Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 911 Technical Forum


Reply
 
LinkBack Thread Tools Rating: Thread Rating: 1 votes, 5.00 average.
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Mar 2015
Location: Dallas, Texas
Posts: 17
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
Old 02-10-2018, 09:06 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
4flyboy's Avatar
 
Join Date: Jul 2006
Location: Delray Beach/So. Cal
Posts: 2,502
Garage
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
__________________
Scott

"Houston, Tranquility Base here, the Eagle has landed"

Silver 1984 M491 Sunroof Coupe
Old 02-10-2018, 11:12 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Mar 2015
Location: Dallas, Texas
Posts: 17
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
Old 02-10-2018, 11:19 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
4flyboy's Avatar
 
Join Date: Jul 2006
Location: Delray Beach/So. Cal
Posts: 2,502
Garage
Even better! Glad it fired, I had reference sensor problems and Ingo went waaay beyond the call
__________________
Scott

"Houston, Tranquility Base here, the Eagle has landed"

Silver 1984 M491 Sunroof Coupe
Old 02-10-2018, 11:25 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
john walker's workshop's Avatar
 
Join Date: Mar 2001
Location: Marysville Wa.
Posts: 17,912
Time to boot?
__________________
8009 103rd pl ne Marysville Wa 98270
206 637 4071
Old 02-10-2018, 11:34 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Dec 2007
Location: Just a little north of 13669/Nation's capital
Posts: 937
Send a message via AIM to brighton911
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.
__________________
1986 Targa Guards Red
2012 Cayman S
Old 02-10-2018, 01:17 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 

Tags
3.2 , ca139ex , dme


All times are GMT -8. The time now is 11:20 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

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