20 replies to this topic

[electricfurnace]

My 1997 MPI is still hunting and the revs are wavering at warm idle and I just cannot figure out why. When cold it is ok.

Diagnostics check was inconclusive.

I cannot see/feel/hear any air leaks,or exhaust leaks, plus it passed MOT a month ago so emmissions should be ok.

I have replaced the following with new parts throughout:

Idle Control Valve
Throttle Position Sensor
MAP Sensor
Coolant Temp Sensor
Air Temp Sensor
Coilpack
ECU Relay
New Oil, Filter, Plugs, Air Filter
New Flylead for coolant temp sensor as per Rover bulletin
Extra Earth Strap from Alternator top bolt to slam panel

I'm really at a loss! Anyone have any ideas?

[Miniminx71]

I had the same problem on my MPi and it turned out it was running a bit lean. Lean mixtures create more heat so can cause the engine to misbehave once it gets to temperature. Did the diagnostics measure the fuel mixture?

[electricfurnace]

Don't think they did measure it...trying a different place on saturday. I assume mixture can only be adjusted by rover t4 diagnostics?

Edited by electricfurnace, 28 August 2014 - 08:58 PM.

[Midas Mk1]

tried an acr4? you'll be able to see readings from the sensors and injection components etc, to see whats going on.

[electricfurnace]

Difficulty is finding somewhere near me in South Wales that a) has the right equipment and b) knows what the ******* they are doing on an MPI.

[Miniminx71]

Mine was fixed by my usual mechanic. It didn't go anywhere special. DMS Motor Vehicle Services in Pontypridd? Just googled them and they say they've had specialist Rover training. Might be worth giving them a ring?

[FlyingScot]

Don't think they did measure it...trying a different place on saturday. I assume mixture can only be adjusted by rover t4 diagnostics?

Nope mixture cannot be adjusted as such. The sensors tells the MEMS unit the operating conditions and it adjusts the fueling and the timing.

FS

[electricfurnace]

Had it re-diagnosed at a good place today, Dave Coe in Swansea.

Cylinder leak so needs top head rebuild. Not the best news!

[Fossy313]

At least you have finally found the problem mate.... Maybe when you get the head off you will have a better idea of what the cause is.

[electricfurnace]

Thats odd....changed throttle body to a new one and all is well, no hunting!

[Fossy313]

Might have been the seal in the throttle body there is a small seal underneath which could have been faulty which could have produced a leak?

[Ruckus]

The plastic ones get so hot they warp over time.

 

Alloy one is the way to go.

[MiniCooperMan]

Hi i have a similar problem with my 1998 MPI,revs just under 1000 then drops too nearly zero,then back again If you rev it it splutters jerks rev her up black smoke from exaust ,weired thing is it can run perfect for say a couple of weeks ,then she plays up again,any advice please,regards Bill

[Ruckus]

Hi i have a similar problem with my 1998 MPI,revs just under 1000 then drops too nearly zero,then back again If you rev it it splutters jerks rev her up black smoke from exaust ,weired thing is it can run perfect for say a couple of weeks ,then she plays up again,any advice please,regards Bill

I don't know about the smoke but the rest sounds like the problem I chased on mine for a year or so. Mine was the Idle control valve and TPS, once they got set up correctly all is prefect now.

Edited by Ruckus, 12 September 2014 - 06:35 AM.

[miniphil53]

Hi

Not sure if this will help you but this is the problem I had 2 weeks ago.

 

I had re sprayed the front and had disconnected the battery and ECU for some welding.

When I came to refit and start the engine it stalled after a couple of minutes, 

Re checked connection that I had moved when cleaning, it seemed ok.

Went to Stanford Hall from Birmingham Just come off the M6 and it stalled started straight away on the key.

It did it again going and 3 times coming out of the grounds.

Ran OK on the motorway but stalled near home.

Looked on the forum Tried Catclearer and idle control valve still the same.

Disconnected battery left over night.

Unplugged the ECU sprayed contact cleaner on the pins checked all the cables going into the plugs .

I fitted an extra earth cable to the block.

 

Problem gone.

 

I have disconnected the ECU before with out problems.

So perhaps the earth is braking down as it did start straight away on the key.

I hope this  helps