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? :p

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.http://www.bimmer.info/%7Ebill/diesel%20speed%20limitation.jpg




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? :p

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.http://www.bimmer.info/%7Ebill/diesel%20speed%20limitation.jpg

please post if for me.

thx.

Dave.
Uganda

[High Compression II]

You guys are amazing!-

Looks like Ill go for it then! I know with MY luck it will be something more complicated than a brake-switch--Any idea where its fitted?--Is it the type above the brake-pedal, or the 'hydraulic type' switch, fitted on a brake-line somewhere??

(If ive got hold of a whole lot of trouble, I wont blame you guys, Really ;) )

Very interested in the OBC 'Valet' mode, Was this just a joke, or do such features really exist--It sounds a bit 'gimmiky' to be on what I always thought a 'class' sort of car..............
Ive been doing a LOT of research on the 'web, Would it be fair comment to say, the reliability is perhaps a little questionable of all these (rather daft) electronic systems?--This is something my Mercedes cars had little of, being rather basic in comparison, but hideously reliable, if a little boring to drive!

Thanks again guys, looks like youv'e got another 525 in the club! :)

I take part in a couple of online Forums, mainly relating to the use of BioDiesel, and Vegetable oils as fuels in diesel vehicles/engines. I am considered as something as an authority (Cant think why!) on the subject, and Im a regular contributor sorting out guys problems. Its rather strange being the Noob, with the silly questions!, but you guys have been most friendly and helpful, something you dont always see in the Online communities everywhere.

If any you guys need advice on BioFuels or related issues, Ill try and help out, Also, Ill list my experiences with the new-beast as soon as I get hold of it, and sort it. :D

[timeout]

I probably got it all wrong :( , but to me it looks as if 'Engine runs max 1200 rpm (1400rpm auto)' relates to answer No. 15, which is 'road speed sender (or lead)' ?

[billb]

I probably got it all wrong :( , but to me it looks as if 'Engine runs max 1200 rpm (1400rpm auto)' relates to answer No. 15, which is 'road speed sender (or lead)' ?

Check the matrix again.

[SRR2]

15 is clearly the brake switch. 16 is the road speed sender and that's a possible cause for "hesitation".

The question I have is what's the purpose of the brake switch limiting engine speed? To take advantage of engine braking? To prevent accidental application of power while the car can't move? Guaranteeing that all engines/transmissions pass the torque converter stall speed test? (j/k)

[timeout]

15 is clearly the brake switch. 16 is the road speed sender and that's a possible cause for "hesitation".
(j/k)
thanks, time to get my glasses I think.

[SRR2]

Once you enter The Matrix ....