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
> TPS on DJet with 2056, Idle circuit
thomasotten
post Sep 13 2026, 11:44 AM
Post #1


Senior Member
***

Group: Members
Posts: 1,589
Joined: 16-November 03
From: San Antonio, Texas
Member No.: 1,349



I have a 2056 cc engine running D-Jet. All new lines, harness, everything. The engine has 96 mm pistons and larger valves - 44/36. I had to tune the MPS away from the original factory settings or it was just running too lean. So I richened it up and it runs really well now, checked MPS and adjusted with an AFR gauge. Only worry is my ECU mixture knob has no effect. The throttle position sensor has been rebuilt and calibrated with a new board. I double checked and triple checked the calibration because I know that it won't go into the idle circuit, where the mixture knob has authority if the TPS isn't calibrated correctly. So, the next thing I tried was changing out the ECU. Still acts the same. Idle mixture knob has no authority. So I am wondering, is there something about adjusting the MPS that will cause the computer to never use the idle logic? I know it doesn't have any feedback that you get from an O2 sensor, but I am wondering if signals from the MPS can keep it from going into idle mode.

Thanks
User is online!Profile CardPM
Go to the top of the page
+Quote Post
mgphoto
post Sep 13 2026, 12:24 PM
Post #2


"If there is a mistake it will find me"
***

Group: Members
Posts: 1,495
Joined: 1-April 09
From: Los Angeles, CA
Member No.: 10,225
Region Association: Southern California



Idle is controlled by the TPS, and the Pot on the ECU, it has to adjusted for proper function.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
914werke
post Sep 13 2026, 12:44 PM
Post #3


"I got blisters on me fingers"
**********

Group: Members
Posts: 11,746
Joined: 22-March 03
From: USofA
Member No.: 453
Region Association: Pacific Northwest



what is the problem you are addressing?
Too high an idle?
Have you smoked your engine to eliminate air leaks that would defeat idle adjustments?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mgphoto
post Sep 13 2026, 01:09 PM
Post #4


"If there is a mistake it will find me"
***

Group: Members
Posts: 1,495
Joined: 1-April 09
From: Los Angeles, CA
Member No.: 10,225
Region Association: Southern California



TPS needs to be bench adjusted with the throttle body, the ECU “pot” is adjusted with the air screw for idle mixture, they seem to be very picky about this reading in England.
When your car was setup the technician who made the initial adjustments put a detent in the ring around the ECU knob using a soldering iron to indicate the adjustment position.
You need to have the ignition timing adjusted, then after the engine is warm, the air screw is adjusted for idle.

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
thomasotten
post Sep 13 2026, 02:02 PM
Post #5


Senior Member
***

Group: Members
Posts: 1,589
Joined: 16-November 03
From: San Antonio, Texas
Member No.: 1,349



QUOTE(914werke @ Sep 13 2026, 10:44 AM) *

what is the problem you are addressing?
Too high an idle?
Have you smoked your engine to eliminate air leaks that would defeat idle adjustments?


The only problem I am addressing is that the ECU knob has no effect. The engine has all new vacuum lines and was smoke tested. TPS calibrated on bench. Question I have is if anyone has found if there are conditions where the ECU knob will have no effect, especially when MPS is adjusted for larger displacement engine.
User is online!Profile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
4 User(s) are reading this topic (3 Guests and 0 Anonymous Users)
1 Members: chmillman

 



- Lo-Fi Version Time is now: 13th September 2026 - 03:11 PM
...