No RPM signal with stimulator

[enginebob]

I am assembling a ms-II with 3.0. Have down loaded and installed the latest code version. Installed the coil negative input circuit and also the VR circuit. Connected the jumpers for the coil negative circuit. When doing the tests at step 55 the tach jumps back and forth through the range. When doing the test for the 0 2 sensor where the power is unhooked and hooked back up while changing the pot position that works. Also have tried it with and without D2 jumped. Battery is at 8.8 volts. Have rechecked connections and everything seems OK. Out of ideas. Need help.

[Matt Cramer]

You will need to jumper out the zener diode in D2 to get a good RPM signal on the Stim.

[enginebob]

Got the meter out and did some component testing. Here what I found on the input circuit.
C3 .700
C2 19.67
C9 0.00
C10 9.64
C4 3.15
C6 3.14
C8 0.00
C5 5.28
C7 5.27
R2 1.00
R9 .995
R10 1.00
R5 2.162
R8 2.162
R11 .964
Looks like the problem is with C9 and C8. Is it common to see bad parts?

[Matt Cramer]

Please explain why you are attempting to troubleshoot a lack of RPM by examining the throttle position input circuit.

[Bernard Fife]

ebob,

If you are using 2.905 code, then the rpm will jump from 0 to 8000 rpm until you set the ecu type. See the red text in the blue box here: http://www.megamanual.com/ms2/code.htm

Also, if you have the ignition settings misconfigured, such as setting up for a missing tooth wheel when the stim is delivering a distributor type signal, then the rpm can jump around as well. See: http://www.megamanual.com/mt29.htm#i

Lance.

[enginebob]

In the assembly manual it is listed as input section so I thought it covered most of the sensor or signal inputs. Doesn't say what is all part of that step other than the EGO input is one of them. Are there diagrams for different circuits so they can be checked? Went back and set the ecu type code again, must not have clicked on burn last time. Now everything seems to be working so far.

What is the correct way to test capacitors?

[Matt Cramer]

Please see this link for schematics.

http://www.megamanual.com/ms2/pcb.htm