Timing advance stock ecu

[Rev]

Well trying to check static timing today noticed a few things.
Looks like I am running about 9.5 deg of advance which is ok as I boost spike well above 18 psi and run a safc2 which is supposed to advance the map a little.

> when I took more fuel out at idle with the safc timing was pulled by about 1 deg at about 1300 rpm when reducing fuel from -34% to -48% at 800 rpm so at low revs timing decreased not increased as people say. Well I guess the stock ecu doesnt like too much leaning at the warm day idle temps I had with my quick response celica air temp sensor?

> Next when the spark plug shorted out as my timing light connecteor was not insulated i noticed timing would surge to about 3 degs more advance around 13 deg intermitantly.

> Finally and most disturbing I thought I would see what happened with AC on ( ac fluid cold, engine warm. Well revs dropped the engine got rough and timing occilated quickly between 14 and 8 advance. This was with the diagnostic port bridged and in neutral so I hate to think how it would be with additional load in drive .

I have been thinking the manual ecu adds timing when the AC is on even though it loses torque on hills it generally seems more responsive with ac on. Any one know what might be happening to cause such dramatic changes in idle timing?

 

[gorganl2000]

http://www.toyotagtturbo.com/forums/showthread.php?60728-Blitz-Access-ecu/page10

on that last page texx explains stock timing
seems the stock ecu is a bit complex

 

[weeJohn]

With the bridge in the diagnostic port I thought timing was locked to 10 degrees? If you remove the bridge what timing do you read on idle?

 

[Rev]

@goganl2000 > Thanks Fantastic read confirms Ac on changes timing . Temp correction being only 5deg timing is very interesting also.
I wonder what the target engine speed mentioned under the > Stable Idling Correction heading ?

@ weejohn > Part way though I checked the diag.port and the paper clip was tight in place but a lot of cream in the port from previous owner so maybe wasn't working. It was informative to watch the timing move about though but from what you are saying I might have to check it again I will remember to remove the connection next time , thats a good tip.

 

[corofin12345]

on the stock ecu or plug&plays with TE1&E1 bridged and engine at full operating temps the revs's will drop to the proper idle for timing.. weather the dizzy is set advanced or retarded, it will still idle at the set rev for timing with TE1&EI bridged

 

[Texx]

Bridging terminals TE1 and E1 locks spark advance at 10° and disables the idle air control valve, this is assuming that the idle switch in the TPS is closed and the A/C is switched off. If the idle switch is open or the A/C switched on the ECU will monitor and adjust spark advance in closed loop and also begin to pulse the idle air control valve to prevent the engine from stalling.

Bridging terminals TE1 and E1 will not automatically set the correct idle speed for adjusting the distributor, the engine should be at operating temperature, all electrical loads and A/C switched off, if the car has an automatic transmission it should be shifted into neutral and the handbrake applied. Bridge the terminals, run the engine at 2500rpm for several seconds, allow the engine idle to stabilise, idle speed should be approx 750rpm, any higher or lower and it should be adjusted via the idle screw on the top of the throttle body, if the cooling fan comes on during this process allow it to finish and begin the process again. Once you have a steady 700-800rpm idle speed with TE1 and E1 shorted you can then check and adjust the distributor if necessary.

 

[Rev]

Thanks guys - Lots of issues for me to work at there - my revs were too high and radiator fan came on at one stage and I should not have been listening to the cricket on the radio. Timing is very important appreciate the input , I will do it all again and report back .