Poor Cold Starting

[DLM48]

MY 945 24tic is having a few problems cold starting.............starts in about 20/30 seconds after some cranking - usually two goes on the key. The problems seems to be that the glow plugs are not activating at least the light on the dash is not coming on.

So are the glow plugs activated on every cold start? Are they temperature dependent i.e. are they only activated if the air temp is below xx deg? OR what?

cold start device is working fine as i have a VERY fast idle until it warms up - but the the idle is very fast normally i suspect the fuel mixture has been played with for extra performance.

thanks in anticipation

[craig8661]

the cold start can stick hence fast idel when runing just try nudging it with your hand and if it drops just look at the meck may be dry as for cold start look in the pipes for air if thats ruled out look for your heater relay im not sure where its located will look in mine soon if your heaters are working right you should hear a audible click from under the bonet after about 20 secs or other test you can do is vault meter on the plugs and earthed to battery and get some one to turn the ign on if you get 12 volts the electronics are fine then suspect the glow plugs i have 2 down on my engine and both behind the pump

[craig8661]

found the heater controle module thats just abouve the battery see photo
http://i19.photobucket.com/albums/b165/mistonia/volvo%20crap/IMG_2508.jpg
cheak this lever on your pump
http://i19.photobucket.com/albums/b165/mistonia/volvo%20crap/IMG_2509.jpg

[jor]

As per Craig's post the usual culprit is the glow plug. I changed mine a year ago buying the cheapest type (non branded) and guess what - they have just needed replacing again. TFB suggests checking the resistance between the connector part and earth, having removed the copper strip that connects them. I could not get consistent values (above 4ohm is bad) and wasn't certain I was doing it right, so I took out the 4 easily accessible ones and connected them to a battery, one at a time. Working ones definitely will light so watch out for the carpet. None of them did so they have been replaced with 4 Bosch ones. I'm sure the other 2 are also kaput, but it starts well enough so will do the others 'sometime'.
The engine will start on compression alone when the temp is somewhere around 35C.
I know engines will start on 3 functional plugs - as the first time I did mine I forgot to connect the copper strip to the inner 3 plugs, so if you find that the ones you test are working then the trouble lies elsewhere. The fact that the light is not coming on is a bit suspicious of an electrical rather than a plug problem. There is a diagram of the glow plug circuit on Ross Winberg's volvoturbodiesel.blogspot.com, however I can report that I know nothing about electricity so to me it's meaningless. However if the plugs work and you can get hold of a working relay and the thing still won't start then by exclusion it's got to be the switch that's faulty. The one part of the relay that's easy to look at is the fuse visible at the bottom after you undo two nuts and the connectors.
My guess is that the switch is bust.


john

[DLM48]

As per Craig's post the usual culprit is the glow plug. I changed mine a year ago buying the cheapest type (non branded) and guess what - they have just needed replacing again. TFB suggests checking the resistance between the connector part and earth, having removed the copper strip that connects them. I could not get consistent values (above 4ohm is bad) and wasn't certain I was doing it right, so I took out the 4 easily accessible ones and connected them to a battery, one at a time. Working ones definitely will light so watch out for the carpet. None of them did so they have been replaced with 4 Bosch ones. I'm sure the other 2 are also kaput, but it starts well enough so will do the others 'sometime'.
The engine will start on compression alone when the temp is somewhere around 35C.
I know engines will start on 3 functional plugs - as the first time I did mine I forgot to connect the copper strip to the inner 3 plugs, so if you find that the ones you test are working then the trouble lies elsewhere. The fact that the light is not coming on is a bit suspicious of an electrical rather than a plug problem. There is a diagram of the glow plug circuit on Ross Winberg's volvoturbodiesel.blogspot.com, however I can report that I know nothing about electricity so to me it's meaningless. However if the plugs work and you can get hold of a working relay and the thing still won't start then by exclusion it's got to be the switch that's faulty. The one part of the relay that's easy to look at is the fuse visible at the bottom after you undo two nuts and the connectors.
My guess is that the switch is bust.


john

thanks i thought that it cant be a plug issue as i would expect the light to still come one even were the plugs duff
thanks

http://photos1.blogger.com/blogger/2157/1425/1600/g11.jpg

RELAY 130 is clicking

BUT no 12V at glow plug buss rail

so it would seem that i have a problem with the relay or one of the two sensors the temp sensor (199) or the fuel valve one (195) on the injector pump

fuses 8,9&10 are OK

need to double check the glow plug bulb is good - it is

the cold start lever on the pump moves a little 1/4"/3/8" when you pull forward on the top slot where the ball that contact the throttle lever is

there is a micro switch on the pump at the back of the throttle lever but the actuator is no longer there - is this the fuel valve sensor?

