No idle after long stand still

Niels911SC · Niels911SC's Garage

I brought in my 911 for a full bare-metal respray about 9 months ago. I finally got it back 2 weeks ago and it immediately started up again. A lot of blue smoke from oil seeping into the cylinders, but aside from that it ran fine. After running for a minute however the idle started going up and down more and more. I took it for a drive and when it was warm it wouldn't idle anymore at all. At speed when I put it in neutral the engine stalled. While driving however it felt absolutely fine. I drove it hard and ruthless for an hour and she performed perfectly except for not wanting to idle.

So my question, what's the first step?

timmy2 · timmy2's Garage

How old is the fuel you are running?
Can you get some Techron and fresh gas to run through it?
If it doesn't clear up after a tank of fuel, then test your fuel pressures or other components.
From looking at your garage I see you have a '78, so all the CIS threads are a good read.

If you left fuel in the tank for 9 months then you should drain it and freshen it up as mentioned earlier.

Bob Kontak · Bob Kontak's Garage

The first step, without over-thinking it, would be to add air into the intake by turning the air-bypass screw counter-clockwise.

Now, the chance that this is the only issue is slim but it is the first step.

Did it idle ok last year?

Here is the air-bypass (idle) screw.

Niels911SC · Niels911SC's Garage

Although I agree 9 month fuel is not optimal to say the least, if it had really gone bad it wouldn't make power as it did, and it wouldn't idle when cold/just started either.
Reading up on the CIS threads is a good one, I just don't know where to start haha

Niels911SC · Niels911SC's Garage

Ok Bob, I'll try that when I get to my car this weekend! It did idle last year, but I wouldn't rule out that something has happened to my settings... (long story)

Niels911SC · Niels911SC's Garage

I feel like the stupidest man on earth but after some fiddling with the air-screw, and dissassembling the WUR to clean it and putting it back together, the car won't start anymore at all.

I'm trying to follow this guide, (chapter "Engine fails to start cold or warm) but I can't seem to find the problem...

On page 10 it says clamp off the feed hose to the CSV and then try to start. It doesn't start, but according to the booklet it should start then stop. This doesn't happen.

I haven't checked the control pressure though, still waiting on a set of pressure testers to arrive.

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by Niels911SC

I feel like the stupidest man on earth but after some fiddling with the air-screw, and dissassembling the WUR to clean it and putting it back together, the car won't start anymore at all.

I'm trying to follow this guide, (chapter "Engine fails to start cold or warm) but I can't seem to find the problem...

On page 10 it says clamp off the feed hose to the CSV and then try to start. It doesn't start, but according to the booklet it should start then stop. This doesn't happen.

I haven't checked the control pressure though, still waiting on a set of pressure testers to arrive.

Niels,

Welcome to the 'stupidest man on earth club'. I have joined this group so many times and won't be the last. If you have ignition and no significant unmetered air, you could almost tell if the engine would start or not if you know the control and system fuel pressures. Using fuel pressure gauge for fuel injection troubleshooting is MANDATORY.

My '78 SC has been sitting in the garage for 2 years now with the same fuel without any additive. I have a bottle of Techron but too lazy to put it in!!! Occasionally I would run the engine for atleast 30 mins. and did it last November. And tried it again last week. Adding fuel treatment is a good course of action but do not always blame the fuel for your trouble. Unless the fuel is contaminated with water, which could be the case.

How could work on the WUR without having a pressure gauge in hand? Keep us posted.

Tony

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by Niels911SC

On page 10 it says clamp off the feed hose to the CSV and then try to start. It doesn't start, but according to the booklet it should start then stop. This doesn't happen.

The page 10 instructions are to determine if your CSV is leaking and if it starts then stops you are to examine the auxilary air valve for proper functioning.

If you have disabled fuel flow to the CSV you may want to assist starting with some starting fluid.