911 3.2 stalling occasionally

[dave99]

Again, I thank you all for your help.

I have checked all hoses around the air intake etc. but all looks good, unless something is piped wrong.

I mixed water with washing up liquid and sprayed it around the area where the air intake meets the engine. There was a lot of bubbling so that was a good find. Thanks Be911SC
So I'll be ordering a set of gaskets and seals ASAP.....

Thanks,
Dave

[dave99]

Hello Again,
I have removed the right hand inlet manifold and Have found a few issues...

Two of the three lower gaskets below the spacers are missing parts, it looks like it has been that way for a while. I can only imagine the other side is the same. Also, from over filling it with oil, there is an oily build up inside the manifold.

I guess a major clean up is in order!!

I will post pics when I can. I am amazed it actually ran as well as it did!!!

Thanks,
Dave

[dave99]

Here is what it looks like now...






I have a bit of work to do yet. I damaged one 'o' ring on one of the injectors so will need that. I have the gaskets and the surfaces are clean. What do you think about spraying the manifolds in silver to freshen them up?

Thanks.

Dave

[dave99]

Hi,
I'm not sure if you can see this picture but the blue pipe runs from the upper sensor to the lower port.
The Pipe in the bottom left runs near the oil tank and is blanked.

The other pipe on the sensor is pipes along the right hand manifold and is also blanked with a screw.....

I am absolutely sure that isn't right!!?

Thanks,

Dave

[dave99]

Hi Again,

Decided to spray the manifolds and am glad I did! Have the gaskets and spacers in place ready for the manifolds when they are dry....
Can't wait to assemble her and see if she runs better...
Dave

[Jcslocum]

Have you serviced the "triangle of death" yet? You have it all apart so it's quite easy at this moment. Also the fuel lines are very easy when the intake is stripped.

[dave99]

Hi,
I like the 'triangle of death' thing!!!
I had serviced her prior to the strip down thinking that would solve the running issues....
The plug changes are a bit tedious!

Dave

[Skip1]

You stated:

"I'm not sure if you can see this picture but the blue pipe runs from the upper sensor to the lower port.
The Pipe in the bottom left runs near the oil tank and is blanked.

The other pipe on the sensor is pipes along the right hand manifold and is also blanked with a screw...?"

While I'm not looking straight at my engine right now, I believe there should be another hose (similar diameter as the blue hose in your picture), that runs to the ambient air valve or recirculating valve depending on what diagram / name you look at. The part number of the valve I have is: 930-207-227-00. The hose that linke the two is 830MM long with p/n 999-239-010-40 Pelican Parts - Automotive Parts and Accessories - Porsche & BMW. Hope that helps.

[dave99]

Apologies for the slow reply.
Would I be right in saying that the one of the pipes runs to the air valve and the other returns? Also, is the function of this valve purely for cold starts and should not affect the running of the car at normal temperatures if it was left disconnected?
I have no idea where this valve is located on the engine or if it was discarded when the engine was fitted (before I owned the car).
If the above is true, are there any side effects to leaving this disconnected?
Cheers,
Dave

[Skip1]

I don't believe so (at least not exactly). The small hose I have, runs to the top of the air valve - with larger hoses running to oil tank from one side of the valve and to the back / base of the throttle.

In the first attached picture (provided by another Pelicaner) you can see two references to the air valve. Hope it is starting to make a little more sense now.



Am also attaching the vacuum line routing diagram I have - on the right you'll see a line to the Air Valve (that's the part I'm talking about (note the three different lines from it).

[dave99]

Thanks for that Skip1, It really explains the system.
Only problem is that the air valve appears to be missing!!

Really appreciate the help,
Dave

[Rodsrsr]

Thats not a direct vacuum leak it's ported. (its above the throttle plate) Leaving it unpluged wont effect the idle at all. Check all the hoses that connect to anything below the throttle plate for cracks. A leak on one of these and the car will run like crap.

[rusnak]

It's still downstream of the AFM, giving "false air" readings via vacuum leak.

