a little WD-40 on the new O-rings to make installation easier. Be very careful when removing the injectors, they have to come straight out to avoid damage. It's a little tricky.

So you are saying that the receptor can be removed without destroying them? If they are crimped then how do you remove them without damaging the intake runner machined hole or the receptor?
I don't have the Bentley manual but will hope to find the procedure in the Porsche factory manuals, unless soemone can describe briefly the method to get them out of the intake in this post.
Thanks for the info so far everyone.......unfortunately I was really hoping to avoid removing the intake manifold to do this repair.

No need to remove the intake manifolds, the injectors will pop out. Soak the seals on the injectors with WD-40 before you try popping them out. Look at the injectors and decide where you would apply leverage so they are forced straight out. I remember disconnecting the fuel lines, and carefully applying leverage to the injectors by prying up on two sides. Do not pull on the fuel lines!

Just removed mine after finding sloppiness. 5 came out with the sleeves included, one sleeve stayed in the runner and is tight so i might leave it alone. I decided to order new sleeves too as the old o-rings are so hard, I dont know if i can get it off without destroying the sleeve. The injectors came out without much difficulty by using a leverage screwdriver handle under the pliers. I left the lines on so I wouldn't slip and mess up the threads on the injectors.

Anybody think it would be better to soak the injectors in a Techron/Feul mixture or just any carb cleaner?


SCott

Just for the record I was talking about the screw-in injectors with a copper base gasket/washer.

Thanks for the many replies, been working late and hadn't had the time to respond. Below are pictures of the runners I have out (included a picture also of the ride, it is a 77 targa converted to look like a C2 convertible). I am presently soaking the injectors in techron. I can turn my injectors pretty easily. but do not have a lot of up and down play in all except one (I may decide to change the seal in this one). The upper seals do not seem cracked. The reason why I took apart my CIS/runners etc was because I having a miss after the car warmed up - say a half hour into driving. Start up fine etc. So I assumed after many frustrating months of trying to find a vacuum leak to take apart everything, clean it up, remove all the garbage emissions/smog stuff AAR etc, seal everything up in the airbox, add the pop off valve, replace all vacuum lines, intake manifold hoses etc. I am really queazy about attempting to pop out the injectors - as from looking through the boards some folks have had a real hard time taking them out - then broke the injectors. you know how it is with these motors on projects, anything you think will take you and hour usually takes you a day so I'm trying to be a little careful. I'm thinking about sealing the top of each with some permatex hi temp. Could someone show pics of their technique of pulling out these injectors the proper way as none of the books I have (101 porsche, haynes manual, CLYMER manual - shows how. - i think this would be an excellent additinal tech article to have on the site.

http://forums.pelicanparts.com/uploa...1100689701.jpg http://forums.pelicanparts.com/uploa...1100689748.jpg http://forums.pelicanparts.com/uploa...1100689776.jpg

oops - forgot to post photos of the old 2.7 motor I'm trying to resurrect.

http://forums.pelicanparts.com/uploa...1100691234.jpg

To remove Injectors in car or out- take a open end wrench that is smaller in size than the wrenching head if the injector. Fit it under the wenching head between the manifold and the wrenching head. Between the wrench and the manifold insert a taped flat blade screwdriver and carefully pry up. The O rings stick after years and get hard. They'll either stay on the injector or in the manifold. If they stay in the manifold simply pry them out.

The injectors are very sturdy and the only things to worry about are kinking the plastic fuel lines and breaking the thermoplastic sleeves that protrude into the intake port.

Put them back in with some silicone direlectric grease smeared on the O ring with the ring on the injector. They'll push back in by hand into the manifolds (intake runners). They'll also pull back out much easier.

There is a seal between the sleeves and the runners but I have never tackled this in that they are held in place by peening.

Try the above but spray some WD-40 on. The idea is to find a way to apply leverage up-wards so the injectors come straight out. Don't apply any side-way pressure, just straight up. Re-attach the lines hand-tight so that the nut protects the threads when you are prying.

