New Member - 1993 BMW 525i M50, Need help

[Ali]

Hi Everyone,

I've been looking for a good BMW forum for quite some time and here I am, was a member of the similar Merc forum (Benzworld, I wonder if anyone here has heard of it), anyway I had a W124 1990 230CE and was just looking for more power and a brand change (the Merc was great just wanted to know what Bimmers are like) I have been looking at BMWs for quite some time and almost came close to buying a beautiful blue 1994 318is twice !!! but I don't know why everyone I know is against these cars (BMWs), when I asked them the reasons I got were.

1) Not as reliable as Mercs or japanese cars of the same era (early 90s)
2) Outrageously expensive parts compared to Mercs.
3) Very common overheating issue (very important since I live in the Middle East - Dubai and summers are scorching here).
4) Airconditioning isn't any good (important for the same reason as above).
5) Here in Dubai most small - medium workshops don't take BMWs in but will look at Mercs, according to them the fuel management system and electronic are too complex prone to fault compared to W124s or W126s.
6) Most BMW workshops are run by arab expatriates and labour charges are phenomenal in these places.
7) Resale value (due to depreciation) is crap.

Anyway I've bought this 1993 BMW 525i M50 (By the way how can I tell if my car has VANOS or not) end of Jan and the used car dealer had promised to fix all minor faults and handover the in 3-5 days, guess what it's still in the workshop, I was hoping with your help I might be able to just take the car back and diagnose some of these things myself, problems are

1) All doors open only from the outside inside door handles don't work.
2) When I release the accelerator to change the gear the car backfires (loud bang), louder at higher engine speeds.
3) Steering vibration gradually increases at over 60mph (90kmph) even after twice balancing and aligning the wheels.
4) Very manual shaky gear stick.
5) Mysterious oil leaks the guy claims to have repaired the engine and transmission oil leaks thrice !!! and it still leaks.

Please someone help me, by the way can anyone give me any info about my car with the VIN No. which is WBAHD51050BG50725,
Thanks

[shogun]

The car was built in 07/1992. Engine is M50B25, tranmission is manual and the transmission type is S5D 310Z.
1) You have to remove the door panels and check inside if there is anything dislocated.
Antway, it is very strange that ALL doors do not open. Usually one door makes trouble but not all at the same time.
2) You have to change all wear parts such as distributor cap, distributor rotor, spark plugs and so on.
Is there a shop where they can connect your car on a diagnosis computer. That is the easiest to find the culprits. Otherwise it is just searching in the dark for something, especially if there is no good mechanic.
3) steering vibration: wheel balancing, and it could also be worn parts in the front suspension.
4) gear stick: have to check the connections of that.
5) That is difficult to answer if we do not know where the leaks are. Do you have a digital camera and can make some ppictures and post them here?

As for the carfax you asked me on private message: This does only apply for cars registered in USA, where dealers report all damages etc. to a central reporting system. Your car was apparently registered in Europe (it is an ECU model) and therefore a carfax info does not exist for your car.

Go to my website and then go to e34.net, there are many good repair tips, also for the front suspension, what could be wrong and what would have to be changed.

The aircon problem can be fixed by installing a bigger compressor, no problem at all. My one works perfect also in ambient temperatures of +/- 40 degree C.

Take yur time and read all the links and repair pages on my website. Takes a long time but it will help you. There are also links to other pages, and also wiring diagrams.

[Interceptor]

1) All doors open only from the outside inside door handles don't work.
2) When I release the accelerator to change the gear the car backfires (loud bang), louder at higher engine speeds.
3) Steering vibration gradually increases at over 60mph (90kmph) even after twice balancing and aligning the wheels.
4) Very manual shaky gear stick.
5) Mysterious oil leaks the guy claims to have repaired the engine and transmission oil leaks thrice !!! and it still leaks.

Please someone help me, by the way can anyone give me any info about my car with the VIN No. which is WBAHD51050BG50725,
Thanks

According to the VIN, the car was made 07/'92, so it should not have VANOS. M50 with VANOS is named M50TU. More info at:
http://www.realoem.com/bmw/select.do...&kind=P&arch=0

Regarding the vibration of the steering wheel, it can be caused by warped discs, front bushings or steering links, maybe even the tires/rims/bearings, but that's not likely.

To fix oil leaks, you first must be sure your compression is good on all cylinders - maybe it burns oil? For leaks, try changing the valve cover gasket, oil filter housing o-ring, oil level sensor rubber ring, etc.

Backfire means you have unburnt fuel that detonates in your exhaust system - check all sensors, including o2 - your mixture is probably not ok.

Shaking of the gear shift knob can be easily fixed by changing a small plastic part under the shift stick - let the mechanic do that instead of you.

I don't have a clue about the doors

[bimmerd00d]

The car was built in 07/1992. Engine is M50B25, tranmission is manual and the transmission type is S5D 310Z.
1) You have to remove the door panels and check inside if there is anything dislocated.
Antway, it is very strange that ALL doors do not open. Usually one door makes trouble but not all at the same time.
*absolutely correct, there's a little red cable with hooks on either end connecting the door hinge to the latch mechanicals.

2) You have to change all wear parts such as distributor cap, distributor rotor, spark plugs and so on.
Is there a shop where they can connect your car on a diagnosis computer. That is the easiest to find the culprits. Otherwise it is just searching in the dark for something, especially if there is no good mechanic.
*You dont have a distributor cap, you have individual coil packs on each spark plug. I would recommend starting with spark plugs (get the stock ones, stay away from multi-electrode plugs and platinums) and coil packs. New air filter.

