some questions on e34 engine

[thomask]

Dear all si fus...At last, I have my first bmw last saturday. It's a manual e34 24v 520i 1991 model. I have driven it for a few days now and I'm not sure of a few things. I'm not really good in engine technically and would like to seek for advice from the experts here... 1. I notice that at 5th gear, the rpm shows 3000 when at the speed of 100km/h. Is this normal cos even my friend's perdana doesn't go so high?2. There is a very loud "wuong wuong wuong" noice which I tought coming from the engine. But today I ask my friend to carefully listen to it, the sound was from behind. The faster I go, the lounder it is and It's really annoying. What could be the problem? exhaust? wheel bearing? gear box? With this sound, I couldn't really enjoy the listening to music. 3. The car performance some times smooth, some times a bit jerky. Is this normal? 4. The digital display on the milelage display cannot be seen already. Can this be repaired or I have to replace the whole odometer?I really appreciate some advice here before I go to the mechanic which sometimes am not sure whether to trust them or not... :dunno:

 

[Lionel_Koh]

Congrats for getting ur 1st E34......91 model shuld be M50 engine and it's a one of the best engine for bimmer series....

1.rpm 3000 at 5th gear for 100km/h is normal....in fact mine m20 engine is around 3500rpm.....

2.Pls check ur tyre....my experience was the tyre...how old the tyre?

3. Pls send ur car for dynos....for ur case ...i suspect is the spark plug....

4. I think it can be repair...hv to change a new one..try at the chop shop..

Again, this is my opinion only...do send ur car at workshop for checking....in fact....it's better to service ur car once u get ur car......Enjoy ur drive n do join us for TT

 

[jeffreyewe]

First of all, Welcome, welcome...

hmm..let me try and answer your questions...


1) Normal

2) "Woung woung woung"
i) Check tyre pressure
ii) Check wheel bearings
iii) Check rear differential bearings.

3) Probably needs some minor tune-up. AFM,CO, throttle body and throttle positioning switch need to be readjusted.

4) SI board kaput.


Hope this helps,


my 2 rupiah

 

[wolverine]

Hi thomask,

1. At 5th gear,rpm 3000,on an even straight road, u should be doing 110kmh.

2. Check ur tyres 4 uneven wear, wheel bearings, and ur differential.How's
the diferential oil condition?

3. When is it smooth and when is it jerky?Be a bit more specific...

4. Like jeffreyewe said, ur SI board kaput...get it fr chopshops.

Hv fun n Good Luck,

Regards B)

 

[thomask]

Dear all,

Really thanks for your input and advice. I think I should really send in for a workshop to repair. But I have a BIGGER problem now...my car won't start this morning...sigh...and worse thing is...i don't know any mechanic now and have to rely on a mechanic introduced by the used car dealer which..am not sure to trust him or not...

mafia offered to help...I think I'll give him a call later....thanks mafia...

 

[thomask]

ohh....by the way, the workshop name is something like "BM mall" in cheras and the mechanic is called Ah wai. Anyone know whether this workshop can be trusted?....Thanks a lot...

 

[ALBundy]

For the odometer, have to replace it. Anyway Ah wai should be able to resolve most of the issues.

 

[WhiteTip]

Hi Ah Wai is call BM World. I tried. Not too bad.. But please remember to nego on pricing...

BTW, he is driving a gold color E34 as well.. Feel free to talk to him

 

[525iBoy]

Hi Thomask

you are in good hands with Ah Wai. I may two friend all use him and feel his prices are OK, quality of work good, turnaround fast and best of all he can repair e34's blindfolder. 24v .20 is a more complex engine at 12v so diagnosis a bit more difficult but Wai should be OK

Your 300O rpm at 100kms. Wolverine is right. it shoudl be 110kms at 3000 rpm. I know bec I recalibrated my speedometer. at now ifeel its acc _+3%. if you feel it should be higher then your speedo may be inaccurate. btw 3K rpm at 100km is quite average. No use comparing our cars to the perdana. It's a totally different beast!!. ie. better!!!. the Perdana & most jap engine is geared more for high rpms and with a very different power delivery curve and gearing compared to UDMs. (they usually use a different stroke/bore ratio giving higher rpms but lower torque)

Your m50 UDM with torque curve peaking around 4500+ rpm are geared for optimum power deliver at the 160+kmph range where most people from the "Fatherland!!" drive. Perdanas & most Jap 2 ltr designs are often geared lower in 5th for better fuel economy but geared too low for optimal power delivery at highter speeds. ie. when car feels non reponsive at higher speeds bec. it is not in the "power band" . This is bec speeds are lower - much lower in Japan so the cars are designed more for those conditon.

large drone from rear. Its 99% a wheel bearing or a tire. If it gets louder and louder and really drones. I would say that 90% it's a wheel bearing. best replace both at the same time, aswhen on fails the other fails in a few months. cheap to replace if the bearing so don't worry.

if car is jerky, it is either ignition or fuell . usually ignition. check your plugs (correct ones? good condition? gapped correctly) and coils (I thik you car has 6!!) if coils fail!! ouch 250 -300 each!! - this is why I drive a 12 v! if not these then it you AFM or worse of all DME board. not to worry those these v. rarely fail.

enjoy...

