yet another CIS hard start.
 

SmileWavy So I'm new to the CIS and and the board. I have read up on it and I've learned a lot and still learning.
On to the car 1981 911 SC ROW, I made a smoke machine to check for vacuum leaks and have found the injector seals leaking, while I was there I have found 3 bad injectors. So once I get the new injectors and seals I will retest for vacuum leaks again.
My issue is that during the fuel pressure tests the injectors keep dumping fuel. The Air plate seems to be in the correct position. If I slightly pull the lever down I can get the injectors to stop.
So I know I need to start with fuel pressures but I need to be able to perform the tests. The car does run just hard to start.
I have a feeling the mixture screw is set too rich?
I know diagnosis over the internet is tough so let me know what other infor you need to help me.

You've already found a key problem--the injectors are spraying when they shouldn't. The fact you can stop the spraying by pulling down on the plunger is significant because it likely means the plunger arm is getting stuck, or the pin in the fuel distributor is getting stuck, or the stop adjustment for the arm is out of adjustment. The spraying of fuel could also contribute to your hard start situation.

Before worrying about the mixture screw, solve the situation of the spraying injectors. Clean and inspect the plunger in the intake, and check the free movement of the mechanism. Find out why the plunger can be "pulled down" to make the injectors stop spraying. Once that is resolved, proceed with your pressure tests.

Look at my fight with CIS by doing a search on my username.

Although I not recommend it as a first step follow this procedure out of the Bosch manual (I also did that when I revised my CIS system).

With 1 injector out and connected to the fuel line (injector in a small container, engine dead cold).

Jump the fuel pump in the relay box upfront so that the FP runs when key in position 2.

Put your allen key in the mixture adjustment screw and turn clockwise until the injector starts to spray (not drip). When it sprays a nice pattern turn the mixture adjustment screw half a turn counterclockwise. The injector should stop spraying .This gives you the base setting.
If you have a 81 SC CIS you have a 089 WUR and the opening bar for your injectors is 2,5bar.

Leave the car for a while as you have dumped quite a lot of fuel in the intake chambers by doing this procedure. Best is to remove all injectors but that is a drag with hard fuel lines.

Michel

I think this is it took another look when I got home. It's ever-so slightly that it needs to move to stop. The plate moves free through the whole stroke and bottoms out (too soon I think). I took pics but its so minute that it doesn't show.
I'll adjust it, clean it up and install the new injector seals and injectors, do another smoke test. and give you guys an update.
Thanks:D

Replace your injector sleeves and o-rings while you're in there.
Porsche 911 & Turbo CIS Fuel Injection - Page 4

You need help?
 

67flat4,

My only advise to you at this point is be careful and listen only to the people who knows about CIS. Focus on Ossiblue's advise and you'll be in good hands. Others are offering you advises while they could not even fix their CIS own problem/s. So be wise and use your good judgment. Just my two-cents.

Tony

Thanks Tony, and I want to thank you already, I've read many of your posts and have learned a lot about the CIS design and function. Sometimes I forget to KISS (keep it simple stupid) I'm a big fan of that philosophy but am very forgetful. You seem to always remind people of this. SmileWavy

update
 

So all 6 injectors,sleeves and o-rings replaced. It's a little better. I adjusted the air plate took 1.5 to 2 turns out and the injectors no longer run constantly. on to the pressures. all at 65*F

cold is 2.2 bar this might be off I'm going to retest again. I think i may have had the wur hooked up to power before I did the test.
warm is 3.3
system is 4.5

I think I need to retest for air leaks first. but while getting the fuel pressures I noticed once the car was turned off I instantly loose 1bar then loose another .5 in another 30-60 secs. It does hold at 1.5 for whats been 10 min now. Not sure what normal is just noticed it.

WUR pressures change when hooked up to 12v.
AAV moves when hooked up to 12v.

I did search on the fuel accumulator. no leaks from bottom port with the air plate lifted. however the hose that is connected to the bottom port spewed with the air plate lifted I think this normal as it appears to be hooked to the return line?

After replacing the injectors I did have to bump the idle up. It wouldn't stay running.
I am going to double check the pressures. but what do you guys think so far.
once the car is running it does run good.
thanks.

This should help...

http://forums.pelicanparts.com/uploa...1335242544.jpg

59*F
cold 1.95

http://forums.pelicanparts.com/uploa...1336409144.jpg
So cracked air box has been found. Not what I was hoping for. I guess my next step is to pull the intake and look for additional leaks.
Is it likely that this is the only leak or is the intake going to be leaking elsewhere?
it was so small I wouldn't have caught this leak without the bubbles.

Is it cracked or is it at the rubber boot?

These boxes are made in two pieces. It is likely leaking at the seam. I like the soap test, but has anyone tried a vacuum test? Pulling some vacuum and seeing if it holds might replicate engine running conditions a bit closer. Plus it would allow one to know if back of the airbox is cracked where one can't see bubbles. Just a thought.....

CIS troubleshooting...........
 

