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schoppa
08-06-2013, 12:29 AM
Hi,

today we had about 28 degrees (82.4 F) in Germany. I had a day off and cruised around in the city, basically to buy some beer for Silverstone meeting next weekend (feel free to meet me for a good German Holsten beer from the boot of BI ZT 260) :) After a short stop and restarting, the engine idled like running rich or some cylinders are missing. Pushing the throttle to 1500 rpm the engine sounds well. After driving a few miles on the high way back home, ideling was well again, no problems. The problem is reproducible in hot weather after each stop and engine turn off. Any ideas?

Cheerio
Marcus

colintf
08-06-2013, 12:35 AM
Hi,

today we had about 28 degrees (82.4 F) in Germany. I had a day off and cruised around in the city, basically to buy some beer for Silverstone meeting next weekend (feel free to meet me for a good German Holsten beer from the boot of BI ZT 260) :) After a short stop and restarting, the engine idled like running rich or some cylinders are missing. Pushing the throttle to 1500 rpm the engine sounds well. After driving a few miles on the high way back home, ideling was well again, no problems. The problem is reproducible in hot weather after each stop and engine turn off. Any ideas?

Cheerio
Marcus

Don't worry Marcus
Most do that in hot weather stop start or queues

See you at MG Live for a beer and a chat
Where you camping? General or quiet campsite??
:cool:

scooter
08-06-2013, 10:19 AM
This is just a hotstart problem due to the high under bonnet temps. What happens is the fuel rail gets hot and the injection system has to get rid of the fuel vapour in the rail. It does this by holding the injectors open longer to let the vapour out of the system. There is no return to the tank in the Ford system which means that unless the car is using more than idle fuel amounts there is not enough fuel flow to keep the injector rail cool.

schoppa
08-06-2013, 10:44 AM
Don't worry Marcus
Most do that in hot weather stop start or queues

See you at MG Live for a beer and a chat
Where you camping? General or quiet campsite??
:cool:

Ah, I understand. I know this behaviour from my old BGTV8, but didn't thought that a modern car has this problem too. :confused: Okay, if this is normal I have to live with it.

I'm leaving Germany tomorrow and stay in the south for a few days before going to Silverstone. I contacted the MGOC garage as well and hope that they give me a time slot and can help me with my AC problem (I've posted that a few weeks ago).

I've booked general campsite. Yes, please come over for a beer!

Cheers
Marcus

colintf
08-06-2013, 11:43 AM
Ah, I understand. I know this behaviour from my old BGTV8, but didn't thought that a modern car has this problem too. :confused: Okay, if this is normal I have to live with it.

I'm leaving Germany tomorrow and stay in the south for a few days before going to Silverstone. I contacted the MGOC garage as well and hope that they give me a time slot and can help me with my AC problem (I've posted that a few weeks ago).

I've booked general campsite. Yes, please come over for a beer!

Cheers
Marcus

Gutes Fahrt Marcus
See you next Friday :thumb

NOCTURNAL
16-11-2013, 10:07 PM
do you still have this Issue Schoppa ?

Whilst Mine has it Now, I don't subscribe to the "they all do that Sir" routine, as Mine didn't for 5 Years, so want to know whats changed ...

Just wondered if you had encountered it at all, ?

Nick

AndyG
17-11-2013, 12:01 AM
Has no one suggested "remove the sound proofing/Under bonnet insulation?.

That will hold the heat in.

NOCTURNAL
17-11-2013, 06:23 PM
I've seen that Andy, but that doesn't give a reason in my case why it didn't used to do it for the first 5 years plus of ownership, but I have another problem now in that the Fan isn't kicking in so I won't post further on Schoppa's thread.. I commented as I've seen Brians technical description for it (the normal Hot weather/traffic syndrome) and whilst I would never question Brian's knowledge in the slightest, I have zero Car knowledge, However as an Engineer, I'm inquisitive to find out why this should start happening to a car that has previously not suffered?

My own car had never suffered for years of ownership, I had one incident, looked here and found Brian's equivalent statement in another thread, never had another incident...

I've recently started getting it the last two summers, and now have similar symptoms that are obviously related to another fault, SO my comment was really why would it start happening to a previously unaffected car? (my current predicament aside as thats different affecting in cold weather as well and one for another thread.)

