New Guy Needs Help

[bird]

Hi-I have just inherited a 1984 911,it runs fine but has a few issues,I've attempted to search these out in the forum archives before posting but didn't have a lot of luck navigating it...anyways the car's speedo is inop,the tach is very irratic,the a/c compressor will not kick on and the blower motor will not work.I did find a post that suggested that an external voltage regulator with sticking contacts could be going out causing multiple electrical problems.I have 14-15volts at idle and at 3000 rpm it jumps up to 16.5 volts-its this normal or out of range??I've checked all fuses and they are good and checked for fire at the compressor and have nothing,but without a manual I'm not sure which fuse controls what or where the a/c relay to check it.Also the car is all original except for the stereo/amp and a car alarm.Any help would be muchly appreciated-THANKS!

[ivangene]

irratic tack and dead speedo - voltage regulator or dead battery cell

GUESSES

16.5 is high - sorry I typed above before reading your whole popst
get a manual - Bentley.....worth every penny!!

[rusnak]

I agree with Ed. A 911 Carrera Service Manual from Bentley Publishing will be a great help.

It's common for the AC switch to go out. It's the right hand of the two in the center console. I would check there next. It certainly sounds as if the VR is bad.

[DRACO A5OG]

Welcome Brother.

OK, let's try the easy stuff first:

Disconnect the Battery and then pull the gauges from the dash, they pull right out, but not too far. Pull the clock out then use the clock hole to push out the Speedo then Tach.

Check the connections, label each and pull them and check for looseness & corrosion. This is an opportune time time squeeze the connectors for a tight fit. Prior to re-attaching them use a dremel with polish bit and polish the male connectors coming off the gauges. Paying attention to the Ground Connections ( brown wire, normally )

More Difficult but Doable:

Now, if both Tach and Speedo are erratic, that could mean your reference and speed sensors may by on their way out. I wished mine did that when they went out but nope usually it is very sudden wit no warning.

If you have not buy the Bentely Manual to get the OHM's reading specs.

Open your engine lid, remove the Heater Tube and right behind it you will see the connector assembly for the CHTS (#3 cylinder head temp sensor, REF & Speed Sensors. Check the OHM's.

If they do not obtain proper readings then it will be time to replace those. Do a search, may threads on replacing them using OEM or BMW cheaper parts ( yes, BMW Cheaper ). WYIT ( while your in there ) If you have the single wire CHTS, I urge you two upgarde to the Dual wire component, That is the White Connector on top of the assembly.

Hope this starts you in the right direction!

Jim

+1 on what the two Gentlemen stated in front of me, check the VR 1st!

[ivangene]

OH and while we are on the subject...DONT DRIVE IT at 16+ volts or you will be buying a new battery too! (or worse)

IIRC pre 84' is a simpler (ie less expensive) alternator...but has an external regulator (also cheap) unlike the post 84's with built in and hella spendy alernators!!!

best of luck - rememeber its a hobby mean no deadlines....

[dicklague]

you should have 13.5 to 14 volts when running. If you have 16 don't drive it and don't do anything until you find out why you have 16 volts.

[Techne]

And I bet if we had a few pictures and a proper introduction this will be a lot easier to fix

Forum protocol, and all......

[RWebb]

to do the easy stuff first, remove the battery and take it to Sears or to a parts store & have them test it

don't worry about removing the gauges yet

also, figure out how far away the nearest place that can fully test your alternator & voltage regulator is

[DRACO A5OG]

If you have AAA, they will come to you and check your entire system and give you a print out.

I would get AA anyways to flat bed her, never ever allow a standard tow of your baby.

[bird]

thanks guys for all the input,its been really helpful

I forgot to mention before that the sticker in the lh door jam has a date of October 1983,I'm not sure if this would mean 1983 or 1984,wouldn't depending on that year determine weather its an external or internal voltage regulator?If its external where would it be located?If its internal I assume I would just replace the whole alternator assy?

I also checked the a/c switch on the rh side of the console,it has 6 wires plugged into the back of the switch,with the key on none of them were hot...I'm assuming it needs a hot wire to power it so which fuse or relay feeds power to this switch so I can go there.

Thanks again for you help!

[Barrpete]

Originally Posted by bird

thanks guys for all the input,its been really helpful

I also checked the a/c switch on the rh side of the console,it has 6 wires plugged into the back of the switch,with the key on none of them were hot...I'm assuming it needs a hot wire to power it so which fuse or relay feeds power to this switch so I can go there.

Thanks again for you help!

