The MGF Register Forums

Hi Guys, I live in the Solihull area and was wondering if anyone has a fault code reader.
I took my f out over weekend and when the engine got up to temperature it started to judder quite bad, I have replaced plugs, coils and leads, problem still there. Looking at the symptoms fan comes on tick over 1200 rpm even when up to temperature and when it cools down it drives lovely,
Maybe a sensor, don't know.
Any advice appreciated.
Andy

Coolant temperature sensor is suspected here. If it fails, the ECU will assume a low temperature, just to be on the safe(st) side.
The guage in the dash uses a different sensor, so that might be working as expected while the ECU hasn't got a clue about the coolant temperature.

Quite easy to replace and not that expensive.


PS. having a T4, but not even close to Solihull .... the closest I get is the Freelander 2

Thanks Eric, I have done a quick search on the forum, some suspect the throttle body, but mine is a metal one, but thanks I will replace the temperature sensor .

If it’s not too urgent I could pop in with my PScan on the Saturday afternoon next week, Andy. I’ll be collecting some wheels from a company in Longbridge (B45) before 12.00 and go on to Stoneleigh from there.

Thanks, I live close to stoneleigh only a10 minutes drive.
PM me and I will give you my address.

PM sent.

Michael ,many thanks for stopping by and diagnosing the problem which I had on my F with your diagnostics tool, which turned out to be the TPS sensor and the camshaft sensor. I thought it would have been the coolant temp sensor which I purchased an original MG one which is now surplus.
Much appreciated Michael.
Andy

Was a pleasure, Andy, I’d do anything for a good cuppa.

Sensors already sourced at Stoneleigh, see you tomorrow. Just hope it’s really them and not the wiring …

Me too.

I have replaced parts today and problem still exists, the problem starts exactly driving for about 10 miles, like pulling out the choke.
The only thing I have not replaced is the coolant temperature sensor as Michael's gadget said the values were good.

Time for a www.pscan.eu ?

I have seen coolant temp sensors which are good when cold or warm and then fail as they get hot. The one inside the automatic transmission of my 607 does that, and I have had the coolant one do the same. I'm not saying it is that, but you need to drive it until it fails and then look at live data to see what has gone out of wack.

Thing is, the TPS isn’t giving any reading at all, as a replacement made no change I guess it’s a broken wire in the engine loom. Had that too a couple of years ago. Swapped the complete engine loom for a good replacement, all probs sorted.

Could it be the ECU itself, when the car reaches up to temperature there is a funny smell coming from the engine bay.

Andy, the engine bay smell is unlikely to be the ECU: the charcoal cannister is in that locale, and you'll get all sorts of hot oil/ combustion gas type odours in this area.

Ideally, we'd need to pop the pscan.eu back on the car to see whether the faults that I guess Mykel will have cleared reappear. If new sensors, and continued sensor faults, then this would appear to point more towards a loom fault IMO.

Andy, for a start here’s the TPS connection to the big connector on the ECU. It’s all straightforward, no slices or taps in there so should be quite easy to measure: If you’ve got a multimeter, you could try a first measurement between pins 1 (+) and 3 (GND) on the TPS connector; with ignition switched on this should give a 5 volts reading. If there is no voltage, you would have to disconnect the big connector on the ECU and find pins 20, 34, and 46 and check connection to the relevant pins on the TPS connector. I guess that one of these wires must be broken.
To find the right pins on the large connector, here’s the layout:

Thanks Michael

The "sockets" in the plug are very small so when testing them I use a straightened paperclip or a sewing needle in the relevant "socket" to attach the multimeter lead to.

Thanks for all the replys guys. I was chatting to a mate a few days ago and I was telling him about this problem, he mentioned have you checked the catalytic converter. No I havent, So last night I inspected underneath and banged the cat with the palm of my hand as he said to do, and there was a rattle in there, could this be the problem as when it gets hot could be trying to choke the engine and cause that smell.
Before I splash out on a replacement I need to be sure, any comments guys.
Andy

Every issue you encounter reminds me of my first MGF, Andy. I also had a rattling cat back in the days and when I took it off in the end, the core had indeed shrunk to a potato-sized something. Obviously, I had to swap the cat for the emissions test, but apart from that no negative issues could be noticed when driving.
I had a look at the fault list recorded last weekend, and the dreaded P0170 error (fuel trim malfunction) is on that list. This could be a hint to a dying cat (or a faulty lambda sensor). But it didn’t show up again after the errors were erased.
Btw: would it be okay for you if I posted the screenshot with the error codes here?