525 TDS automatic power problems - BMW Forum

Tony777 · 06-23-2008, 03:44 PM

Hi everybody,

Can anybody please give me some advice.
I have a 1994 525 TDS touring automatic but it has developed a problem.
The engine revs fine when she is either park or neutral.
When I put it into drive, reverse or one of the lower gears and
the engine is cold, she pulls away but a bit sluggish. Once she gets going,
she runs fine. When the engine is at operating temperature and I try to pull away,
the gearbox is in drive and I put my foot on the accelerator, nothing happens
It's like the throttle cable has been cut but it still has resistance.

If i put it into neutral, the engine revs as freely as it should.
Has anybody got any ideas what may be wrong?

Thanks,
Tony

darkhorse737 · 06-23-2008, 08:50 PM

have u changed your air & fuel filter lately?

from what you describe, i can deduce a number of probs:
1) EGR stuck open
2) injector probs
3) clogged CAT(if equipped)
4) turbo and intercooler probs

you want to narrow the choices down... you'll need to be more specific because diagnosing by remote control is quite a hit-or-miss thing. As in all engines, there are several factors that come into play-even when the same symptoms display... it dsnt necessarily mean that Peter's fix will apply to John's car ;-)

other Q's i have:
1) do you hear the turbo kick into action at all
2) no power under load.... engage ebrake, step on the brake, shift into D and rev... what is the difference now?
3) are you new to diesel engines( God bless you if you are trying to compare gas and diesel in terms of acceleration)

Tony777 · 06-24-2008, 02:48 PM

Hi there,
I have recently replaced the air, fuel and oil filters but that was about 1000 miles ago and it has been running fine.
She still starts first time after the glowplugs go out.
She revs fine when it's in neutral or park.
When I finally get her moving, she drives fine,
kickdown works all ok, accelerates really well as it should.
If I select drive, I can push the accelerator to the floor and nothing happens at all. the revs do not rise at all, not even 5rpm
As I said, when I am at a standstill, drive is selected, I press the accelerator and nothing happens. The engine carries on at tickover. If I am on level ground or slightly downhill, she will roll and when she gets to about 5mph, the accelerator starts to work and then I can drive it as normal

If I have the car in neutral or park, the engine revs nice and freely.
Today, I have checked the autotrans fluid, and it was fine.
And the answer to your last question is Yes, I have had diesel cars since 1987 when I had a Citroen BX but my 525 TDS is the best diesel that I have owned. I used to have a 525TD and a few other diesel cars

darkhorse737 · 06-24-2008, 05:21 PM

you checked transfluid.... what was the color... red or brown... does it smell burnt? ;-) what about tranny filter. have u replaced it lately? if not maybe time you should. Some of the symptoms you describe point to stuck valves in the tranny valve body... or oil starvation because of a clogged transmission filter.

the quality of the oil oftentimes comes into play. loss of viscosity in your oil(or wrong grade of autotrans fluid will keep your tranny from working properly.

when I am at a standstill, drive is selected, I press the accelerator and nothing happens. <<< when you say "nothing happens"... does the engine rev? If yes, you might consider torque converter problems OR the internal bands in your tranny have worn themselves out.(I have never done a tds tranny as of this writing, so i can't really say if there are provisions for adjustment)

If however, the engine will not rev when u are in "D"... my suspicion is that you have an electrical prob. If this be the case, the only thing I can suggest is to have you car scanned. It reduces the guesswork; and will provide us some point from where to start probing n;-)

Tony777 · 06-25-2008, 02:37 AM

The engine revs do not increase at all when I click it into drive and press the accelerator. The fluid seems ok and there are no burning smells. I did not know there was a transmision filter!

darkhorse737 · 06-25-2008, 10:47 AM

Quote:

Originally Posted by Tony777

The engine revs do not increase at all when I click it into drive and press the accelerator. The fluid seems ok and there are no burning smells. I did not know there was a transmision filter!

ahhh.. now i am almost convinced your problem is electrical/electronic in nature.
Locate a shop that can do a scan on your transmission- let's see...

re: YES, your car has a Transmission Filter. It's one of the most neglected parts and do need attention every 30,000 miles or so(depending on mfr's specs).

a dirty/clogged filter results in oil startvation to tranny oil pump and torque converter-and the result of course, is.... "tranny don't work right"

Then consider also the kind oil ATF you use... there are varying viscosities, and some ATF fluids just will not work with BMW.( i wouldn't know the transmission model used for the TDS; so check with your local dealer whether your tranny takes the usual MERCON-DEXRON II or III... or whether it rquires a different spec. )

Tony777 · 06-26-2008, 04:08 PM

Thanks for your advice,
I took the select economy/snow/performance switch apart as a long shot but still no good.
I will have to take it to somewhere that can test the electrics. Hopefully, I will not get stitched up!
Thanks again,
Tony

darkhorse737 · 06-26-2008, 10:07 PM

I wish i could have been of better help to you Tony... but please let us know what happens.

I could use the education for some stock knowledge and future use :-)

Good Luck & Best Regards fr Cali ;-)

Tony777 · 06-27-2008, 02:27 PM

Hi there,
I have a Mercedes mechanic who thinks he knows what the problem may be and he is going to come round one day next week.
Hopefully, he will be able to tell me what is wrong with it (fingers crossed)
I have a nasty feeling that it's going to be expensive
Thanks for the help and advice,
Tony