1982 Diesel SdV - Glow Plug - and - AC question

[Aaronz28]

Greetings - just picked up a really nice 82 Diesel that i'm having a blast with.

2 issues are coming up =  1) (and I think its just the relay)  the glow plugs are not lighting up  -  i'm not getting 12v from the battery across the relay -  I ordered a new one from the part store - but if that turns out not to be it - what might be preventing the glow plugs from lighting... i can get the car to start with a short burst of ether  - and then it runs like a champ -  - but when cold, the "WAIT" ligt comes on, and simply does not go off and the car will not start without an ether shot.

2) - the ac compressor will not engage - no voltage at the AC com either -  its not seized,  fuse (on the panel) is now blown -  any other ideas?

Thanks

Aaron

[bcroe]

I am looking at an 81 book, do you have your 82 factory service manual yet? 
There may be a second book for electrical stuff. 

What I see, is the WAIT light operates off the GAGES fuse.  But the glow plug
control operates from a DIESEL fuse, check it out.  There should be a diesel
glow plug controller which drives a very large relay, connected by a heavy
lead between the battery and the glow plugs.  When you turn on the ignition,
one terminal of that relay should be at battery, and the other close to ground
(0V).  There are also engine temp sensors, but I would expect the WAIT light
to stay off if they were the problem.  Bruce Roe

[Aaronz28]

Bruce - thanks - 1) i did order a manual but it hasn't arrived yet - (just picked up this C-lac last night)
I ave a 79 Coupe as well, which I have the service manual for - and the Diesel engine portion should be the  same - so i'll look tomorrow.

I don't fully understand how a diesel engine runs compared to a regular gas engine - but i did find the glow plug relay and glow plug controller - it would seem however, that the point of the relay would be to provide 12v to the glow plug when you want the engine to start - no?


when fooling with the relay harness - i heard it click a few times -    and as you might suspect, the car fired right up.... so perhaps the relay was stuck???  won't know until tomorrow when i try starting it again.

thanks - 

any advice on te AC compressor not getting voltage?

[bcroe]

I would definitely NOT assume 79 is the same components as 82, though the
function is about the same.  Basically turn on the glow plugs for 10 seconds,
then start cycling them off and on as the WAIT light is turned off.  When the
engine starts, or is already hot, the glow plugs are off. 

Maybe you have a loose connection keeping it from operating.  Bruce Roe

[TJ Hopland]

I have been more or less daily driving an Olds diesel for the last 5 years now.

First thing, starting fluid is VERY dangerous on diesel engines especially when its used like it is on a gas engine.  If you had any working glow plugs chances are good you would no longer have a working engine.   Starting fluid can work with some diesel engines but there is a very specific way it has to be done and it requires a built in system or 2 people.   The Olds is not an engine that does well with starting fluid.  Starting fluid took as many of those off the road as any other issue they had.   From the factory they all had stickers under the hood saying to never use starting fluid. 

   79 was a different glow system so there is almost no useful info there.   The new system came in 80 I think.   The solenoid is usually pretty reliable.  Weak points are the glow plugs and the controller.   The controller is a stand up sensor right behind the oil fill tube.  The oil cap usually touches the plug on top of it.   I think its a 6 pin connector.  The sensor threads into the intake into the coolant crossover passage.    There were slight variants in the similar systems year to year and even model to model in the same make.    I would have to see if I have an 82 manual to refresh my memory on the details.   There may be an external inhibit switch that would prevent them from running but in that case the wait light won't come on.   The wait light has its own relay and won't come on again after the first time it shuts off unless you turn the key off and try again.  I have been lucky and not had a lot of glow issues with my 5.7's so I will have to get some books out and refresh my memory to give you specific places to start checking.    My recommendation don't keep using starting fluid, manually running the plugs is safer but be careful how long you run them.   Some models of plugs won't take more than about 10 seconds of glow time before the tips swell up which makes them a huge pain to try and change if you are lucky.  If you are not lucky the tips break off and the only way to get them out on this engine is remove the heads.   Some diesels have big holes for the injectors and sometimes you can get lucky and fish the broken tips off through the injector hole but the 5.7's are not that way, the injector hole isn't much bigger than the glow hole both are much smaller than a spark plug hole. 

