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-   -   No start, but a bit different (http://forums.pelicanparts.com/porsche-911-technical-forum/641719-no-start-but-bit-different.html)

Christien 11-25-2011 10:36 AM

No start, but a bit different
 
Any ideas what might be causing this? It wants to start - it will turn over once or twice every few seconds. Electrical connections are all good, at least on a 2-minute inspection. Fuel pump fuse is fine. It started fine yesterday when I backed it out of the garage, sat overnight outside (no rain) now this. Here's a video:

http://www.youtube.com/watch?v=SYNt2MeSdX8&feature=youtube_gdata_player

DRACO A5OG 11-25-2011 11:30 AM

Shame on you sir for letting your baby sit out in the cold Ontario weather :-(

Check the voltage on the battery, it may not have enough amps to start her.

J

Christien 11-25-2011 12:35 PM

It was 10 degrees yesterday! :) (celsius, that is)

I just put the charger on and it was indeed showing only about 60%. I always assumed that it would either start or fail to turn over the starter and crank at all. We'll see if this gets it.

DRACO A5OG 11-25-2011 02:28 PM

That will do it and 10c will weaken her as well. You should be fine Ontario, eh :D

Christien 11-25-2011 06:42 PM

Nope, that didn't do it. Put the charger on for a couple hours, and used a booster pack. Same thing. I had it out to boost the minivan yesterday (my wife left the interior lights on again...) but I can't imagine I did anything to mess it up - I've boosted hundreds of cars.

DRACO A5OG 11-25-2011 06:49 PM

Hmm, no click no nothing?

OK, check the ground at trans and the connectors at the starter/solenoid.

Christien 11-25-2011 06:57 PM

No, it's cranking and tries to fire ocassionally, just like in the video. I'm going to have to start checking the regular things.

DRACO A5OG 11-25-2011 07:08 PM

a '72, hmm Sorry can't help on the ignition issue, but I remember reading another poster about something to do with his pop off valve or something like that???

Break a Leg Brother!

Christien 11-25-2011 07:12 PM

That's CIS. I know what to do, was just hoping someone might have a flash of brilliance. :)

NeedSpace 11-25-2011 07:17 PM

Does the engine compartment smell like gas? If not, my guess is fuel starvation. I had a very similar problem in my old mercedes. After a lot of guess work, I found out that the weber carbs had another fuel filter in it. When I opened it up, it was loaded with crud. Weird thing, I had driven it for about 2000 miles before that happened, not sure why it happened out of nowhere. You could have someone trying to start it while you force carb cleaner down the carburator to see if it is fuel delivery.

If it smells as though the engine was flooded (a lot of gas smell in the engine bay), my guess would be electrical. You may be getting weak/little spark. A good way to check this is if you take out a spark plug and the plug is wet.

Thanks for the youtube, makes it MUCH easier to diagnose.

Christien 11-26-2011 05:49 AM

Definitely getting some fuel smell. My fuel filter is mounted in the engine bay for easy access to replace, so I pulled that off to see if it was clogged - gas is flowing through just fine. I pulled the air box off and squirted plenty of fuel to fill the bowls by hand. No go. I hooked up the timing light to check for spark, and I'm getting spark, at least on one cylinder.

?????

Christien 11-27-2011 05:13 AM

Any ideas?

NeedSpace 11-28-2011 05:31 AM

OK, it you have fuel delivery, then it is probably electrical. I would check the spark at all three plugs. Take out each spark plug and look at the spark you are getting. also, examine each plug to make sure that they are wet with fuel (to double check they are getting fuel). The spark should be strong. the 2 times my car sounded like yours, it was 1) clogged carburator, and 2) bad spark. My bad spark due to moisture in the air on my old ignition system. I upgraded to electronic ignition and after some fumbling, I eventually got it to work.

I don't know how, but does anyone know how to measure the amount of spark rather than looking at it? For instance, can you hook up a multimeter to the coil? What voltage are you supposed to get?

BTW, Christien. I am heading to toronto tomorrow on business. I'll wish you good luck when I get off the plane.

cmcfaul 11-28-2011 12:17 PM

Spray some carb cleaner dcown the stacks and crank. Should act like starter fluid.

Chris

73 911 E

Bob Kontak 11-28-2011 12:51 PM

Is there a choke on the carbs? I have CIS and I did mess with a Rochester carb - that one time - so I am no expert.

It sounds like it is not getting enough air but that is a guess.

Joe Bob 11-28-2011 01:18 PM

Spark, fuel (pressure on 70 psi + on CIS) and air.

Pull a plug wire, put another plug in the end, crank motor with plug close to a ground....you'll know if you have spark or not.

Fuel pressure....shot of ether and it coughs, it a fuel problem. Lifting the flap inside the air box will let you hear the pump going....if not prolly a relay under the front hood drivers side. Pump runs, may not be enuff pressure....you'll need gauges.

Air.....well check the intake filter.

NeedSpace 12-01-2011 03:23 PM

So have you had any luck?

Christien 12-01-2011 04:46 PM

I haven't had a chance to dig it into. I pushed it into the garage a couple days ago, and it's sat. It's off the road for winter, anyway - the salt trucks have been out in full force this week. I'll get to it this weekend and see if I can get it started. Just one more thing on a long list of small projects for the winter.

When you pull a plug wire to test, can you hold the wire with your bare hand while cranking? I always assumed that, since the timing light can sense the current pass through, it might be dangerous to hold the wire.

Joe Bob 12-01-2011 04:49 PM

Bare hands and cranking to check start? Sure, if ya want yer sperm to do the 'Macarena".

Gloves and/or an insulted set of pliers will work. Hell....borrow the old lady's rubber dish washing mitts. Or better yet, have her hold it.

Bob Kontak 12-01-2011 05:11 PM

Quote:

Originally Posted by Joe Bob (Post 6404950)
Or better yet, have her hold it.

The dancing banana is feisty today.

Just lay it on top of the valve covers while your helper turns it over. You will see spark if it's there.

It kicks real hard when you eat secondary voltage. I don't care for the sensation at all. Not one little bit.


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