525TDs revs great, but wont go faster than 30!

[High Compression II]

Got a chance of a great 525TDs, but it has weird problem While the engine sound fine, no noises smoke or anything like that, No dashboard warning lights etc. the vehicle will not go faster than 30 miles an hour! which is 1500RPM in drive. The fault I have been told is not intermittent and present all the time/temperature/conditions etc.

Its an Auto with I believe a M51 Diesel engine and 5HP18 ZF Trans, and was registered in 1993.

I need to find if this is an engine based fault--which for me would be OK!, or are the gearbox electronics 'telling' the engine to stay at 1500 as a limp-home mode?
Another issue is the vehicle is around 300 odd miles from me, so proper diagnosis by myself is difficult!

Is there any way of 'disconnecting' the electronic control of the gearbox if this is the fault, and if so, would the vehicle drive, all be it not correctly?

Any guesses/wild stabs in the dark?

Any info or past-cases/on similar vehicles would be interesting to hear!

Im a fair Diesel engineer, and am an electronics technician by proffession.

I plan to buy this as my first BMW, having had Mercedes for many years, and convert it to use vegetable oil as fuel like the Mercs before it.........But thats another story!

[632 Regal]

is the obc set for valet service limiting the top mph?

[High Compression II]

I am just getting to grips with all the info Ive been researching on this car. I didnt even realise the OBC would have such a setting.

Ive been offered this car, which looks to be pretty good condition and great price, but havent seen the thing yet, only emailed pics, as its 300 odd miles away!.

If its this valet setting, How would it be re-set to normal?

Thanks, Your info is invaluable

[Anthony (M5 in Calgary)]

is the obc set for valet service limiting the top mph?

Hey Jeff, quit baiting the noobs!

[632 Regal]

I'm not baiting, thats the first logical thing I can think of to limit the mph.
you should be able to reset it assuming you have the code that someone used to set this option, look in the owners manual under OBC features/settings.

Hey Jeff, quit baiting the noobs!

[Anthony (M5 in Calgary)]

I'm not baiting, thats the first logical thing I can think of to limit the mph.
you should be able to reset it assuming you have the code that someone used to set this option, look in the owners manual under OBC features/settings.

I thought you were baiting!

The OBC speed limit only rings the gong when you exceed the set limit, not limit your actual speed.

I'd guess there's a fuel delivery problem but I know jack about diesels otherwise.

Seriously HCII, what does the car do as it is accelerating from rest? Will it surpass 1500rpm in any gear? Does it take forever to reach 30mph or does it pull well then peter out?

[632 Regal]

Really.... *has to check now*

The OBC speed limit only rings the gong when you exceed the set limit, not limit your actual speed.

[Bill R.]

see if its faulty.

Got a chance of a great 525TDs, but it has weird problem While the engine sound fine, no noises smoke or anything like that, No dashboard warning lights etc. the vehicle will not go faster than 30 miles an hour! which is 1500RPM in drive. The fault I have been told is not intermittent and present all the time/temperature/conditions etc.

Its an Auto with I believe a M51 Diesel engine and 5HP18 ZF Trans, and was registered in 1993.

I need to find if this is an engine based fault--which for me would be OK!, or are the gearbox electronics 'telling' the engine to stay at 1500 as a limp-home mode?
Another issue is the vehicle is around 300 odd miles from me, so proper diagnosis by myself is difficult!

Is there any way of 'disconnecting' the electronic control of the gearbox if this is the fault, and if so, would the vehicle drive, all be it not correctly?

Any guesses/wild stabs in the dark?

Any info or past-cases/on similar vehicles would be interesting to hear!

Im a fair Diesel engineer, and am an electronics technician by proffession.

I plan to buy this as my first BMW, having had Mercedes for many years, and convert it to use vegetable oil as fuel like the Mercs before it.........But thats another story!

[Paul in NZ]

all i can say is Wow,bill you are da man.........

[Kakaire]

see if its faulty.

please post if for me.

thx.

Dave.
Uganda