Thread: TD5 rough running.

Water in fuel, There is a drain at the bottom where the water sensor plugs in you could try draining it se if that helps. The filters are cheap enough. I know a man in Tecoma that might have one!

Originally Posted by Bohica

Water in fuel, There is a drain at the bottom where the water sensor plugs in you could try draining it se if that helps. The filters are cheap enough. I know a man in Tecoma that might have one!

I thought so too. It was the MIL that threw me. Also, tank was drained and filled with new diesel. Course, there could be water and who knows what else in the filter. Luckily I have a filter here. The bloke in Tecoma will only want me to take him fishing.

The MIL can be "officialy" triggered only by two things on a Td5: the CPS or TPS, i've seen rare cases when low fuel pressure can trick the ECU into a driver demand fault. Did you check if you get HP from the pump? the fact that you hear it running is irrelevant

Another thing is that the water in fuel warning circuit is a completely idiotic design that's why at a point LR got rid of it. The sensor is connected to the fuel pump relay's output and when it detects water there is a huge voltage drop on that circuit which can affect the pressure, maybe LR wanted to make an extra protection cos if that warning stays on for long it will blow the fuel pump's fuse too. I disabled mine

Originally Posted by sierrafery

The MIL can be "officialy" triggered only by two things on a Td5: the CPS or TPS, i've seen rare cases when low fuel pressure can trick the ECU into a driver demand fault. Did you check if you get HP from the pump? the fact that you hear it running is irrelevant

I wasn't able to do that test you said across fuse 21, my MM is too primitive, and then we discovered we had screwed up with the crank sensor wiring. Fixed that, replaced the injector harness and the car fired up and drove at 100 kmh for about two hours going home. I put the pump out of my mind at that point. Car ran fine until this arvo when the MIL thing happened, and still ran fine until I shut it down, then this.
Still, I did give it a full throttle hit to overtake up the hill and that's when it happened, so I guess it may have starved at that point, which could of course be what you said about the pump. Still don't get why it was ok, and now it's like a 5 cyl petrol with three of the leads off.

Originally Posted by sierrafery

Another thing is that the water in fuel warning circuit is a completely idiotic design that's why at a point LR got rid of it. The sensor is connected to the fuel pump relay's output and when it detects water there is a huge voltage drop on that circuit which can affect the pressure, maybe LR wanted to make an extra protection cos if that warning stays on for long it will blow the fuel pump's fuse too. I disabled mine

Yeah, I read your posts about it on a thread from around 2105/7 while searching before posting. Seems like a bloody good idea to me. You wondered how many folk would have replaced a pump due to the constant fuse blowing.

I'm going to do the filter anyway, as it's been sitting around, on and off, for more than four years. But if the pump is down in HP, would that cause the seriously rough idle, rev up ok, but absolutely no power? Unless it's allowed air into the system I guess. Not sure if it can.

I appreciate your input, and I'm sorry I'm so long winded, but four years! I want it to go, and I've had no hands on stuff with a D2 TD5 for longer than that.

One of the symptoms of a pump not delivering enough pressure is that the engine is running fine untill some power is needed, the filter is on the return and LP circuit, the HP is delivered directly to the head.

Originally Posted by sierrafery

Another thing is that the water in fuel warning circuit is a completely idiotic design that's why at a point LR got rid of it. The sensor is connected to the fuel pump relay's output and when it detects water there is a huge voltage drop on that circuit which can affect the pressure,

Re-reading your reply, maybe that is exactly what happened. I was giving it some juice, up hill, and the water freaking sensor kicked in, the huge voltage drop to the pump caused the " I'm not here anymore" from the engine for that moment when I needed all the fuel it had and then it all settled down when I backed off....
Hmm. Still can't figure why it's idling like a red motor with four of its leads cut.

Originally Posted by sierrafery

One of the symptoms of a pump not delivering enough pressure is that the engine is running fine untill some power is needed, the filter is on the return and LP circuit, the HP is delivered directly to the head.

You posted this while I was replying to your previous. Could the stupid water filter thing have caused this? I gave it a bellyfull a few times coming home with no probs.
I seem to recall the filter light coming on a few times before the car went into hibernation, even though I changed the filter and cleaned the plugs etc.

You said that you fitted used injector harness... that's something which doesnt help at all with the symptoms, you need a diagnostic tool to watch live data for a clear answer. To rule out the water warning unplug the sensor and drive it so.