After I pull the injectors and replace the seals, should they still be able to be turned freely or will everthing fit, tight smug and non moveable.

I replaced the sleeves and both o-rings. Mine still can be turned with some effort, but feels snug and is much better than before. I had to use a soft rubber piece and a rubber mallet to get a couple and the injectors back in. Why just a couple? Good question. Haven't started the car yet as I need to check for fuel leaks, having the entire CIS system out. That's tomorrow.

Interesting how many people have a 911 and an E30 :) Good taste, I suppose.

E30's and 911's are timeless German Classic Design - no riceburning, changing the car look every year, trendy, britney spears stuff.

followed the great suggestions from the posts and got the injectors out using the method shown below, after soaking the seals with WD variant. The looser injector came out sleeve and all. Could this have been the source of my vacuume leak? Do I need to replace the sleeve now or should I put the same back in with a new upper seal with some permatex? - Thanks again in advance for the assistance. Sometimes I feel I'm in an AA meeting :). Good to see that even after a contentious election folks can still hang out and be nice to each other. Long live the 911 - the ultimate uniter

http://forums.pelicanparts.com/uploa...1100747063.jpg http://forums.pelicanparts.com/uploa...1100747114.jpg http://forums.pelicanparts.com/uploa...1100747249.jpg

That loose sleeve may be one of those factors of high Idle. Get some seals from out host. I imagine that the sleeve peens gave way. I think if you look and try to match the hammer marks that hold them in, it will work as original. I think there are three hit marks. I'd stay away from the permatex, but all of this is guessing. You've gone into a new area. Great photos!
Interesting post!

I decided to go ahead and replace the sleeves also. They are $3 each and getting the old 0-rings off the sleeves without damaging them would be difficult anyway.

There are injector holders that unscrew (female hex facets), and there are ones that just pull out (but not very easily). Mine pull out, but I wish they were the screw-type. I think they all take the small but thick donut o-ring, which can be found cheaply at any autoparts store. I think it's probably the same as virtually any other CIS injector car.

Re vacuum leak from injectors: I have seen very loose injector seals without giving problems because, once the engine runs, the suction in the runners seats the injectors somewhat. Replacing the O-rings is good but, check EVERY hose and hose-clamp, get new gaskets and boots for the intake runners, inspect the pop-off valve, etc. In the past, a lot of leaks came from the gaskets where the the intake runner mounts on the cylinders. Porsche replaced the 2-bolt connection with a 3-bolt connection later on with the 964's? Another leak source can be both hoses from the oil filler pipe: one goes to the breather cap, the other to the boot on top between airbox and throttle body. Make sure there is a clamp on both ends.

I have ordered the sleeves also after knocking the remaining out of the intake runners has the O rings where all hard. Might as well change it all while I have them off the car. I have taken the time to clean up the engince a bit, and also changed the o-ring found on the oil thermostat since the CIS is removed.- Also have removed all smog related items from the engine AAR etc. and blocked all their related vacuum sources. Also thinking of removing the decel valvce - any thoughts on this? WIll post additional picks soon. Thanks for all the help.;)

folks, put everything back together and I am still getting a miss when the car warms up. After starting up can drive around for about 30 minutes with no miss, then it starts up especially changing into 2nd gear. I have sealed everything up on the CIS, my WUR is about 5 months old - I can't figure this out. Any additional advice would be greatly appreciated.

