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TD5 Defender Starting Problems


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Hi,

I’m having problems starting a TD5 engine that I rebuilt. It’s in a 2004 Defender.

The engine turns over well and has a new starter motor. All of the injectors click when tested with a Nanocom. No security codes are shown.

I believe that the issue is related to the crank sensor date that the ECU gets. With Nanocom and Lynx tools, I’m seeing a cranking RPM of 220-235. I’ve seen online that the TD5 needs a cranking RPM above 300 for the injectors to fire. The engine definitely sounds likes it’s turning over well, with a cranking RPM that is equal to or better than a TD5 Discovery I have that starts well.

I’ve tried different crank sensors with and without the NSJ000010 spacer, a different ECU, and a new plug and shielded wiring direct from the sensor to the ECU, with the same 220-235 RPM results.

Any ideas would be greatly appreciated!

Thanks.

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What's the history with the engine? Has it gradually got worse to start or have you just bought it?

Can you hear the fuel pump come on when you put the ignition on? Is it quiet or loud?

Yes, you're quite right about the crank sensor, if it doesn't work then the engine wont start.

Regards

Steve

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The truck was used by a construction company, until an array of issues not related to the engine running resulted in it being parked in a junkyard for 6-8 years. I was told that it was started briefly about 3 years ago when in the junkyard. I brought it and did a full restoration and engine rebuild. I did not try starting it prior to the rebuild.

The fuel pump comes on, and to me sounds normal.

Any chance the flywheel could be a crank signal issues?

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I've thought about tow starting it, but it really appears to me that the cranking RPM is higher than what the tools are displaying. The starter is new, with a new large battery, and I tried with a battery booster pack too. There appears to be a discrepancy between the true cranking RPM and what the ECU is showing. If the true engine RPM is higher than what the ECU is operating on, would tow starting damage something?

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My first port of call for TD5 starting issues is the injector seals. The copper washer wear or can get damaged when fitting, which allows the fuel pressure to leak into the cylinder instead of getting pressurized as it should. Did you take out the injectors? What exactly did the engine rebuild include?

The crank sensor usually works or not, so if you get an rpm signal you can assume it is fine. No harm in swapping it if you can get a known good one to try of course. 200rpm should be enough to start a TD5 if it's in half decent shape. They don't need that much, easy to tow start as well (unless the injector washers are worn!).

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9 hours ago, landroversforever said:

What's the battery condition like? I had a td5 I was looking at that would seemingly crank ok.... but on looking at the voltage while cranking it would dip right off.

Too low voltage can cause the ECU not to fire the injectors, so the engine can fail to start even if turning over seemingly OK.

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I checked the immobilizer, tried with an auxiliary ground to the engine and ECU, and with a booster pack to keep the voltage up when cranking. No success.

What voltage is needed to be maintained to fire the injectors?

My plan now is to check battery voltage when cranking, check the fuel pressure at the regulator, and the timing.

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I thought minimum voltage for the ECU was 10V, but probably some margin on that.

Fuel pressure shouldn't be a problem for starting, as long as there is fuel flow. The pump injectors of the TD5 will allow it to fire even without the electric fuel supply pump (it will run at limited power though).

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20 hours ago, chris2010 said:

Tend to disagree there , Iv had a discovery and also my own defender would not fire with a faulty fuel pump .

pressure was to low .new pump and fix

I've had several fire up no problem with the electrical pump unplugged. First one by mistake while troubleshooting the fuel system, checking the fuel pump fuse and forgetting to put it back, then a couple more for testing purposes. If the pump is faulty, it's often blocked or restricted internally so the pump injectors can't suck in enough fuel. Same with a clogged fuel filter. So no argument on a bad pump causing starting problems, I just don't think pressure is the problem.

TCI, I'd look at the injector washers if you don't find any other obvious faults.

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On 2/11/2022 at 2:12 PM, TCI Land Rovers said:

Thanks. I found a gauge, and the pressure at the temperature sensor on the regulator is around zero. I'll look at that system and see if I can find the problem.

 

On 2/11/2022 at 2:12 PM, TCI Land Rovers said:

Thanks. I found a gauge, and the pressure at the temperature sensor on the regulator is around zero. I'll look at that system and see if I can find the problem.

Good news , pull the pump out and see what the filter on the bottom of the pick up is like , chances are your pump has failed . 

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I fitted a new pump, filter head and regulator to my Td5 when I first got it, and it wouldn't start after I'd fitted everything. 

It turned out that the non-return valve in the filter head was fitted to the wrong outlet on the filter head! And that was on a brand new, genuine LR filter head...

I'm sure if you've had the filter head apart you'll have put it back together correctly, but could be worth a check.

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