3) steering vibration: wheel balancing, and it could also be worn parts in the front suspension.
*Most likely your thrust arm bushings. Not a terribly cheap replacement if you have it done. You might try ordering Bruno's Thrust Arm bushing inserts (www.racingking.ca)

4) gear stick: have to check the connections of that.
*Check your transmission mounts for wear (easy and cheap to replace yourself), Check the shifter bushings for wear, just shake the assembly from under the car and if it moves more than about 5-10mm, you should rebuild your shifter linkage.

5) That is difficult to answer if we do not know where the leaks are. Do you have a digital camera and can make some ppictures and post them here?

As for the carfax you asked me on private message: This does only apply for cars registered in USA, where dealers report all damages etc. to a central reporting system. Your car was apparently registered in Europe (it is an ECU model) and therefore a carfax info does not exist for your car.

Go to my website and then go to e34.net, there are many good repair tips, also for the front suspension, what could be wrong and what would have to be changed.

The aircon problem can be fixed by installing a bigger compressor, no problem at all. My one works perfect also in ambient temperatures of +/- 40 degree C.

Take yur time and read all the links and repair pages on my website. Takes a long time but it will help you. There are also links to other pages, and also wiring diagrams.

See my additions above.

Also if you haven't found it, www.bmwe34.net

[winfred]

1) All doors open only from the outside inside door handles don't work.

someone probably took the door panels off and didn't reinstall properly

2) When I release the accelerator to change the gear the car backfires (loud bang), louder at higher engine speeds.

probably a fuel problem related to a misadjusted or bad sensor

3) Steering vibration gradually increases at over 60mph (90kmph) even after twice balancing and aligning the wheels.

most likely a bent rim or out of round tire, jack up car then spin the wheel and look at it to see if it rolls true or has a lump in it, you can also swap the rims front to back on the car and see if the problem changes

4) Very manual shaky gear stick.

needs bushings, plastic cup on bottom of shifter and knuckle in back of tranny and sometimes the linkage between

5) Mysterious oil leaks the guy claims to have repaired the engine and transmission oil leaks thrice !!! and it still leaks.

kinda hard to say without looking at personally, wash it well with degreaser and see where it's coming from

[shogun]

Ali, one more info:
if the repair shops are not that good in your country, invest about US $ 150 in a PEAKE diagnosis / fault finder. This unit is not available outside the USA. Your car does not respond to the socalled 'stomp test' which you might have heard of. That is only available on US cars and maybe on cars for Canada.
I bought it from the USA and it is very easy to handle, even if you are not a computer freak. Just insert it in the diagnosis port of your car and it will help you very much for the engine diagnosis.
My friends in Japan always ask me on the meetings to check their engines, apparently I am the only one in Japan, which has this device. You can get info and order from here, and it saves you a lot of money. Very handy and I always keep it in my glovebox
http://www.peakeresearch.com/

[Jon K]

So you know Ali, there is no distributor on the car. The M50B25 has a direct-fire system. You have coil packs. Pulling the valvecover cover will show you 6 Bosch or other brand coil packs directly sitting on the spark plugs. It's hard to test these since they're ~$90 ea and there's no real way to check if they're failing other than swapping them out with known good ones...

Edit: Also, since the production date is 7/92, the motor SHOULD in theory be vanos since i believe euro models got the M50B25TU before the US did. 1993 year models here in the US are vanos cars.

[Tiger]

I agree with Winifred.

1. Door handle linkage inside the car is not hooked up.


I also agree with Shogun on the Peake Diagnostic scanner... along with Bentley Repair manual foe E34... tells you how to fix just about everything.

[Ali]

Guys,

Anyway I can look under the bonnet and find out by any tell-tale signs if it has VANOS or not, also is there a resonable increase in bhp with VANOS for the 2.5 M50, also things I have done so far
1) For the backfire put in 2 bottles of Lubri-Moly fuel system cleaner (the only fuel additive recommended by Mercedes).
2) Changed plugs from NGK to Bosch Super,old plugs had a bit of oil on the threads.
3) Also changed air filter and bought a fuel filter although I don't think I will be able to do this myself have to get this done at a service station.
4) Workshop guy says the backfire could be related to the exhaust system and something just blocking the flow could this be a cat, even though catalaytic convertors were not common in these parts and emission control is never taken seriously here.
5) One more thing this was an ex-police patrol car I've seen a pic of a similar one on this site (white n red)

I feel no difference in the car with the change of plugs n filters, what else.

Ali

[Jon K]

Guys,

Anyway I can look under the bonnet and find out by any tell-tale signs if it has VANOS or not, also is there a resonable increase in bhp with VANOS for the 2.5 M50, also things I have done so far
1) For the backfire put in 2 bottles of Lubri-Moly fuel system cleaner (the only fuel additive recommended by Mercedes).
2) Changed plugs from NGK to Bosch Super,old plugs had a bit of oil on the threads.
3) Also changed air filter and bought a fuel filter although I don't think I will be able to do this myself have to get this done at a service station.
4) Workshop guy says the backfire could be related to the exhaust system and something just blocking the flow could this be a cat, even though catalaytic convertors were not common in these parts and emission control is never taken seriously here.
5) One more thing this was an ex-police patrol car I've seen a pic of a similar one on this site (white n red)

I feel no difference in the car with the change of plugs n filters, what else.

Ali

There is a buldge on the crank case if you have VANOS. There is no bhp gain since non-vanos cars had different cams that compensating for variable timing. If you had oil on your plug threads, check your valve cover gasket. the fuel filter you CAN do by yourself. Remove your rear passenger wheel (obviously put the car on jack/stand) and you will see the fuel filter canister right there. Crimp the fuel lines shut and replace. The backfire could be anything from bad timing to bad injection to exhaust pressure etc. It's unlikely your car has a catalytic. When you replaced your plugs you saw the coil packs you took off. See if a local shop can confirm they're good. Check the Peake tool for any misfires.