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Procta

Member Since: 03 Dec 2016
Location: Sunderland
Posts: 5183

90roy wrote:
Replaced turbo and wastegate actuator today and it's not made much difference really. Maybe a bit quicker to pick up at speeds below 50, but top end power is still a problem. It takes ages for me to get to 70 and if I encounter a slight gradient it slows down to 60ish. I have no chance of getting it to 85 (defender top speed) unless I'm going down hill 😁

I chose not to replace the manifold (incl wastegate) as I could not work out how to take off the cast iron elbows for cylinders 1 and 4 from my old one, and fit to the new. Does anyone know how to do this?

Could there be another issue with the engine to make the top end speed restricted?

Cheers in advance... R

Have you checked for inlet and manifold leaks, also leaks from the EGR if its got one. My old 300 TDI was very sluggish off the line, and wasn't took keen on picking up the pace, I got an EGR delete kit and it made a massive world of difference. i did hear a clicking noise like tappets, one of the lads pointed me to the inlet, and sure enough, it was blowing from there. So it might be worth just checking while its on tick over. Also has it had a timing belt change recently? they may not have timed things up properly.

Defender TD5 90 ---/--- Peugeot 306 HDI hatch back

Success is 90% Inspiration and 4 minutes Preparation # you can make it!

22nd Nov 2022 5:53am

Barneyboy

Member Since: 19 Nov 2014
Location: Exmoor
Posts: 1626

1986 Defender 90 2.5 n/a Diesel ST Nato Green

Hi 90Roy just a thought, have the turbo hoses been replaced? Could it possibly be a hose delaminating ie collapsing internally, if it is, when on boost the hose will collapse in on itself blocking the airway, I hope you get to the bottom of the issue

cheers Paul

22nd Nov 2022 6:14am

I Like Old Skool

Member Since: 23 Feb 2015
Location: Manchester
Posts: 814

1994 Defender 110 300 Tdi ST Coniston Green

Could be the fuel lift pump, but not for the reason you might think....

My 300tdi was intermittently losing power when on the motorway at full speed of around 85-90mph, so full fuel flow required. This suddenly got worse after an off-road foray.

I found out that the fuel lift pump was not working, but that wasn't the issue either. In the fuel lift pump is a nylon gauze strainer and this was clogged up with crap from the tank. While waiting for a replacement pump to arrive I cleaned the muck out and refitted the non-operational lift pump and full power was restored.

Turns out (and I read this on the internet too, so it must be true) that the type of injection pump used on our Tdi engines will suck its own fuel quite happily without the lift pump. My experience suggests this is the case.

When the fault first showed up the flow must have only been restricted enough to be noticeable when driving flat out for a while where the fuel filter got drained and fuel being pulled through the partially blocked pump strainer was not enough to refill it. Once more muck was dislodged and blocked the pump even more the problem got worse and the engine would splutter, shake and cut out, but would then restart after a couple of minutes and if allowed to idle for a bit (allowing fuel to seep through while using minimal fuel for the engine) I could then drive another mile or so before it would start struggling again.

It ran fine with the failed pump fitted while I got around to fitting the replacement.

This fuel strainer in the lift pump isn't mentioned in any of the service manuals/schedules I have ever seen so it was a surprise to me but always worth checking it occasionally as it is only 1 screw to remove the cap from the lift pump. Because it is upstream of the fuel filter it will catch any lumpy bits that might be picked up from the fuel tank and only lets finer stuff through to the fuel filter.

22nd Nov 2022 2:04pm

90roy

Member Since: 21 Jun 2016
Location: Middlesbrough
Posts: 130

Hello all,
Thanks for the replies.
I shall have a look at the lift pump incl filter and check over the hoses as they were not changed.
The inlet and exhaust manifold seems to be leak free and I don't have an egr valve so can rule this out.
I didn't replace the inlet manifold / wastegate as I couldn't figure out how to change over the elbow pipes for 1 and 4 cylinders. I guess the valve could be not sealing properly also, although it does move quite freely in the manifold.

Should I be able to hear a whistle when the turbo is on song? If not it points to leaky hose I guess.

Thanks,
R 300tdi 90 1996.

22nd Nov 2022 7:32pm

Jon w

Member Since: 22 Dec 2015
Location: North East Wales
Posts: 209

Check boost pressure from inlet manifold if possible, this will show how much boost the engine is receiving and may point to a leak from turbo pipes or even intercooler leaking from the matrix

23rd Nov 2022 12:27pm

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4410

Quote:

Check boost pressure from inlet manifold if possible, this will show how much boost the engine is receiving and may point to a leak from turbo pipes or even intercooler leaking from the matrix

And when you do decide to fit a boost gauge, a worthwhile addition by the way, then RSpec do a lovely OE looking gauge:

https://www.rspec.co.uk/product-page/diese...-0-3-bar-1

and one with green illumination

https://www.rspec.co.uk/product-page/diese...ge-0-3-bar

I have the first one and it looks excellent in the Defender dash

23rd Nov 2022 12:50pm

90roy

Member Since: 21 Jun 2016
Location: Middlesbrough
Posts: 130

Jon w wrote:
Check boost pressure from inlet manifold if possible, this will show how much boost the engine is receiving and may point to a leak from turbo pipes or even intercooler leaking from the matrix

Thanks, will do.

R 300tdi 90 1996.

23rd Nov 2022 6:20pm

90roy

Member Since: 21 Jun 2016
Location: Middlesbrough
Posts: 130

geobloke wrote:
Quote:

Check boost pressure from inlet manifold if possible, this will show how much boost the engine is receiving and may point to a leak from turbo pipes or even intercooler leaking from the matrix

And when you do decide to fit a boost gauge, a worthwhile addition by the way, then RSpec do a lovely OE looking gauge:

https://www.rspec.co.uk/product-page/diese...-0-3-bar-1

and one with green illumination

https://www.rspec.co.uk/product-page/diese...ge-0-3-bar

I have the first one and it looks excellent in the Defender dash

Cheers. I think ill get this to replace the clock which doesn't work, and it'll tell me what's going on with the turbo hopefully. 300tdi 90 1996.

23rd Nov 2022 6:21pm

90roy

Member Since: 21 Jun 2016
Location: Middlesbrough
Posts: 130

I had a quick look for the lift pump at the weekend (it was raining so only a quick one) and couldn't see it.
Where is it located please?

Any pics appreciated.

Thanks

Roy 300tdi 90 1996.

28th Nov 2022 11:12am

jfh

Member Since: 08 Jan 2014
Location: West Coast
Posts: 359

2007 Defender 110 300 Tdi SW Chawton White

Driver's side on R/H drive

Click image to enlarge

28th Nov 2022 11:20am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4410

Drivers side of the engine. Stand by the wing and look down behind the injector pump. Silver domed thing with a priming handle on the right hand side.

It will only pump if the lift pumps internal lever is sitting on back of the cam. If the priming lever seems to have no resistance then turn the engine over a little to engage and retry priming.

28th Nov 2022 11:21am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4410

Check out these videos on lift pumps from Mike at Britannic, really interesting...

https://www.youtube.com/watch?v=6IIGwI_aY4U

https://www.youtube.com/watch?v=BdooeegtYOY

28th Nov 2022 11:34am

90roy

Member Since: 21 Jun 2016
Location: Middlesbrough
Posts: 130

Brilliant! Thanks chaps.

R 300tdi 90 1996.

28th Nov 2022 7:08pm

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