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mg_tf
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Discussion Starter #1
Morning All

My first post here as I've just joined following the purchase of a very nice 2003 TF with just 50200 miles for the better half. On the drive home with her new pride and joy through rush hour traffic I noticed that a sporadic niggle. it only seems to appear when you pull up and stop take it out of gear, it flutters like its going to cut out the engine warning light flashes on and off. When you give it a little revs all is back to normal.

The car had a quarter tank of fuel when I picked it up and it had been sat unused since Easter. Once I got it home I had a better look around it and on removing the petrol cap to say there was an inrush of air (it sounded like me running up stairs). We have filled it with BP extra fuel and I will dose it with Redex over the weekend.

The better half drove it to and from work yesterday a 25 mile ish round trip said it happened once on the way to work and wasn't much better on the way back.

It doesn't appear to be temperature related and both the oil and water temps seem to be where they should be.

I'm guessing at the moment it's fuel related as the fuel tank seems not to be "breathing", but I am hoping that you esteemed lot will be able to point me in the right direction.

Many thanks in advance

Tubs
 

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MG TF
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:welcome:

When opening the filler cap the inrush of air (and noise) is normal.

I would from the description that the problem could be with the ignition system, perhaps the leads and/or the coils this tends to manifest itself when damp or when the engine is hot.

A flashing engine warning light is more of issue than a static light.
 

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mg_tf
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The reason the air rushes in is that the tank is supposed to be under slight negative pressure so fumes don't escape.

As for the fluttering, ChrisT's suggestions sound about right. You could also try resetting the idle. This involves some kind of sequence with pumping the accelerator five times completely down with the ignition set to a particular position, then waiting for so many seconds and restarting. Obviously, I can't remember the details! You can search for how to do a reset on this forum. Maybe worth doing as it's simple to do.

Just found the destructions:

Rare cause of this problem- but easy to rectify if present: to reset the TPS, switch ignition on, and depress throttle fully five times in 20 seconds, and switch off for 10 seconds. This resets the TPS.
 

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mg_tf
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Discussion Starter #4
Many thanks for the responses so far, I will reset as per the instructions and a new set of leads wont hurt either and neither break the bank so all good

Cheers for the help

Tubs
 

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mg_tf
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Discussion Starter #5
Just a quick update, fitted new coils and leads took it for a nice run to get it warmed up and all good so far. The better half will take to work today so that'll be the acid test.

Thanks for your help guys much appreciated

Tubs
 

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You say that you have just bought the car and it has been sitting since Easter. How long is it since it has really been driven?
These cars do suffer from old fuel breakdown which can give rise to the symptoms you describe. As you fill up with new fuel you may find that the problem disappears.
This is fairly typical of cars that are mainly only used during the summer months as the low mileage suggests.
The flashing engine management light is probably caused by the engine being at the point of stall but keep an eye on it.

Mike
 

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mg_tf
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5 posts, and no-one has taken the time to explain the most FUNDAMENTAL rule of this forum! :frown:

Come on people..

We need to see pictures of the car!
 

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mg_tf
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Discussion Starter #11
You say that you have just bought the car and it has been sitting since Easter. How long is it since it has really been driven?
These cars do suffer from old fuel breakdown which can give rise to the symptoms you describe. As you fill up with new fuel you may find that the problem disappears.
This is fairly typical of cars that are mainly only used during the summer months as the low mileage suggests.
The flashing engine management light is probably caused by the engine being at the point of stall but keep an eye on it.

Mike
It was used as a daily driver till Easter when the previous bought herself a BMW convertible. As I previously said there was only a quarter tank in it when I picked it up, and I filled it up with BP Ultima once I got it home.
Now the new coils and leads have been fitted it is running great acorrding to the better half.:smile:
 

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mg_tf
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Discussion Starter #12
Right a quick follow up, after a couple of days of the coil packs / leads being changed the problem returned.

So having trawled the forum and finding similar faults I'm now hedging my bets on the MAP sensor. The days the car was ok were when it was a wee bit chillier, the problem seemed to be worse the warmer the ambient temperature.

This seems to fall in line with the MAP issue. I have TOAD diagnostic software which I bought last year for a problem on my BMW, I also had a very nice USB lead to connect it from the car to the laptop, but since we've moved the lead has vanished and I'm awaiting a shiny new bluetooth plug to leave in the car so I can monitor it on the move, got to love geeky technology, hopefully it'll arrive so I can get some readings.

So MAP sensor is ordered and will be fitted Saturday morning.

I've got a feeling this is going to be a Johnny Cash car and I'll be replacing it "one piece at a time", Still at least I can fix the majority of the things myself.

Happy Spannering

Tubs
 

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mg_tf
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Discussion Starter #13
The Saga continues

So imagine the scene, drove the Johnny Cash car on a 20 mile round trip yesterday to pick up the MAP sensor top down glorious weather smiling like a Cheshire Cat, JC didn't mumour once, had I been hasty in my evaluation of the fault? With a house full of guests and BBQ to sort out I delayed my spannering till this morning, and I would now like to enlighten you with the next part of the saga.