You are moving in the right direction. Air leak is the Achilles heel of CIS and if you could minimize any significant source of air leak in the system, the rest of the troubleshooting would be easier. The reason why your fuel mixture was set too rich in the beginning was due to this unmetered air. Someone had adjusted the mixture to compensate for the unknown lean condition.

I've been trying my best to tell people that adjusting the fuel mixture without verifying the absence of air leak/s in CIS would make a bad situation worst!!!!!! After you have corrected the vacuum/air leak in the system, proceed checking the fuel pressures. Keep us posted.

Tony

Once you pull everything off, do a leak test on each component. Hoses, vacuum lines, devices etc. If there are more, you'll find them. Replace the injector sleeves and o-rings too.

OK so I'm going to bull the air box. I found a leak on the underside on the rt that i can't get to.what all parts need replacement. so far I've got
6 intake gaskets
6 intake boots
throttle body gasket
FD gasket

already replaced the injectors,sleeves and o-rings.
I remember seeing a thread on this but have searched again and can't seem to locate it again.

Thanks again for all your help.

Consider the need for a new or used airbox.

Unless you are really, really good at solvent welding ABS type plastic plus being able to pressure test it.

Partial engine drop and lots of patience. Long arms and a good assortment of swivels and extensions. Did I mention lots of patience?

Pressure to CIS
 

67flat4 Where on the system did you add pressure? I was thinking of doing the smoke machine thing, carb spray has yielded no results, but pressure and soap solution seems a good alternate. TIA

hose at the split in the brake booster. I did make a smoke machine and the only thing that showed with it was the leak at the injectors. I then switched to the soapy water and found one crack. Then found another leak with the carb cleaner. I wasn't able to get the soapy water to the bottom on the rt side. So in all a combo of all 3. you can skip the smoke machine the bubbles work a lot better.

Is there another place to hook up pressure if I have no Brake Booster? I saw where someone ran a hose into the throttle body and taped it all up. Is there a better option? This is on a 73.5 T. Thanks

Places where compressed air.........
 

Randy,

There are several places or connections to introduce compressed gas/air into the system namely:
1). Brake booster vacuum line connection by the air box.
2). Throttle body
3). Oil cap
4). Injector hole
5). Pop off valve
6). Vacuum line
7). Spark plug hole
8). Exhaust/muffler
9). Others

Choose a convenient spot and plug the other orifices to maintain a positive pressure inside the engine/system during the test. A constant supply of low pressure air/gas between 2 - 3 psi is sufficient to locate these hard to find air leaks.

Tony

Thanks Tony!
Been busy trying to get my CIS in order. It was running so good and all of a sudden it went crazy. So all the things I was procrastinating doing, I've been doing. All fuel lines replaced, fuel pump, check valve, injectors cleaned, new seals, accumulator and fuel filter, plugs, wires, points, cap and rotor,..... Ready to check fuel pressures but want to find and fix all vacuum leaks. Thanks Pelicans! Really!
A couple of pics of injectors I did with carb cleaner and Ultrasonic. I've been documenting everything so here's my chance to post a couple of pics.
: {)http://forums.pelicanparts.com/uploa...1336680949.jpg
http://forums.pelicanparts.com/uploa...1336681024.jpg
http://forums.pelicanparts.com/uploa...1336681069.jpg
http://forums.pelicanparts.com/uploa...1336681120.jpg

I cut off the end of those metal brushes, put a slot in it and used that to hold the pintle on the injectors open while running it in carb cleaner in the ultrasonic.
Last picture is a piece of a dental tool I was using to pull out the injector seals. It broke off and fell in the injector hole! Crap! ( Well I was thinking worse!) I used a magnet on the end of a drill bit, stuck it into the hole and I'll be dipped in..... It came out! Whoo hoooo! You know what that felt like!!!!

http://forums.pelicanparts.com/uploa...1337622093.jpg
Here is the tool I used to pull the injector sleeves. Just put some bends in some wire. worked great. had to really yank on 2 of them too.
So the update is the air box has been pulled, my box has the internal cold start manifold. Will the replacement from the host come with it? or will i need to split and swap? :confused:
I found some cut wiring I'm not sure were it goes. I'll snap a pic later. It comes out of the harness were the WUR hook up and the power to the heater blower. come from. It's a brown wire and a red with white line? anyone know what that could be.

I'm done!!! for now
 

I got around to looking for air leaks and the only place was at the decel valve. Thanks for all the info on how to do it. Ended up taking the car to Frank Hanrahan. He hooked it up to check CO and it was past 10%. It's suppose to be 1.5 - 2 %. Even though I thought all my injectors were fine, one was bad. I did the ultrasonic cleaning and watching their flow in glass jars but obviously I'm not a professional and still missed my #5 not misting like it should. New injector and mixture adjust while hooked up to see CO and it's running so sweet. I didn't solve the problem to the end, but did get my fuel hoses replaced along with a lot of other parts that were 38 or 39 years old! Learned a lot too!
Thanks Frank and Pelicans.http://forums.pelicanparts.com/uploa...1337623985.jpg

