Troubleshooting E30 A/C

There is either one or two pressure switches near the receiver/dryer that sense system charge. If it is too low it won't allow the clutch to engage. Sinc you know the clutch is good electrically, I would suspect you are just low on freon.

I too suspected these switches but I'm not getting any voltage to them either. I know there's a relay under the dash somewhere as I can here mine click on and off but I haven't searched for it yet as it started raining. Any idea where it lives? It seems to control the clutch and the idle increase at the same time.

The idle increase, or lack of it, is a symptom of the malfunction, not a cause. Fix the button so it turns on and I'll bet the engine will respond in kind. I hate to suggest it, but you've looked for a blown fuse, right? The relays are located either under the hood or under the dash. Or Both. You said that you can hear the relay click, so you'll need a helper to press the button for you as you poke around under the dash.

Some time ago I posted a step-by-step troubleshooting proceedure for the 85 e30 A/C, but it looks like I never saved a copy. Basically, you work back from the compressor, which you have already checked. Next, you need to connect +12v on the other side of the high cut-off, then the low cut-off switches. If the compressor still starts through them, then they're not the cause. Next would be the evaporator temp switch (viewable from the driver's side under the dash - it prevents the evap core from freezing up) The input wire color is violet on the '85 325e (and blk/wht going to feed the low temp switch) .

After that, it gets dicey because you'll have to go into the dash. Since you say you're getting click when you turn on the dash controls, my guess is that the compressor relay is working (located in the fuse box.) Hopefully, it may just be a bad connection.

I can't remember any more w/o gooing through the Electrical Troubleshooting manual. There are unloader relays, etc. Good luck.

Nedavno F.Robert Falbo pise:

| Some time ago I posted a step-by-step troubleshooting proceedure for | the 85 e30 A/C, but it looks like I never saved a copy.

This?

Hope link is OK.

There are interlocks to prevent the system 'working' if the charge is low. On a car this age there are almost certainly leaks, so the first thing to do is have a leak test performed and sort these before having it re-charged. However, a usual place is the compressor seals and this might prove expensive to fix.

Yes. Thanks. I never saved a copy and I'm not great on searching for Usenet stuff. Hopefully that will help him.

There is a little confusion here so I'll try to straighten it out. I have two cars, one is working fine the other is not. The clicking under the dash is on the working vehicle.

It was low but it's charged now (by bypassing the rest of the system with 12v to the compressor)

Fuse was the first thing I checked. Will be trying a few other things in the next few days.

To the person who posted the troubleshooting info (and the link to it), I appreciate it. Will archive it for future reference...

Well, believe it or not, the major problem with the system that I can find so far is that the low pressure valve is leaking. I'll be replacing it with a new part shortly. For now, the plastic cap that covered the original R-12 valve is screwed on tightly (I took off the

134a adapter valve). When I c>>> I have an 87 325is that I'm trying to get the A/C functioning in and

Nedavno F.Robert Falbo pise:

I just bought (cheap) a/c set from a wrecked e30. I think I have almost all parts, but I have 1.6 liter carburetted M10 engine, and this is probably from 320i.

Now I have a problem (and this is probably first one, more to come) compressor mount does not fit. I checked ETK and found that I have to find different mount. But looking at the photo, compressor mount for my car has three mount points, and I checked my engine - it looks like it could fit on the drivers side of the engine.

Now my first question. Is a/c compressor on all e30 on the passenger side of the engine?

My second question. How do I raise rpm when a/c is on. On FI engine it is not a problem, but how is it done on a carburetted engine?

Sounds like a lot of work is about to commence...

I'm positive that the compressor mounts would be different from a 6 cylinder car to a 4 cylinder. Don't know if they'd be different between different 4 cylinder engines of the same time frame as I think they pretty much use the same block, except for the M3 engines (S18 I think). Can't guess which side your's mounts too either...

First question, don't know. The second is that when you find the car with the mount you need, there will most likely be a solenoid next to the carburator that pops out slightly to bump up the idle. This part may be a challenge as I haven't seen a BMW with a carb in a long time (and it was dead in the breakers yard).

Nedavno Psycho pise:

| I'm positive that the compressor mounts would be different from a 6 | cylinder car to a 4 cylinder. Don't know if they'd be different | between different 4 cylinder engines of the same time frame as I think | they pretty much use the same block, except for the M3 engines (S18 I | think). Can't guess which side your's mounts too either...

I have 4 cylinder M10 engine, I think that later on M10 was replaced with M40 or something.

| >Now my first question. Is a/c compressor on all e30 on the passenger | >side of the engine?

Anyone from Europe with M10 engine and A/C?

| >My second question. How do I raise rpm when a/c is on. On FI engine | >it is not a problem, but how is it done on a carburetted engine? | | First question, don't know. The second is that when you find the car | with the mount you need, there will most likely be a solenoid next to | the carburator that pops out slightly to bump up the idle. This part | may be a challenge as I haven't seen a BMW with a carb in a long time | (and it was dead in the breakers yard).

I will probably have to custom make compressor mount, as there are few E30 with A/C where I am. As for the rpm control, I checked Haynes manual, and it seems that there is some "idle speed air valve" that is controlled by "idle speed boost valve" fitted to VW HZ engines. "As load is placed upon the engine , and the speed falls below 700 rpm, the air valve admits extra air... and the idle speed is increased".

Now I just have to find one :-)

I have another question now. I have to change vibration damper (the thing at the end of a crankshaft), as I can put only one V-belt on mine, and now I will need two.

Is this easy, can I make some mistakes when changing?

I know this is probably a cardinal sin, but check with your local dealer about the bracket. You might find that they can get you one (NOS) that's laying around somewhere. I learned that lesson with an E30 dashboard. Easier and cheaper than having it refinished...

The damper may be easier to fond than you think. As for the idle issue, look for any older vehicle with a carb and look for a small solenoid with a plunger mounted near the linkage. All it does is bump the linkage a bit and increase the idle. That's how it used to be done before FI. The solenoid is 12v and you tie it in to the 12v source to the compressor, compressor is running, idle goes up a bit.

Nedavno Psycho pise:

Check the prices :-(

I am going to make an adapter plate, so I can use bracket that I have. It looks like simplest solution.

That will be hard to find. As I wrote there are few cars with A/C where I am. But I am going to play with "11 CONTROL BOX" see:

This seems to open throttle plate a little for a cold start. I read somewhere that with vacuum hose disconnected engine revs should be ~1800 rpm. Perhaps I can use some electrically controlled valve that will cut vacuum supply when I turn on A/C. Maybe additional load form A/C compressor will lower rpm to acceptable value?

Nedavno Yvan@office pise:

| That will be hard to find. As I wrote there are few cars with A/C | where I am. But I am going to play with "11 CONTROL BOX" see: | |

I checked, it is called "throttle governor" in Haynes carb manual.

| This seems to open throttle plate a little for a cold start. I read | somewhere that with vacuum hose disconnected engine revs should be | ~1800 rpm. Perhaps I can use some electrically controlled valve that | will cut vacuum supply when I turn on A/C. Maybe additional load form | A/C compressor will lower rpm to acceptable value?