Hello world. Just bought an 1985 524td and had a few concerns regarding cold starts
For context:
-The vehicle WAS filled with gasoline, I’ve since drained it, put diesel, and got that all situated.
-A few of the dashboard lights such as the D indicator doesn’t work (this will make sense later)
-When the vehicle is warmed up and running, the idle seems a bit high sitting around 1050 RPM
-The garage the vehicle in is around 50 degree Fahrenheit
Idle issue:
Whenever I try to cold start the car, the glow plug light does not turn on and will not start unless I use starter fluid. Once the car is warmed up it will start just fine without the use of starter fluid.
My concern is either the glow plug light isn’t working (best case) or the entire system just isn’t turning on. I’ve never worked on a diesel e28 so I’m not sure how the glow plug system entirely works
I think it might be the high idle causing it not to start properly on cold starts. It wouldn’t make sense that glow plugs would be the issue for not starting when starter fluid seems to work just fine.
Also my check module right next to the sunroof will only show a check for washer fluid, and won’t flash all the lights when I click reset. Not sure if anyone else has had this issue or knows a solution
Let me know what you guys think would be the best solution
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High idle not causing start / Glow Plugs not working
Re: High idle not causing start / Glow Plugs not working
For starters, you shouldn’t use starter fluid at all. It can cause severe damage to your diesel engine. If you must, spray a rag with gas or starter fluid and place it by the intake. The fumes should be enough to start it.
You most likely have bad glow plugs. If the glow plug wait light isn’t coming on at all you may have a bad glow plug relay or bad fuse to the light. There is an orange glow plug wait light that should come on when you put the key in the ignition and put it to the 1 position. After a short time a green glow plug ready light will come on which tells you it’s ready to crank. The first light should come on even with bad plugs.
in this weather my car was extremely difficult to start and and wouldn’t start at all on really cold days to the point where I killed my battery trying. My glow plug wait light would come on but not the green glow plug ready light. I swapped all 6 plugs and now it fires right up and all lights work. The job took a couple hours and required several extensions and u joints. Major pita. But I got it done. Glow plugs 4 and 6 were the biggest pains. I recommend a flexible magnetic extension as the nuts that hold the wires in place on the glow plugs are tiny and extremely easy to lose (6mm iirc). I lost a couple even with the magnet but found a bunch of stainless nuts at Lowe’s that worked. If you do end up needing plugs, buy beru or Bosch plugs. Do not get autolight. The heads snap off those apparently.
Here is a useful link for some diag.
https://www.grandmarq.net/gadget73/Ford ... engine.pdf
also I don’t think you understand what glow plugs do. They are not spark plugs. Diesel requires heat and compression to ignite. The glow plugs function as a heater pre heating the air in the cylinders to help the diesel ignite. They stay on for a short time after the car starts to help warm it up. Once the engine is warm, it fires right up because the air in the cylinders is already hot and the glow plugs aren’t needed to preheat. The starter fluid explodes in the cylinders because of the high compression of the diesel engine. There are so many reasons using it is really bad for a diesel and should be used only as a last resort in the absolute smallest quantity needed to get started.
hope this helps. I’m not new to diesels as this is my fifth one and also own an F30 328d, but I am new to the E28 and haven’t had my 524td for long. I’m sure some of the more experienced folks will chime in. This place has been a great help for me.
good luck!
You most likely have bad glow plugs. If the glow plug wait light isn’t coming on at all you may have a bad glow plug relay or bad fuse to the light. There is an orange glow plug wait light that should come on when you put the key in the ignition and put it to the 1 position. After a short time a green glow plug ready light will come on which tells you it’s ready to crank. The first light should come on even with bad plugs.
in this weather my car was extremely difficult to start and and wouldn’t start at all on really cold days to the point where I killed my battery trying. My glow plug wait light would come on but not the green glow plug ready light. I swapped all 6 plugs and now it fires right up and all lights work. The job took a couple hours and required several extensions and u joints. Major pita. But I got it done. Glow plugs 4 and 6 were the biggest pains. I recommend a flexible magnetic extension as the nuts that hold the wires in place on the glow plugs are tiny and extremely easy to lose (6mm iirc). I lost a couple even with the magnet but found a bunch of stainless nuts at Lowe’s that worked. If you do end up needing plugs, buy beru or Bosch plugs. Do not get autolight. The heads snap off those apparently.