I fitted the new sensor fairly quickly would have been quicker if my allen keys could be found but that another gripe. All done we set off to see the outlaw's and we hadn't got out of the end of the road before the hateful orange flashing light comes on to a full on rave laser show. Power was down then on then off, we had reached the A13 by this time anf thought I try and give the beans to no avail.1 junction less 2 miles and we're on our way back, power just not there and now its starting to smell fairly bad. Get it back on the drive to find smoke bellowing out from the underside. At this point I'm beginning to see this a real sign something is well and truly amiss. Open the boot smoke! pull out all the contents and the liner the paint below show definite signs of high heat. Take a peek underneath to see a cherry red CAT, I'm fairly sure a CAT resembling a Turbo on full chat isn't a good thing and seeing as how it was melting the boot liner.

Hose pipe summoned liberal spraying of the effected area's panic averted.

So in summary a blocked CAT seems to manifests its self as a failed MAP as if you cant get Air in, it'll have the same affect as not being able to get Air out.

There is one silver cloud out of all of this, I have convince the better half that a full 4 branch stainless system will stop it ever happening again.

Now which one do I choose? Answers on a post card of the electronic equivalent.

Tubs
 

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Whilst a blocked cat would have a significant impact on performance I don't know about the over heating. Unburnt fuel normally causes this to happen. Also faulty map sensor and persistent misfiring. Have a look at the colour of the plugs to see if they are sooting up.
 

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mgf
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i agree with barking dog... unspent fuel in the cat will catch fire... why? because its a very fine mesh filter.. like a sponge :)

its says that if the car cant idle... it might be the IAC is sticking, or even the idle screw isnt set properly... a number of things can cause bad idle.. but i think your mixture is too rich... so either the ecu cant set the timing or an injector isnt closing or the air isnt sufficient to burn all the fuel.

read this to understand how the IAC and ECU work together..

if the ECU cant get the right info... you should get fault codes... if not its because the sensors are giving readings within spec the ecu expects... but not correct for the condition actually there, so the ecu tries to set a wrong condition.. and still the sensors arent telling it something is wrong.

MGF & MG TF Owners Forum - - Rev fluctuating (1/1)


from that link i quote Badger "I had an issue with high idle; found to be a warped face on the crappy plastic inlet manifold (drawing air) I fitted an alloy manifold and 52mm throttle body from a Freelander, this cured the high idle but now I had hunting at idle. A re-set would cure the hunting for a bout a day but then it would come back.

I suspected the IAC so I fitted a new unit, this made no difference.

The cure for me was to get the engine up to normal operating temp and do a TPS re-set, re start the engine, unplug the IAC, remove the plastic inhibitor on the head of the idle screw, wind in the screw until the RPM just started to rise and then wind the screw out to get your 850 RPM, switch off and a final re-set.

Since then the idle (about 3k miles) the idle has been rock solid steady."


make of that what you will, Badger replaced the IAC, it made no difference..he had to reset the Throttle Position Sensor....


but.. for some reason you have an abnormally high unburnt fuel content in the cylinders , being pushed out and collecting in the cat - where it caught fire... Tubsie.

i would also suspect the condition of the oxy - Lambda sensor now.. since with unburnt fuel going past it... it wont be reading correctly because it wont be getting up to temp.. so it will be lying to the ecu too.
 

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mg_tf
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Discussion Starter #17
Hi Guys

Thanks for the responses, and what you say certainly makes sense, however it ticks over ok, this only appears to manifest itself under load, as said before I have now changed the coil packs and leads new plugs the old ones were a nice straw colour, and I've now changed the MAP sensor prior to this mornings run.

I have read on here that some CATs had ceramic blocks in them that can deteriorate

So once again I'm dazed and confused, I will wait for the my Bluetooth OB2 plug to turn up and see if I can get a reading out of it. Seeing as we want to be keeping the car for the foreseeable future a new exhaust is probably worthwhile.

Cheers again

Tubs
 

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mg_tf
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Discussion Starter #18
The saga continues,

OB2 plug has arrived and I have stored codes

P0300

P0313

So if any of you esteemed enthusiast have any idea's I would be truly grateful.

Cheers

Tubs
 

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mg_tf
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Discussion Starter #19
A section of Julians comprehensive list from another post

P0300 Random/Multiple Cylinder Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected
P0305 Cylinder 5 Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0307 Cylinder 7 Misfire Detected
P0308 Cylinder 8 Misfire Detected
P0309 Cylinder 9 Misfire Detected
P0310 Cylinder 10 Misfire Detected
P0311 Cylinder 11 Misfire Detected
P0312 Cylinder 12 Misfire Detected
P0320 Ignition/Distributor Engine Speed Input Circuit Malfunction
P0321 Ignition/Distributor Engine Speed Input Circuit Range/Performance

There doesn't actually appear to be a P0313 so that's a little worrying, more of a concern is why / how the misfire is occurring seeing as I have changed the coil packs and leads, am I now looking at changing the engine bay wiring loom?

Cheers

Tubs
 
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