3.2 dme tunning!

[DRD]

Just wanted to share some info with you guys. I have a 85 3.2, has had a idle hunting problem since day 1 of owning the car.After a long researching of the fi system I have found out some some good info.
Found out the the idle problem was a vacum leak in the cooper tube from the throttle body to a regulator assembly on the left side, replaced the rubber hose that was crimped on the tube and the idle prolem is gone.
Also the C02 adjustment screw on the airflow meter works good at 9 to 10 turns out, factory was 5 turns way to rich.
Also there is a switch on the dme brain, factory is stock fully counter clock wise, I now have the switch set for a +6% fuel increase and timming is at 0. I found a post on renn list that tells the settings on the dme switch.
Basically, keeps the timming the same and adjusts the fuel, or retards the timming -3 degrees and adjust the fuel for not so good gas.
Final results, A car that idles nice, has no flats spots anywere in the power band, and has good bottom end mid range pull for around town, and excellent throttle response. A 100% improvment from the way the car was tuned from the factory! She now runs like it should!

Here are the seetings: I am position 3 now.

Postion 1 is fully counter clockwise:
Fuel Ignition
1 0 0 stock setting
2 +3% 0
3 +6% 0
4 -3% 0
5 0 -3deg
6 +3% -3deg
7 +6% -3deg
8 -3% -3deg

DRD
Darren

[This message has been edited by DRD (edited 05-10-2001).]

Can you post your findings?

TIA


------------------
Nick Hromyak
'85 Carrera 7 & 9 Fuchs
Havin' Fun in Sacramento

[DRD]

[This message has been edited by DRD (edited 05-10-2001).]

DRD,

Do you have the Catalytic converter connected?

I understand running too rich will over-heat and destroy (possibly clog) the cat.
Your thoughts?

Have you tried a dial-back timing light to see if these are indeed changing the ignition timing?
I wonder if it affects timing only in the upper RPM range or idle.

John Walker, are you reading? Do you know?

TIA
Nick

[This message has been edited by nhromyak@yahoo.com (edited 05-10-2001).]

[johnd]

where is the co adjustment on a 84 911? I'll try that but will stay away from the dme pot

I understand the mass air flow sensor co adjustment is in the front on the
bottom
cover, you can adjust it if the plug is removed. Of course, the plug needs to be drilled out. This is a Government regulation thing. I understand after the plug is removed it is the allen type adjustment.

Good luck.
Nick

[movin]

How did you come by the rubber boot? Parts supplier said I had to by the copper tube with the boot and it was expensive.

Originally posted by DRD:
Just wanted to share some info with you guys. I have a 85 3.2, has had a idle hunting problem since day 1 of owning the car.After a long researching of the fi system I have found out some some good info.
Found out the the idle problem was a vacum leak in the cooper tube from the throttle body to a regulator assembly on the left side, replaced the rubber hose that was crimped on the tube and the idle prolem is gone.
Also the C02 adjustment screw on the airflow meter works good at 9 to 10 turns out, factory was 5 turns way to rich.
Also there is a switch on the dme brain, factory is stock fully counter clock wise, I now have the switch set for a +6% fuel increase and timming is at 0. I found a post on renn list that tells the settings on the dme switch.
Basically, keeps the timming the same and adjusts the fuel, or retards the timming -3 degrees and adjust the fuel for not so good gas.
Final results, A car that idles nice, has no flats spots anywere in the power band, and has good bottom end mid range pull for around town, and excellent throttle response. A 100% improvment from the way the car was tuned from the factory! She now runs like it should!

Here are the seetings: I am position 3 now.

Postion 1 is fully counter clockwise:
Fuel Ignition
1 0 0 stock setting
2 +3% 0
3 +6% 0
4 -3% 0
5 0 -3deg
6 +3% -3deg
7 +6% -3deg
8 -3% -3deg

DRD
Darren

[This message has been edited by DRD (edited 05-10-2001).]

[movin]

How do you estimate the various positions on the DME pot? is there a spring detent for each position?

[Jorgeman]

Originally posted by nhromyak@yahoo.com:
".... you can adjust it if the plug is removed. Of course, the plug needs to be drilled out...."

Good luck.
Nick

Take a look at my picture titled the Engine Room at: http://www.pelicanparts.com/cgi-bin/pmpre/pm.cgi?login=Jorgeman&ID=25513&ID=25513&action=display
If you look at the front boss on the Mass Air Flow thingy you can see where to drill a 1/8 or 5/32" hole. Then hit it with a blast of compressed air and it'll USUALLY blow out the
metal plug at the bottom of that boss. You can then come up from the bottom of the boss (forget the size) with an Allen wrench to adjust.

George 86T

[nhromyak]

Movin,

There is a click, sort of like speed bumps, when you turn the dial clockwise. Each "bump" would be the next setting.

Good luck

------------------
Nick Hromyak
'85 Carrera 7 & 9 Fuchs
Havin' Fun in Sacramento

[poorsche]

Anyone else with these experiences?
How did you come to the conclusion that 9-10 turns on AFM was right and that setting for the brain.
I'm very interested in this. My plug is drilled out and from experience about everything else on this car I doubt its been adjusted properly (by PO or his/her mechanic).
Can you do damage by just playing with AFM, turning adjustment in or out until running ideal.
Do you have to do anything prior to adjusting brain (i.e. battery disconnect,...)

I love to adjust things. Usually ending up going too far or ending worse off.

Joseph '86 T-look

[This message has been edited by poorsche (edited 06-07-2001).]

[GIBSON]

Darren, I'm interested in the idle hunt you described. My 86 Carrera has had a hunt at idle off and on for the last several years.
Sometimes it goes right to idle as sits there, other times (usually when hot) it will hunt for several seconds then idle just fine. Is this similar to your cars idle?
I'll check the copper line next.
THanks
Bruce Herrmann
86 Carrera

[movin]

My airflow box adjustment screw was only 2 1/2 turns out (factory). At 8 1/2 turns it seems to idle smoother but I'm wondering does this affect mixture across the board or just low range? Does the DME pot, position 1 or 2 affect the mixture across the entire range? Finally, will any deviation from factory settings be counterproductive or incompatible with a performance chip?