P38 Paul Posted November 29, 2015 Share Posted November 29, 2015 Hello peeps , My P38 is playing up again , I went to start it on Saturday & it was very difficult to get going , once it started it ran very unevenly & stalled every time I took my foot off the throttle , If I hold it just above tickover it keeps surging & trying to cut out , but If I rev it over 2000rpm it seems a lot better but still has a hint of a misfire , It was running ok the last time I drove it , The car runs on lpg & petrol but no matter what it runs on its still the same so I doubt that it is a fuel issue . Any ideas please would be of a great help . Quote Link to comment Share on other sites More sharing options...
elbekko Posted November 30, 2015 Share Posted November 30, 2015 Step 1 would be to check the spark plugs. Quote Link to comment Share on other sites More sharing options...
P38 Paul Posted February 7, 2016 Author Share Posted February 7, 2016 Got round to changing the plugs today but still no joy , I don't think its a misfire anymore as I have removed the plug leads one by one & all make a slight change to the engine speed . Are there any sensors that I need to be checking ? Thanks in advance , Paul . Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted February 7, 2016 Share Posted February 7, 2016 Mass air flow meter would be the one I would look at. It needs to read 22-25KG/hr at idle and 90+ at 3000rpm,engine hot,all loads off. Without this the oxygen sensors will not switch and the engine ecu will log faults for them. I have answered questions like this a hundred times on several forums,there MUST be loads of similar threads / posts on this subject... Quote Link to comment Share on other sites More sharing options...
P38 Paul Posted February 7, 2016 Author Share Posted February 7, 2016 Mass air flow meter would be the one I would look at. It needs to read 22-25KG/hr at idle and 90+ at 3000rpm,engine hot,all loads off. Without this the oxygen sensors will not switch and the engine ecu will log faults for them. I have answered questions like this a hundred times on several forums,there MUST be loads of similar threads / posts on this subject... Hi Alley V8 , Does the petrol maf sensor have a default setting like the diesel maf sensor when you unplug it ? Regards Paul . Quote Link to comment Share on other sites More sharing options...
Dave W Posted February 8, 2016 Share Posted February 8, 2016 If you unplug the MAF sensor the ECU will use a default setting, however, that wouldn't normally affect the LPG system unless that also uses the MAF reading. I ran mine for about 3 months without the MAF sensor connected without any issues after a faulty MAF sensor was stopping it accelerating. It's worth checking the air pipes are all good and not split/disconnected - a split air pipe can allow air to bypass the throttle and MAF, causing the engine to run lean on both fuels. Quote Link to comment Share on other sites More sharing options...
P38 Paul Posted February 28, 2016 Author Share Posted February 28, 2016 Hello peeps , Just a bit of feedback for all of you , It was the MAF sensor that had failed , so thank to Ally V8 , elbekko & Dave w , for all you input & help . Kind regards , Paul . Quote Link to comment Share on other sites More sharing options...
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