3.0L EST coversion questions

[ssprague]

I bought a 89 3.0l mercruiser that has been coverted over to GM EST , I think it is stuck in base timing mode ? Timing does not advance only a degree or two . The wire for the interupter was not hooked up when i bought the boat ? i jump the two pins for base timing and no change in rpm or anything . Does anyone have wiring instructions for this coversion ? Boat runs but not sure if it was done correctly ...

 

[Don S]

Re: 3.0L EST coversion questions

It's not instructions, but below is the wiring diagram of how it should be wired. You may have slightly different colored wires, but each terminal does the same thing regardless the wire color. The second pic shows the proper way to time it and put it into and out of base timing mode.
The pictures came from the OEM service manual #13 you can download from the adults only sticky (first post in this forum)

 

[ssprague]

Re: 3.0L EST coversion questions

ok heres where it stands .. I jumpered the wires and connected 3rd pin to 12v source and definately heard a change in rpm so i set timing at 1deg atdc ... removed jumpers and the timing did advance to about 14 deg ? seems a little high but dosent run bad... I just dont understand why when i throttle the rpms up it only seems to advance a few deg ? shouldnt it advance to about 25 to 27 deg ?

 

[Don S]

Re: 3.0L EST coversion questions

It will go up that many degrees when you take it out of base timing mode. That is normal. Here is the graph for the EST module. IF you aren't getting advance, the module may be defective.

 

[ssprague]

Re: 3.0L EST coversion questions

Thanks don ....

Is there anyway to test that module or do i need to just fork out the 80 greenbacks to try it?

 

[fat fanny]

Re: 3.0L EST coversion questions

The guys @ Napa used to test em but you have to find the right guy all they do is hook it up to some sort of cycle tester and see if the cycle heat changes all I can say about the modules is do not!!!!! buy after market only the GM Delco or your just throwing your$ away

 

[ssprague]

Re: 3.0L EST coversion questions

Anyone know the correct Part# for the GM Delco module ? Also one more question ? Should i be running my spark gap at .035 or should i open them to .045 now that im runing the delco EST ignition ?


Thank you all for your help

 

[fat fanny]

Re: 3.0L EST coversion questions

Mine is a 95 and the listed gap is .035