Nick

AndyG
17-11-2013, 07:59 PM
I've seen that Andy, but that doesn't give a reason in my case why it didn't used to do it for the first 5 years plus of ownership, ................Nick

Umm. I have been lucky it has never happened to me.

I did remove mine within a couple of weeks of ownership but that was due to it dropping onto the engine.

There were 5 of us in the 35 degrees of Croatia and it did not happen to any of us, even after 2 days where the cars were parked up in the heat outside the hotel.

Maybe it is a drop in fuel pressure due to age or a very small hole in the system that is too small to allow the fuel to leak. (Just a complete guess)

NOCTURNAL
18-11-2013, 04:10 AM
Umm. I have been lucky it has never happened to me.

I did remove mine within a couple of weeks of ownership but that was due to it dropping onto the engine.

There were 5 of us in the 35 degrees of Croatia and it did not happen to any of us, even after 2 days where the cars were parked up in the heat outside the hotel.

Maybe it is a drop in fuel pressure due to age or a very small hole in the system that is too small to allow the fuel to leak. (Just a complete guess)
(cool thanks Herman, dropping back from WYSIWYG editor has indeed allowed me to quote again :D )


Kind of my theory Andy... something must be changing/degrading/wearing out?? I have separate issue now anyway, but am still interested in the resolution to the more general issue.

Nick

NOCTURNAL
18-11-2013, 04:11 AM
Umm. I have been lucky it has never happened to me.

I did remove mine within a couple of weeks of ownership but that was due to it dropping onto the engine.

There were 5 of us in the 35 degrees of Croatia and it did not happen to any of us, even after 2 days where the cars were parked up in the heat outside the hotel.

Maybe it is a drop in fuel pressure due to age or a very small hole in the system that is too small to allow the fuel to leak. (Just a complete guess)
(cool thanks Herman, dropping back from WYSIWYG editor has indeed allowed me to quote again :D )


Kind of my theory Andy... something must be changing/degrading/wearing out?? I have separate issue now anyway, but am still interested in the resolution to the more general issue.

Nick

ian w
18-11-2013, 09:29 AM
Mine has also only just started doing it this summer. the only thing that has changed is that my cooling fan no longer runs on full speed all the time.

Ian

colintf
18-11-2013, 10:24 AM
Do things run hotter due to the changes in fuel supplied at the pump now?

:cool:

colintf
18-11-2013, 10:25 AM
And I mean the pump at the garage not the cars pump :cool:

LeRoiDeLaRue
13-03-2014, 07:33 PM
Mine does it too ... is there no fix, such as putting some slots in the bonnet, like TVR did with the Chim and after market to Griff?

Herman
13-03-2014, 07:54 PM
Mine does it too ... is there no fix, such as putting some slots in the bonnet, like TVR did with the Chim and after market to Griff?

Not really.

LeRoiDeLaRue
13-03-2014, 08:01 PM
Hmmm.... I had a problem on acceleration twice on return home the other day. I spoke to chap who supplied a replacement engine to a former owner and he identified a possible dodgy fuel pressure switch as maybe not responding swiftly enough on demand ... maybe it is linked?

Herman
13-03-2014, 08:14 PM
Hmmm.... I had a problem on acceleration twice on return home the other day. I spoke to chap who supplied a replacement engine to a former owner and he identified a possible dodgy fuel pressure switch as maybe not responding swiftly enough on demand ... maybe it is linked?


If it is something else (or also happens when cold) it might be pump, sensor, dodgy COP or plug.

If they're all OK and it still happens it is most likely vapour in the fuel line due to heat build up. TADTS

WNJ516
13-03-2014, 10:26 PM
Would be interesting to know what fuel pressure the rail is at, and what temp the fuel rail is when this rough idle occurs. What temp does petrol boil at, to cause this vapourisation. I don't presently suffer with it but should it occur will try and take those measurements.

Cribbit
13-03-2014, 10:33 PM
Suffered quite badly from this today. Did an hours drive, stopped for an hour and then had really lumpy idle. Drove for 20 mins, stopped for 20 and same again. Then drove for an hour again and stopped for 10 mins and it was fine. Whilst I do quite like the car's shake and the lumpy low idle noise it makes and the burbling when you bring the revs up with no load it's probably not generally good for the car. It does seem quite random as to when it does it, and it's more frequent since I had the kenne bell heater bolted to the top of the engine. I have no insulation under the bonnet, and plan to fit some vents if I ever get round to having some body work mods done, so will be interesting to see if this helps.