On your AC question again I would have to pull out a book but there is a electronic relay for the compressor clutch located in the blower control module that is screwed into the top of the AC/heater box under the hood.   One of the wires in the connector is the signal 'in' from the climate control head in the car.   This is the first place to check and see if the head is even telling the clutch to try and engage.   If its not you have to trouble shoot on the inside the car controls.  If that wire is telling it to run then you have to see if the module failed and its not going further than that.   If the signal is good out the module then its normal AC stuff like a low pressure or a faulty high or low pressure switch or wiring issues.   There isn't really anything I can think of in the AC system unique to the diesels.   

[Aaronz28]

i'll get on both of those today -

i'm getting no voltage at the compressor - but pressure is low indeed-   
i thought the low pressure switch was located in the compressor - may not be as this is the shallow later style compressor not the big old harrison comp.

thanks

[TJ Hopland]

I'm not going to be able to look for my books for a few days.   

Once you get it so you hear the glow plug solenoid clicking you need to check the glow plugs themselves.  Easy to test with a simple ohm meter.   Pull the lead wire off one plug at a time.  Stick one meter wire to a good ground, stick the other wire to the tab on the glow plug.    A good plug will have a very low ohm reading,  I think single digit like say 2 or 3 ohms.  There may be some that were in the teens but either way very low ohms.    If you are reading 100's or 1000's or anything with a K its shot.    Next move the wire to the harness connector.   Here you should be reading the rest of the glow plugs that are still connected.   Assuming there is at least one good one you should get a very low ohm reading here too.  We don't really care what the reading is as long as its very low.   What we are looking for here is that the harness is good.   Flex it around a bit to make sure you just didn't get lucky and get a cracked wire to make contact.   Later GM glow harnesses had fusible link wires within the harness,  these I don't think did.

With summer temps these will start fine on 5 good glows.   Less than that gets iffy and it depends on where they are in the firing order.   It will smoke like crazy and be rough for a minute or so but they will usually start.  If you want to start one with minimal smoke or when its below freezing is when you need all 8. 

Original AC glows were the 8G.   They are still available so if you really like to stay stock and AC you can do it.  Downside is they can swell if they are on too long.    AC 60G is a later design for the 6.5 diesels which are supposed to be internally regulated so in theory they won't have issues if they are on too long.   Some say they don't heat as fast as the original did.  On most of the older diesels forums everyone recommends the Bosch 80034.  They say the Bosch heats faster than the 60g so its closer to what the 8g's did.   I finally got sick of replacing 1 or 2 plugs per year and switched to the Bosch about 3 years ago and have not had one go out since.  In the 5.7 they don't seem to have any issues running with the stock glow system and I run mine all winter where its often below zero F.    The terminal is a different width between the Bosch and 8g.  I can't remember which way but its easily fixed with a pliers.  I think the Bosch may be more narrow.   Too smush em I had to remove the plastic holder from around em,  half of em were cracked, missing, or melted anyway so no great loss.

Cranking speed is everything when starting a diesel so making sure you got a good matched set of batteries with good cables and connections is critical.   Miss matched batteries and bad cables and connections just eat away at each other and kill batteries.     

Another diesel tip is make sure you are running a diesel rated oil.  Original summer spec was 30w and if you look its still out there but its not easy to find or cheap usually.   15w-40 is what most people run if they don't ever plan to encounter say below about 50*F temps.   Its available everywhere usually from at least 2 or 3 brands.  If you are a synthetic fan or its going to get cool then 5w-40 makes a HUGE difference in starting.    Shell Rotella T6 is the most common brand you see in synthetic and places like wally world sell it for about half what parts stores get for it.    I used it for several years till my stuff started leaking and burning a lot and I got cheap.  I found a local store brand synthetic blend 5w-40 that comes in a 2 gallon jug for the price of a gallon of the T6.   I now use that stuff in pretty much all my engines gas and diesel. 

