Occasional rough running

T

TrentSC

Member
I've got a curious problem with my new Z4 (it's a 2006 E85 2.5i Sport) and I'd be grateful for advice...

It runs exclusively on Shell V-Power super unleaded, and three times over the past 6 weeks it's suddenly started running painfully roughly - spluttering, as though it's running out of fuel for 5-15 minutes. It continues to drive, but if I take my foot off the gas the engine dies. It happened again today and I stopped for 5 minutes; when I fired up again, it was perfect.

On the last two occasions it's been on around a third of a tank, and on the possibility that it was a batch of iffy petrol I've just brimmed it.

Has anyone else experienced something similar or might know what it could be? From my perspective it's not electrical (no engine management warnings when I plugged it in the first time, and no warning lights on the dash), so it could either be crap in the tank, crap in the fuel filter or summat else.

Thanks in advance.
 
maybe you have to use a injector cleaner
i had in 2016 also roughly - spluttering engine i had a bad lambdasonde
 
Could the high pressure fuel pump be on its way out? I would have gone with intake if you hadn’t have said you didn’t get any codes.
 
Silverzedtom said:
Could the high pressure fuel pump be on its way out? I would have gone with intake if you hadn’t have said you didn’t get any codes.
Click to expand...

E85 doesn't have HPFP! but it does have the usual one in the tank.
 
TrentSC said:
I've got a curious problem with my new Z4 (it's a 2006 E85 2.5i Sport) and I'd be grateful for advice...

It runs exclusively on Shell V-Power super unleaded, and three times over the past 6 weeks it's suddenly started running painfully roughly - spluttering, as though it's running out of fuel for 5-15 minutes. It continues to drive, but if I take my foot off the gas the engine dies. It happened again today and I stopped for 5 minutes; when I fired up again, it was perfect.

On the last two occasions it's been on around a third of a tank, and on the possibility that it was a batch of iffy petrol I've just brimmed it.

Has anyone else experienced something similar or might know what it could be? From my perspective it's not electrical (no engine management warnings when I plugged it in the first time, and no warning lights on the dash), so it could either be crap in the tank, crap in the fuel filter or summat else.

Thanks in advance.
Click to expand...


Hi TrentSC.
You don't have to guess here!!
This is exactly what live data is for.
Can you record the data when it happens? And post it on here?
Have you got a suitable scan tool that will do this?
Even set up a video camera on it to catch when it happens?

There are experts out there who can diagnose a car from the drivers seat (well, almost!), no swaptronics (swapping parts) or any other potentially expensive guesses! And I know there are loads on here. Me included. This is my job!!

Give us some clues.....get that live data!! :D
Andy.
 
andyfanshawe said:
TrentSC said:
I've got a curious problem with my new Z4 (it's a 2006 E85 2.5i Sport) and I'd be grateful for advice...

It runs exclusively on Shell V-Power super unleaded, and three times over the past 6 weeks it's suddenly started running painfully roughly - spluttering, as though it's running out of fuel for 5-15 minutes. It continues to drive, but if I take my foot off the gas the engine dies. It happened again today and I stopped for 5 minutes; when I fired up again, it was perfect.

On the last two occasions it's been on around a third of a tank, and on the possibility that it was a batch of iffy petrol I've just brimmed it.

Has anyone else experienced something similar or might know what it could be? From my perspective it's not electrical (no engine management warnings when I plugged it in the first time, and no warning lights on the dash), so it could either be crap in the tank, crap in the fuel filter or summat else.

Thanks in advance.
Click to expand...


Hi TrentSC.
You don't have to guess here!!
This is exactly what live data is for.
Can you record the data when it happens? And post it on here?
Have you got a suitable scan tool that will do this?
Even set up a video camera on it to catch when it happens?

There are experts out there who can diagnose a car from the drivers seat (well, almost!), no swaptronics (swapping parts) or any other potentially expensive guesses! And I know there are loads on here. Me included. This is my job!!

Give us some clues.....get that live data!! :D
Andy.
Click to expand...

Hi Andy,

The first time it happened it cleared after a few minutes and a subsequent scan drew a blank. On the second time, it lasted longer, but cleared once I'd restarted the car after an hour and again, nothing showed up when I took it into the local shop.

What kind of live scanning tools are available? I'm assuming I'd need to plug summat into the car's reader port and Bluetooth it to my Android phone. Any not-too-horribly-expensive suggestions?

Cheers.
 
There's loads available out there and i'm sure others will chip in, but as a minimum we need live data displaying all o2 sensors and short and long term fuel trim.
Yes, there are bluetooth ones available and cables you can buy to plug into a laptop and use INPA, but I don't use them much at all.
Here's a good start..
https://www.ebay.co.uk/itm/2017-New-Autel-MaxiScan-MS509-OBDII-EOBD-Auto-Code-Reader-Car-Scanner-Diagnostic/272934441956?epid=630613798&hash=item3f8c2913e4:g:HagAAOSw-W5Uti2g

Try and catch it in the act and record the live data. I sometimes get a friend to video it on their phone.

My suspicions is that your car is running lean intermittently, but need evidence to support this. Reasons can be many.

Don't hesitate to pop back for advice.

Andy.
 
Strangely I have just been looking at my daughter in laws old Ford Focus that had similar issues. First thing was to pull the spark plugs and they had developed a massive gap. Simply re gaped and car runs fine so worth a quick check on your car.
 
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