theiceman

I have an interesting starting issue . If I leave it for a couple of days it will start no problem on first fire , the longer I leave it the worse it gets. Last night I started it after being away for a week . I had to crank for about 10 seconds . and slowly it began to fire during that ten seconds and crept to life with a small pop.
When it does start it goes to about 1400 rpm and is fine, as the car warms up it drops to 900-950 no problem. After that everything will be fine , even next morning cold it will be ine.
I was going to check the cold start valve and thermo timer first but does anyone have any similar experiences ? I don't think the WUR could cause this as when it does start it runs idles and warms up fine.

any opinions ?

Peter Zimmermann

ice: The first thing that I would do is remove the air filter & cover, then look inside, and up at, the bottom of the fuel distributor, where its center plunger is. Check if it's gummy, and seeping a smelly, dark red residue. Also, I would remove the air dome (the rubber piece that connects the throttle body to the sensor plate housing) and be sure that the sensor plate and its housing are clean. You could also have an injector that is very slightly hanging open, making it difficult for the system to prime. The "pop" worries me, have you checked the airbox around its perimeter to make sure that it isn't cracked?

Houpty GT

I am dealing with a few similar issues though I am trying to figure it out and do all the test I need to before I post asking for help. The problem is I just have not put the time into my 1981 that it deserves.

I am assuming with mine when it is so difficult to crank after several days that the fuel is running back into the tank and the lines are filling with air. I was playing with my fuel pump relay some and noticed that it does not run during cranking and if I maually operate it then it will start much easier. The relay rest in the fuel pump running position but as soon as the ignition is turned on it goes to the off position. This could indicate that it is an air in the fuel line problem or that my electrical system is not operating correctly since the pump does not run until the car fires up.

My car also makes a chirping or barking sound from the exhaust when it is under load and will also back fire out the intake pop off valve if I really play around with the throttle. I know I need to check things like the spark plugs and set my valve lash before I really start changing parts but I am still suspicious of the entire thing being fuel system related.

Where is the best place to get a CIS injection gauge? Do they sell for any less than $220 new?

Peter Zimmermann

Houpty: Your fuel pump is not supposed to operate until the engine cranks, so that is working correctly. I'm pretty sure that theiceman's CO% is close, based on his description, but that is the first thing that I would check on your car. Also, never quickly rev a CIS 911 when the engine is cold - it doesn't like that! Jay Laifman, on this forum, recently bought a CIS pressure gauge, but I'm not sure from where, hopefully he'll see your post. In the meantime you might want to check with Baum Tools or Assenmacher Specialty Tools, I'm pretty sure each has a web site.

Hopefully you're all using the best gasoline available in your area, Chevron Premium is the only gas that's ever been in my SC - it starts at the touch of the key after two weeks.

Jay Laifman

Here I am. Yes, I bought a pressure gauge, two in fact. I bought the $200 and change one from Performance Products (which is made by Baum) and the $60 one from JC Whitney. I used the Performance Products one and it worked fine (though you had to release the pressure for every test). It is beefier than the JC Whitney one, but not by much. I don't know how accurate the JC Whitney one is. I have no reason to doubt it. Actually, I've been meaning to ship it back to JC Whitney. If you want to buy it from me instead, I'll ship it to you. (I'm desparately overdue to get to ship something for Art, so I better do it immediately!)

(The reason I used the PP one was that I ordered it first, not knowing about the JC Whitney one, but they were back ordered. I then found out about the JC Whitney one, with still a couple weeks until the PP one was to arrive. So, I ordered the JC Whitney one, and the PP one arrived the next day!)

Jay Laifman

Oh, I should add, if you want to buy the more expensive one from me, I'll sell it too - just not at the JC Whitney price!!!

theiceman

Thanks Pete

I am on vacation and have to leave my car for a week. When I get back next Saturday I will start checking , is there any way to check a hanging up injector ?

Peter Zimmermann

Yes, but you need a tester, or know someone who you can send your injectors to. However, it might be tough to find because of the extended period of downtime before starting gets harder. Let us know what you find when you get back, and enjoy your own down time.

psychoideas

1976 911S CIS

Pete,
While you're here. Are there base start postions for the Air Bypass Screw and the Idle Mixture Screw?

I've just started my car for the first time in the 14 years that I have owned it. I've done the following:
Pump delivery volume.
System Pressure.
Cold Control Pressure.
Warm Control Pressure.
All injectors spray an equal amount.

If I lift the sensor plate and "Prime" the system it starts and runs if I keep the revs up about 2500, but won't idle.
When I got the car there was an "Idle mixture screw" tool sitting in the idle mixture screw! I'm guessing that someone played with it before thay gave up and sold the car.

So is there a setting like some small engines have as a starting point? eg."Turn idle screw all the way in till it stops and then back it out 1 and 1/2 turns"

Ice, sorry for highjacking your thread but I thought I'd jump in because it's fuel related.

TIA,

Frank

Peter Zimmermann

Frank: No basic setting. What we always do after fuel distributor replacement is gently lift the sensor plate arm and adjust the mixture screw (don't leave the allen wrench in the hole!) until the injectors just squirt when the arm comes off its stop. (Obviously, ignition on, system pressurized). Then you have to keep it running for a few minutes until you can take a CO% sample. Good luck with it; wow, 14 years. That's got to be some sort of perseverance record!

psychoideas

Hi Pete,

Yes, some sort of record, although probably not one to be proud of. A dastardly combination of moving house, not having a shed, and a one time business loss, at least I didn’t have to get rid of it.

Thanks for the advice, I did just that, connected the fuel pump to run and adjusted the mixture screw so the injectors just start to fire when the sensor plate comes off the stop.

It was a long way out! I guess that I moved it about 2 to 3 full turns. I think someone had a bit of a play with it 15 years ago.

I have the battery on charge tonight and will try and crank it tomorrow after I get back from a welding job that I have to do for a friend.

I’ll let you know what happens.

Thanks again,

psychoideas

Pete,

You are a God among men!!

I did what you suggested and it fired off the key and even idled straight away

It does idle very low though.

What is my next step? I tried opening the Air bypass screw about half a turn but it seemed to make it idle slower.
How do I speed the idle a little?
More mixture adjustment?? Richer??

Thanks for you help.

Frank

P.S. She's still undrivable so I can't get it to a CO tester just yet.

Peter Zimmermann

Frank: Good work! Yes, you can try to adjust your 3mm screw clockwise in 1/8 turn increments to see if that helps - it should...

theiceman

Wow great thread , no problem with the Hijack Frank as this is a related and info filled post. I figured when I get back I will use my digital camera when i start the car and post it .. a pic is worth a thousand words so a vid should be worth more.
Some fantastic roads here in Vermont ... just about every other car is an Audi but have only spotted two of our generation P cars .. a Carerra at a marble museum here and a beautiful black early SC in Manchester ..
I also scored some techron gas treatment to help clean things up .
Will touch base when i return guy s...

Houpty GT

I guess you misread. I was saying the relay won't kick on till after the the ignition fires up. I would think the fuel system needs to be pressurized so the injectors can work during cranking. I am going to check all this when I get a gauge and work on the car more.

You said I should get the CO% check. I set the dwell so is that sufficent enough?

I really need some time to work on this car. I just hope I don't break some undriven 14 year record!