starting the 350, have timing set at 8deg with the est wire plugged.

it idles around 800 with the wire disconnected.

Right now I still have the 305 ecm installed, but have the 350 esc and knock sensor.

When I plug in the est and start it back up, it wants to idle around 1200. Is this because of the 305 ecm? I have a 350 ecm I just havent gotten it in yet.

Any thoughts?

 

The 305 and 350 use the same ecm, the only difference is the prom. Use the prom from the 350.
Timing should be set to 6 degrees btdc with est disconnected.

Also follow the tech article for resetting the iac and tps

 

Yeah, I meant the Prom, not the ecm.

I swapped the 350 prom in and same thing...

stupid question now is whats iac and tps? gonna have to do some research now.

would that cause my idling issue?

We have the timing set to 8deg with the est pulled, runs good, idling around 750 or so. When we hook up the est, it advances out to like 30ish deg, is that normal? from what I have read, it sounds about right.

 

the iac is the idle air control valve which sits under your throttle body and throttle blades, it basically opens up to route more air around your throttle blades when you're idle and not on the gas to keep the idle rpm up so you dont stall. when you hit the gas it closes some because you're getting enough air with the blades open. it has a 4 wire plug connector on the left side of the throttle body.

the tps is the throttle position sensor, its sends a zero to five voltage to the ECM, close to zero (around .54) when you're not on the throttle and the throttle blades are near closed, and up there above 4 when the blades are fully open. so if you play with your idle screw, you're going to throw the sensor off. it is located on the left top side of the throttle body, above the idle air valve, it has a 3 wire connector.

this is the technical article
https://www.thirdgen.org/tpimod2

there is a better more detailed article ive seen posted in threads, maybe someone could post it up

 

TPI chips kick in quite a bit of timing advance even at idle. 8* intial to a few degrees shy of 30* with EST connected sounds totally normal to me.

 

Yeah, after a bunch of reading that sounded normal to me too.

Thanks guys for all of your help. I will be doing the IAC reset, and hopefully that clears it up.

Its idling around 1200 right now with the EST Connected. Idles around 700 with the EST disconnected. We shall see

 

IAC reset was the win!

I did it wrong at first as was wondering why it wasnt working...

Did it again right this time and Its idling around 600-700! perfect!

How important is checking the TPS voltages now that its idling correctly??

Now all I need to do is figure out why my rear brake caliper is sticking and get my exhaust back together and im good to go

thanks again everyone for your help, really made a huge difference!