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Repair/service needed for 1986 635csia

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Ronnie Wilson View Drop Down
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    Posted: 28 Feb 2016 at 5:25pm
Hi all,

Just joined the club. Last year I purchased a 1986 635csia. I would like to service the car myself, but need a repair manual. There seems to be no service/repair manual for the 6 series. Someone has suggested that the Baileys E28 manual is the one to go for. Could anyone let me know if this is indeed the best manual for the 6 series.

Thanks everyone, it would be much appreciated.

  
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Lokoktentek View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lokoktentek Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2016 at 9:07pm
It depends what you want to repair. Engine is the same as in E28 535i and E23 7-series. I would say that the E28 is the most similar to yours as E28 was the base to build E24 after 1982...

So what do you want to know?

Edited by Lokoktentek - 29 Feb 2016 at 11:01am
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Ronnie Wilson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ronnie Wilson Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2016 at 9:35pm
Hi, Thanks for getting in touch. Just need a manual that covers as much as possible. Just like an haynes manual. One issue i do have is when the car is started from cold, you need to gentle press the accelerator for around 30 seconds, if not it idles quit rough. rev it and it will always stall when the revs fall.It also smells as though its running a bit rich. When its driven its fine from then on. when looking at the mass air flow meter. at some point the last owner has put some silicone around the potentiometer casing at the bottom of the mass airflow meter. 

 Thinking of getting a new one, but Bmw want £350 + vat. Poor idling seems to be a common problem. But Before I go down that line, the car has not had a full service for sometime.So i think this is the first step.
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Lokoktentek View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lokoktentek Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2016 at 11:02pm
Normally that plastic black cap is on top but in these engines it was turned around ;)
If you temporarly turn your air flow meter to let the engine working and have this black cap on top, youcan take this cap out.
It is normally glued from the factory but this air flow meter can be adjusted and maybe that was done by last owner.
When you take this cap out you will see small triangle shaped piece of metal which turns on two small brown tracks.
If these tracks are broken you can try to bend that metal to force them to run just next to broken line.
You will also se a plastic circle with numbers and teeth and a spring on it. This generally corrects the amount of air which is send to the ecu.
Mark the original position of the spring and try to tighten the sprin about 3 teeth and see how the acceleration will response.
If there is a silicone around it then definitely someone was doing inside. Maybe there is another reason but try to play with this.
Anyway before you buy anything you can try to install different air flow meter borrowed from any M30 motor (big six) and try to se the difference...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ronnie Wilson Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb 2016 at 11:26pm
Thanks for that.
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Mike Fishwick View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike Fishwick Quote  Post ReplyReply Direct Link To This Post Posted: 29 Feb 2016 at 10:52am
You will find that the various manuals tend to regard the injection system as something beyond the readers abiity to understand!

The airflow sensor of the LE-Jetronic etc system does not give a decent reading at the low air flow rates associated with idling, cold mixture strength being controlled more by the coolant temperature sensor.  It therefore follows that the air vane return spring tension will not have any real effect on cold idle mixture.

I would first look for air leaks, from places such as around the injectors - try spraying WD40 on suspect areas, as this will act as a fuel, and cause the engine to speed up a little.

It is a pity that our Club does not have a technical library giving inforamation on systems such as this.
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Lokoktentek View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lokoktentek Quote  Post ReplyReply Direct Link To This Post Posted: 29 Feb 2016 at 11:05am
I am not sure if there was no bosh motronic system in this year of production...
But anyway you are right that on cold engine the ecu gives like default rich mixture until it reach proper temperature...
Maybe this pipe connecting air flow sensor with throttle... Maybe vacuum tubes are broken? If there was no service for years, everything could happen...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike Fishwick Quote  Post ReplyReply Direct Link To This Post Posted: 29 Feb 2016 at 4:24pm
LE Jetronic is not Motronic - LE is an analogue injection system, Motronic is a digital injection/ignition system.

An early Motronic system uses the same vane-type airflow sensor as the LE system, but has a built-in ignition system, rather than a seperate unit.  They respond to similar diagnostic techniques, however.


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Lokoktentek View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lokoktentek Quote  Post ReplyReply Direct Link To This Post Posted: 29 Feb 2016 at 6:41pm
Yes i know what you meant but wiki says that they've changed jetronic to motronic after 1982...
I had E28 525e 1986 and there was motronic 1.3
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike Fishwick Quote  Post ReplyReply Direct Link To This Post Posted: 01 Mar 2016 at 10:37am
Jetronic systems have a seperate igition unit, whereas Motronic has a single integrated unit.  Some later Motronics do not have an airflow sensor, using a calulation based on the throttle sensor output (ie throttle opening angle) and rpm - known as an alpha-n system.

It does not matter whicvh system your car has - the basic diagnostic procedure -  looking for air leaks - is the same.  Too many people get themselves entangled with electronics, and not enough with basic procedure, usually replacing airflow sensors and llamda probes to no effect.  look hard at the rubber hoses and bellows before anything else.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Robert Quote  Post ReplyReply Direct Link To This Post Posted: 03 Mar 2016 at 12:11pm
One other area to check might be the idle control value or L-SHAPE IDLE REGULATING VALVE as they call it. They are really quite easy to check to see if they are working properly. I can't remember exactly but it just involves taking the resistances across the three terminals. A quick search on the net gave http://www.pelicanparts.com/BMW/techarticles/JF-Tech/BMW_E30_3_Series_Idle_speed_troubleshooting.htm.

Yes I know that is for the E30 but the ICV is exactly the same part number for your car as it is for mine.

My experience was a poor idle, garage said all was fine and while driving back from said garage the ICV failed completely and spot welded a chip in the ECU. Nice.
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Ronnie Wilson View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ronnie Wilson Quote  Post ReplyReply Direct Link To This Post Posted: 03 Mar 2016 at 11:22pm
Thanks Robert.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ronnie Wilson Quote  Post ReplyReply Direct Link To This Post Posted: 03 Mar 2016 at 11:24pm
Thanks Mike. I'll do that.
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