Does ANYONE know? 7-series engine issues.

[codename07]

I bought a 1995 BMW 740i about a month ago. I updated the headlights, tail-lights, side markers, emblems, and I'm planning on tinting the driver and passenger side windows. (the rear windows are already tinted) Anyway, the car has a rough idle until the engine is warm. I heard this is a common problem, but I want to know whether there is anything I can do to fix it without changing the engine block. I changed the air filter, spark plugs, and oil. Still the same issue. There is an air sensor on my air filter that i heard could be faulty causing this problem. Does anyone know what I could do? The engine runs great, but on a cold start, it will hit 1000rpm when i start it, then fall right away to 500rpm. I have to run it to 1000rpm again to keep it from dying. Once the engine is warm, it runs great and idles at 800 or even 500rpm smoothly. I read in the car's manual that you shouldn' t warm up the car just sitting there. I understood this to mean that I should take off as soon as the car is started, even on a cold engine. Is this correct? (I keep the car under 2000rpm of course till the engine has warmed up) Please let me know if there are any fixes for this rough start. Any advise?

Stefano

 

[Orh LuLu]

Re: Does ANYONE know? 7-series engine issues.

. I read in the car's manual that you shouldn' t warm up the car just sitting there. I understood this to mean that I should take off as soon as the car is started, even on a cold engine. Is this correct? (I keep the car under 2000rpm of course till the engine has warmed up) Please let me know if there are any fixes for this rough start. Any advise?

Stefano

Thats what i understand too from Manual... Logically it will be faster to warm up the car on the move than just leaving it there with engine on. Every morning i just start my engine and move on immediately. I find it perfectly alright. Maybe mine is a 2.5 yrs old 7 so might not experience what you experience on an older version.

Pop by bmw.sg monthly meetup at kallang.. Very few 740s ard here. Cheers!

 

[diablo_728]

Re: Does ANYONE know? 7-series engine issues.

er bro i think he is not from sg and his 740 is e38.

 

[B_73_M]

Re: Does ANYONE know? 7-series engine issues.

Try checking your idle control valve.

 

[codename07]

Re: Does ANYONE know? 7-series engine issues.

Yeah DIABLO_728 I am not from Singapore, I'm in America, west coast almost. And yes my 740i is an e38.

And B_73_M, I am not sure I know exactly what the idle control valve is, but I will look it up in the manual or get it checked out at a shop. Is it computerized? (the idle control), and is it located near the throttle cable and all that? Anyway, thanks for the tip.

 

[B_73_M]

Re: Does ANYONE know? 7-series engine issues.

Hi,

Try searching thru this site where is it located based on your bmw model and yr made... RealOEM.com Online BMW Parts Catalog

Yeah DIABLO_728 I am not from Singapore, I'm in America, west coast almost. And yes my 740i is an e38.

And B_73_M, I am not sure I know exactly what the idle control valve is, but I will look it up in the manual or get it checked out at a shop. Is it computerized? (the idle control), and is it located near the throttle cable and all that? Anyway, thanks for the tip.

 

[codename07]

Re: Does ANYONE know? 7-series engine issues.

Thanks B_73_M, the link was very helpful. I will be looking around on the site for a while. Looks very informative and helpful. Thanks.

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

I'm currently facing the same problem with my 1995 E34 530i V8, my workshop did a check and told me that my Air Flow Sensor is faulty. I'm going to buy the parts and have it replaced, will let you know if that will solve the problem.

 

[codename07]

Re: Does ANYONE know? 7-series engine issues.

I'm currently facing the same problem with my 1995 E34 530i V8, my workshop did a check and told me that my Air Flow Sensor is faulty. I'm going to buy the parts and have it replaced, will let you know if that will solve the problem.

Yes, a mechanic friend of mine mentioned the Air Flow Sensor as well, but I did not believe it was that simple. However, I was probably wrong. Please let me know the outcome of your problem is, I would REALLY appreciate it.

Thanks,

Codename07

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

Yes, a mechanic friend of mine mentioned the Air Flow Sensor as well, but I did not believe it was that simple. However, I was probably wrong. Please let me know the outcome of your problem is, I would REALLY appreciate it.

Thanks,

Codename07

I'm still in Indonesia and will only have time to go back to Singapore to buy the Air Flow Sensor sometimes next week.
Will keep you posted on the result after replacing the parts.

 

[codename07]

Re: Does ANYONE know? 7-series engine issues.

I'm still in Indonesia and will only have time to go back to Singapore to buy the Air Flow Sensor sometimes next week.
Will keep you posted on the result after replacing the parts.

ok, i will wait, no problem. Thanks for keeping me posted!

codename07

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

Sorry for the wait, I finally got the Air Sensor replaced, and yes it solved the problem, my V8 is again running smooth like silk...

 

[codename07]

Re: Does ANYONE know? 7-series engine issues.

Sorry for the wait, I finally got the Air Sensor replaced, and yes it solved the problem, my V8 is again running smooth like silk...

