Ihave a 1999 Laguna mk 1 turbo diesel with 93000 miles which is difficult to start when the weather is cold. Once started is ticks over and runs perfectly. A garage replaced the T.D.C. senser and air mass meter which made no difference. The glow plugs and it circuits have been checked twice with no fault found. Could it be the coolant temp senser, if so where is it [ the Haynes manual SEEMS to suggest there are 3, 1 for dash guage, 1 for glow plug ECU and 1 for injection ECU! ]
Anyone got any other idears??
stever
Laguna Starting Problem
-
elma
- Posts: 3745
- Joined: 13 May 2007, 02:17
- x 287
-
stever
- Posts: 3
- Joined: 25 May 2007, 09:37
Yes thereafter it starts easily for the rest of the day, but glow plugs and the circuitry has been checked twice by two different garages and pronounced perfect. But it is a temperature problem as the colder it is overnight the harder it is to start, at the moment it is not too bad. Exhaust is visible when cranking so I guess fuel is getting in O.K.
stever
stever
-
AndersDK
- Posts: 6060
- Joined: 21 Feb 2003, 04:56
- x 1
temp gauges are usually located in waterways on engine itself. Like next to the thermostat in its housing etc.
I dont think its a temp sensor issue. If any temp sensor fitted is to the glow plug timer box, then its used for setting the glow time on the plugs. Not wether the plugs are heated or not.
Glow plugs have a limited service life. Approx 60Kmiles on average.
They fail by going open circuit - or high ohmic. Sometimes they simply will not glow hot enogh any more, i.e. they start glowing red hot instead of white hot (which they should).
They are VERY easy to check for the DIY owner :
You reckon the glowplugs as being the small 'spark plug' look-alike devices connected to a single common heavy gauge wire. This wire carries the +12V feed from the timer box relay, when its first activated.
Unscrew the wire from all plugs - then check the ohmic resistance from the wire tip of the plug to nearby engine earth.
You should get a reading resembling a shortcircuit - i.e. very low ohms reading like 1-2 ohms depending on the cleanliness of the meter probes contacting earth and plug tip.
Anyone you know off with a cheap hobby multimeter can check this for you.
Any plug not reading approx 1 ohm (or in effect reading shortcircuited) is defective. Usually they fail high by 2 - 30 ohms or even disrupt completely.
They are priced at approx £8-12 each depending on exact type, and all 4 are replaced at once.
You can also check if the plugs are activated by the ignition key as they should :
Simply connect a voltmeter to the wire mentioned above and engine earth.
The meter should read at least 10.8V when you initiate the heater time by the ignition key.
If you get a low reading less than 10.8V, the first check should be battery pole clamps. Disconnect and clean both battery poles and clamps.
If that does not help suspect the battery itself. These have an average service life of some 5-8 years of branded good quality batteries, all dependent on usage of course.
I dont think its a temp sensor issue. If any temp sensor fitted is to the glow plug timer box, then its used for setting the glow time on the plugs. Not wether the plugs are heated or not.
Glow plugs have a limited service life. Approx 60Kmiles on average.
They fail by going open circuit - or high ohmic. Sometimes they simply will not glow hot enogh any more, i.e. they start glowing red hot instead of white hot (which they should).
They are VERY easy to check for the DIY owner :
You reckon the glowplugs as being the small 'spark plug' look-alike devices connected to a single common heavy gauge wire. This wire carries the +12V feed from the timer box relay, when its first activated.
Unscrew the wire from all plugs - then check the ohmic resistance from the wire tip of the plug to nearby engine earth.
You should get a reading resembling a shortcircuit - i.e. very low ohms reading like 1-2 ohms depending on the cleanliness of the meter probes contacting earth and plug tip.
Anyone you know off with a cheap hobby multimeter can check this for you.
Any plug not reading approx 1 ohm (or in effect reading shortcircuited) is defective. Usually they fail high by 2 - 30 ohms or even disrupt completely.
They are priced at approx £8-12 each depending on exact type, and all 4 are replaced at once.
You can also check if the plugs are activated by the ignition key as they should :
Simply connect a voltmeter to the wire mentioned above and engine earth.
The meter should read at least 10.8V when you initiate the heater time by the ignition key.
If you get a low reading less than 10.8V, the first check should be battery pole clamps. Disconnect and clean both battery poles and clamps.
If that does not help suspect the battery itself. These have an average service life of some 5-8 years of branded good quality batteries, all dependent on usage of course.
Anders (DK) - '90 BX16Image
-
stever
- Posts: 3
- Joined: 25 May 2007, 09:37
Thanks for the info but the glow plugs have all been checked both by myself [ as you described ] and by two garages. It was suggested to me that if I disconnected the battery for about an hour this would reset the ECU. Tried it, I think the car is running better but will have to wait for some cold weather to see if starting is improved!
In the mean time I am totally bafled!!
stever
In the mean time I am totally bafled!!
stever