Pop-off valve: removed
 

I was able to identify WHERE the pop-off valve was leaking from, and this evening - I decided to give a try at scuffing/re-working the area. Unfortunately, the area that was leaking was in a very tight spot; against the wall of the airbox, and I could not get the old 'stuff' out of the pop-off valve to airbox interface.

I then re-assessed the situation: the pop-off valve was installed incorrectly anyway (90 degrees out of phase), so I decided that I was going to go to work with my dremel and attempt to remove it.

Seeing that it was not held in place very well in the back area, I decided to grind away the adhesive on the front of the air box, and pull the old pop-off valve out (carefully).

Here are the results:

After removal:

http://forums.pelicanparts.com/uploa...1387425950.jpg

The old pop-off valve (with some hardened adhesive still stuck on it) - yes, I had to remove the toilet seat off the top to complete this job:

http://forums.pelicanparts.com/uploa...1387426039.jpg

After cleansing the area:



http://forums.pelicanparts.com/uploa...1387426100.jpg


While in the process of making the part order I placed with our host a couple days ago - I purchased a new pop-off valve "just in case".

Well, I guess that I will be installing a new pop-off valve, as I am sure that I can get it in there much more cleanly than before.

I've got some JB Weld, should I use this? I've never seen the "amazing goop" around... maybe I haven't been looking for it.

Good job!!!!!!
 

Brian,

So the time and effort I spent testing your WUR and FD was well worth it!!!!! I did not have any difficulties communicating with you as a matter of fact you are a very fast learner!!!! I spent many hours trying to develop a technique to locate air leaks for DIY'ers like you or me. And you were asking me over the phone the right questions one after the other. BTW, I think I mentioned to you this before that I bought 4 CIS air boxes this year and all the sellers said they were all working when removed from the car. All four (4) air boxes were leaking and cracked in several places. No wonder the previous owners ditch the CIS units.

So would you agree with me that removing the air box was a good decision? Do you want to remove the pop off valve and re-install it back in minutes? I have another trick for you to share.

Tony

Tony -

I agree that removing the airbox was a good decision. Even though I really did not want to do it, I have been able to effectively identify the air leaks, and now I am scratching my head trying to figure out why I didn't test this airbox like this before I installed it. Lesson learned.

I really believe that having you test my FD and WUR was time well spent. I will be spending a little more time puttering around the garage this weekend, and will be putting the air box back on. Really - when this car is running with out all the back-fire issues - I will then have a sense of relief that I made the correct decisions in trouble shooting.

It is really disappointing to me that people ditch the CIS for carbs because a vacuum leak eludes them. A testament to my age, I have to state that I have only worked on one engine with carbs (our boat) and I am not comfortable with making adjustments to that thing (line trimmers and leaf blowers don't count). The CIS system really is a work of art (so to speak) considering the technology available to Porsche during the years leading up to the EFI systems: simple and effective. The problem that I see is that a piece of plastic (such as the air box) with 30 years of cycling through hot/cold temps is bound to wear more quickly than perhaps an aluminum going through the same temp/durability cycles. Nothing is perfect, and I am not even sure that one of those metal air boxes would have lasted longer than the one I took off of the car originally.


I have to put the new pop-off valve in first, and you are making a suggestion on how to remove/install in minutes: I am all ears over here!

Examine that rubber boot on top of the intake closely (Part# 930-110-358-05-M260), especially where the hose connection is. One of the mechanics at my shop showed me that mine was split as he was preparing to swap it over into the SC it was destined for.. also showed me a neat mod (on the motor coming out of the car) where a thin SS rod was inserted through the ribs lengthwise to stop the boot from distorting under heavy load. Not sure it's necessary but couldn't hurt!

did a little digging on sealant.....

Another person suggested RTV.

Mine appears to have been installed with an epoxy done by the previous owner.

I can recall having a couple of backfires when I first got the car. I would guess I cleaned and sealed up the CIS system and adjusted to factory specs some 6 or 7 years ago (~45,000 kms). Aside from some minor enrichment and idle speed adjustments, haven't touched it and the car runs well and starts first crank every time - hot or cold. Never backfires since setting up the system properly.

Airbox testing - part 2
 

I decided to use the "regular" JB Weld, not the Kwik-set stuff and installed the new pop-off valve yesterday.

I did it at the office so that I could test the resultant product today.