AndyG
14-03-2014, 01:45 AM
Try running without the under engine plastic tray.

I removed mine years ago mainly to aid the view of any liquid leaks.

I understand it was fitted for something to do with high speed running. As I rarely exceed the NLS by much for any length of time :) I have not had any problems.

Without it it would allow the air from the rads escape.

Herman
14-03-2014, 07:50 AM
Try running without the under engine plastic tray.

I removed mine years ago mainly to aid the view of any liquid leaks.

I understand it was fitted for something to do with high speed running. As I rarely exceed the NLS by much for any length of time :) I have not had any problems.

Without it it would allow the air from the rads escape.

Problem is that hot air rises. So when the car is parked, hot air will always travel to the bonnet and not to the underneath of the engine bay,
You may get a little more cooler air depending whether it's windy outside when parked up.

AndyG
14-03-2014, 12:28 PM
Problem is that hot air rises. So when the car is parked, hot air will always travel to the bonnet and not to the underneath of the engine bay,
.

But it would help to draw in more cool air from below and reduce the air temp above the engine.

Herman
14-03-2014, 04:33 PM
But it would help to draw in more cool air from below and reduce the air temp above the engine.

Hardly, as the air has limited way of escaping there will be no significant flow unfortunately.

Had to get my science book out for that one :)

LeRoiDeLaRue
14-03-2014, 09:39 PM
Fascinating ... maybe discrete slits in bonnet plus removal of a tray I never even knew was there ... I am shocked I spent six two on a two six and never even bothered looking underneath the thing :-/

AndyG
14-03-2014, 10:27 PM
Hardly, as the air has limited way of escaping there will be no significant flow unfortunately.

Had to get my science book out for that one :)

Ah, but that's how hurricanes are formed cool air meeting hot air.

LeRoiDeLaRue
14-03-2014, 10:37 PM
My temp gauge reaches :
:
:
:_____________________
:
:

...... After 10 mins driving and stays there, no matter what ..... after 570 miles in three days , 460 of them in 24 hours, I wonder is the needle stuck or is my cooling system really neat?

Herman
14-03-2014, 10:48 PM
My temp gauge reaches :
:
:
:_____________________
:
:

...... After 10 mins driving and stays there, no matter what ..... after 570 miles in three days , 460 of them in 24 hours, I wonder is the needle stuck or is my cooling system really neat?

Needle stays round the middle between 75 and ~100 degrees or so.(someone will correct if wrong)
Done not to alarm the driver when temperature fluctuates

It's not a real representation of the actual temperature

pider100
15-03-2014, 03:59 AM
I have had this problem bad since I bought mine. Last week, changed all the spark plugs for the NGK recomended upgrade, which handle the temperature better apparently. (Bought them a while back as part of the Terminator SC upgrade which I STILL haven't got round to!!!!) So far been running great, but no sunny hot days as yet to test it.

pider100
15-03-2014, 04:04 AM
I have also got a marine 100mm duct fan to install, to draw cooler air from below the belly pan up to the top, and I intend to put vents in the bonnet during the SC install.

Julianp
15-03-2014, 10:45 AM
This sounds like fuel vaporization, which affects the fuel/air mixture and can cause the engine to misfire and idle roughly. I used to get this periodically with my (standard) 260 in heavy traffic in Paris during hot weather. On a couple of occasions it triggered the check engine warning light and I had to reset the codes, but it always fixed itself once the car had cooled down.
Julian.

LeRoiDeLaRue
15-03-2014, 11:03 AM
Oooh ... any links to the kind of bonnet vents that might suit our motors? Anyone know any good specialists doing such work in the north of UK?

Nich
15-03-2014, 11:28 AM
When you go Green Jim you will be able to see where this link leads to:

https://www.two-sixties.co.uk/mgoc260/html/f0rum/showthread.php?9665-Bonnet-vents-How-they-are-performing&highlight=bonnet

Nich.

Nich
15-03-2014, 09:12 PM
What about this:

6148

connected to this:

6149

Using the wireless remote to activate the fan when necessary.

