E23 732i - cold start issue
Discussion
I recently purchased an e23 from BMW nut e21mark (take a look at his projects!)
The car was running well and I drove it from London to Scotland, and it's now very grouchy when it comes to start - it needs around 1 minute of increased revs to ensure it doesn't stall - it's fine after that.
Any ideas what the issue is? I also need to make the speedo and rev counter work.... ! I want to use the car as a daily driver while my merc is off the road, collect clients etc - so it needs to start and work every time.
The car was running well and I drove it from London to Scotland, and it's now very grouchy when it comes to start - it needs around 1 minute of increased revs to ensure it doesn't stall - it's fine after that.
Any ideas what the issue is? I also need to make the speedo and rev counter work.... ! I want to use the car as a daily driver while my merc is off the road, collect clients etc - so it needs to start and work every time.
That's a fairly basic injection system, it has a cold start injector controlled by a temperature time switch in the thermostat housing and an auxiliary air valve to increase the idle speed.
The first thing is to ensure that ALL basic settings are correct, eg. valve clearances ( not too tight) spark plugs, and throttle switch and mixture settings.
It sounds as though the air valve is stuck shut, follow the air pipes from the manifold/throttle to find the valve and remove it, look into the valve, there should be a gap visible, there is a slide inside that is controlled by a bi-metal strip, it opens when cold and close when it is hot, the bi-metal strip is heated with 12v so will close if the ignition is left turned on. the valve have been known to stick. They can be adjusted (unofficially). On the side of the valve is a small nut, loosen it and turn the valve to open the gap, power up the valve and see if the slide moves to the closed position, if not you will need a new one, however, if there was no visible gap and you "adjust" it, at least you should have an increased idle speed when the engine starts, perhaps this will help.
The first thing is to ensure that ALL basic settings are correct, eg. valve clearances ( not too tight) spark plugs, and throttle switch and mixture settings.
It sounds as though the air valve is stuck shut, follow the air pipes from the manifold/throttle to find the valve and remove it, look into the valve, there should be a gap visible, there is a slide inside that is controlled by a bi-metal strip, it opens when cold and close when it is hot, the bi-metal strip is heated with 12v so will close if the ignition is left turned on. the valve have been known to stick. They can be adjusted (unofficially). On the side of the valve is a small nut, loosen it and turn the valve to open the gap, power up the valve and see if the slide moves to the closed position, if not you will need a new one, however, if there was no visible gap and you "adjust" it, at least you should have an increased idle speed when the engine starts, perhaps this will help.
Fantastic, many thanks for the useful post. I have a lot to learn about older vehicles, I shall try and head down to the garage tomorrow armed with this useful information. The car had been stood for 10 years up until a few months ago, and while it has now been recommissioned further work on making it run optimally is clearly necessary.
It did get me back from London to Edinburgh though and was very comfortable, now the discs and pads, power steering fluid, auto fluid have been changed it's driving very well indeed.
My mechanic does have a chap who is well versed in setting up older BMW engines such as this one so I may make use of him.
It did get me back from London to Edinburgh though and was very comfortable, now the discs and pads, power steering fluid, auto fluid have been changed it's driving very well indeed.
My mechanic does have a chap who is well versed in setting up older BMW engines such as this one so I may make use of him.
Cooperman said:
They are superb cars and that one looks great for its age.
Thanks - I was very lucky that Mark has so many projects on he was able to let one go. The car has less rust than my 1991 merc w124 (just starting to go on the arches) - it's a real time warp on the outside. I used to walk by a 728 e23 in silver ever day on the way to school (!) and have always loved the shape. Of course the 10 years that preserved the bodywork also mean the old girl needs waking from her sleep in other ways!
Stopping at 1am on the way home:
Shamelessly stolen from Mark!
And the internet!
steve6304 said:
That's a fairly basic injection system, it has a cold start injector controlled by a temperature time switch in the thermostat housing and an auxiliary air valve to increase the idle speed.
The first thing is to ensure that ALL basic settings are correct, eg. valve clearances ( not too tight) spark plugs, and throttle switch and mixture settings.
It sounds as though the air valve is stuck shut, follow the air pipes from the manifold/throttle to find the valve and remove it, look into the valve, there should be a gap visible, there is a slide inside that is controlled by a bi-metal strip, it opens when cold and close when it is hot, the bi-metal strip is heated with 12v so will close if the ignition is left turned on. the valve have been known to stick. They can be adjusted (unofficially). On the side of the valve is a small nut, loosen it and turn the valve to open the gap, power up the valve and see if the slide moves to the closed position, if not you will need a new one, however, if there was no visible gap and you "adjust" it, at least you should have an increased idle speed when the engine starts, perhaps this will help.
Steve, I went to discuss with my mechanic this morning and he'd just replaced the temperature control switch and the car is far better - from cold, it needs around 10 seconds of extra throttle to ensure it runs properly. So it sounds like this was an issue, and that there are further issues with the air valve as you describe - the car overheated in traffic today, so I assume this is related. Anyway, I did a good long trip in it and it was very comfortable, so will look into this further when I get back. The first thing is to ensure that ALL basic settings are correct, eg. valve clearances ( not too tight) spark plugs, and throttle switch and mixture settings.
