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Low power/hesistancy

Justino

Member
Just had a weekend in Wales, around Snowdonia, Evo triangle etc (although now is all average speed cameras). All told did 450 miles between Friday and Sunday, before being packed away for the winter.

On the way back, on a motorway section after about 5 hours of driving, the car had low power, poor acceleration, best described as loss of torque - similar to old fashioned carb icing up, ie fuel starvation. I had to down change and rev it to get it to accelerate anything like it should, but still down on power. Wasnt a misfire, which would have suggested coil pack, and no EML.

The fuel light had come on, but range was still 60 miles, so perhaps 2-3 gallons remaining. Initial thoughts were perhaps it was moisture in the bottom of the tank as I'd not had the fuel light come on for a few years as always try to keep the tank as full as possible to reduce the chances of condensation forming.

I pulled over and turned ignition off, checked the oil etc, but everything looked ok. Was stationary for about 3 or 4 mins. When I started back up the problem had gone, back to pulling nicely, and did last 35 miles home no issues at all.

Any ideas - is this the hesitancy i have read about elsewhere, but saying that you couldn't rev through this. Car has just gone over 38,000 miles this weekend, and serviced this summer - Insp II. Car was running BP Ultimate fuel.

Any ideas appreciated.
 
Always check for codes first, they won't necessarily flag the component but they do direct you towards the issue, if you don't you can end up chasing your tail as these symptoms could be so many things from VANOS as mentioned, a sensor to fuel pump or even as one of my other cars had this year with the exact same symptoms a Cat that was breaking up inside restricting flow. Drove fine for ages then suddenly lost all torque feeling like the brakes were on! Stop and all was fine again.
 
I'd put good money on it being a bad exhaust cam position sensor. Get the codes read, if you get p0017 flagged it's an easy fix. Part # 13627796054
 
I'll run the codes later - just to clarify, I had no EML show, so if if it was the cam sensor, is that correct?
 
Justino said:
I'll run the codes later - just to clarify, I had no EML show, so if if it was the cam sensor, is that correct?

You won't always get the EML light, most sensors have a criteria to setting the EML light off (working out with a certain set range) and also a frequency of occurrences to set an EML off.
 
Ok, have run Inpa. It has a few codes over the past 400 miles, ie this weekend and some time before. Cant see the dates on Inpa.

Corresponding with yesterdays mileage is P0369 which is Cam sensor B bank 1, 61512km, so is this the exhaust sensor or inlet? Occurence - once

Also have, but with no outward symptoms:

P1413 Secondary air pump relay - signal low 60456km - 3 times
P1661 Timeout EWS (electronic immobilizer) telegram 60456km - once
P3228 E-box control fan circuit - open circuit 60456km - once

so these issues were all at the same time, maybe 3 or 4 months ago, before the service, so unsure why they weren't cleared.

And then at 60560km no code, but an error relating to 'Monitoring of the motor torque limitation', again no symptoms, frequency once.

Is there a way to have Inpa in English?
 
Yes that relates to the exhaust cam. It's pretty easy to check if they are bad but I'm fairly sure that's your problem.

https://www.pelicanparts.com/techarticles/BMW_Z4M/155-FUEL-S54_Engine_Camshaft_Sensor_Testing/155-FUEL-S54_Engine_Camshaft_Sensor_Testing.htm

Andy is correct in saying they won't necessarily flag an eml light, yet.

P0365 Camshaft position sensor B circuit bank 1
P0017 Crankshaft position camshaft position correlation bank 1 sensor B.
 
Good article, so will have a look at testing the sensor, thanks

Could just be a dirty connection. It was very wet yesterday, although the engine bay is dry, the general humidity etc could be a cause??

Not sure about the other codes. It may be a case of clearing them and see if they return. I have edited my post for the frequency of occurence.
 
Justino said:
Good article, so will have a look at testing the sensor, thanks

Could just be a dirty connection. It was very wet yesterday, although the engine bay is dry, the general humidity etc could be a cause??

Not sure about the other codes. It may be a case of clearing them and see if they return. I have edited my post for the frequency of occurence.

Yup I'd clear and start from scratch as not to confuse matters. Bonus with INPA I find is periodically, once a year for me after winter resetting the adaptations and let it start from scratch, no particular reason but if I was changing a sensor I would certainly do this.

INPA should be English, sounds like you've got a copy with the German software installed (you can't switch languages within the version you have installed). Have a search around the web for an up to date English version, fairly straightforward to find. :wink:
 
Justino said:
Are the OEM sensors made by Meyle?
I've found them online for c £60
No. Bosch iirc.
But cheap out on them if you must, easy to swap when they go bad. Personally I'd just get the genuine BMW item from the dealer with the 2 year fitted warranty that provides.
 
Justino said:
just trying to avoid paying double the price if it was the same brand

Yeah, fair enough for a part so easy to replace. The OE manufacturer for these is fact VEMO.
https://www.onlinecarparts.co.uk/vemo-7002621.html

https://forum.bmw5.co.uk/topic/128884-what-water-pump-viscous-fan-thermostat/?tab=comments#comment-1385932
 
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