Temperature sensor
Discussion
I think I have found why my plugs are sooting.
With the engine warm and the temperature gauge reading about 50°, the temperature sensor (pins 7 and 25 on the ECU) is reading 300 ohm, which I think is saying the engine is at 100°.
Assuming this is the fault, can anyone explain why the ECU uses more fuel when the sensor is reading to hot? I would have thought it would use more when the engine is cold, i.e., like a choke.
With the engine warm and the temperature gauge reading about 50°, the temperature sensor (pins 7 and 25 on the ECU) is reading 300 ohm, which I think is saying the engine is at 100°.
Assuming this is the fault, can anyone explain why the ECU uses more fuel when the sensor is reading to hot? I would have thought it would use more when the engine is cold, i.e., like a choke.
Just a quick copy/paste from my RR Manual- excuse poor correlation !
I reckon 300 ohms should give you 80 DEG about right if its fully warmed up.
I would suspect your gauge sensor being at fault only showing 50 DEG.
Fuel and Coolant Ohm-meter Reading
Temperature Should be
“C “F Ohms
-100 140 9100- 9300
00 32" 5700- 5900
200 680 2400 - 2600
400 1040 1100- 1300
60" 1400 500 - 700
80° 176O 300- 400
1000 2120 150 - 200
HTH
Brgds
Ian
I reckon 300 ohms should give you 80 DEG about right if its fully warmed up.
I would suspect your gauge sensor being at fault only showing 50 DEG.
Fuel and Coolant Ohm-meter Reading
Temperature Should be
“C “F Ohms
-100 140 9100- 9300
00 32" 5700- 5900
200 680 2400 - 2600
400 1040 1100- 1300
60" 1400 500 - 700
80° 176O 300- 400
1000 2120 150 - 200
HTH
Brgds
Ian
The temperture sensor has to be miles out to cause the ECU to loose mixture control. I tried experimenting on a hot engine, and the ECU still held the mixture correctly with an additional 500 ohms, and did not loose control until I reached near an extra 1k ohms, and this is making the engine look cooler than it is, not hotter. If the plugs are fouling badly, the ECU should be generating a fault code, so worth borrowing a fault code reader. A slight misfire can cause the ECU to overfuel as well as it thinks unburnt fuel in the exhaust is the same as a lean mixture, so it puts in too much fuel. Are all 8 plugs the same, as the two banks are fuel controlled separately.
Edited by blitzracing on Wednesday 1st October 19:50
All 8 are equally sooty.
She runs reasonably well, but starting gets worse as plugs soot. Clean them and all is OK, but you can just feel its not as it should be. I'll try the temperature sensor anyway, they are only £12 delivered off ebay.
TVRs are known for two bad things and I have them both this morning. First she died in the middle of a junction and I had to get out and push. Quick clean of a few plugs got me going again (luckily I kept the tools in the boot). Then on the railway bridge she started to cough, I gave some extra throttle coming out of the bend and that was it...car sideways, front inch off the stone wall, over compensated, rear now an inch off wall, turned in again and dabbed the brake.
Arrived at work with black hands and a white face ;o)
She runs reasonably well, but starting gets worse as plugs soot. Clean them and all is OK, but you can just feel its not as it should be. I'll try the temperature sensor anyway, they are only £12 delivered off ebay.
TVRs are known for two bad things and I have them both this morning. First she died in the middle of a junction and I had to get out and push. Quick clean of a few plugs got me going again (luckily I kept the tools in the boot). Then on the railway bridge she started to cough, I gave some extra throttle coming out of the bend and that was it...car sideways, front inch off the stone wall, over compensated, rear now an inch off wall, turned in again and dabbed the brake.
Arrived at work with black hands and a white face ;o)
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