Here is a useful link for some diag.
https://www.grandmarq.net/gadget73/Ford ... engine.pdf
also I don’t think you understand what glow plugs do. They are not spark plugs. Diesel requires heat and compression to ignite. The glow plugs function as a heater pre heating the air in the cylinders to help the diesel ignite. They stay on for a short time after the car starts to help warm it up. Once the engine is warm, it fires right up because the air in the cylinders is already hot and the glow plugs aren’t needed to preheat. The starter fluid explodes in the cylinders because of the high compression of the diesel engine. There are so many reasons using it is really bad for a diesel and should be used only as a last resort in the absolute smallest quantity needed to get started.
hope this helps. I’m not new to diesels as this is my fifth one and also own an F30 328d, but I am new to the E28 and haven’t had my 524td for long. I’m sure some of the more experienced folks will chime in. This place has been a great help for me.
good luck!
Re: High idle not causing start / Glow Plugs not working
Pop the cover on the glow plug controller and see if the fuse link has melted. If thats open the glow plug system does nothing.
The orange light should come on even if you have bad glow plugs, but the green light will not. If the green light comes on after the amber, thats basically the self-test for the glow plug controller telling you all 6 are good.
I don't know if BMWs have a lamp check function that kicks them all on when cranking, but if they do not, thats also easy to deal with. Unplug the smaller connector on the glow plug controller. Find the terminals marked L1 and L2. With the key on, if you ground the pin in the connector for L1, the amber light should come on. If you ground L2, the green light should come on. If that happens, the bulbs are fine. If it doesn't, either the bulbs are bad or you have no key-on power to the + side of the lamps.
Speaking of key-on power, while you're poking around in the small connector, verify you have key-on power at pin 15 on the glow plug controller. If that doesn't work the glow plugs also don't do anything.
Just for completeness, may as well confirm that you have a good ground at 31 in the small plug, and that the fat cable by the fuse link has battery voltage.
If all that checks out, the glow plugs are also easy to check. Unplug the larger plug from the top of the controller. The pins are numbered 1-6, this corresponds with cylinders 1-6. Ohm check from ground to each of the terminals in the connector. A good glow plug should be around 0.5 ohms (less lead resistance). A bad one will be open circuit or at least much higher resistance. If you have any bad ones, replace all 6.
My own glow plug controller is screwy. The one in the car decided to turn itself on while driving and it melted the relay inside the box. I got a used one and the orange light doesn't work now, but the glow plugs do. I've been poking at it when I have time and motivation but so far haven't traced down the fault in the controller. If I can't figure it out by spring I'll just get another one. The lamp is fine, its definitely an internal controller fault, and all 6 glow plugs still measure fine.
re: the high idle system, thats intentional for cold starts. Its a dumb mechanical system using what amounts to a thermostat with a cable on it to pull the throttle open a bit so it starts easier when cold. There is also a cold timing advance solenoid that operates in the injection pump to help it start quicker. You can hear when that shuts off, the engine will clatter less at idle.
The orange light should come on even if you have bad glow plugs, but the green light will not. If the green light comes on after the amber, thats basically the self-test for the glow plug controller telling you all 6 are good.
I don't know if BMWs have a lamp check function that kicks them all on when cranking, but if they do not, thats also easy to deal with. Unplug the smaller connector on the glow plug controller. Find the terminals marked L1 and L2. With the key on, if you ground the pin in the connector for L1, the amber light should come on. If you ground L2, the green light should come on. If that happens, the bulbs are fine. If it doesn't, either the bulbs are bad or you have no key-on power to the + side of the lamps.
Speaking of key-on power, while you're poking around in the small connector, verify you have key-on power at pin 15 on the glow plug controller. If that doesn't work the glow plugs also don't do anything.
Just for completeness, may as well confirm that you have a good ground at 31 in the small plug, and that the fat cable by the fuse link has battery voltage.
If all that checks out, the glow plugs are also easy to check. Unplug the larger plug from the top of the controller. The pins are numbered 1-6, this corresponds with cylinders 1-6. Ohm check from ground to each of the terminals in the connector. A good glow plug should be around 0.5 ohms (less lead resistance). A bad one will be open circuit or at least much higher resistance. If you have any bad ones, replace all 6.
My own glow plug controller is screwy. The one in the car decided to turn itself on while driving and it melted the relay inside the box. I got a used one and the orange light doesn't work now, but the glow plugs do. I've been poking at it when I have time and motivation but so far haven't traced down the fault in the controller. If I can't figure it out by spring I'll just get another one. The lamp is fine, its definitely an internal controller fault, and all 6 glow plugs still measure fine.
re: the high idle system, thats intentional for cold starts. Its a dumb mechanical system using what amounts to a thermostat with a cable on it to pull the throttle open a bit so it starts easier when cold. There is also a cold timing advance solenoid that operates in the injection pump to help it start quicker. You can hear when that shuts off, the engine will clatter less at idle.