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Originally Posted by LanzaroteSteve
TPS looks fine as does the connector. Can anyone explain exactly how this TPS actually functions?
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Throttle pedal position is measured by a dual potentiometer, the two have different overall resistances. One sends a decreasing voltage signal and the other a increasing signal. The ECU looks at these and determines pedal position. If the two signals don't match what the ECU is looking for an error code is tripped and engine goes into limp.
Quote:
Originally Posted by LanzaroteSteve
The mechanics are working fine and the cable to the pedal works as is should.
I want to try every other option prior to pulling the diesel pump only to find it's something else causing the problem.
So far I think I need to go in the following order but if anyone spots something I've missed feel free to let me know.
1. TPS and wiring
2. ECU?
Now here I'm thinking that these two could be the problem as the car I believe should return to idle if I put my foot on the brake pedal??? I.e the ECU should over ride the TPS and return to normal idle if it detects the brake pedal is pressed???
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The system might not be that advanced to know you are pushing on the brake.
Quote:
Originally Posted by LanzaroteSteve
3. The Injectors.
4. The Fuel delivery valves (although when the problem started the first thing I did was to change the seals and copper washers on these)
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You need to gain a better understanding of how this system works, these are not electronic unit injectors. Delivery valves are just check valves. Neither of these will cause a run away.
Quote:
Originally Posted by LanzaroteSteve
5. The fuel pump. Could something mechanical inside be stuck wide open pushing full fuel? I'm leaning towards this as the fuel seems to be really shooting out of all high pressure lines (I disconnected these to see if I had a problem with just one fuel delivery valve.
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More accurately it is called an injection pump, the fuel pump is something that moves fuel from the tank to injector pump.
Given lots of fuel is coming from the injector line, the power transistor / FET in the ECU that controls the fuel solenoid may have failed in a conductive state or the circuitry that drives it has cause it to turn on.
I'd unplug or back probe the fuel control solenoid and measure voltage. I don't know what it should measure.
There is even a chance the harness has rubbed through and the fuel solenoid is being activated.
There is a chance that the crank position sensor isn't sending a RPM signal to the ECU but I don't know the system well enough to say for sure.
The problem may or may not be related to the oil line coming off. What did you do to get it into a running state? The rev might be part of the preexisting condition.
It would be a great help if you had a scan tool with live data.