: Rover 45 Intermittent loss of power problem


Tridge
27-11-2007, 20:09
Hi, I have a W reg (2000) Rover 45 1.4is with an annoying fault. I will try and explain as best as possible. What I am finding is i start the car no problem, I drive for 15 -20 mins stop for a short period eg filling up at the petrol station. I start thr car no problem but when I go to pull away I put my foot on the accelerator and there is nothing there it almost sounds as if the car is going to die on me but if i keep my foot on the accelerator hard enough and long enough the engine seems to clear its self and I suddenly surge forward. Generally I seem to drive through the problem and it does not bother me again until the next time. It does not happen all the time and it can hapen from cold (but not very much).
So far I have had the ECU checked - nothing was wrong but they reconfigured another one to try and there was an improvement.
Spark plugs have been changed
Oxygen sensor was faulty for MOT so has been changed
Recently we have tried swapping the coil packs but it has made no difference. Various other obvious things have been checked but to no avail. The garage I use is a Rover specialist but they have not come accross this problem before. The only time there seemed to be an improvement was between the ECU being changed and before the faulty oxygen Sensor was replaced.
Has anyone got any ideas or things i can ask the garage to see if they have checked them?

KSeriesMike
28-11-2007, 21:46
First off i would have said check the lambda (exhaust oxygen) sensor but seeing as thats been done, it leaves a few other possibilities..

When you say the car clears itself after a while.. it makes me suspect fuel rather than ignition.. i might be wrong though. I would have thought ignition problems would cause problems from the start and wouldnt clear.

If it were my car, I'd be wanting to check the operation of the fuel pump, and check if the fuel filter has been replaced. (depending on mileage)
I'd be wanting to confirm that the fuel system is getting up to pressure properly. Dont know how to go about doing it though.. (maybe a garage job)

I think faulty mass air flow sensors can cause running problems like this too, as the ECU is unable to accuratly set the correct fueling for the amount of air taken through the intake.. but i dont think the 1396cc K series engine is fitted with one.

Tridge
01-12-2007, 17:14
Many thanks for your reply. Have checked fuel in tank - no water etc. I think the garage have tried swapping a crank shaft sensor but this has not worked either. I will chat with them on monday with your thoughts but would be grateful for any others if any one has some.

mihai
02-12-2007, 08:18
Tridge i have the same problem but rarely.. and only if I push very slow on accelerator .. the RPM is going under 1000 .. to 700 or something like that.. the engine sounds like it will die... stay there 2 seconds.. and then back to normal.

It hapend 2 times at round maxim..
But as I say.. only if i presh the paddle very slow and the take the foot off.

Stu68
10-12-2007, 20:25
Hi

This sounds very familiar, had similar probs with my 214. Got it sorted for 9.00!

Check this thread:

http://forums.mg-rover.org/showthread.php?t=220785

Stu

MarkR45
12-11-2010, 12:19
Sensor problems on my Rover45 causing major engine hesitation shortly after starting but then seemlingly to run normally.
Plugging in a ScanGauge showed all sensors OK but major fluctuations in oxygen and the short term fuel trim when conditions constant.
Crucially the Xgauge function showed the engine starting correctly in open loop control and problems only starting when switching to the closed loop mode (when the oxygen sensor affects fuel delivery). After a while (minutes) the ECU gives up on the closed loop control and reverts to open loop control for the rest of the journey and all then seems normal.
I unplugged the oxygen sensor and this set the engine in open loop mode only and the problem disappeared. Hooray - definately the oxygen sensor then.
In all this the engine warning light did not come on! Replacing the oxygen sensor (easy, I did this from underneath not as the Haynes manual) and reconnecting it sorted it properly.

So if you want to diagnose whether the fault is either in your primary engine sensors used to look up the fuel table or else in the oxygen sensor that then trims the fuel value I recommend you try disconnecting the oxygen sensor to see the effect. If the sensor is faulty it will be better for the engine to run without the sensor until you can replace it. Don't worry about the post catalyser oxygen sensor as this does not affect the fuel trim.