Here are the mystery wires?http://forums.pelicanparts.com/uploa...1337700326.jpg
I think it gets hooked up to this? anyone with a smog pump know what this is supposed to do. Can I delete it and just hook the hose up and bypass?http://forums.pelicanparts.com/uploa...1337700405.jpg
found the bushings missing on the throttle plate and a hose that is cracking. The air box has been repaired prior so I think instead of another repair its time for a new one. Has anyone ordered a new one does it come with the cold start manifold? the one I removed had it and would like to replace it with one that has it as well.
Thanks

Got some time to work on it again. Still not sure what the extra wires are for haven't started to check power there yet. So the AAR is not opening fully? haven't found much on the search maybe searching for the wrong thing. but anyway here is is after 20 hours in the freezer.
http://forums.pelicanparts.com/uploa...1340305103.jpg
it was at the same spot when I put it in the freeze too.
I'll be checking if it closes here in a while. I did verify it moves with power but that was all. So is it supposed to open all the way?:confused:

You might want to spent some time with your AAR

Look at my thread
http://forums.pelicanparts.com/porsche-911-technical-forum/678022-euro-sc-troubleshooting-over.html

I do not know what the temp outside was before you put it in the freezer but that AAR could be stuck open.

Well I spent the weekend working on the Porsche. I ended up repairing the air box. I did test the box prior to installing and found 2 leaks so after those were repaired in it went. It wasn't as difficult as I thought it would be with so many people saying an engine drop is needed. I can say it is not needed nor would I have just so some hose clamps can be the facing same as factory.
My first drive after everything was together I said to myself "Now that is what it's supposed to sound like."
The AAR was torn apart. After some tinkering I realized that drilling the rivets was not needed and that just punching the pins back and forth was able to adjust the AAR. Its still out of adjustment as my cold idle is 3k but its a trial and error at this point.
I would like to thank the Pelican community for their assistance. All of the information I needed and used came from the board.
now to get it hooked to an exhaust sniffer and then smog tested. (fingers crossed)
Its been off the road for 3+ years. And now back on the road.SmileWavy

Great job. I too have dismantled my CIS system with the engine in the car.

I would call it do-able: not easy ;o)

What I do not understand is that you dismantle your CIS but not your AAR. Drilling the 4 rivets IS easy !:D
What you are doing by knocking its plug is correct but you are now guessing.

I would open it and put it on a 13,5 volt source (that is important as mine did not close 100% with a simple battery given 11.8 or so.).
Put it in the freezer for 1 hour. You should see full opening. Apply straight away 13,5v and it should be 100% closed in about 5 minutes.

If you have 3K idle that is too much. I suspect it is also not closing 100% even after engine heat got to it, so your mixture and idle setting is based on an AAR that allows air through (I know it is metered air but it is still extra air that would otherwise not be able to pass the throttle valve.)

Good luck!

Michel

The brass ”plug” is the only adjustable part. The large aluminum one is just a plug and adjusts nothing.
I drilled and tapped the brass rod that supports and positions the bimetallic strip on my aar to make it adjustable like an adjustable wur..

I did verify that it was closing all the way before I even messed with the adjustments. car runs great warm. just high idle cold.
I fallowed http://forums.pelicanparts.com/porsche-911-technical-forum/551321-auxiliary-air-regulatory-adjustment.html
for the adjustment and believe I too have "over shot the adjustment" I will have to remove the AAR to make the adjustment. Do you guys want pics of the step by step. (Haven't seen any on here yet). but the link above describes it well enough.
I can even redo the removal of the cap to show how to get to the plug out to be able to see the nut.

Vereeken- I did remove the rivets but it wasn't needed as the adjustment is at the other end. just letting future readers know it's not needed.

timmy2-I'm not going to go so far as to make it adjustable once its set it should good as its a press fit.

I made mine adjustable so I could tweak it with the car running at cold idle. When I opened mine I found a portion of the bimetallic strip had a groove worn in it. Ergo the need to adjust.

A couple of photo's would be great for other people if you have the time.

I remember I scratched my head on how to remove the plug....

For what it is worth my bimetallic spring wouldn't hold for more then a couple of heat cycles and I had to replace it...i think the metal gets tired.

Seems you have arrived!

Michel

Did you replace the bimetallic strip or the entire AAR?
If the strip, where did you source it?

Here are some pictures of the easy mod to adjust the brass plug (adjusting the tension of the bimetallic strip) and of the inside of the AAR.
Also a shot of the little worn spot on the bimetallic strip. (Blurry but you can see it)

http://forums.pelicanparts.com/uploa...1340680051.jpg

http://forums.pelicanparts.com/uploa...1340680075.jpg

http://forums.pelicanparts.com/uploa...1340680104.jpg

http://forums.pelicanparts.com/uploa...1340680170.jpg

I only replaced the bi metallic strip. I think it came of a Volkswagen Golf from the early 80s.
I just looked for the same resistance.

I see you have again another shape of hole in the AAR. I can not believe how many different types of holes in the AAR exist. I have seen at least 4 different sizes and contours.

Michel