 

[thomask]

Hi 525iBoy,

Thanks for the explanation. Now I understand and feel comfortable with the higher rpm. I guess I shouldn't compare UDM with perdana than...hehe..sorry sorry...

With you and whitetip recommendation, I think I'm more convinced to go to Ah Wai now. Will plan for a day to toll my car there...many many thanks...

 

[flash]

Sorry to hear that you are facing some problems with your newly acquired E34. But take heart, spend some moolahs on your babe and you won't regret it. You can't go wrong with Ah Wai. In fact, I could be sending my car there next month to flush my gearbox.

 

[thomask]

Thanks flash...I do really hope I won't regret buying this dream car of mine....Anyway, will only be sending in to the workshop this Friday. Poor car...sleeping at home for 2 days....

 

[erica34]

hi thomask... congrats on your purchase... good choice... e34 the best!... hehe... spend the necessary the soonest to get the car into good shape and you'll surely enjoy the drive...

 

[flash]

Originally posted by thomask@Jun 28 2005, 06:33 PM
Thanks flash...I do really hope I won't regret buying this dream car of mine....Anyway, will only be sending in to the workshop this Friday. Poor car...sleeping at home for 2 days....

Well, when I got my E34, I have planned to perform a revamp of most of the wear and tear parts. Completed about 75% and have a bit more to go. After that, upgrade part.

Did a test on my Newbie yesterday. At 3k rpm, my speed was around 137kmh. At 2.4k rpm, my speed was 110kmh. At around 160 - 180kmh, I should be bang on the rpm where my engine would be giving its highest torque figure.

By the way, I have a 5 speed ZF auto gearbox.

 

[Lionel_Koh]

Originally posted by flash@Jun 28 2005, 06:57 PM
Did a test on my Newbie yesterday. At 3k rpm, my speed was around 137kmh. At 2.4k rpm, my speed was 110kmh.

By the way, I have a 5 speed ZF auto gearbox.

Sure or not...so much difft btw auto and manual 137km/h at 3000rpm...Sure ur FC is fanstatic at the highway

 

[flash]

Originally posted by Lionel_Koh+Jun 29 2005, 10:19 AM-->QUOTE (Lionel_Koh @ Jun 29 2005, 10:19 AM)

 

[E34EuroTouring]

Hi Flash,

Do you know what model tranny you have ?. I think your 520i diff is 4.45 ratio. I would be very surprised if it were 4.10 or 3.93.

My 525i euro manual has S5D 310Z Getrag tranny (same as US E36M3 S30 engine) and a 4.10 open diff. My car does 100Kmph at 3K rpm in 5th gear. I computed that this makes its stop speed of 200Kph only if the aero-dynamics is not limiting. It does sound strange. But cruising at 100kph in the higway on 5th, I just put my foot down (no downshift) and car goes to 140Kph pretty quick!.

For a station-wagon , I supposed BMW designed it this way. My tires retain stock diameter with 235/45/17, so speedo is +/- 10kph accurate. Need a Vbox to determine actual speed though.

 

[flash]

Originally posted by E34EuroTouring@Jun 29 2005, 05:22 PM
Hi Flash,

Do you know what model tranny you have ?. I think your 520i diff is 4.45 ratio. I would be very surprised if it were 4.10 or 3.93.

My 525i euro manual has S5D 310Z Getrag tranny (same as US E36M3 S30 engine) and a 4.10 open diff. My car does 100Kmph at 3K rpm in 5th gear. I computed that this makes its stop speed of 200Kph only if the aero-dynamics is not limiting. It does sound strange. But cruising at 100kph in the higway on 5th, I just put my foot down (no downshift) and car goes to 140Kph pretty quick!.

For a station-wagon , I supposed BMW designed it this way. My tires retain stock diameter with 235/45/17, so speedo is +/- 10kph accurate. Need a Vbox to determine actual speed though.

Maybe someone can do the maths... I have the 5 speed ZF auto gearbox (A5S 310Z or also known as 5HP18). Not sure what ratio my rear diff has though. :dunno:

My take off from standstill is weak but when I get moving above 90kmh, the acceleration is pretty good.

 

[thomask]

Hi all,

Will be going to Ah Wai place tomorrow. I heard there is a workshop in USJ called M Speed in USJ which is good. Would like to find out from si fus here which one is better with a reasonable price. Does any one know a workshop called MS Motor in Sg. Besi? Are they good? I heard they also sell spare parts?...Many many thanks...

 

[flash]

Originally posted by thomask@Jun 30 2005, 12:07 PM
Hi all,

Will be going to Ah Wai place tomorrow. I heard there is a workshop in USJ called M Speed in USJ which is good. Would like to find out from si fus here which one is better with a reasonable price. Does any one know a workshop called MS Motor in Sg. Besi? Are they good? I heard they also sell spare parts?...Many many thanks...

Personally, I find each workshop have their strong points. For a particular problem with my E34, I go the workshop that I know is better to deal with that problem. I try not to stick to any particular workshop as in the past. :cry: