2003 1.8T - intermittent misfire on starting - Page 3

Hawkesman · 12th March 2019, 17:39

Thanks John, but it must be the HG because I put new plugs in last week which I checked today. The ones in 1-3 looked almost like new, but no. 4 was black. I also shone a torch onto the top of no. 4 piston and it was slightly damp, whereas the other 3 were dry. So unless I'm missing something (and I hope I am!), then that seems pretty conclusive to me. I'd be very happy to be proved wrong though : )

Hawkesman · 12th March 2019, 17:41

PS, I can't find any roving engineers near me (Reading).

pletevl · 13th March 2019, 09:21

Quote:

Originally Posted by Hawkesman

Thanks John, but it must be the HG because I put new plugs in last week which I checked today. The ones in 1-3 looked almost like new, but no. 4 was black. I also shone a torch onto the top of no. 4 piston and it was slightly damp, whereas the other 3 were dry. So unless I'm missing something (and I hope I am!), then that seems pretty conclusive to me. I'd be very happy to be proved wrong though : )

Wouldn't a black spark plug be an over rich mixture ? overfuelling ?
Surely if it was water getting into the cylinder, it would be nice and clean.
And we all know that too rich a fuel mixture would cause missfiring.

stevestrat · 13th March 2019, 09:49

http://www.mg-rovermobilemechanics.com/ cover the whole of the UK, cost of work plus fuel cost to get to you but I'd try to get the car looked at by someone with MGR knowledge before calling them. There's a garage in High Wycombe was highlighted to me when I was compiling the T4 map, ex MGR mechanics. https://www.mgrs.co.uk/.

Hawkesman · 13th March 2019, 13:01

Thanks for all the input guys.

One thing I forgot to mention was that the inlets in the head were all clean as a whistle except for no. 4, which had black gunk accumulated at the bottom. Not sure whether that clue is any help? I have some pics but I don't know how to upload them.

Hawkesman · 13th March 2019, 16:39

One last symptom it's been getting. After 3 or 4 miles the fan kicks in, big time. When I've stopped to check under the bonnet it carries on running for a bit then stops. There are no obvious signs of coolant loss, but the hoses are bulging. After switching off, gently releasing the coolant filler cap unleashes a lot of pressure and hissing, followed by a torrent of COLD coolant when I loosen it a bit more. When at last I can release the cap fully the coolant settles down to around about the bottom of the tank.

I've bled it, refilled with about around 1/2 to 1 litre, then tried driving again and it did the same thing. Note that at no time during any of my issues has the temp gauge been anywhere but at the halfway point. Any further thoughts? Thanks.

stevestrat · 13th March 2019, 17:17

The mid point on the gauge covers too great a temp range (75°C to 115°C) to be of any real use. The onboard diagnostic is more reliable.

Start the engine, press and hold the trip reset button until the display shows "test 1". Release the button then immediately press again and keep pressing repeatedly until it shows "test 19", release the button. The display will alternate between "Log 1 -on" & "Log 1 -off". While it is showing "Log 1 -off" press the button and press repeatedly until it shows "7" then release the button. This will give a live and accurate reading of the coolant temperature.

roverbarmy · 13th March 2019, 17:57

Cold coolant could mean a dodgy thermostat (not opening to allow circulation) or a dodgy waterpump (not circulating).

Hawkesman · 13th March 2019, 18:59

Quote:

Originally Posted by roverbarmy

Cold coolant could mean a dodgy thermostat (not opening to allow circulation) or a dodgy waterpump (not circulating).

Is there a way to test if it is one of these?

Hawkesman · 13th March 2019, 19:36

Thanks yet again John.

So, if it is the thermostat, then it's locking the coolant inside the jacket thus causing an overheat which the temp gauge isn't picking up for some reason?

If it is the water pump then obviously the effect would be the same... but can they fail (i.e. stop pumping) without leaking? As they are toothed then that seems unlikely. As far as I know there is no sign of leakage anywhere, however I will check again tomorrow.

Sorry if I sound a bit lost. The last car I worked on regularly was my old '67 Minx, and I really understood how that car worked and could do just about anything to it (I still have it, by the way, though it's not run since '92.) I do miss a nice simple RWD engine layout, with everything mounted on the outside and easy to get at!