Before you start tearing into the switches, check the fuse on the fuse panel in the luggage compartment (assuming you haven't already), the AC relay on the same panel and check the relay in the smugglers box. Assuming that 84 is the same as 86.

If all of those check out OK, check to see if the temp switch is working. That's the one on the LH side. Just bypass the switch by connecting the 2 wires - should be green & green w/white stripe. Be careful not to damage the white capillary tube coming out the switch. It looks like a white wire but it's not. If you damage it you'll need to replace the entire switch.

[bird]

thanks barrpete....you were right,I had visually inspected fuses,but when I put my test light on the blower mtr fuse it was no good,I replaced it,now I have a blower motor that responds to the switch high- low commands,but its very very weak,I can barely hear it running with ign key on and engine off,when I put my hand on it I can barely feel it vibrating,but it defiantly speeds up and down as I move the fan switch selections

I did as you suggested and unplugged the temp control switch and jumped the 2 wires behind and that fixed my other problem-no power at the a/c compressor.Now that I have a hot wire at the compressor I would expect it to engage the clutch...but its not,so I assume the clutch is bad??

To sum it up ... to get this a/c system going I'm thinking I'm going to need a blower motor assy,a temp switch assy, and an a/c clutch and or compressor assy ??

To address the other concern mentioned earlier...Ive determined this is an '84,and have not located an external regulator,so to repair the overcharging concern,I'll take the alternator out and replace the VR and/or the alternator assy

Man....this is starting to sound expensive!

[darrin]

speaking of expensive, overcharging the battery can cause it to boil sulphuric acid into the area below/around the battery. Sulphuric acid causes/accelerates rust.

Speaking from experience, I'd a) refrain from driving/starting the car until you determine why the battery's being overcharged (i.e. replace the voltage regulator), and b) pull the battery and, if there's evidence that the battery has leaked, thoroughly clean the area below/around the battery with an appropriate acid neutralizing solution.

In my case, the overcharging battery fried my tach, requiring repair at North Hollywood Speedometer.

[schumicat]

when people refer to year of a car it is always referring to model year. you are looking at the build date. car built in Oct. 1983 would be a 1984 model year. with rare exceptions (such as the 1995 US model BMW M3, which was built until Nov. or Dec. 1995), around july/aug. is when car makers switch to making next year's model.

Originally Posted by bird

thanks guys for all the input,its been really helpful

I forgot to mention before that the sticker in the lh door jam has a date of October 1983,I'm not sure if this would mean 1983 or 1984,wouldn't depending on that year determine weather its an external or internal voltage regulator?If its external where would it be located?If its internal I assume I would just replace the whole alternator assy?

I also checked the a/c switch on the rh side of the console,it has 6 wires plugged into the back of the switch,with the key on none of them were hot...I'm assuming it needs a hot wire to power it so which fuse or relay feeds power to this switch so I can go there.

Thanks again for you help!

[Barrpete]

Originally Posted by bird

Now that I have a hot wire at the compressor I would expect it to engage the clutch...but its not,so I assume the clutch is bad??

To sum it up ... to get this a/c system going I'm thinking I'm going to need a blower motor assy,a temp switch assy, and an a/c clutch and or compressor assy ??

Man....this is starting to sound expensive!

Before buying another temp switch you may be able to R&R the one you have. While replacements are available, they aren't the same size so you have to modify the housing to make it fit. The switch works via a set of contacts inside that are open/closed by a bellows at the end of the capillary tube, the other end of which is inserted in the evaporator. As the evaporator gets colder the gas in the capillary contracts which contracts the bellows inside the switch and opens the contacts. Over time those contacts get dirty and and switch stops working. You can open up the housing and clean the contacts and your back in business. Of course if the capillary tube is kinked or broken then you'll need a new switch after all.

AC can be a very slippery slope indeed. Before diving in and replacing components piecemeal I recommend searching to see what others have done. As long as your going to tear into the evaporator anyway maybe now is the time for some upgrades. There are more efficient blowers and evaporates available and so it starts.

Here's a thread to get you started:

Ultimate AC Thread

And some websites;

RennAire Porsche 911 Air Conditioning Products, Porsche Air Conditioning, Porsche compressor, Porsche condenser, Porshe condensers, Porsche drier, Porsche driers, Porsche evaporaotr, Porsche evaporators,Porshe barrier hoses, Porsche air conditioning upgrades, Porsche air conditioning updates, Pors

Oh, and for your VR replacement:

Pelican Technical Article: 911 Alternator & Voltage Regulator Removal/Replacement

Good luck!