A/F set up ?
Thread Starter
Race Car
Joined: Dec 2006
Posts: 4,089
Likes: 6
From: Tampa Florida
A/F set up ?
86 S/C
With S/C disconnected and blowing in to the air direct up no stream interference to Maf.
From cold to warm these are the readings:
With a John Speak rebuild from my euro installed for testing I am finding the following:
Speak Maf: Car idle: wants to stall idle fluctuates from 0-1,200 have to feather gas for about 30-Seconds.
Cold start: Warm idle
A/F 10.7 13.1
Rpm 760 840
Maf-V 2.70 265
Maf From Pin 3 to 6 its at 315 Ohms Pin 3 to 5 4.1 Ohms
Modified Maf with two adjustments: Car starts right up idles great.
Cold start: Warm idle
A/F 14.7 15.1
Rpm 760 830
Maf-V 2.42 242
Maf From Pin 3 to 6 its at 427 Ohms Pin 3 to 5 4.1 Ohms
I had to adjust this Maf but now it seems lean under Wot I will test this later.
I am sure I can adjust it out.
Mt question is why does the Speak work fine on my 85 Euro but not on my 86 S/C and the Co adjustment is not at factory from the Speak Maf unit 316 Ohms.
I have my Idle screw all the way in and smoke tested and the only leaks are from the idle control valve. I found this leak on every one I tested and it is small.
With S/C disconnected and blowing in to the air direct up no stream interference to Maf.
From cold to warm these are the readings:
With a John Speak rebuild from my euro installed for testing I am finding the following:
Speak Maf: Car idle: wants to stall idle fluctuates from 0-1,200 have to feather gas for about 30-Seconds.
Cold start: Warm idle
A/F 10.7 13.1
Rpm 760 840
Maf-V 2.70 265
Maf From Pin 3 to 6 its at 315 Ohms Pin 3 to 5 4.1 Ohms
Modified Maf with two adjustments: Car starts right up idles great.
Cold start: Warm idle
A/F 14.7 15.1
Rpm 760 830
Maf-V 2.42 242
Maf From Pin 3 to 6 its at 427 Ohms Pin 3 to 5 4.1 Ohms
I had to adjust this Maf but now it seems lean under Wot I will test this later.
I am sure I can adjust it out.
Mt question is why does the Speak work fine on my 85 Euro but not on my 86 S/C and the Co adjustment is not at factory from the Speak Maf unit 316 Ohms.
I have my Idle screw all the way in and smoke tested and the only leaks are from the idle control valve. I found this leak on every one I tested and it is small.
Rennlist Member
Joined: Feb 2002
Posts: 7,060
Likes: 42
From: Cambridge England
If the MAF can be adjusted for idle CO of 1% when used with your stock Euro, then that pretty well rules that out as the problem. Have you tried a stock 85/86 LH EPROM with your s/c car (with s/c disconnected )?
Thread Starter
Race Car
Joined: Dec 2006
Posts: 4,089
Likes: 6
From: Tampa Florida
No not yet; I can only believe that your Maf is correct although the readings of 315 Ohms was a little high but the Euro runs fine. With your Maf the car has all kinds of idle issues when cold so I am assuming I am adjusting out these issues with the adjustable Maf. I will install my stock chips tomorrow and see what happens, do I need to do both chips or just one?
Thanks
Thanks
Trending Topics
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
9 Features and Characteristics That Only Porsche People Understand
Verdad Gallardo
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way
Joe Kucinski
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)
Verdad Gallardo
Porsche 911 GT3 S/C vs 718 Spyder RS: 10 Categories, One Winner
Joe Kucinski
This Builder Is Turning Heads With Its Slantnose 911 Creation
Verdad Gallardo
Porsche 911 GT3 Artisan Edition Pays Homage to Japanese Culture
Verdad Gallardo
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look
Verdad Gallardo
10 Porsche Colors That Have More Personality Than Most People
Verdad Gallardo
Guntherwerks' Final Speedster Creation Is the Ultimate Porsche Restomod
Verdad Gallardo
Thread Starter
Race Car
Joined: Dec 2006
Posts: 4,089
Likes: 6
From: Tampa Florida
LH 928-618-123-04 24 pin chip 28 pin socket also 2 284-986-516
Lh chip stock 2287355631
on Lh board 228 832 1495-4 and 2 284 496 516
Johns Maf
Lm voltage at idle: 2.70
Lm voltage between pins 6&7 car not running 1.7 volts
10.2 A/F at start up cold
12.2 when warm
Johns has cold start issues but after 20-Seconds idles fine
Lh chip stock 2287355631
on Lh board 228 832 1495-4 and 2 284 496 516
Johns Maf
Lm voltage at idle: 2.70
Lm voltage between pins 6&7 car not running 1.7 volts
10.2 A/F at start up cold
12.2 when warm
Johns has cold start issues but after 20-Seconds idles fine
