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Why am I limited to 3000rpm or 60mph


Froggie
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Hi all

I've just put a new (well recon) engine in my Disco TD5 (2001) and it is as if it has a limiter fitted. I can accelerate fine up to 3000rpm or 60mph then there just is no guts left in it. Its baffleing me, all i can think of doing now is taking it to LR and getting the ECU checked out...

Any ideas?

Thanks

Steve

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Fuel pump is probably fked, you need a fuel pressure check, I suspect you will find it is dropping off under load. It won't show as a fault code in the ECU so ignore anybody who tells you otherwise as they are talking out of their bottom. The only way to be sure is to plumb a gauge (or a Testbook) into the fuel rail and go thrash it up a hill.

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Fuel pump is probably fked, you need a fuel pressure check, I suspect you will find it is dropping off under load. It won't show as a fault code in the ECU so ignore anybody who tells you otherwise as they are talking out of their bottom. The only way to be sure is to plumb a gauge (or a Testbook) into the fuel rail and go thrash it up a hill.

Agree 100%....could also be the fuel pressure reg.

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Could it be the waste gate?

i have a NANOCOM connected and when the revs get to about 2500k (under load) the turbo pressure drops to zero.

The engine was a straight swap, we didnt touch the injectors. Would the ECU need updating when a new engine is put in.

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  • 3 weeks later...

Hi all

I've just put a new (well recon) engine in my Disco TD5 (2001) and it is as if it has a limiter fitted. I can accelerate fine up to 3000rpm or 60mph then there just is no guts left in it. Its baffleing me, all i can think of doing now is taking it to LR and getting the ECU checked out...

Any ideas?

Thanks

Steve

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I have a similar problem. My 11year old TD5 Disco (only 52k miles) starts and runs superbly. But if I take it out on to a dual carriageway under acceleration in 3rd and 4th it starts to miss horribly at just below 3000rpm. In 5th it becomes gutless under load above 2700rpm. Yesterday coming back from the East Midlands in 5th the vehicle would not accelerate over 70mph but would do more and above 3000rpm downhill.

What does this tell me. 1. There can't be a problem with the fuel pump. I guess it either works or doesn't. 2. It cannot be the dual mass flywheel/clutch disintegrating (as I have heard can happen) as it was smooth when doing 3000rpm down hill (that was the intended check to get it to 3000rpm).

I like the possibility of fuel filter or separator being clogged. What normally happens with the regulator? Does it fail or go out of calibration? I have no error messages. Could it be that it just does to much around town stuff and too little hard work?

Any help would be much appreciated because I do not want to get into the grips of LR dealers or local garages as they will happily take my money changing things that are OK.

sharp'i's

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Unplug the MAF sensor and go for a drive...

Mine had the same symptoms. Unplugging the sensor sets a default value, truck then ran fine. Plugged it in and problem came back. New sensor and all was well.

Free and simple to check - you don't even need any tools :D

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Unplug the MAF sensor and go for a drive...

Mine had the same symptoms. Unplugging the sensor sets a default value, truck then ran fine. Plugged it in and problem came back. New sensor and all was well.

Free and simple to check - you don't even need any tools :D

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The engine was a straight swap, we didnt touch the injectors. Would the ECU need updating when a new engine is put in

did you actually swap the injectors over? if not then i suspect that is the problem. the ecu is reading the wrong injector codes, causing limp mode maybe?

not too clued up on all this electrical witchcraft that these modern lumps use, prefer the mechanical ruggedness of my 300.....

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Not having the right codes only makes your engine a little "rough", no power or limitations matters (my ouwn expirience having not a single code agree during 2 years). It seems like you have a wastegate actuator arm stuck (same sympthoms a few weeks ago in my 2001). Go for a WD40 and pliers ride.... it's the cheapest way to find out....

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  • 3 weeks later...

I have finally got around to trying out the TD5 without the MAF sensor connected. It ran a lot better but still had the missing at around 3000rpm but not so bad. This could be just under using the diesel engine. However as I say the engine seemed uninhibited and ran with more power. What does the MAF sensor do as it is still disconnected and it works fine? Is its purpose to cut the fuel supply when your foot is off the accelerator?

I may try changing the fuel filter before I do anything else.

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It's function is to match the air flow into the engine with the amount of fuel the ECU is injecting to get the maximum power. If it was better without, then the old one was completely kaput, fit a new one and you should see an improvement again :)

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It's function is to match the air flow into the engine with the amount of fuel the ECU is injecting to get the maximum power. If it was better without, then the old one was completely kaput, fit a new one and you should see an improvement again :)

Surely t'other way round - the airflow meter tells the ECU how much air has gone in so the ECU can inject the correct amount of fuel. It doesn't control the amount of air :P

Can I also add: "Pah, these diesels with all their complicated and unreliable electronics, you want a nice V8 with fuel and sparks" :lol::ph34r:

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