g60 c/o pot tuning....questions

[steveo29 0]

ive been playing around with the c/o pot values....i have a sns chip,red inj blah blah

 

although im reasonbly happy with the way the car runs...i cant tell a differance between like 400 and 600...maybe its a touch better at high revs with 400 ohms??

 

my question is...should there be a big noticable differance between 400/600 ohms....if so what should i be looking for

 

BEFORE YOU ALL SAY GET A WIDEBAND..I WILL WHEN I CAN,BUT ID LIKE IT BEST/SAFEST FOR NOW

 

cheers

steve

[Banana Man 0]

400 ohms I would think your car runs outragously rich the normal figure for the co pot with the stg 5 sns is around 800ohms but every car is different so that is just a rough figure.

[beavis 0]

The CO pot figures are just rough indicators to set the car up if you do not have access to any gas analysing tools. Roughly speaking the CO pot settings end up between 600-850ohms on cars we set up on the wideband. We set the CO pot to run at 14.5-15 AFR at idel to pass emmitions and economy (well as economic as G60's get). The CO pot only controls off boost fueling and at part throttle on vacume. I in doubt then set it on the richer side of the scale. Do not fear though, you ain't gonna melt a piston with a incorrectly set CO pot, weak fuel pumps and failing injectors are the culprits of that.

If you have a spare day, give us a bell and we can give your car the once over, Wide band, fuel pressure etc to check all is sweet.

[steveo29 0]

beavis....so 650 ohms ish may be a good idea until i get chance for a wideband???

 

any tell tale signs of going to far either way.....i dont get any black smoke that i notice and the plugs are clean

 

oh and while im asking....i asked this before but never got a firm answer......do you aj the pot hot or cold?? reason i ask, if i set mine when stone cold then go for a drive ,the setting will be differant hot/cold. it returns to the same value at the same temp as when set if you get my drift

[billinjah 0]

bit of a ressurection but what was the answer to this last question? i assume the co pot is set up hot? and its pins 1 and 3 right? gonna have a little play i think im way too rich atm.

[flusted 0]

My co pot is adjusted to 450ohms as per the sns instructions that came with the chip for the red tops, went through emmissions fine at mot time, does puff a bit of black smoke on hard acceleration

[beavis 0]

Pins 1&3 ..The two outer pins of the Pot are the ones to test the base resitance, regardless of the temperature this value is fixed. To adjust the resitance, screw the adjustment screw anti clockwise to lean the base mixture off which increases resistance and vice versa to richen.

[steveo29 0]

if testing the idle mixture on a wideband...do you leave it all hooked up or disconect the blue temp sensor and rev 3 times etc?

 

i just tried mine...14.7 afr all hooked up....and 11.xx with btc off

 

edit...co pot had little effect shifting the co reading...although it it goes up n down with a multimeter on the pins

[JMC 0]

Hmm, this makes interesting reading. My resistance measurement is 1.7k ohms between pins 1 and 3 when cold. This strikes me as being massively high compared to the recommended values above. Any thoughts...

[beavis 0]

if testing the idle mixture on a wideband...do you leave it all hooked up or disconect the blue temp sensor and rev 3 times etc?

 

i just tried mine...14.7 afr all hooked up....and 11.xx with btc off

 

edit...co pot had little effect shifting the co reading...although it it goes up n down with a multimeter on the pins

 

All adjustment on the CO pot is done whist all other senders are plugged in to get an accurate reading and obviously when the engine is warm. The mixture becomes rich whist the blue temp sender is unplugged as the mixture is not burn't correctly as the ignition timing is retarded to a fixed constant with no ECU trim.

[beavis 0]

Hmm, this makes interesting reading. My resistance measurement is 1.7k ohms between pins 1 and 3 when cold. This strikes me as being massively high compared to the recommended values above. Any thoughts...

 

Yes 1.7k ohms is very high/lean. At idle. The senders tend to fail to a higher value as the internals degrade. They usually have a date stamp stamped into the white part of the plastic. If it has 09/91 etc stamped into it it may well be time for a new one.

[Riley 0]

Is it adjusted with everything plugged in and up to temp then? No certain procedure is there i mean?

 

Neil. :)

[steveo29 0]

if testing the idle mixture on a wideband...do you leave it all hooked up or disconect the blue temp sensor and rev 3 times etc?

 

i just tried mine...14.7 afr all hooked up....and 11.xx with btc off

 

edit...co pot had little effect shifting the co reading...although it it goes up n down with a multimeter on the pins

 

All adjustment on the CO pot is done whist all other senders are plugged in to get an accurate reading and obviously when the engine is warm. The mixture becomes rich whist the blue temp sender is unplugged as the mixture is not burn't correctly as the ignition timing is retarded to a fixed constant with no ECU trim.

 

thanks for the reply...so i guess mines about spot on then? sits at about 14.7 afr and fluctuates maybe 0.2

 

how come the corrado bently says its all done with the bts off and rev 3 times blah blah :geek:

[JMC 0]

Hmm, this makes interesting reading. My resistance measurement is 1.7k ohms between pins 1 and 3 when cold. This strikes me as being massively high compared to the recommended values above. Any thoughts...

 

Yes 1.7k ohms is very high/lean. At idle. The senders tend to fail to a higher value as the internals degrade. They usually have a date stamp stamped into the white part of the plastic. If it has 09/91 etc stamped into it it may well be time for a new one.

 

That'll be me being a dummy then :oops: I just measured the resistance of the co pot with the engine off. I presume I was meant to be at idle from what you said above. Doh. Looks like I'll have to do that again. However checking the bentley manual that value of mine isn't far off what it should be at 15 degrees, and there is a huge temperature variation (which I would expect for a resistor). I thought you said the resistance was independant of temp Steve?

[flusted 0]

if you measure between pin 1 and 2 it gives thew reading that the ecu reads