TD5 Defender help - Low power

**nathanmac36** · 6th October 2020, 07:52 PM

Hi all,

2001 TD5 Defender with ~350K Kms was low on power and loosing coolant slowly so I had it looked at by a reputable LR mechanic. The mechanic advised the head gasket was no good and pressurising the cooling system causing the coolant loss.

I pulled the head off myself (which was pretty easy) and gave it to the mechanic to check and refurbish. Got the head back after a week and it had been pulled apart, skimmed, pressure tested, inlet valves replaced, exhaust studs replaced and injectors had new washers and O rings. They put my timing pin back in the cam to lock it in place.

At the same time of doing the head gasket I also replaced the following:

- Inlet manifold gasket
- Water Pump and cover (proflo brand)
- Injector loom
- Oil Cooler and filter gaskets
- Oil Cooler radiator core
- Oil Cooler reducer hose (small one at the back)
- Exhaust manifold gasket (had manifold checked by an exhaust shop for warping)
- All turbo gaskets
- fuel pressure regulator gaskets and O ring
- Fuel cooler coolant hose to radiator
- Oil Cooler coolant hose to radiator
- radiator pressure and flow tested
- intercooler cleaned out
- New oil, air and fuel filters (mahle)

I used Elring brand Head gasket of the same thickness as what came out and AMC head bolts. I've also installed a boost gauge and VDO coolant gauge to replace the standard one.

After refitting everything and firing the car back up it is no better on power (worse actually) but seems to idle and rev smoother. I followed the RAVE for setting TDC and locked timing before removal then setting the chain tension upon refitting.

Any ideas as to what could be causing it to be worse for power after all this? There has been considerable money invested into this issue that has yielded worse results than before.

I have thought that it could be the transfer case as it is a 61D 1.211 Disco TC but the power is definitely worse than before HG.

Thanks

**shack** · 7th October 2020, 09:05 AM

Of the jobs you have done on it, the performance related ones are:

Cam timing
Injector bump
Inlet and exhaust /turbo gaskets
Intercooler hose fitting

Those are the only ones that will effect the engine.

Did the engine get hot at all before the pull down?

**PhilipA** · 7th October 2020, 09:13 AM

I vote injector bump seeing all the work done.
Also wastegate jammed partly open, modulator wrongly plumbed/failing?

Regards PhilipA

**nathanmac36** · 7th October 2020, 11:54 AM

Originally Posted by shack

Of the jobs you have done on it, the performance related ones are:

Cam timing
Injector bump
Inlet and exhaust /turbo gaskets
Intercooler hose fitting

Those are the only ones that will effect the engine.

Did the engine get hot at all before the pull down?

All inlet and exhaust/turbo gaskets seem to be okay. No exhaust leaks and inlet gasket was bolted back up before the head went on so it was lined up and torqued correctly.

Cam timing is possible but the crank was locked at TDC the entire time and the head was given back with the pin in place. The timing chain was tied to the sprocket and the links lined up with the mark when taking it apart and putting it back together. I turned the crank by hand all the way around until the links lined back up and there was no indication that anything was fouling

I've checked turbo hoses and there's no leaks. They're newish silicone hoses.

Injector bump I didn't check before putting it all back. I assumed it would have been set correctly by the mechanic. I'll have to look into it.

Cheers

**nathanmac36** · 7th October 2020, 11:58 AM

Originally Posted by PhilipA

I vote injector bump seeing all the work done.
Also wastegate jammed partly open, modulator wrongly plumbed/failing?

Regards PhilipA

I will have to look into injector bump as I didn't check it before firing it up.

Wastegate doesn't seem stuck. I can move it open and closed with some pliers and it springs back just fine.

No modulator in the defender. Wastegate is plumber straight from the hot side of the turbo.

Thanks

**shack** · 7th October 2020, 09:35 PM

It wouldn't make a lot of difference, but did the injectors go back in the same holes?

**Lionel** · 8th October 2020, 08:14 AM

Since it was down on power before all the work was done, have you checked the MAF sensor? My TD5 was down on power due to this cause - easily checked by unplugging it to see whether the default ECU setting improves the power delivery.

If it does, it's time to invest in a new MAF sensor.

Cheers,

Lionel

**Xtreme** · 8th October 2020, 10:15 AM

Originally Posted by Lionel

Since it was down on power before all the work was done, have you checked the MAF sensor? My TD5 was down on power due to this cause - easily checked by unplugging it to see whether the default ECU setting improves the power delivery.

If it does, it's time to invest in a new MAF sensor.

Cheers,

Lionel

I've got a spare MAF sensor which you are welcome to borrow and try.
It was just returned from a Td5 Disco owner who used it for about 5 weeks while he was waiting for delivery of a new one from UK. So it's had a recent test and I know it's OK.
PM me if interested, I'm in the Hornsby area.

**nathanmac36** · 8th October 2020, 12:23 PM

Originally Posted by Lionel

Since it was down on power before all the work was done, have you checked the MAF sensor? My TD5 was down on power due to this cause - easily checked by unplugging it to see whether the default ECU setting improves the power delivery.

If it does, it's time to invest in a new MAF sensor.

Cheers,

Lionel

Hi Lionel,

The MAF was replaced around 18 months ago after the same mechanic advised that it was dud. The new MAF was VDO branded and it made absolutely no difference.

I've tried both original and new MAF before and after head gasket was done and neither has made a difference.

I have not checked with a scanner to see if the MAP sensor is faulty. I tried unplugging the MAP and there was a noticeable drop in performance from the already poor performance so assumed it was okay.
I might try another MAP sensor anyway.

Cheers

**nathanmac36** · 8th October 2020, 12:24 PM

Originally Posted by Xtreme

I've got a spare MAF sensor which you are welcome to borrow and try.
It was just returned from a Td5 Disco owner who used it for about 5 weeks while he was waiting for delivery of a new one from UK. So it's had a recent test and I know it's OK.
PM me if interested, I'm in the Hornsby area.

Thanks Xtreme but I've got 2 MAF sensors, one new and one original that was on the car when I bought it. Neither has made a difference.

I mentioned in another post that I'll try the MAP sensor as RAVE indicates the MAP has more to do with fuelling than MAF.

Cheers

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