D-jet miss in '73 Volvo B20

The TVS was replaced with a brand new one. There was no change in the miss after that was done.

Yes, the photo is of the old one, but as I believe I detailed all that has been done within my most recent summary (above).

jim

Hi Jim,

so still problems with new TS and no problems if you omit pin 9 ?

"so still problems with new TS and no problems if you omit pin 9 ?"

That is correct. And I cannot tell any difference in acceleration when #9 IS connected.

Hi Jim,

please remove ECU connector and TS connector and measure resistance of 9 and 20 to ground and all other pins of TS connector.

9 and 20 must act one after the other and then ECU reacts by enriching fuel mixture. I assume that you have an isolation problem or fake impulses on 9 and 20.

Hi Dr. D-jet,

Let me make sure I know what you are suggesting. I am putting your comments in italics.
"please remove ECU connector and TS connector and measure resistance of 9 and 20 to ground and all other pins of TS connector."

Do you mean connect a VOM to the spade connectors of the TS and then to ground to see the resistance?

What should the resistance be?

Or are you asking me to check for continuity between the wires from the TS connector to the ECU connector? I have done that.

"9 and 20 must act one after the other and then ECU reacts by enriching fuel mixture. I assume that you have an isolation problem or fake impulses on 9 and 20."

Removing the ECU connector from the ECU is very difficult because in this particular car I need to remove a good portion of the air conditioning unit because of where everything is located. I can do it but want to make sure I am doing what you are suggesting before I undertake this two-hour process.

jim
P.S. Does the 'notify of reply" work. I check the box but I never get a notification.

 

Hi Jim,

all I want to see is whether there is a break or isolation issue on your engine wiring harness. That could either inhibit or create fake impulses from 9 and 20. You cannot measure that while TS and ECU are connected as ECU has pull up resistors inside. You should also make sure that impulses from 9 / 20 only occur when pressing down gas pedal not while it comes up.

ECU integrates pulses from 9 and 20 only if they come one after the other and then depending of pulse speed enriches fuel mixture. That is why removing 9 or 20 is enough to disable acceleration enrichment. Fake pulses would create false enrichment.

When TS is disconnected you should see less power when accelerating.