...and I did... (in the laundry tub again) - and it appears that the next leak is at the #4 runner input. It looks pretty beat up from somone before getting a bit careless with the air box (or ...I suppose it could have been me, but I try to execute due care when working with parts on cars.)



http://forums.pelicanparts.com/uploa...1387662140.jpg


So I attempted to clean this area with a small piece of sand paper, and applied some JB Weld:

http://forums.pelicanparts.com/uploa...1387662210.jpg

And I am letting the airbox sit over night before test #3.

Stepping back a moment, I most certainly am aware that the rubber boot from the aluminum intake runner will cover this area. I am sure that I am being a little cautious attempting (perhaps overkilling) this repair, when I am "sure" that it is not introducing a leak to the system. Then again, I was "sure" that there wasn't a leak in the system causing the backfire.

Airbox test: passed!
 

It has been an interesting holiday season over here, which started with me making plans to get this car back into one piece, and is wrapping up with me scratching my head trying to figure out what I did to deserve the number of interruptions.

During this break, we had a power outtage that relocated my holiday to a nearby family member's house (thank you!). We were out for 6 days (interruption #1), and in short, when the power came back - it took out the well head pump motor (interruption #2). All that time I was so stubborn about getting a generator: that is this summer's addition to this house - even though I never saw the reason to invest before - I do now.

To the topic: I tested this airbox multiple times, and for whatever reason I could not get the stoppers to be air-tight from a port seal standpoint. So, I installed some rubber gloves on the port opening, and then put the stoppers in the ports. Tough to put in words, but I then put my bike pump on it, and applied pressure, until one of the stoppers became a projectile. My wife was ammused.



http://forums.pelicanparts.com/uploa...1388798505.jpg


Confident that I now have an air tight airbox, I put some time into it yesterday and today: the airbox is now installed.

Because I figure that someone may be going through an installation/removal like me - here are a couple handy tips on installation:

With the car rear in the air, you can drop the engine a couple inches (if you feel the need to do so) for more room.
Install runners #4/#5/#6 on the airbox, in addition to the bracket that holds the #6 to the airbox bumper, put the gaskets on, and put he runners on the cylinder heads.
From there, do a hand tightening on the nuts, leaving some room to move the system.

Install the various components around the back of the airbox (the CSV was a bit of a pain), and then put the other side (#3/#2/#1) runners on.

Of course, this is the condensed version, and I am sure others have been able to navigate through this install more quickly than I. My most time consuming part of the install was --- after I was done putting on the runners and the TB, I realized that in my pile of parts was sitting the breather hose. I then had to put the breather hose on AFTER all of the stuff was in the way. Wow.

Thanks for the update. Been wanting to ask for an update, but resisted. Glad I didn't. Sounds like you have had your hands full.

Congrats on getting the airbox sealed. A big step is now behind you.

I'm sure once you get the mixture adjustment dialed in, the engine will run smooth. Exciting...............

Update:

I got a little time to work on her this past weekend. I feel I've made decent progress, but I am not really super motivated to work on this car given the sub-ridiculous-ly cold temps we've been getting here in SE Michigan.

Here is where we are as of today:

http://forums.pelicanparts.com/uploa...1390365942.jpg

Next steps:

Re-connect the shift coupler, lower her back to "ground level" and reconnect the battery, and the other electrical things I disconnected before I pulled the CIS.

Oh yeah: I did grab a new battery - as the old one would not hold a charge any longer. The old one has been sitting for a long while, and well - that is just what happens with batteries.
I also splurged on a wire wrap (DEI brand) for the wire-bundle that goes over from the shroud to the driver panel (16-pin wire harness), I think it looks much better, than the busted old aluminum heat shield one I had there before.

Next day I get a few hours to work, we're going to hold our breath and pull her out to the ice-covered drive way and give it a shot!

That's annoying...
 

I had a couple hours to play in the garage today, and reconnected the coupler, FP relay and the new battery.

I tried to start her: no luck. When I pulled the key from the ignition, the starter motor kept running, not sure why, but the (new) battery kept turning the starter for a little bit (about 20 seconds) and stopped after I turned the key in the ignition through the start-on-off cycle. When it was turning, it sounded like it was getting fuel and spark, as it would occasionally jump as if it was going to start. Anyhow - I smelled fuel, quite strongly so, I stopped messing and looked around a bit; fuel was dropping from the transmission cross-member. I know there is a fuel line that goes from there up to the engine which appears to be leaking (...and likely to be replaced in the near future - if it is not just a question of just tightening it).

CIS start-up.......
 

