What happens if I disconnect the idle positioner?

ruechaos · ruechaos's Garage

Hey guys! The car is running pretty good, mostly thanks to all the great help I've recieved on this board! Just a few little things to get it all "just right".

One of the little things being the idle. At start it's right around 900, and once it gets warm, around 1k to 1.1k. Is that normal?

I was thinking that maybe it has something to do with the idle positioner, so just to see what would happen, I disconnected it. Once while the car was cold, and once while the car was warm. It made no difference in the idle, when I dosconnected it, no one bit. Now is that normal?

Thanks a lot for all the help you guys have been. All I need is a lower valence, and she'll be good to go!

-Tony

Porsche944 · 09-05-2003, 06:21 AM

You need to disable the idles stabilizer and then set the mechanical idle.

To do this you connect a dwell/tach to the primary (green) wire at the ignition coil, start the engine, let it warm up, and then put a jumper wire between pins B and C of the diagnostic plug on the driver side fender.

Now you can adjust the idle by-pass on the throttle body to set the idle to 840 +- 50 RPM. Remove the jumper, and you're done.

ruechaos · ruechaos's Garage

Sweet. Thank you kindly!

-Tony

SoCal Driver · SoCal Driver's Garage

Think Wilks has the process on his web site. Used to as one methode of getting rid of the return to idle stumble that the early 944's experiance. Keep us posted on how it works for you.

afx · 09-05-2003, 11:55 AM

Quote:

Originally posted by Porsche944

To do this you connect a dwell/tach to the primary (green) wire at the ignition coil

What is a dwell/tach and where do I get one?

SoCal Driver · SoCal Driver's Garage

Good car parts store or Snap-On or Sears or Mac Tools.

Porsche944 · 09-05-2003, 01:07 PM

A "Dwell/Tach" is a multi-function tester. You can test engine RPM for 4,6, & 8 cylinder engines, voltage, and ignition point Dwell.

Dwell refers to the relationship between how long igintion points are open and how long they are closed. The units are dgrees.

Any good parts store like Pep Boys, AutoZone, Advance Autop, etc. should have them.

afx · 09-08-2003, 10:20 PM

So what does the Dwell/Tach do while you are trying to adjust the idle? Does it just allow you to see what RPM you are at? If that is it, would you not be able to just look at the tach?

SoCal Driver · SoCal Driver's Garage

Quote:

Originally posted by afx
So what does the Dwell/Tach do while you are trying to adjust the idle? Does it just allow you to see what RPM you are at? If that is it, would you not be able to just look at the tach?

Would take a very long screwdriver or some creative mirror placement.

Then you could run back and forth between the drivers seat and the engine compartment.

speedracing944 · speedracing944's Garage

Isn't it also more sensitive? (Dwell Tach)

afx · 09-08-2003, 10:57 PM

Quote:

Originally posted by SoCal Driver
Would take a very long screwdriver or some creative mirror placement.

Then you could run back and forth between the drivers seat and the engine compartment.

I was just thinking I could get my dad to watch the RPM while I adjusted. Would that be good enough? I would rather do that then pay like 30 dollars for the gauge. But if it is needed I will go out and buy one tomorrow.

SoCal Driver · SoCal Driver's Garage

I've found your problem!!!!

Here:

""'
84NA Engine, '87NA Brain/AFM/wiring
harness, all in an '87S Body....AND IT
RUNS!!! kinda...
""
Do hope you also installed the test plug for the 87 hardware. You have to jump between pins B and C then adjust the idle. Other wise the DME keeps trying to adjust the idle.

Also installed the idle possistioner from the 87 including all of the vacuum valves and such.

Check the DME temp sender too.

Of course your temp gauge sender for the 84 block is a single pole unit while the 944S temp gauge AND warning light require the two pole sender that penetrates the water jacket.