13th March 2019, 09:49	#24
stevestrat This is my second home ZT260 #243 (resting) Join Date: May 2010 Location: Prestonpans Posts: 22,474 Thanks: 650 Thanked 4,624 Times in 3,358 Posts	http://www.mg-rovermobilemechanics.com/ cover the whole of the UK, cost of work plus fuel cost to get to you but I'd try to get the car looked at by someone with MGR knowledge before calling them. There's a garage in High Wycombe was highlighted to me when I was compiling the T4 map, ex MGR mechanics. https://www.mgrs.co.uk/. __________________ Steve T4 Location Map

13th March 2019, 17:17	#27
stevestrat This is my second home ZT260 #243 (resting) Join Date: May 2010 Location: Prestonpans Posts: 22,474 Thanks: 650 Thanked 4,624 Times in 3,358 Posts	The mid point on the gauge covers too great a temp range (75°C to 115°C) to be of any real use. The onboard diagnostic is more reliable. Start the engine, press and hold the trip reset button until the display shows "test 1". Release the button then immediately press again and keep pressing repeatedly until it shows "test 19", release the button. The display will alternate between "Log 1 -on" & "Log 1 -off". While it is showing "Log 1 -off" press the button and press repeatedly until it shows "7" then release the button. This will give a live and accurate reading of the coolant temperature. __________________ Steve T4 Location Map

13th March 2019, 17:57	#28
roverbarmy This is my second home Roverless + 1.7D Sportage Join Date: Aug 2014 Location: East Norfolk Posts: 7,050 Thanks: 729 Thanked 2,021 Times in 1,449 Posts	Cold coolant could mean a dodgy thermostat (not opening to allow circulation) or a dodgy waterpump (not circulating). __________________ Oil in my veins!

12th March 2019, 17:39	#21
Hawkesman Regular poster Rover 75 Saloon Join Date: Dec 2018 Location: Reading Posts: 43 Thanks: 22 Thanked 2 Times in 2 Posts	Thanks John, but it must be the HG because I put new plugs in last week which I checked today. The ones in 1-3 looked almost like new, but no. 4 was black. I also shone a torch onto the top of no. 4 piston and it was slightly damp, whereas the other 3 were dry. So unless I'm missing something (and I hope I am!), then that seems pretty conclusive to me. I'd be very happy to be proved wrong though : )

12th March 2019, 17:41	#22
Hawkesman Regular poster Rover 75 Saloon Join Date: Dec 2018 Location: Reading Posts: 43 Thanks: 22 Thanked 2 Times in 2 Posts	PS, I can't find any roving engineers near me (Reading).

13th March 2019, 13:01	#25
Hawkesman Regular poster Rover 75 Saloon Join Date: Dec 2018 Location: Reading Posts: 43 Thanks: 22 Thanked 2 Times in 2 Posts	Thanks for all the input guys. One thing I forgot to mention was that the inlets in the head were all clean as a whistle except for no. 4, which had black gunk accumulated at the bottom. Not sure whether that clue is any help? I have some pics but I don't know how to upload them.

13th March 2019, 16:39	#26
Hawkesman Regular poster Rover 75 Saloon Join Date: Dec 2018 Location: Reading Posts: 43 Thanks: 22 Thanked 2 Times in 2 Posts	One last symptom it's been getting. After 3 or 4 miles the fan kicks in, big time. When I've stopped to check under the bonnet it carries on running for a bit then stops. There are no obvious signs of coolant loss, but the hoses are bulging. After switching off, gently releasing the coolant filler cap unleashes a lot of pressure and hissing, followed by a torrent of COLD coolant when I loosen it a bit more. When at last I can release the cap fully the coolant settles down to around about the bottom of the tank. I've bled it, refilled with about around 1/2 to 1 litre, then tried driving again and it did the same thing. Note that at no time during any of my issues has the temp gauge been anywhere but at the halfway point. Any further thoughts? Thanks.

13th March 2019, 19:36	#30
Hawkesman Regular poster Rover 75 Saloon Join Date: Dec 2018 Location: Reading Posts: 43 Thanks: 22 Thanked 2 Times in 2 Posts	Thanks yet again John. So, if it is the thermostat, then it's locking the coolant inside the jacket thus causing an overheat which the temp gauge isn't picking up for some reason? If it is the water pump then obviously the effect would be the same... but can they fail (i.e. stop pumping) without leaking? As they are toothed then that seems unlikely. As far as I know there is no sign of leakage anywhere, however I will check again tomorrow. Sorry if I sound a bit lost. The last car I worked on regularly was my old '67 Minx, and I really understood how that car worked and could do just about anything to it (I still have it, by the way, though it's not run since '92.) I do miss a nice simple RWD engine layout, with everything mounted on the outside and easy to get at!