Last tip is to check for water in the fuel.   Easiest way to do it is get some sort of sucking device like the nifty hand pump brake bleeder kits you can now get for $20 and disconnect the fuel return line where its hose between the frame and engine.   It should be on the passenger side of the car top of the frame rail.   Return line comes off the top of the injection pump as hard line then changes to hose kinda under the Ac compressor for its short run to the frame.    Pull the line off the engine side and connect the pump with the little jar.   Get a good sample of fuel, disconnect, and have a look at whats in the jar.   Water will separate and go to the bottom.   Diesel tends to have a yellow tinge to it so its really easy to see the water.  If you are not sure what its supposed to look like add a little water to your sample.   If you do this don't put it back in the tank.   If there is no water and you didn't add any you can just dump it back into the tank.   If there is water keep pumping and see if you can get it all out.   Beware that the water in fuel light won't come on till there is around 2 gallons of water in the tank so there could be a lot in there and you don't know it.    The fuel pickup is higher in the tank so their ideal was the water would stay in the bottom where it could not be picked up.   The return line is in the very bottom of the tank specifically to be used to 'drain' the water.    Good idea on paper but in practice was something that also killed many of these engines especially with how bad the fuel supply was back in their day.    I have been running older diesels 5.7's and 6.5's  about 30k per year for the last 6 or so years and have not had any signs of water in any of em so I have not bothered trying to change to a better filter design but many people do go to a more industrial style filter that integrates a water separator.

Good Luck and enjoy your unique ride!

   

[Aaronz28]

thanks for that helpful read -

it was the relay that was preventing it from starting -  i have ordered a new set of GPs just to be safe - from Accurate Diesel and a GP controller which I"ll keep on hand just in case.

also did an oil change yesterday with Rotella T 15w40 -   I've been hesitant to use Synthetic in an older engine becuase of the worry of lifters going flat in conventional gas engines, - but i have to confess i'm not even sure whats in this motor - i'll have to do a bit more research..  For winter oil - conv or syn and what variety?

I'm near Detroit, so we get harsh winters and I'll be driving it year round...

The AC is also fixed - it was simply low on R12 and corroded terminals were preventing the AC comp from coming on... now it spits ice cubes! 

Thanks

[TJ Hopland]

For a freezing climate no question I would go with a 5w-40.   Back in the day a common failure on these was to have the oil pump drive shafts snap due to the excessive load from cold thick oil not to mention its all about cranking speed, the more speed the better chance of a cold start.   To get the 5w you have to go to at least a synthetic blend or a full synthetic.   

An 82 should have come with a DX block which had roller cam and lifters so no worries about zinc.   Only the originals had typical flat tappet lifters.   They must have known it was an issue because there were a few of the D blocks that had rollers too.   Since most of the D's failed under warranty most were replaced with DX's so very few D's still around.  The D or DX is visible side center of the block just below the head line.    Its pretty big embossed letters so even if its dirty you can usually make it out. 

You will want to make sure your block heater is working.   With a block heater these won't have any issues starting well below freezing and you will get heat before you get to work.    Without the block heater if everything is good you have a decent chance of starting but will take forever to get any sort of heat in the car which can really stink if your windows are iced up.    In my Eldo I would actually remove the fan in the winter.   That made a huge difference in how fast it would heat and how warm the heat was.   Even sitting in traffic below freezing the heater core was enough to keep engine happy.   Got that tip from a friend that used to have a bunch of 5.7's.   You just have to remember to put it back in when temps start getting above freezing.

[Aaronz28]

thanks again-   i put new belts on it yesterday -  taking the fan off in the winter might not be a bad idea - pretty easy to access
or the venerable cardboard in front of the radiator

i don't know why I typed 82 - but its actually an 81 -   i got the service manual -

and will check the block heater

thanks

Aaron

[TJ Hopland]

81 I think would have still been a factory DX block.  80 seemed to be the transition year for blocks, injectors, and intakes.

The cardboard didn't work for me on my 80.   I think just the airflow from the fan over the engine was keeping the temps down.