Fed the glow plug buss rail with 12V and cars starts fine so this IS a glow plug actuation issue.

[tfb]

The glow plug funtion is activated by a coolant temp sensor that's hidden on the engine block around the back of the IP.
The manual suggests the following glow plug times for coolant temp
9 seconds for -20C
6 seconds for 0C
4 seconds for 20c
3.5 secionds for 40C
0 seconds for 50C

The dash light is controlled by the Glow plug relay, but it doesn't exactly mirror what the glow plugs are doing. The glow plugs can still be heating when the dash light is off, but if the light is on then the glow plugs are on.
I would suggest that you use a multimeter to measure the voltage to the plugs to confirm the function of the relay (but it does sound like it is working to a degree).

From your description I would guess that one or more plugs have failed. No 5 and 6 are a bugger to get to withour removing the injectors or pump. I would try removing and testing the resistance of No1 to 4 and replacing if required. If this makes starting tolerable then leave No5 and 6 untill you have a good amount of free time and something to go and kick to take out your frustrations!

Regards
TFB

[craig8661]

allso to add what you can do is take the live feed of to the plugs tape it up and turn ignition on and put a live from the battery to the rail see if that improves the starting up on it

[DLM48]

As per Craig's post the usual culprit is the glow plug. I changed mine a year ago buying the cheapest type (non branded) and guess what - they have just needed replacing again. TFB suggests checking the resistance between the connector part and earth, having removed the copper strip that connects them. I could not get consistent values (above 4ohm is bad) and wasn't certain I was doing it right, so I took out the 4 easily accessible ones and connected them to a battery, one at a time. Working ones definitely will light so watch out for the carpet. None of them did so they have been replaced with 4 Bosch ones. I'm sure the other 2 are also kaput, but it starts well enough so will do the others 'sometime'.
The engine will start on compression alone when the temp is somewhere around 35C.
I know engines will start on 3 functional plugs - as the first time I did mine I forgot to connect the copper strip to the inner 3 plugs, so if you find that the ones you test are working then the trouble lies elsewhere. The fact that the light is not coming on is a bit suspicious of an electrical rather than a plug problem. There is a diagram of the glow plug circuit on Ross Winberg's volvoturbodiesel.blogspot.com, however I can report that I know nothing about electricity so to me it's meaningless. However if the plugs work and you can get hold of a working relay and the thing still won't start then by exclusion it's got to be the switch that's faulty. The one part of the relay that's easy to look at is the fuse visible at the bottom after you undo two nuts and the connectors.
My guess is that the switch is bust.


john

when i replace mine i will use the hotter Bosch ones that elsberg use i think the Part number is on the VEG OIL thread

[DLM48]

allso to add what you can do is take the live feed of to the plugs tape it up and turn ignition on and put a live from the battery to the rail see if that improves the starting up on it

did that read my updates :)

[craig8661]

lol was scouting and missed it the mirco switch was a throtle possition sencor i was told as the new pump didnt have one fitted so had to have it transferd over obvisly you need to see if the relay itself is getting power to it on a main feed
allso i dont kno but i have a fourtrak and if the rezistance changes too much on the heater plugs the heater relay dosnt work but not sure if this applys to volvo if you can get to fault you could allways throw a little switch and a austin starter relay in and have a live feed of the batter to relay then the heater rail

[DLM48]

i guess it is time for the Volvo Diesel manual.

as well as a magic wand giggle

regards

[jor]

Don't quite understand how a manual is going to help - by connecting power to the plugs and getting the engine to start you have shown that the plugs (bosch no is 0 250 201 032) are working. This narrows it down to either relay or switch. Looks like you need to get your hands on a working relay.

john

[tfb]

David
would you like me to mail you a copy of the glow plug cct diagram?