Have your mixture tested/adjusted with a CO meter. JW recommends rich around 3.5% Also, check your ignition wiring. After dark, with the engine running, open the lid and check for ignition sparks jumping from the wires. SmileWavy

Gunter I actuall did that last night before reading your post - excellent suggestion though. today I checked my injectors by having my wife turn the car over and two injectors squirt but they are not as "conical" as the others. May have to invest in two injectors as spark is good, no air leaks that I can find. Thanks as always for the advice guys. below are when I put the CIS together with the runners attached - looking like a mechanical spider - found it easier to install this way making sure all the runners are on propertly other pic is it installed and with my healy sprite.

http://forums.pelicanparts.com/uploa...1101595883.jpg http://forums.pelicanparts.com/uploa...1101596191.jpg

If the car still has points, then check your timing and dwell (point gap) if you haven't already done so. What is the condition of spark plugs, plug wires, distributor cap and rotor? Jim

Jim I replaced the points with a pointless system 2 years a go, the plug cables are fairly old but I checked them in complete darkness and there is no arching. All the plugs almost new bosch platinums that show some black carbon but not excessive. I pulled each plug at ide and each one had an effect. I'm thinking now it is either two injectors I have that seemed to not have the perfect conical discharge (even after I soaked them in techron for a qeek) or the fuel pump gettting defective and not maintaining the sufficent pressure making my car run lean as a result. I need to find out if the pump is operating correctly - what pSI is optimal because I think this is the problem at this point

For 1977 911 CIS system pressure is 65 to 75 psi. Spark plug wires could have an internal flaw that manifests itself (opens up) when warm, causing miss. Lack of arcing only proves the insulation is still okay. Jim

good point

Yes to fuel pressure check. Couple things not connected to your problems: General consensus seem to favor copper plugs, not platinum. And: Isn't there a recommendation to go back to the 11-blade fan for better cooling? Something to consider in the future. Cheers.

Yea I know I should change the fan, but you know how it is, car funds are competing with my two year old. The car's temperature has not been a significant problem though since the exhaust has backdated headers and no thermal reactors. Will update soon.

I will also update the plugs - there seems to be no difference in performance anyway.

Yes, $$$ is always an issue. The 2.7 liter is a maxed-out 2.0 liter and with the increase came a problem with heat dissipation, ergo the fan-upgrade. Try a fuel pressure test. Trouble shooting is a process of elimmination; find what works. You'll feel sooooo good when you finally find it!

Guys I am ready to shoot this motor. I took the car out for a spin to get gas, still having the slight miss. I appeared to run out of gas, I got new gas and cranked it up. It would idle fine, but when I pressed the gas it would act like it was not getting fuel and backfire/pop etc. I finally tried to coax (sp) the car back to the house, car backfired like never before this time. IT finally died on me, no matter how I cranked - no start. I pulled on of the injectors while cranking, it pulsed once, and then dribbled - so I though aha - fuel pump. I let the car sit a couple of hours in front of someone's house then came back and It cranked up the first hit but still running rough. Next day I drained the gas tank. day after I replaced the fuel pump since mine was making a lot of noise. I did not have a chance to test the pressure in the system since I cannot find a shop to take the car now (I just ordered the system from JC whitney). THinnking this would solve the problem - cranked it up - still running rough even after trying to adjust the mixture it has a slight miss.

what has been changed the past 6 months:
cap and rotor, plugs, fuel filter, fuel pump, Fuel Accumulator, WUR, added pop off, changed all seals/sleaves for CIS system. Changed two injectors that worked but didn't have the smooth conical shape. Car has no exhaust leaks from the heads.

THings left - plug wires, take apart fuel distributor

HELP!

You mentioned that you've tried to adjust the mixture. Have you had the mixture checked yet with a CO meter? Find out where your actually at.

I've been able to adjust it previously without the meter to good results so I have a good idea of the mixture - can't find the sweet spot like before.

I recommend you do the system pressure tests before spending any further time on the system; certainly do not "throw more parts" at it. Once you have the pressure test results the trouble shooting guide from one of several good books/manuals covering the Bosch CIS systems will help take you through finding the source(s) of the problem(s). If you need help with the troubleshooting there are numerous people here on the board that have the information. Once it's running well and if well maintained a Porsche 911 CIS system can run trouble free for years. Jim