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MG MGF Technical - Reving engine

Hi all,

First day of sunshine, day before going on holiday and the car plays up.

I have a 1.8 vvc, Driving along and the car started reving as if the accelerator is stuck...but on inspection it is not. The butterfly is closing as it should. It runs at a tick over of about 2000 rpm with a sucking noise from the filter. If you rev it it stays high and slowly drops.

I guess one of the sensors has packed up. I have rulled out the throttle body by rep[lacing with my old one to no avail.

Has anyone heard of this problem before?

Regards

don
don k

Don, the simple things first, check the stepper motor valve is seating correctly, remove from plenum and clean the valve and seat. If problem persists then check/replace the oil temp sensor on the hydraulic controller. Other than that you need to have it checked on a diagnostics computer to pinpoint the defect.
mike

thanks mike i will check this out
don

Checked all that i can so Car now towed to epsom mg rover for diagnostics and repair, they have said the tick over when they started it up was 4000 ....ouch now glad i didn't try and drive it there hee hee.

will post findings

don
don k

Well garage called to say ECU, Stepper motor and temp sensor all shot :-( an expensive day

Cost of running an mgf vs enjoyment of mgf now in question!!

don
don k

"Well garage called to say ECU, Stepper motor and temp sensor all shot :-( an expensive day "
Ask for the parts to be retained as the ECU can be checked for about 20quid, I find it a hard to swallow all three are shot. Ask for a print out from test book as well.Call me sceptical;-))
mike

Hi sceptical;-))

I would wonder at this as well,
Don, which garage is quoting this ?

M.
Mike (Mersea)

"Call me sceptical;-))"

mmm me too. I feel that they have me by the short and curly's. I always work on my cars myself, but once you are into the realms of electronics you are in there hands some what.


I have already stated that i want the old parts returned. Garage is main dealer MG rover in epsom EMG

mike where do you get the ecu checked out?

don
don k

Don, you could refit the ecu back to the car when it is returned to see if the problem 'returns'. You can find companies that repair ECU's in the Auto Trader usually.
HTH.
Mike.
mike (sceptical)

I have been getting a similar problem with my 1.8mpi, Car starts to high rev just about the time the thermostat will be opening for the first time. If you rev it it fall slowly After a while when the car is operating at full engine temperature the problem seems to diminish. I am sure that it is the sensor on the water manifold and is acting like an automatic choke. But not being sure it may have to go in to be checked with the testbook. The last time I did that it was a rotor arm tracking problem (£7.20 for the rotor and £75.00 for the labour to fit it) so I am a bit loathe torepeat the experience.
Nkosi_Ecosse

All shot ?
Can't believe, but who knows. There would be more damages if the 5V supply for the sensors increaeses by any reason from inside the ECU.

The sensors are all _resistor like_ NTC's with app. 2k Ohm.
http://www.mgfcar.de/sensor/index.htm
There are no Testbook requirements to check each individual sensor from that circuit ;)

Had similar high idle troubles for a couple of month. Changed the coolant sensor, changed the TPS. Pulled sensor connectors and cleaned them etc. etc. with no result. The only Testbook indication was _coolant sensor_ failure and vacuum failure. The latter cause I had once pulled off the vacuum hose from the inlet manifold while the engine was running. So this didn't count.

Notice, the wires of the sensors have two ends. One at the sensor, the other at the ECU connector.

In my case the final solution was to re-route the ECU connector wires. Lead in smooth curves to the connector.
A cable tie had come off from the ECU bracket or had never been on. The ECU harness had dropped with stress to the ECU connector.

I've no evidence than the experiance:
After I led the cables, I never again had the idle problems. This is nearly two years ago. Didn't touch the connector sin
ce that date, though.

http://www.mgfcar.de/mems1.9/connection_Dsc02514.jpg

Good luck with it.

Best
Dieter
Dieter K.

Update,

Car now ready for pick up. Reminded garage that i would like all old parts. They now tell me that there is a £100 surcharge on the old ecu if i retain it as they send them back to mg rover for reconditioning.

Q. is this normal?

looking forward to getting the car back :-)

don
don k

New ECU, Stepper motor and coolant sensor + diagnostics tot £672 car seems to run fine now but engine bay warning light came on last night and engine stalled- thats never happened before, maybe a trip back to garage

don
don k

Dooh, a huge invoice. I'm sorry for you.

I think the surcharge is usual.

Don't get me wrong, but I presume the next they will change is the harness between the ECU and the sensors.
Dieter K.

Don,
Think about getting a parts and labour warranty from the AA ??

You have to wait 15 days before your first claim though.

Warranty Direct do a similar, slightly more comprehensive policy, also slightly more expensive, but you can claim straight away, providing it breaks down.

Adrian
Adrian Clifford

I think some policies (WarrantyDirect) do not cover electronics.

You should check!

Peter
P J Stubberfield

I have only just seen your e-mails & even though I am a novice & it may not be helpful. On my 1994 Rover 220 Gti, in 2001 I had a problem with the engine over revving, holding the revs & even increasing without me even being in the car, especially in hot weather it drove me mad. After spending ages on the ECU diagnostics machine they couldn't tell me anything & wanted to charge a fortune. So I bought a replacement ECU unit for approx £100.oo & the problem was sorted.
Gary Wright

This thread was discussed between 28/03/2005 and 13/04/2005

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