It sounds as though the air valve is stuck shut, follow the air pipes from the manifold/throttle to find the valve and remove it, look into the valve, there should be a gap visible, there is a slide inside that is controlled by a bi-metal strip, it opens when cold and close when it is hot, the bi-metal strip is heated with 12v so will close if the ignition is left turned on. the valve have been known to stick. They can be adjusted (unofficially). On the side of the valve is a small nut, loosen it and turn the valve to open the gap, power up the valve and see if the slide moves to the closed position, if not you will need a new one, however, if there was no visible gap and you "adjust" it, at least you should have an increased idle speed when the engine starts, perhaps this will help.
The chap at the hand car wash asked if I'd just had it resprayed - a good compliment! Here it is cleanish!
I have one of these too which like yours has been off the road for a very long time. Yours is in a better shape than my project.
Mine too runs like a bag of poop but after many hours of searching I came across this. It is a guide for the L-Jetronic Bosch injection. It was used on all manor of cars back in the late 70's and early 80.
Have a look at this guide and it will show you how to go through the entire injection system- ignore the fact that it is for an Alfa as 95% of it is exactly what you have.
http://www.hiperformancestore.com/Ljetronic.htm
Mine too runs like a bag of poop but after many hours of searching I came across this. It is a guide for the L-Jetronic Bosch injection. It was used on all manor of cars back in the late 70's and early 80.
Have a look at this guide and it will show you how to go through the entire injection system- ignore the fact that it is for an Alfa as 95% of it is exactly what you have.
http://www.hiperformancestore.com/Ljetronic.htm
overheating was always an intermittent issues with these models. Make sure that when the engine is at normal temp, thermostat open etc there are no "cold spots" on the radiator particularly in front of the viscous fan. If there are cold spots it would indicate a blockage in the radiator. The viscous fan needs hot air flowing over it to make it cut in
This is my 728i which since the advent of the colder weather needs to be revved for a minute or so or it dies when put in gear (it is an autobox). When it is cold it seems to hunt to keep the revs from dying,I'm guessing this is a feature of the injection cold start mapping.So thanks Steve this info about the valve which is the first place I will look,plugs and filters are all recent so should be ok. I luckily managed to pick up a front exhaust box off ebay for 15 notes delivered which was a relief as the exhaust bits seem a bit thin on the ground!
What fantastic responses to my original post, and some lovely e23s on show. My mechanic replaced the temperature sensor and now the car needs revving for 5-10 seconds from cold rather than 1-2 minutes. It's an auto - I'd love the manual, and I'd love black leather (mine is cloth).
However, I did Edinburgh to Inverness and over to the west coast this weekend, and have definitely bonded with the car (I even did lots of overtakes on the way back!). The car is still too slow, so I need to go through the fuel injection system. My understanding is that the e32 had around 200bhp - mine feels miles slower than my merc w124 that has 180 ish, even when using kickdown or using the lower gears on the auto section. It feels a little hesitant before a weak surge.
Anyway, it was great to get to know the car better this weekend. The ride is fantastic - it's lovely and compliant, but fairly firm when cornering. What an interesting car. A couple of photos from the road trip today
However, I did Edinburgh to Inverness and over to the west coast this weekend, and have definitely bonded with the car (I even did lots of overtakes on the way back!). The car is still too slow, so I need to go through the fuel injection system. My understanding is that the e32 had around 200bhp - mine feels miles slower than my merc w124 that has 180 ish, even when using kickdown or using the lower gears on the auto section. It feels a little hesitant before a weak surge.
Anyway, it was great to get to know the car better this weekend. The ride is fantastic - it's lovely and compliant, but fairly firm when cornering. What an interesting car. A couple of photos from the road trip today
V8 Fettler said:
If this concerns the K-Jetronic auxiliary air valve, contact cleaner aerosol spray can fix the problem, also removing and soaking in meths. I had 3 Granadas with K-Jetronic, they all suffered this problem. The permanent fix was to carry a spare valve in the car, never needed.
Thanks, I'll try this, it seems there's good support for the fuel injection system which is great. 0a said:
Do your cars have leather? How do you find the performance - mine needs tuning - it's really slow at the moment, as I say well below my merc which isn't befitting of a BMW!
I love the red one!
The Alpine white car had black leather, the red one had the original cloth.I love the red one!
Performance wise, the red one was a manual and had done 40k from new so it went like stink. Absolutely brilliant to drive!
The white one had the switchable auto but still went well, they should feel fairly quick, I think we spoke before re the 528i I had for sale. As I said I've got a guy through here in glasgow who knows just how to set these cars up perfectly, let me know if you need any help.
Dinoboy said:
The Alpine white car had black leather, the red one had the original cloth.
Performance wise, the red one was a manual and had done 40k from new so it went like stink. Absolutely brilliant to drive!
The white one had the switchable auto but still went well, they should feel fairly quick, I think we spoke before re the 528i I had for sale. As I said I've got a guy through here in glasgow who knows just how to set these cars up perfectly, let me know if you need any help.
Regarding the 528 - on retro rides?! I've got my guys on the case but may get back to you regarding your guy in Glasgow. Did you get the 6 you wanted? 735 manual sounds like great fun! Performance wise, the red one was a manual and had done 40k from new so it went like stink. Absolutely brilliant to drive!
The white one had the switchable auto but still went well, they should feel fairly quick, I think we spoke before re the 528i I had for sale. As I said I've got a guy through here in glasgow who knows just how to set these cars up perfectly, let me know if you need any help.
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