Oh GOD, thank you! It seriously put my heart to rest. I was worried that I had a major issue on my hands. One last thing though, how much did it cost to get fixed altogether? (in dollars)? Thanks for all the help, I appreciate it alot. And one more question.... do you have to have a certified BMW shop do the work, or can you have a typical mechanic do it? Thanks,

Codename07

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

I always got my parts from Eng Soon Singapore (big thanks to this forum for the info), the Air Sensor comes with a housing unit. But end up the housing doesn't fit wit the connecting pipe to the air filter, so the mechanic only replaced the actual air sensor itself, without changing the housing. It cost me SGD340.

I'm based in Batam Indonesia, and there's no BMW agent or certified workshop here. But this workshop I went to is very experience with both Merc and BMW, I just bought my parts from Singapore and they do the replacement. With my car I see that it's actually a very simple job, just removed the old/faulty one and replaced with the new one.
But I won't say that any typical mechanic could do a good job, it's always best to get those with experience to fix your BMW.

I hope that with that, you can also solve your problem...

 

[codename07]

Re: Does ANYONE know? 7-series engine issues.

I always got my parts from Eng Soon Singapore (big thanks to this forum for the info), the Air Sensor comes with a housing unit. But end up the housing doesn't fit wit the connecting pipe to the air filter, so the mechanic only replaced the actual air sensor itself, without changing the housing. It cost me SGD340.

I'm based in Batam Indonesia, and there's no BMW agent or certified workshop here. But this workshop I went to is very experience with both Merc and BMW, I just bought my parts from Singapore and they do the replacement. With my car I see that it's actually a very simple job, just removed the old/faulty one and replaced with the new one.
But I won't say that any typical mechanic could do a good job, it's always best to get those with experience to fix your BMW.

I hope that with that, you can also solve your problem...

Oh, ok, I will have an experienced BMW mechanic do the work. Good idea. I tried to calculate the cost in American dollars, and it should be about $223 or I can't do math. I have a couple of connections for parts so I might be able to get the parts for a good price. I will try and get it fixed soon, but I am pretty busy lately. When I get it fixed, I will probably post whether it all worked or not. That way I dont leave this forum hanging. LOL. Anyway, you've been very helpful, and I appreciate it very much. Thank You,

Codename07

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

Yes, do let us know when the problem is fixed...

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

Oh, ok, I will have an experienced BMW mechanic do the work. Good idea. I tried to calculate the cost in American dollars, and it should be about $223 or I can't do math. I have a couple of connections for parts so I might be able to get the parts for a good price. I will try and get it fixed soon, but I am pretty busy lately. When I get it fixed, I will probably post whether it all worked or not. That way I dont leave this forum hanging. LOL. Anyway, you've been very helpful, and I appreciate it very much. Thank You,

Codename07

Hi, I've forgotten to mention 1 important point, your workshop should have this electronic checking device (sorry don't know actual name), where they plug into a socket near the engine compartment, and it will shows what's the fault. With mine, it show's that the Air sensor is faulty, that's why I got it replaced and problem solved.
Think it's better to have a proper check before spending that few hundred bucks and problem still not solved?

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

Here are more reasons why you should have your car checked before buying the (wrong) parts...
I got the below from the E34 website, just thinking that it may be useful to you in solving your problem?



A major problem with the Bmw E34 especially the M30 3.5l out of the 535i: erratic idle.
Don't expect your M30 to idle like a new car, but here is some tips to improve it:
Check list from the less expensive to the more. Start by pouring some injector cleaner in at least two tanks of fuel.

pardon me?pardon me?r intake leak:
A leak in the intake or vacuum leaks (check the dipsick o-ring seal and oil filter seal) will make your car idle roughly.

Valve setting:
If you didn't adjust your valve lately, check your valve adjustments.

Spark plugs:
Old spark plugs will make your car idle and run rough. Change them, good time to try those expensive Bosch platinum +4. Some owner use a slightly greater clearance: set them slightly larger to 0.86-0.91mm (0.034-0.036in) to help improve the idle with the stock plugs.

Distributor cap and rotor:
After a lot of miles (or km) your rotor and cap will be sad looking or cracked, check for yourself.

Ignition wires:
Check the ignition wire resistance with a multi-meter, it should be around 0 Ohm.

Idle Control Valve (ICV):
This expensive part gets dirty. You should clean it (along with the throttle body) each time you adjust your valves with carburator cleaner. If there is no improvement and your ICV had never been changed (there is sometimes a year stamped onto the casting), change it.

Other considerations are: leaking injector, faulty temperature sensor, faulty oxygen sensor, check all electrical connections

 

[codename07]

Re: Does ANYONE know? 7-series engine issues.

Hi, I've forgotten to mention 1 important point, your workshop should have this electronic checking device (sorry don't know actual name), where they plug into a socket near the engine compartment, and it will shows what's the fault. With mine, it show's that the Air sensor is faulty, that's why I got it replaced and problem solved.
Think it's better to have a proper check before spending that few hundred bucks and problem still not solved?

Ah yes, their little diagnostic tool/computer thing. Ok, I will have them do that. And yeah, i was planning to take it to a shop and have them make sure there wasnt anything else wrong. And bu the way, thanks for the additional tips, I might use a couple of them later. Ok you will be hearing from me when and if I get the issue resolved.

Codename07

 

[Batam Man]

Re: Does ANYONE know? 7-series engine issues.

Yes, do let us know the result, maybe we can learn something from your experience if/when we encountered similar problem (touch wood..)