Just have to work out where to mount the fan.

Nich.

LeRoiDeLaRue
16-03-2014, 10:49 AM
Thing is, I dont actually see the engine overheat ... the needle stays where it stays.

The flattening on acceleration needs sorting though - at 3500 yesterday in second it happened and two scallies in a standard ford focus flew past me :fight2

... i actually felt myself blushing ...

backing the foot off a smidgeon and then immediately back on cures it though

not the blush ... the fuel supply thing

Nich
16-03-2014, 11:15 AM
It's not necessarily the engine that overheats but the fuel rails that get too hot. This vapourises the fuel in the rails and causes flat spots in acceleration. It might also be the fuel supply system i.e. the pump, have you checked for separation? Have you got the orange clip mod? Is it a COP breaking down? Lots of things to check but you need to get it sorted you can't carry on being overtaken by scallies.

Nich.

LeRoiDeLaRue
16-03-2014, 12:27 PM
It's not necessarily the engine that overheats but the fuel rails that get too hot. This vapourises the fuel in the rails and causes flat spots in acceleration. It might also be the fuel supply system i.e. the pump, have you checked for separation? Have you got the orange clip mod? Is it a COP breaking down? Lots of things to check but you need to get it sorted you can't carry on being overtaken by scallies.

Nich.

Cheers Nich - indeed i cant :) It is also about the old MG motto - safety fast

Mark Sibley of GT Racing in Honiton was very helpful when I rang him to confirm the replacement engine was indeed supplied by him back in 2010.
He suggested it may be the fuel pressure switch on the fuel rail that might need replacing, as a first fix - can these be checked on a diagnostic? Throttle position sensor was also mentioned as a possible, along with a microweep on fuel line.

Yes the fuel filter has had the clip has been put on under previous owner.

NOCTURNAL
16-03-2014, 12:31 PM
What about this:

see above

connected to this:

see above

Using the wireless remote to activate the fan when necessary.

Just have to work out where to mount the fan.

Nich.


whilst I would rather get to the bottom of the issue, if this would cure the symptoms, I'd consider it..... can we have an expert opinion on how long a solution like this might take to cool the fuel rail once applied? Lets assume some form of ducting to ensure cooling of the actual rail area as well...
what I am saying is once it had reached this 'faulty' state is that too late to turn on the fan?? or would it need to be running permanently?

still interested in the 'why' when it hasn't done it for many previous years of identical driving patterns..

Nick

Herman
16-03-2014, 01:10 PM
Vapour in the fuel rails is not uncommon on cars with a non-return system.
It can also be rather random. I have noticed it on mine in 7 years of ownership probably twice.
Both times the symptoms went away after a few miles of normal driving

As the problem is with heat soak from the engine, getting the heat out is the best option.
Bonnet vents will prevent heat build-up and allow hot air to escape, reducing the chance of vapour lock.
It could create another problem though with regards to water ingress and the electronics (injectors, COPs etc)

If the symptoms are caused by a failing COP it would gradually get worse until the COP fails consistently under load.

Any issues with the fuel supply (pump, pressure sensor, pump module or filter separation) would most likely be noticed on every run.

I don't think an additional fan will cure the problem because the radiator fan will be running most of the time when stationary anyway

peterv8
16-03-2014, 02:13 PM
Maybe this or something simular is a solution?

Open the hood electrical to let the heat out when staionary.:)


http://www.youtube.com/watch?v=3MTN82KqHRc

ksilver
16-03-2014, 05:20 PM
Random thought; if this is something more are experiencing as the cars get older, could it be the fan/relay failing?

I had a fan/relay problem which I eventually replaced with a Kenlowe and relay from Jules and have had no issues since, but in the midst of the problem/diagnosis I had Brian fit a Kenlowe switch which is a simple manually adjustable fan control, it's still there as insurance.

LeRoiDeLaRue
16-03-2014, 06:23 PM
my fan works fine

SJR
16-03-2014, 06:34 PM
My bonnet vents made a huge difference to this problem, I can't remember having any vapour lock issues since doing the vents but I had lots before.
https://www.two-sixties.co.uk/mgoc260/html/f0rum/showthread.php?8607-Bonnet-vent-project

SJR