Help! It won't start!

[nmcm]

Believe me when I say that I have been looking through this site for help but I need more.

This past weekend was not a good one but here is the whole story:

I have a beautiful 1973 911T upgraded to "S" specs that has a 76 2.7L engine in it that has CIS injection. Over the last two years I have been resoring this car and now I have only the carpets to put in. Last summer I got the car road worthy and drove it half way across the country (West to East). What a drive! Anyhow, for the winter I had it stored in a heated garage and a month ago it came out where I gave it a nice run for about an hour or so to get it nicely heated up. It was then parked for a month as I worked on it. Last Saturday I got the car started and gave it a wash. Once again, as I was washing it, I had it running so that it could get up to temp. No problems. So, Sunday, the day of my first autocross, I started the car up in the morning, and as I was loading the car the car just quit. I thought that maybe the gas tank was reading wrong so I went and got some gas. The car started then quit 5 to 10 seconds later. I then tryed to restart it and it wouldn't lite at all but it still turned over. I checked the obvious, fuel and spark and the distributor cap was in good shape. I then tryed to start it again to no avail. With a little cool down it might run for a few seconds otherwise it won't light up at all.

One final note. When I try to give it gas as an attempt to stop it from stalling it caughs and splutters for maybe a second or two then quits.

Gentelmen, I need your help. This could take us a few days but since I have no dealer anywhere within 6 hours, I've got the time.

NMCM

[Jim Sims]

Check the 14-pin connector (driver's side of engine compartment)for a loose or corroded pin/socket. Use only a rubber eraser to clean the pins/sockets as these are silver plated. Look for an air leak; there are numerous rubber hoses and seals on the 2.7 CIS system that can fail. Have you suffered a significant backfire lately without an airbox pop off valve installed? If so, look for a cracked or split airbox. I assume you checked the ignition and are getting a spark when you turn over the engine; if not - check the points (dwell) and CDI connections.

[vash]

when you checked for fuel and spark, you confirmed both?

[nmcm]

Ok. When I checked for a spark, I pull one spark plug and had my wife crank the engine while I made contact with the spark plug and the frame. When I did this the spark plug worked. As for checking for fuel, in a past article someone said to start the car then when it stalled I kept the key as is and hopped out and pushed on the lever arm of the fule distributer on the top of the air box (Probably the wrong name but hopefully you know what I mean) and I felt a pressure and I could also hear a squeeling noise.

As for the 14 point connector, I will look at that tonight.

My car does have a pop-off valve but this brings about my first question. Why would a cracked airbox affect the engine. If I'm not mistaken you can start the car just fine without the airfilter cover on and wouldn't that be the biggest leak of all?

As for the air leak in CIS system. Where do I begin and how to I check for a leak on each part of the system? Does anyone have any good diagrams or photos that could help?

Finally, as for as the ignition goes, a friend of mine said that maybe the distributor gap need adjusting. On a 76 CIS how do I check for that and can it be adjusted?

Thanks guys

NMCM

[vash]

you are right, your car will run without air filter cover, but the pop off valve protects the air box below that. i was confused on this too, in the beginning. open the POV and peek in, you will see and enclosed area that goes to the injector runners. this area needs to be airtight.
i tested for spark the same way, and earlysman told me this wasnt reliable. he got me to buy one of those dummy spark plugs with a grounding clip on it. it showed me that my spark was really anemic. my problem turned out to me an intermittent failure of 3 or so beru connectors when the motor got hot. i like to check for fuel by yanking out a fuel injector. then i get my girlfriend to flip on the ignition, i listenfor the buzz of the fuel pump and then i push up on the air sensor bar. i want to see a perfect spray. like an aerosol can. #4 is easy to get to. check to make sure your pop off valve is not loose or the lid is not ajar.

[nmcm]

"he got me to buy one of those dummy spark plugs with a grounding clip on it. it showed me that my spark was really anemic"

"my problem turned out to me an intermittent failure of 3 or so beru connectors when the motor got hot."

What is a bero connector? As for the dummy spark plug, my memory of those is that they have a light bulb in them and they intermintantly flash as the distributor selects that plub. If this is so wouldn't I get the same result as just watching the spark plug? I will give it a try but I am just interested in the difference.

[Early_S_Man]

nmcm,

The blown airbox cracks provides about 1 square inch of additional air inlet area below the airflow sensing plate ... hence the airflow switch may not ever be triggered during the starting process, and even if the fuel pump relay is triggered, airflow volume will be much greater than the volume of metered fuel provided, and much backfiring and rough running will be the result. Ask anyone who has experienced a blown CIS airbox ...

[vash]

a beru connector is the ends of the factory spark plug wires. they go bad. and the spark tester looks just like a spark plug, with an alligator clip coming off the end. i think you get a reliable ground this way, and you dont let your spark plug condition affect the test.

[Early_S_Man]

No, the test spark plug from KD Tools doesn't have a neon bulb in it ... it is just a spark plug with a grounding clip, so part(s) of your body don't serve as a path to ground while you hold the wire/plug ... causing chunks of skin/hide to depart violently after collision with sharp sheet metal in the engine compartment!!!

Beru is the spark plug connector ... if you still have OEM wire set.

[nmcm]

OK thanks guys. I will give this a try tonight and let you know tomorrow

NMCM

[buttjoint]

Insert a screwdriver into the brue connector and hold on to it while some one cranks the engine over. If it zaps you good you know you have good spark, If not you will feel that the spark is weak.

[Jim Sims]

Originally posted by buttjoint
Insert a screwdriver into the brue connector and hold on to it while some one cranks the engine over. If it zaps you good you know you have good spark, If not you will feel that the spark is weak.

Buttjoint, are you an idiot or a sadist? Do you check to see that your saw arbors are tight by trying to hold onto the saw blade as you start the saw? FOR SAFETY REASONS THE ABOVE ADVICE OF HOLDING A SCREW DRIVER IN A SPARK PLUG CONNECTOR SHOULD BE IGNORED! Jim Sims

[buttjoint]

So sorry I forgot about the saftey police on this site. Im not a sadist so I must be a idiot because I've used this method many times.

[slater]

You really shouldn't hold it in your hand. Put it on your tounge and test it like a 9-volt battery.

[nmcm]

Ok, I checked the car with the dummy spark plug and I do have a good spark at least when the car is cold. The airbox does not have a crack and I have cleaned the 14 point connector but still no luck. The Pop-off valve is in good shape and so is it's "o" ring. I didn't have time to check the spray on the injectors but I will do that tomorrow.

Here's my next question. My Dad was saying that on his old cars you used to have to ajust the contacts in the distributor every year or so. Is this true with a 76 engine? If so, where do I measure the gap and how do I adjust it? Here's a photo to help out.

[joet4143]

your points gap at .35 and clean all the connections in and out of the distributor especially the one going into the dist from outside . just had the same problem on o 71 911 no start . hope this helps . by the way the contact point rides the dist shaft and make contact if you turn engine with cap off you should be able to see what your looking for ...also clean these well if you follow through the points you will find the connectors to clean on the inside . also check ground at trans to body .

[nmcm]

Thank you all! The car now runs like a dream again. The problem was indeed the distributor. The points gap had fallen to 0.005" instead of 0.012". Thanks again!

NMCM

[vash]

now i think you are to check dwell and adjust timing?