still no reading from dwell test

[56 nomad]

hello,
i have read many of the posts relating to cis and testing the settings with a dwell meter.
i have tried 2 different and working dwell meters (older sears models) and have been unable to obtain a reading from the test port.....have read some others have had this same problem.
i know i need to trace this down, where to start?
thanks , ben

[john walker's workshop]

no points, so no dwell.

[psalt]

John, he means testing the Lambda FV duty cycle with a dwell meter on an 83 SC.

Ben, try pin 17 at the ECU. GRN/WHT.

[56 nomad]

paul,
will give it a try, would you just clip to the wire or do you hace to jump it...sounds like i also have to pull the seat out..is that right? any thougts as to why no reading at the port in the engine bay, could this non read cause a problem? gas milage is a little low10 to 11mpg in town
regards, ben

[arbita1]

Originally Posted by 56 nomad

paul,
will give it a try, would you just clip to the wire or do you hace to jump it...sounds like i also have to pull the seat out..is that right? any thougts as to why no reading at the port in the engine bay, could this non read cause a problem? gas milage is a little low10 to 11mpg in town
regards, ben

You don't need to take the seat out. Just push it back to the further seating position.

Get a test wire with aligator clips on both sides. Clip on side to the test port green wire pin and the other side to the nut on top of the fan that holds the coil.

Then go to the ECU and unplug the connector from it and test for ground at the pin mentioned above by Paul. If you have ground it is fine. If not there is a break in the wire.

Also, I never had any luck with the analog dwell meters. (I don't know why.) I switched to a Sears multimeter which also had a duty cycle setting and that's what I use now.

[56 nomad]

Originally Posted by arbita1

You don't need to take the seat out. Just push it back to the further seating position.

Get a test wire with aligator clips on both sides. Clip on side to the test port green wire pin and the other side to the nut on top of the fan that holds the coil.

Then go to the ECU and unplug the connector from it and test for ground at the pin mentioned above by Paul. If you have ground it is fine. If not there is a break in the wire.

Also, I never had any luck with the analog dwell meters. (I don't know why.) I switched to a Sears multimeter which also had a duty cycle setting and that's what I use now.

will do if ....a break in the wire what issues might it cause....i have a multi meter, same difference. ben

[Bob Kontak]

The green / white test port wire from Lambda box 17 is a straight wire to the test port.

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_Part6-2.jpg

If there is a break in the wire I can't see any problems except lack of signal from the Lambda box.

[arbita1]

Originally Posted by Bob Kontak

The green / white test port wire from Lambda box 17 is a straight wire to the test port.

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_Part6-2.jpg

If there is a break in the wire I can't see any problems except lack of signal from the Lambda box.

Correct. This would explain the lack of reading you are getting on the meter when you are trying to check the duty cycle from the test port.

[john walker's workshop]

Originally Posted by psalt

John, he means testing the Lambda FV duty cycle with a dwell meter on an 83 SC.

Ben, try pin 17 at the ECU. GRN/WHT.

so much for speed reading.

[56 nomad]

Originally Posted by john walker's workshop

so much for speed reading.

happens sometimes...been there. ben

[T77911S]

Originally Posted by john walker's workshop

so much for speed reading.

thats my problem. kinda like a doctor, i just look for the hi lghts and miss small details sometimes, especially if it is long. the longer it is, the less i read.