can you change the timing without disconnecting TPS?

[GuSpeed]

Hi. I recently change my timing back to stock 20 degree. But when I did this I did not disconnect anything. I just hook up the timing gun to the first spark plug and to battery for power. Then I turned the distributor.

This actually fixed my stalling, idling problem that happens sometimes I get off the freeway or coming to a stop. Is my timing screw up now because I didn't disconnect anything?

[Hijacker]

i've changed my timing in the past while leaving the TPS connected, and I've changed it with it disconnected. The worse that happens is that you fight the computer over ignition timing as you're setting it, but you can get it close to in time. That's why the tick mark seemed to be walking on you as you were rotating the distributor. I fyou're overly worried about it, you can go back and retime it with the TPS disconnected, but I wouldn't lose sleep over it.

[InsanityInc]

If you time it with the TPS connected, the car will not stay in time, and the timing will randomly shift around as you're driving.

[GuSpeed]

is it bad for the car to have the timing done without disconncting the TPS?

[:: orion ::]

No, it's just not the correct way to do it.

The ECU changes timing ALL THE TIME, ,at idle, cruising, under load...and it jumps around A LOT.

Disconnecting the TPS tells the ECU to NOT make any changes, so you can accurately set the base. If you set it with the TPS plugged in, it may look like 20* on the crank pulley, but could be ~17 BTDC b/c at that moment the ECU was pulling 3 degrees. Or it may be set at 28 degrees, b/c the ECU was adding 8 degrees when you set it...and either way, it looked like 20 BTDC at the crank pulley.

FYI...

So set it CORRECTLY.

- Brian

[Chezedik]

Now what if you set it base timing with no voltage to the ecu, can timing be adjusted that way? Or does it just assume that timing has been set to 20' BTC, so it damn well better be close.