I remember reading somewhere about adding a resistor inline in the coolant sensor wiring that essentially fools the ECU into thinking that the engine is running cooler than it actually is and so richens the delivery.
Can anybody provide me with the value of the resistor used(Ohms, wattage) and share their experience?
Thanks.
Nash
81 GTV6
You can fool the ECU allright, but not that you'll gain anything.
At 20*C sensor resistance is 2-3kohms
At 80*C 250-400ohms.
At -10*C 7-10kohms
So, you can solder 4x820ohm resistors on a rotary SP4T switch (single pole,4 throw) placed in series with the engine coolant temp sensor and mount it somewhere within reach when driving and experiment. If you have a chronic lean condition, you may alleviate things a little. Otherwise, you will be running too rich with a high resitance. If you have a cat equipped engine, you will gain about nothing.
Jim K.
At 20*C sensor resistance is 2-3kohms
At 80*C 250-400ohms.
At -10*C 7-10kohms
So, you can solder 4x820ohm resistors on a rotary SP4T switch (single pole,4 throw) placed in series with the engine coolant temp sensor and mount it somewhere within reach when driving and experiment. If you have a chronic lean condition, you may alleviate things a little. Otherwise, you will be running too rich with a high resitance. If you have a cat equipped engine, you will gain about nothing.
Jim K.
If the car is stock there's really no point doing this. If it's not stock then easiest way is to wire in a rotary potentiometer (o-10k ohm) or similar and then tune via an O2 sensor in the exhaust to get the mixture correct. Problem is the mixture will always be "wrong" most of the time.
Another way is to combine the above with a small throttle activated switch (reed switch & magnet is easy) and set it up so that at low throttle openings the ECU sees the "real" temp value and at higher throttle openings the ECU sees the value dialled in on your variable pot. That way the car will cruise OK & get rich enough up high
This worked fine on mine to deal with a bigger AFM & warm cams, fine until I went to a programable ECU, which is just MILES better...
Another way is to combine the above with a small throttle activated switch (reed switch & magnet is easy) and set it up so that at low throttle openings the ECU sees the "real" temp value and at higher throttle openings the ECU sees the value dialled in on your variable pot. That way the car will cruise OK & get rich enough up high
This worked fine on mine to deal with a bigger AFM & warm cams, fine until I went to a programable ECU, which is just MILES better...
83' GTV6, 3.0 24v supercharged
Thanks for sharing your experiences. It was mostly a curiosity question. I suppose sending an incorrect input to the ECU will be negated by the O2 sensor which will again correct the mixture. So nothing gained except when the throttle switch puts the ECU in open loop at wide throttle openings.
Does the LJet go into closed loop immediately after startup or when the engine reaches a certain temperature?
Nash
Does the LJet go into closed loop immediately after startup or when the engine reaches a certain temperature?
Nash