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-   -   3.2 w/factory Motronic Running Poorly and Stalling (http://forums.pelicanparts.com/porsche-911-technical-forum/601687-3-2-w-factory-motronic-running-poorly-stalling.html)

Stophos 04-08-2011 03:39 AM

No issues guys. I appreciate the help. I forwarded the info. thus far and suggested starting with the DME relay since yes it is good to have a spare.

Anymore advice will be appreciated. If there is any success once this has been solved I will be sure to post.

- Chris

Gemballa2006 04-08-2011 05:10 AM

I have these exact sypmtoms on my 86. replaced ref sensors, cht, fuel filter, dme relay, checked dme itself, idle control valve and it still persists. I am ging to my mechanic next week and i have full faith he will crack it, this guy knows these cars inside and out. I will let you know what we find

SlackeR32 04-08-2011 06:52 AM

Hey guys - I am the current owner of the discussed vehicle. I had some time and tools available this morning so did some work for Chris. First I put an ohmmeter on the CHT - 500 ohms at about 50 degrees is too low. Then I unplugged the connectors and tested the speed and reference sensors. Came back with same numbers on both. Looking at the connectors I noticed one of the three clips (elect contacts) had been pushed back in the housing. I removed the rubber backing and pushed it back into place and heard it click. I tested it's security from the front and then buttoned everything up. I left the CHT disconnected to richen the mixture for starting. Started like it should no gas, first try, idled fine. I plugged the CHT back in after about 30 seconds of warming. It stumbled for a sec but then returned to smooth idle. I took the car for a drive everything was perfect.

So in summary there were 2 issues. CHT going bad causing hard cold start. Intermittent connector failure on speed sensor. Car starts using the other sensor (reference) and then switches to the speed sensor - this is why it would start and then die. The connector issue was likely caused when the speed sensor was reconnected after the PPI compression test.

Chris needs a new CHT sensor. $50 and 10 minutes to replace.

I'm going to miss this car. Don't get married! ;o)

PatrickB 04-08-2011 07:18 AM

Never a bad idea to replace the flywheel sensors and CHT. If they are original, they will at some point fail. Another OFTEN missed preventative maintenance issue, is the 25 year old ORIGINAL fuel injectors. Take them out and have them over hauled. You will be amazed at the difference in performance and economy as well!

MH911 04-08-2011 07:53 AM

OUTSTANDING. Glad to hear the problem was resolved so quickly.

dshepp806 04-08-2011 08:38 AM

gotta' watch that fuel pump (pressure readings), too!

best,

doyle

Stophos 04-08-2011 11:09 AM

A successful ending and hopefully a helpful post for someone in the future.
 
Thanks to all!

-Chris

PS. Hey Jon, Be careful what you post or my wife will think I bought a sixth Porsche!:eek:

Nick Triesch 04-08-2011 02:30 PM

First thing I would do is pour in some Chevron Techron and let it run as much as you can. This has helped me several times in the past and will only cost $14.00 for the good stuff. I'm just saying that before you jump for the parts, clean the fuel system. I keep a bit in my tank every few months or so. Nick

DRACO A5OG 04-08-2011 03:59 PM

Try the BG 44K, much better than Techron.

Congrats on the Fix!


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