Brian,

It is very frustrating after doing all these work and the engine failed to start. I know how you felt and very disappointing. This was the main reason why I test run the CIS engines I worked on before putting them back in the car. One thing I do prior to a start-up is perform a fuel pressure test. Run the FP for several minutes without running the engine. Inspect all the fuel lines around the engine and verify no fuel leak is present. Leave the CIS pressure gauge hook-up and do the start-up.

BTW, after putting the air box back on the car, did you do another pressure test for the system? The air box might have passed the pressure test but the system might have some leak some where. Check the following: ignition spark, fuel pressures (control & system), and no significant source of air leak. Engine should start.

Tony

Sounds like the solenoid on the starter needs work or the ignition switch is sticking. Almost better it didn't start so you don't have a starter/ring gear chewed up by the faster spinning engine.

Tony -

I did not do any pressure test with the airbox installed. However, because I was curious, with the ignition in the "on" position, I went around back to the engine to see if the CIS high pitched whine was happening (yup). I put my hand on the plunger to get the gas flowing just to make sure that the gas from the FA was getting to the FD, and then down to the injectors with out any leaks (yup, no leaks!). These were the only lines that I disturbed in this airbox science project, so I wanted to make sure that I did not forget one to tighten one of the lines.

So, on to the next part of this project, where I pull the starter and bring it to a starter rebuild shop to test it (luckily there is one locally that does very good work).

In parallel I will pull the trans carrier to take a look at the fuel line(s) that appear to be leaking everywhere.

While I am on my back fiddling with the starter and the fuel line(s) I will take this opportunity to fix the clutch linkage.

For the record, I am not angry that it didn't start, but annoyed. There is always good news about this project: A) It is not anybody's daily driver and B) it's January, and we have been "blessed" with the most snow I've seen in Michigan in over 30 years. This car won't be road bound until the weather breaks and the streets are clear... running or not.

We have some success to share with the forum today, albeit minor given the amount of time that it's taken to get this far.

I pulled the trans carrier, supported the trans with a jack, and a jackstand and gave it a shot at starting it again, so that I could identify where the fuel leak was coming from.

It started. Ran. No farting, no backfire, and from the short amount of time that I ran it, the idle was a little high but I figured that it was because it was cold. I ran it for about a minute or so, and took a close look at the fuel lines that are near the transmission carrier, and there was indeed a leak. It was bad enough that I shut the car down and snapped a couple pictures of the offending line(s). Enjoy!

http://forums.pelicanparts.com/uploa...1391899135.jpg



http://forums.pelicanparts.com/uploa...1391899441.jpg

Next step: get in touch with Len to get a new supply line and return line, it looks like both are leaking - or am I looking into this too much?

If I can suggest, clean it up with degreaser, etc. and then pressurize the fuel lines to see exactly where the leak is from. Or, are you sure it is on the rubber line at the compression fitting point?? Is there a point further along the fuel lines that may have a hole worn into it?? Or, even a loose connection at the fuel filter/accumulator??

Good luck.

Our leak was the crimp fitting - - replaced with clamp fitting and good to go.
The lines in the tunnel are a bugger to get out/in.

Regards,

Fuel pressure test.........
 

Brian,

Good job!!!! It is getting closer for a road test. Like what I mentioned to you in my PM, you don't need to run the engine to test for fuel leak/s. Hook up the CIS fuel pressure gauge kit and test run the FP. Then do the inspection while the FP is running. If the leak is occurring from the hose/s outside the tunnel, it would be simple and easy to fix. Which fuel line is leaking? Delivery or return?

Tony

I took another very close look at the fuel lines last night to try to determine what was causing the leak/where it was coming from. I found a little crack on the rubber (supply side) fuel line, but (oddly) the gas doesn't look like it's coming from there, but rather - the crimped fittings. And - it is coming from BOTH of these lines' fittings.

So, I will give a shot at putting some hose clamps on there and see if it makes a difference. It is a rather tight spot to work in under there, and I am not sure how I am going to get wrenches in there to remove these lines if/when it is needed.

I hate to say this, but I would replace both of those lines. If you do a get-by fix now and a leak starts while driving you will most likely lose the car, and possibly your life. Fuel lines on a 911 are not to be messed with! If you can't do it, have it done. Please.

You can make new likes with the proper FI hose and Oetiker clamps. These clamps are much better than the standard worm type or even the full circle screw type FI clamps.

http://lakesidedp.com/uploadpics/pcv/clamp.jpg

Clamps, Multi Crimp Rings, Quick Connectors, tools | Oetiker

I used these clamps to make a repair to my 911 fuel lines in the engine compartment. I cut the old ferrules off of the current fitting and installed new hose with the Oetiker clamps.