1994-2002 [Subscribe to Daily Digest] |
Someone posted this two or 3 years ago. Not much detail as I recall. I thing that you have to get in there and let your eyes figure it out.
With TB opened up, can you press on the throttle plate and see that you can close it more that it goes to at rest? Any binding? Every oil the throttle shafts from the inside? Put a small light scratch or cut in the TB bore at the thottle plate rest postion for a reference mark. That visual reference will be useful as you attempt to adjust the throttle stop to get the throttle plate more closed. With carburettors, changing throttle stops could lead to problems. So it might be good to have some reference that you could work back to. Check throttle mechanism for mechanical issues before changing it. If the throttle has some range of motion to close up and you can reduce air flow, this may be all that you need.
You can also check the continuity of the two coils in the IAC and the resistance of the throttle '''switch''' which is really a varable resistor.
You could pinch off or block the end of the evap control system hose to see if the solenoid valve is letting air flow at idle. If you block it and nothing changes, its not the problem. If idle speed goes normal then thats of interest.
TPS at idle, pins 2&3 .8 to 1.2 ohms (2.0 - 3.0 wide open) turbo
TPS at idle, pins 2&3 2.4 to 3.4V non turbo
the TPS specs are different and 'opposite' to each other
IAC coil resistance 9 to 15 ohms non turbo
7.7 +/1.0 turbo
Do not 'test' the IAC with 12V, that will toast it. Some have used a small 9V battery to see that is moves etc. (Pivots should have been oiled when it was cleaned.)
You can rig up the IAC on a turbo engine with the its inlet open and watch it in operation. With a non-turbo engine that cannot be done as the MAF signal would be contaminated.
The TB might have some small hose barbs blocked off with rubber caps that are used for the turbo application. So have a look for such that could be missing. Don't really know if these exist or not on the non turbo TB.
Grab TB and yank on it. Loose to manifold? All intake manifold to head fasterners in place. Some reports of a busted bolt or so over the years. VAC leaks would lean out the mixture and in that case one might expect the running to be poor other than been fast. One method of finding VAC leaks is to get a rubber hose on the end of a propane torch with the burner removed, and let a flow of propane gas wash over susptected areas. If a VAC leak then gets hit with propane gas, the idle will be changed and you will then know where to look. Do such work out of doors with some air circulation but not in a wind. Do not introduce gas needlessly around the plugs or distributor etc. Some hazzards but use some common sense. A waste of time if the throttle TB or IAC is at fault.
posted by 68.93.19...
, Thu, 24 Jun 2004 09:07:32
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
