[bailey08]

my GV (2.5l auto) has it's timing set to 4 deg's (well more like 3.5). Should be 5 deg give or take 1 deg with diagnostic connector bridged . it's 11 deg's unbridged.

would this make it sluggish off the mark and use extra fuel.

I tried to adjust it but the 2 bolts wont budge and I don't want to round them off (almost have now.), there t40 torxs. is there a trick to loosening them.

thanks.

[steak_knife]

Can't see the 1deg making a noticeable diffrence, get your injector's cleaned, give it new spark plug's & an air filter..

The bolt's are loc tighted in, Mr Suzuki doesn't want you playing with it..

[joeblow]

As far as I know the timing (pick up module behind cam) in non adjustable. Even if you do manage to move something the ecu will revert back to the programmed setting.

[bailey08]

timing is adjustable, it's in the manual.

it has new plugs and air filter. I'll look into the fuel injectors.

I have a vacuum gauge hooked up. it runs very well, when i floor it, it only drops to 1inhg (i thought it would drop to 0)

[fordem]

joeblow wrote:

As far as I know the timing (pick up module behind cam) in non adjustable. Even if you do manage to move something the ecu will revert back to the programmed setting.

That depends on which year/model GV and which engine it's fitted with - for example the base timing on a J20A in a 98~05 can be adjusted by rotating the cam position sensor, fitted to the back of the head, behind the exhaust camshaft. The ECU assumes a base timing of 5*, regardless of what the actual timing is and adds additional advance from there based on rpm, airflow, and if it's fitted a MAP sensor. I'm running my J20A with a base timeing of 14* BTDC - measured with a timing light - rather than the 5* specified in the FSM - yes the FSM does tell you how to set the timing.

The same goes for the H25A V6, used on the 98~05 GVs.

The J20A used in an 06 & later GV uses a different "non adjustable" cam position sensor, this fits in the top of cam cover at the back of the intake camshaft.

In this case the ECU sets the timing advance based on it's maps and input from the cam position, MAP, MAF & knock sensors. If the ECU detects detonation it will reduce the amount of advance used.

What's important to understand is that the ECU depends on the mechanical position of the cam sensor to know where TDC is - if you move the sensor the ECU has no way of knowing that, so it accepts the input from the sensor as gospel.

[JrZook]

fordem wrote:

What's important to understand is that the ECU depends on the mechanical position of the cam sensor to know where TDC is - if you move the sensor the ECU has no way of knowing that, so it accepts the input from the sensor as gospel.

Correcto there!

[bailey08]

Ok. So we've sorted that out. Is there a way to remove these stubborn bolts on the h25a.