TFB

[jor]

Here it is, taken from the excellent volvoturbodiesel.blogspot.com

[DLM48]

message 5 in this thread a post by me does have a link to this diagram

thanks

[DLM48]

Don't quite understand how a manual is going to help - by connecting power to the plugs and getting the engine to start you have shown that the plugs (bosch no is 0 250 201 032) are working. This narrows it down to either relay or switch. Looks like you need to get your hands on a working relay.

john

the manual would have lead me to these components and their location..............i hope and - when i get a moment i will remove the relay and check all the feeds probably have to wait till the weekend now - i might see if someone on ebay is breaking a 940 D24tic or try salvo for another relay

thanks

[tfb]

Hmmm....that is slighty different to the cct diagram I have in my manual, PDF file attached

Regards

TFB

[DLM48]

Hmmm....that is slighty different to the cct diagram I have in my manual, PDF file attached

Regards

TFB

thanks these diagrams they do look interesting and i can see the fuse on the relay now

car is not here as the SL500 is playing naughty too the wiper is acting up and i need to fix that so my partner is driving the 945 and with the weather here she wont be swapping it for the punto as it is a 70 mile round trip over snowy icy roads

if the SL is fixed - i should know tomorrow morning - i might swap cars again and get back onto fixing the 945 before the weekend if not it will be the weekend before i get my hands on the 945

thanks for all the help here.

regards

[shrewsbury_sam]

id test the glow plug relay first check there is lives in and out and going to where there meant to. common fault on the 940 diesel is the relay

[Steve V]

Just had similar problems with my 850.
Check the plugs are working by measuring if there is any resistance from the terminal to earth. If they are open circuit they are US.
Another way is to connect a wire to the live side of the battery and touch this on the end of the plug and look for a small spark. If you get one the plug is good. Be careful though not to touch earth anywhere i.e. the engine block or pipes...
Every one of my plugs was gone but at 117K I shouldn't moan.
Starts first touch now. Mint

[DLM48]

Just had similar problems with my 850.
Check the plugs are working by measuring if there is any resistance from the terminal to earth. If they are open circuit they are US.
Another way is to connect a wire to the live side of the battery and touch this on the end of the plug and look for a small spark. If you get one the plug is good. Be careful though not to touch earth anywhere i.e. the engine block or pipes...
Every one of my plugs was gone but at 117K I shouldn't moan.
Starts first touch now. Mint

thanks but i have already proved that the glow plugs are functioning by feeding the buss bar straight from the battery and also when the light on the dash comes on the car starts on almost the first turn - this is i am sure a relay problem

[DLM48]

Well i got seriously fed up with the bad starting when cold and today had a good long look at the problem. I found two wiring diagrams online in fact found a whole 940 wiring diagram thing online and took a copy of that. It is a PDF so if you want a copy PM me please. Anyhow using both diagrams and getting my head into 'electronic' mode i sat down and worked things out. The first diagram has all the bits identified but does not explain the inside of the glow plug relay 'properly' using both i understood the circuit quickly.

Here is what i know now.

The relay box is 'intelligent' it is not just a relay - the glow plugs are well just dumb provide them with 12V and assuming they are good they will glow - at the back end of the engine is the 'critical' 199 sensor. This 199 sensor 'appears to be a temperature sensitive resistance. When the engine is 'COLD' like freezing and below it has a very high resistance which reduces as the sensor heats up to Bonnie Scotland temperatures 2/3 deg above freezing.

With the engine COLD and i mean winter type cold this sensor has infinite resistance (this has still to be measured - when i get a new sensor in my hand) - infinite resistance tells the electronics in the relay box to activate the glow plugs for the maximum 'set time' (i think 40 secs) as the sensor heats up (the car being parked in a less cold area - or the engine has been running recently) or get less cold the resistance changes and therefore the time the glow plugs are actuated is reduced.

So what we have controlling the glow plugs is a variable timing circuit within the relay box with the timing set by a variable (temperature sensitive) resistor sensor 199. Simple yes.
The Relay box also has another trick in that when you move the ign key from pos 2 (ignition on) to pos 3 (engine start) the glow heat circuit is disabled until the ignition switch is cycled back through pos 1 (ignition off).

SO if you are having glow plug activation problems it is really easy to determine which component is faulty.

