stock ecm ?

[BlueBottleZ]

Guess this is a 2 part ? First im trying to bench test a known good opti....with no luck! Give it a power and ground at the respective terminals and then ck the low res terminal out of the opti with a scope....nothing. Thinking that pos its a bad opti we ck 3 others with the same results! Net research shows that the ecm has a resistor that PULLS the low res signal from the opti????? So my ?s are 1. does anyone know how to bench test an opti properly and 2. is this resistor thing true and do we know what that resistance is because i need to duplicate it for the microsquirt i installed! TY!

[Chris]

All that resistor in the pcm should be is a volt meter. Shot in the dark, take a multi meter on voltage, put it on the low/res wire your checking and system ground then try scoping the wire. What are you using a fluke handheld or laptop base? Could it be your timing is really off?

[popo8]

Keeping this BUMPED for BlueBottleZ...

[Chris]

Did he try my idea?

[popo8]

Did he try my idea?

IDK if he has been on this yet. Still the work day part of his day. would just love to see as many ideas as possible by the time he is ready to look at it.


I do know that they were scoping and testing stuff last night, but I was not paying to much attention.

[z28cam70]

when you are checking with the scope what terminals are you putting the scope leads on also what time and gain settings are you using on the scope? like chris said the pcm does have a resistor internally but it is used as a "voltmeter" by the pcm.you dont need to worry about that when checking with a scope because the scope is the "voltmeter"

[Chris]

Your also looking for a digital signal out of the opti

[popo8]

2 optis were sent out to the designer of microsquirt to do some figuring out!

[z28cam70]

ive seen the microsquirt works well with the gm optispark. have seen some problems when used with the MSD optisparks(the only other opti alternative in my opinion).