Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> high exhaust emissions, when idling
DavidSweden
post Jul 10 2019, 02:32 PM
Post #1


Member
**

Group: Members
Posts: 479
Joined: 8-June 14
From: Sweden
Member No.: 17,452
Region Association: Scandinavia



76- 2.0- D jet with Pertronix ignition

Car has high emissions at idle but good at higher rpm. Engine warm

Does this indicate that the engine is miss firing one one cylinder when idling and how do I check that its firing on all cylinders?

The engine sounds fine, any ideas as to what is causing the high exhaust emissions?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
jcd914
post Jul 10 2019, 05:31 PM
Post #2


Advanced Member
****

Group: Members
Posts: 2,081
Joined: 7-February 08
From: Sacramento, CA
Member No.: 8,684
Region Association: Northern California



What emissions are high? CO% HC ppm? Other?

A vacuum leak could create a lean miss at idle that goes away at higher RPM.
Overly rich idle mixture could lean out at higher RPM.

Jim
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Bleyseng
post Jul 10 2019, 08:38 PM
Post #3


Aircooled Baby!
**********

Group: Members
Posts: 13,034
Joined: 27-December 02
From: Seattle, Washington (for now)
Member No.: 24
Region Association: Pacific Northwest



Overly rich? Could be the CHT is going......
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
DavidSweden
post Jul 11 2019, 10:02 AM
Post #4


Member
**

Group: Members
Posts: 479
Joined: 8-June 14
From: Sweden
Member No.: 17,452
Region Association: Scandinavia



QUOTE(jcd914 @ Jul 10 2019, 03:31 PM) *

What emissions are high? CO% HC ppm? Other?

A vacuum leak could create a lean miss at idle that goes away at higher RPM.
Overly rich idle mixture could lean out at higher RPM.

Jim


High HC ppm, the idle is about 700

It sound like its firing on all cylinders, I will check the hoses any other ideas?

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dave_Darling
post Jul 11 2019, 05:00 PM
Post #5


914 Idiot
**********

Group: Members
Posts: 14,974
Joined: 9-January 03
From: Silicon Valley / Kailua-Kona
Member No.: 121
Region Association: Northern California



Turn the idle RPM up to at least 900. We usually run it "just under 1000". I think the factory spec is somewhere between 800 and 950 RPM, depending on the exact year/engine.

Try adjusting the knob on the ECU. Count the number of "clicks" on the knob, or mark it so you can get it back to where it was if you need to. Going counter-clockwise should make the mixture leaner at idle only. If that helps your CO, then you were running rich. If that doesn't help, try going the other way.

--DD
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 29th March 2024 - 01:10 AM