Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   Porsche 911 Technical Forum (http://forums.pelicanparts.com/porsche-911-technical-forum/)
-   -   3.2 Intermittent Spark - suspect CA139EX comparator in DME (http://forums.pelicanparts.com/porsche-911-technical-forum/987158-3-2-intermittent-spark-suspect-ca139ex-comparator-dme.html)

nagromike911 02-10-2018 09:06 AM

3.2 Intermittent Spark - suspect CA139EX comparator in DME
 
Hi y'all.

Getting intermittent spark pulse at the DME pin 1 output to coil. Traced to S800\B CA139EX voltage comparator. I get 4 volt pulses on pin 7 and pin 6 is steady 2 volts reference. I expected to see around 2 volt pulses out on pin 1 but see almost nothing coming out with a scope.

I've searched for this RCA part CA139EX but find very little in the way of availability on the web.

Just wondered if anyone knows of a source for this chip?

Thanks

Mike

4flyboy 02-10-2018 11:12 AM

Mike,

Ingo Schmidt is your guy for this.

ischmitz here on the boards helped me tremendously with time, advice and even a loaner when I had serious issues with my DME unit.

He'll be able to answer this question.

Good luck,

Scott

nagromike911 02-10-2018 11:19 AM

Many thanks for the reply, Scott. Actually, after further investigation the problem was not what I thought. I found I was not giving the cpu time to boot in the DME and was turning the engine over too quickly on the turn of the key. That's why the problem seemed intermittent; sometimes I was a bit slower than other times and then it fires. This has probably been discussed before on the forum but I'll put a message up about JIC. Regards

Mike

4flyboy 02-10-2018 11:25 AM

Even better! Glad it fired, I had reference sensor problems and Ingo went waaay beyond the call

john walker's workshop 02-10-2018 11:34 AM

Time to boot?

brighton911 02-10-2018 01:17 PM

Mike, I can say I do not wait any time at all between key on and cranking and have never had an intermittent start issue. I think there may be something more to your problem after all.


All times are GMT -8. The time now is 04:59 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.