1. Remove the wire from sensor 199 (this is difficult to locate - at first) switch ignition to pos 2 glow plug lamp should light on the dash if the relay is good.

2. Remove wire and measure resistance on sensor 199 (i got 50ohms - DUFF Sensor) cold it should have a very high resistance

3. With the wire off sensor 199 and tucked away somewhere safe and insulated you are providing the relay box with an infinite resistance on this circuit so the relay thinks it is in a sub zero temperature and will run the glow plugs for 40 seconds. Assuming your not in a sub zero temperature situation with this wire off sensor 199 you have manual control of the glow plugs ign switch pos 2/3 - simply by trying to start the engine you will switch off the glow plugs so you can time the glow circuit to suit your needs 5/10/15 seconds dependent on how cold the car is 'UNTIL' you can replace sensor 199.


i hope all of that is understandable and will help someone else.

regards

[DLM48]

Here it is, taken from the excellent volvoturbodiesel.blogspot.com


That diagram above is helpful as it does list/identify the various components however it is not 100% accurate and missing critical information it is also of very poor quality in a visual way and contains at least one silly error. There are much better diagrams available online as PDF's Also someone said in this thread that the glow plug lamp does not mirror the activation of the glow plugs that is not correct - it does.

some great info here

http://www.scribd.com/doc/3698827/tp3908202-940-1995-wiring-diagrams-section-3-39

page 21 is the Pre Heat wiring diagram

[DLM48]

I only got number 1,2 & 3 out before it got dark cold and wet

I got some really cheap genuine Bosch ones off a great guy on ebay he got them into stock for me .

One of the three i took out one was duff - one was a Bosch one was a Bero the other was unbranded. I am expecting the other three to be duff.

The 199 temp sensor has finally arrived at my dealer from Sveeden so if its a nice day tomorrow i will walk to the dealers and get that then have fun with plugs no 5 & 6 no 4 should be quite easy. Then its the sensor. Before i connect the glow plugs to the feed but after replacing the sensor i will check activation times - also the resistance of the sensor at various temperatures before i fit it.

wish me luck

more soon

[Laney760]

Good Luck 4,5,6 DLM48. Although I'm sure your cold starting is probably all connected to glow plugs I just thought I'd throw this into the equation. Neither a diesel specialists, nor my normal garage, nor my father, nor myself recognised that my poor cold starting was down to the D24Tic Bosch starter motor. It turned over at a reasonable rate and I had no reason to suspect it. Since it suddenly died and I replaced it with the alternative Hitachi one, recommended to be the better in faqs, I have no cold starting problems and you wouldn't think it was the same car starting. My Dad has had years of experience with cars and Volvos and is still very surprised about this... maybe someone on here can enlighten me?

[DLM48]

Well on Saturday No 4 fell out easy peasy No 5 was a wee piggy - i got the nut off without dropping it and the plug out without too much of a problem i can actually get the fingers from both my hands onto it. No 6 looks like a total swine and getting the nut back onto No5 looks like fun NOT....Not at the car just now so this will have to wait till later on this week. The 199 sensor is now in stock so i will be collecting that soon too. Fun Times!!!!

[DLM48]

WOOO HOOOO FIXED IT

replaced No6 glow plug at the weekend and put the other five in - lost about 4 nuts on No5 replaced the sensor on the back of the cly head and that was it sorted.....battery was not too happy after sitting for a few weeks but the car started instantly with a wee tow.

[Laney760]

Great to hear a successful update

[Laney760]

Finally, nearly a month later, sorry DLM48, a pic of the 'Bosch equivalent' starter, this one is made by Wood Auto Supplies and now costs £303, just looked on their website, can't get it much clearer, too dark indoors, too light outside

http://www.volvoforums.org.uk/picture.php?albumid=162&pictureid=645

[DLM48]

mine now starts like it never did before the starter hardly turns over the engine before it bursts into life.

[MRDART]

Hi ! There should be a big fuse for the glowplugs, I am not sure about this but I think it is on the underside of the glowplug relay...
A word of advise... check that the glowplugs switch off properly since it is otherwise a matter of minutes before your battery is draine enough so you cant start the engine.... I think that with 6 good plugs it takes about 60 amps....
So also for safety... no rings or watches or such on your hands when doing the fault isolation....