3.0 hiccuping to not starting CDI?

[Hetheca]

Originally Posted by 997at

As Tony has suggested, it's always a good idea to check fuel pressures first (cold and warm). My advice is start here...do one thing at a time. An engine needs three basic elements working together: fuel, air, spark. Start with fuel.
I'd be happy to talk you through the fuel pressure check as would others.

HETHECA: I'll start with the pressure test and then go to the CDI. Tried watching a couple videos but might need some step by step help if someone wants to list out.
I won't get to it until tomorrow.

[997at]

Originally Posted by Hetheca

HETHECA: I'll start with the pressure test and then go to the CDI. Tried watching a couple videos but might need some step by step help if someone wants to list out.
I won't get to it until tomorrow.

Sounds like a plan. I will either paste some step by step instructions, or draft some you can use for the fuel pressure checks.

If fuel pressures check out, there are a few other fuel related checks to do to ensure that you have good spray when cranking...but we'll get to those if needed.

We're not at the CDI/spark phase yet, but word of caution that just observing a spark from a plug is not good enough. I have had a few times where you can see a spark and it is not sufficient once in the combustion chamber to create ignition.

[pmax]

Originally Posted by Hetheca

... but might need some step by step help if someone wants to list out.
I won't get to it until tomorrow.

Good reading material till tomorrow.

http://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies.html

[Hetheca]

Originally Posted by pmax

Good reading material till tomorrow.

http://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies.html

Think there are some great step by steps in this link! Thanks!

[wgirardot]

Originally Posted by Hetheca

Think there are some great step by steps in this link! Thanks!

Easy test for AAR and a few other things at same time:

With engine cold jump fuel pump relay and immediately observe in situ internals of AAR with a borescope for proper function ( should be somewhat open and then closing over a few minutes looks like a setting sun ). At this time you can also observe if fv is buzzing back behind throttle body. Also test air meter plate for some resistance when slightly pushing up activating fuel injectors briefly. These are some issues you can eliminate in a minute or so. Then i’d move on to fuel pressure testing and vacuum leaks. Best advice in long run is to walk this systematically though Tony. My suggestions for testing will at least eliminate a few things that may send you off in a tangent. Keep notes and think things through and research.

Bill

[Bob Ashlock]

If you remain suspicious of the CDI unit, please email me and I will provide some bench-test instructions. I repair/restore these units and my service is available through Pelican. Also, don't forget the infamous "green wire" distributorl cable. It is notorious for causing intermittent triggering of the CDI. That 'wire' is actually a small coax cable and the conductors fracture due to heat/vibration. Sometimes, with an engine that is idling, you can manipulate that cable to see if movement causes stumbling or kills the engine. Also, (I think it was stated earlier) even if you can hear the CDI box "singing", that does not mean it works properly. Certainly no 'sing' means it is bad (or not getting power), but if it does 'sing', that does not guarantee it is working properly. A common failure in these units is the discharge capacitor which degrades with heat and time and causes all kinds of intermittent/weak/no-spark situations. It requires complete disassembly to service. Also, inside the unit is a ground connection to the pc-board that often erodes away due to electrolysis. As it is at the point of failure, it barely makes connection so vibration will cause the unit to die (or work) intermittently. If this is the problem, there is an easy quick-fix that can be done.

[Bob Ashlock]

Also, forgot to mention ... if you do not have access to a known good 6-pin CDI box, I have a test unit/loaner that I can send you to try a quick substitution. You are in the SF Bay area, so shipping cost is $10 or so.

[Hetheca]

[QUOTE=Bob Ashlock;10500844]. Also, don't forget the infamous "green wire" distributorl cable. It is notorious for causing intermittent triggering of the CDI. That 'wire' is actually a small coax cable and the conductors fracture due to heat/vibration. Sometimes, with an engine that is idling, you can manipulate that cable to see if movement causes stumbling or kills the engine.

Quick update, had to take it in to a shop. Seems to be the “green distro wire”. Moving the wire creates a great running car. Moving it again makes a non running car.

I also need a new Fuel distributor tube for cylinder 3 if anyone has any?

Thanks for the info on the CDI. I live in OC so looks like your right next door.