[Rodsrsr]

Originally Posted by rusnak

It's still downstream of the AFM, giving "false air" readings via vacuum leak.

Yes but not at idle which was the original problem. A vacuum leak here will have zero effect at idle.

[Skip1]

Dave,

In one of your other pictures you showed the back of the throttle with the comment "I'm not sure if you can see this picture but the blue pipe runs from the upper sensor to the lower port. The Pipe in the bottom left runs near the oil tank and is blanked." This blanked pipe is the one that would go to the air valve I'm referring to.

Can you get a better picture of the right side of your engine bay (i.e. the oil tank cap area to see where the small diameter hose is running that comes from the above location?

In the enclosed picture, you can see the air valve above my oil cap. The small tube attaches to the top (from the smaller pipe on the back of the throttle), and the larger tube you refer to above, would fit on the side you don't see.

[BE911SC]

Here's what things should look like back there. As Skip said, the braided hose attaches to the air valve on the oil tank. Mine was found to be disconnected at the throttle body so that may be where the grime there came from. (Engine drop on the to-do list this fall.)



Found this cracked hose during the intake job so we used John Walker's trick and heat-shrinked it.

[dave99]

Hi All,
I have had a lot happen since my last post....
I also had problems with cracks on the above hose. I cut the hose clamp, got some heavy duty hydraulic hose and drilled one end 15mm and left the other end 12mm. I then used jubilee clips to keep it together.
Since the air valve is missing on my car, and it didn't run too bad without it with the pipes blanked, I decided to keep it that way until I pick up a new valve. I figure that if there are no vacuum leaks, there should be no problem once warmed up.
The rest of the vacuum system looks in order, the 'y' piece is connected to the fuel regulator and damper and all other pipes are in place.
I assembled the inlet manifolds and when all was fully assembled and checked, I connected the battery and.........DISASTER STRUCK!!!!

The engine made one turn and locked up. I thought it was a bad battery connection but it wasn't. I tried to turn the crankshaft but it would only turn one way for one revolution. This was 10pm last night so before I threw my teddy out of the pram, I quit, had a beer and went to bed feeling sick.

I thought about the issue today in work and the only conclusion I could come up with was that when I was removing the manifolds, a washer or some debris must have fallen into one of the ports with the valve open and entered the cylinder. Then when I cranked the car, the piston connected with it and locked against the head.

I was full sure I would have to remove the engine and box and strip down at least one side of the engine. I had an idea that could work but I really didn't think it would work!

I borrowed a very small magnet on an extendable stick (a bit like a car antennae) from a work colleague. When I got home, I removed the plugs and determined which cylinder was coming up to top dead centre when it locked. It turned out to be the left rearmost cylinder. I wound the crankshaft back until the valve opened fully and inserted the magnet. at first the magnet picked up nothing but I inserted an air blower in to the spark plug hole and blew with the magnet inserted beside the valve.
Lo and behold, the magnet picked up one half of a crushed washer. I tried again and the other half was retrieved!! What are the chances of doing that without an engine strip!!

The engine turned freely now but I was concerned if there was any damage to valves or piston. The only way to find out was to assemble her again.....

I was pretty nervous putting the key in the ignition..... but up she fired and she purred like a kitten! She has never ran so sweet in the 6 years I have owned her. Idle is a little high but I will correct that tomorrow.

Thanks a million to you all, especially Be911sc for the advice on the inlet manifold gaskets. It's so easy to check and makes such a difference. I haven't driven the car yet but hope to tomorrow. I will get back to you to let you know how I get on....

Dave

[dave99]

Here are a few photos of my engine as it is now.....


I painted the fan and the cowl, what do you think?



As you can see the air valve is missing. It now runs like a dream and ticks over at 800rpm without any fluctuation. It is like a different car and for the first time in six years I am really starting to enjoy 911 ownership



Really appreciate all your help!!!

[dave99]

Just back from a 400 mile trip, car performed really well and is much more economical than before. I have much more interest in the car now that it ticks over and will pass gas stations without needing a drink

Thanks again to all here,
Dave