No power beyond 3700rpm!! HELP! - fiesta man

I have just got my car back from having the clutch and slave cylinder replaced, at which time it seems the battery was disconnected. I don't know if this is linked to the problem I have now got, but is is a remarkable coincidence!

Anyhow the problem....

When accelerating the car loses all it's go as soon as the revs reach approx. 3700 rpm, which is very annoying, and very hard to understand. It's almost as if the engine is retarding itself, as the engine note changes quite a bit too.

Does anyone have any ideas why my car should suddenly start behaving in this way, when it was fine prior to the clutch change?

I would be welcoming of any ideas.
No power beyond 3700rpm!! HELP! - fiesta man
appologies for sub-standard spelling above - the post was rattled off far too quickly... shame there's no edit function!
No power beyond 3700rpm!! HELP! - pastyman
Hi fiesta man,

Try disconnecting the battey and going through the learning procedure again, but as the manual tells you to.
To allow the ecu to learn the values of the sensors on you car, allow the car to reach operating temperature at or as near to idle speed as possible, then run it for 2 minutes at 1200rpm. The next step is approximately 5 miles of varied road conditions, after this your car should have re-learnt all its values and hopefully should run a lot better.
This might do the trick.

All the best Pastyman.....
No power beyond 3700rpm!! HELP! - Peter D
I assume the management light has not come on. I ask this as the open loop operation due to a faulty O2 sensor will limit the engines performance and max rpm to protect the Cat The first thing to do is go back to the dealer and ask them what they have done that could cause this problem and hook into the ECU for a sensor check and O2 reading, at least then if after you have tried to fix the problem without success you have an open channel to return to the garage. I have experienced this on a Golf after the clutch and engine mountings were changed. It turns out that the earth for the O2 sensor shares the same bolt on the rear engine mount and this had been disturbed and was causing noise on the sensor signal. Remade a clean earth and AOK. Regards Peter
No power beyond 3700rpm!! HELP! - fiesta man
The car doesn't have an engine light, but it has been hooked up to a ford OBD2 monitor and no faults codes have been revealed. Though there is a question over the values from the TPS - supposedly on the continous monitor no WOT value is being reached, even when the pedal is fully down.

The lambda sensor is only 2 weeks old (see earlier thread), and the CAT as far as I'm aware is fine - I can't see it would have collapse over the few days the car has been in the garage, though if others have experienced this I'm open to their views.

No power beyond 3700rpm!! HELP! - fiesta man
Do any of the tuning people have an idea??

TPS was swapped to no avail, and now the garage is totally stupified - they can't locate the problem....!

I'm presuming the ECU is too stupid to find a fault with a sensor, though one exists.

Can anyone provide me with the test methods for the:

MAP sensor;
Cam & crank sensor;
and finally the Mass Airflow sensor?

I have an oscilloscope and a standard multimeter, so I'm hoping I've got sufficient equipment.

I'm guessing i just need to check all the sensors until I find a dud one.
No power beyond 3700rpm!! HELP! - Another John H
Try this American sites as food for thought:


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