Lack of Power, Help please.

[Eoforwic]

Hi All (please bear with me),

I'm Alex and I bought an Stg1 just before lockdown started in Scotland and drove it back to Hertfordshire in a day where I noticed an issue. In 4th/OD at high RPM, it would slowly start to lose power, however, if I stopped or revved it hard with the clutch in, it would clear and go back to normal.

I thought this, was down to a faulty fuel pump/filter at high rpm, backed up by poor starting.

I fitted a new Bendix pump, replaced all the lines and replaced the filter. This cleared the starting issue, however, on numerous test drives the engine just wasn't right with it either wheezing/spluttering at the biting point, losing power at high rpm or acting like an V8 (read as powerful 2 1/4).

I have now found all the vacuum leaks, including the missing distributor hose on the bottom of the nearside carb, using a cigar. At each point, I have thought I'd found the issue. The wheezing/spluttering at the biting point has now (seems) to have gone and I'm just left with the high rpm loss of power, which if I back off for a while, will go back to having some power (but feels like a 2 1/4). I've topped up the damper oil too (Strombergs)

In between, all the test drives the Clutch Master cylinder ran dry - I have refilled and bled it - long term diagnosis/fix for another day.

I have a Vacuum gauge arriving soon.

What are your thoughts for the high rpm loss?

[map1275]

Exhaust blocked?

[Eoforwic]

Thanks 1275.

I had not considered the pipes, without a cat or an EGR what would be the likely culprit?

[map1275]

Collapsed baffles. As the factory fit is flange joints they are a straight forward disconnect.

Dealt with an F last week with a blocked cat. Pressure at the tail pipes seemed appropriate but power was down and the catalyst is a straight forward removal to inspect. However neither factory silencer for the 109 V8 are straight through. So looking inside doesn't prove much.

[firemanshort]

I am not sure I fully understand what your issue is but.... maybe your carb float is out of adjustment and you are running out of fuel in your fuel bowl of the carb. I am not sure what carb you are running so I could be talking bollox.

[udo1-ton]

Did you check the tank breather pipe and the filler cap? If you have a vacuum in your tank the pump will not be able to provide enough petrol to the carbs.
Also the air filters could be a problem...

[Eoforwic]

I had thought about the carb, it is running Strombergs but I have gone down exhaust route thanks to 1275s advice. I tested it without the silencers attached and couldn't replicate the error, once they were back on - boom no power. On another note - who knew a LR could get even louder?

Re the air filters, they are K&N and I have just serviced them. Not look at the tank, but could run it without the lid tight to test that, if the exhaust doesn't fix it.

I found an original rear silencer on eBay for £35 in BL blue, but can't seem to find the centre silencer at the minute. I have ordered one from JC but deliveries are delayed at the minute...

[Geoff]

What is BL blue?

[Eoforwic]

British Leyland Blue and a sticker. No idea why they have painted it.

[Geoff]

I didn't think that was a British Leyland sticker

[Eoforwic]

I've swapped both Silencers today and the issue has carried on. The Land Rover won't even start now - even had to push it in traffic... It would start but then immediately cut out at idle or the vacuum went to zero when pressing the accelerator.

However, I've pulled the top off the fuel pump and found this residue. I replaced the the fuel lines, filter and pump a few weeks ago so it must be from the tank (10 miles usage). The previous owner had just fitted a tank when I bought it, so I'm thinking it's paint.

It'll probably be every where so I'm going to drop the tank, clean it out. I'll flush the lines and I'm going to have to clean the carbs our too and replace the filters.

Fuel Pump

IMG_20200704_195400_20200704210952405.jpg (78.95 KiB) Viewed 13171 times

[map1275]

Bottom of the pump hopefully.

[Eoforwic]

I've now cleaned out the pump and I've changed the filter.

The filter looked like this...

IMG_20200713_162025 (1).jpg (87.42 KiB) Viewed 12313 times

I have the tank off which was full of rust (sadly) and I've started the cleaning process with thinners and a jet wash. I'm going to use soda water and a battery to get the rest out. I'm unsure whether to try a tank coating like you would with motorcycles.

I've tried starting it now with fresh petrol and it doesn't want to budge, so I'm going to have to clean the carbs

[disco2hse]

That'll do it. It is a pretty ugly mess. Looks like water in there too.

I suggest a carb rebuild is in order (which is not a bad idea anyway) and I would also get a compression test on your cylinders because if any of that crud has made it into your cylinders it will have acted as a pretty good grinding paste. I would also give the facet pump a good long flush with clean petrol or diesel.

[Eoforwic]

Hi.

Thank you for the advice.

I'm planning on rebuilding the carbs after sorting out the inside of the tank. Thinking coating it like a motorcycle tank.

I've cleaned out the pump too.

Not thought about compression, hopefully it didn't make the carb... I have my own tester so will tick that off.