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Re: question about using dwell meter with CIS Posted by Dana [Email]  (#2822) [Profile/Gallery]
(more from Dana) on Wed, 11 Jun 2008 10:23:40
In Reply to: question about using dwell meter with CIS, saab86, Mon, 9 Jun 2008 07:51:37 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I believe the issue here is the control unit may not be functioning. The normal test procedure to make sure that the extreme ends of the control range of the unit is working is to pull the wire off of the O2 sensor (this allows the control unit input voltage internally to go to 1 VDC) which simulates high O2 content and watch for the duty factor of the dwell meter go up. The other test is to take the same removed O2 sensor wire and touch it to ground (the car body)which simulates all of the O2 content is being used and no further enrichment is needed in which the dwell meter will go down. The control unit (depending on the model year) usually has a fixed frequency (~65%) during the initial start up time of the warming of the engine. It is then allowed to control at 50% duty when the engine temperature sensor(s) or time based signal indicates that the O2 sensor has reached sufficient operating temperature to work. Since it is clear that your control unit is putting out a fixed signal, the control unit or the signals which allow the control unit to modulate the frequency valve may not be working. In truth, as you turn the mixture control valve the dwell meter should be responding to keep the mixture constant. That value is normally 50% duty time duty factor or a reading of ~40 for the four cycle scale or ~20 on the eight cylinder scale. If you need additional information let me know, I have a 85 CIS myself. Dana
posted by 141.152.15...
, Wed, 11 Jun 2008 17:52:53, Wed, 11 Jun 2008 10:23:40 <-- Viewing This Message
, Mon, 9 Jun 2008 17:20:26
, Mon, 9 Jun 2008 11:42:08
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