Engine Faults

[Henry]

Started this morning and had stuttering and surging, smoothed out somewhat once the aux air pump switched off. No dashboard lights. Diagnostics tells me p0170/0173. Long term fuel trim tell me 1 to 3 is 15 and 4 to 6 is 19.5. o2 sensor b1s1 is working fine incl heater element. b2s1 is reading permanent 1.2v. Smooth running reads 0/0/0/1.1/2.1/2.5.
This I think points me to a bad b2s1 fault but don’t understand why bank 1 is high as well. High reading pointing to rich mixture ?? The plan is to check wiring to 02 sensor and possibly replace. The IAT sensor is reading fine as is the MAF voltage
MAF at idle reads 14.5 kg/h. Don’t know what that means how does it compare to g/s
Any comments are welcome.

[DogWagen]

Hi Henry

Am interested because I have an ongoing, intermittent fuel trim out of range which I've yet to tackle. If your high values indicates a rich mixture, could this point to either leaky injectors or a vacuum leak downstream of the MAF?

There is a 50skid YouTube video on this topic that may help https://youtu.be/4CcwtaIe5c4?si=

Any help?

Mike

[Henry]

Interestingly because I am due to do a service I started this morning to change the plugs and there was an oil leak apparent in that area although not down the plug holes so I’ve binned the service idea and ordered a rocker cover gasket and the rubber squash washers that hold the cover in place. I was always led to believe that if there is oil getting out then air will get in?? The bits aren’t going to be here till next week. Yesterday I cleared the faults and covered about 20 miles and the LTFT has only gone up to around 12 and the stuttering has gone so I feel I’m not doing any harm for a few days till the bits come. As a side note the o2 sensor which was reading a permanent 1.2v has returned to working normally. I’m reluctant atm to change that as it’s probably just doing its job and telling me I’ve got a problem. I’m hoping it is a vacuum leak rather than injectors and think injectors unlikely to go wrong 3 at the same time.
However to end on a good/high note I have been getting pestered as to what I want for my birthday next month so I have told them to combine there money and get a smoke machine which of course I had to pick and went for the ANCEL S300 at £112.50. Of course I wasn’t in any way influenced by the fact I may have an air leak on the car
I will certainly keep you informed as and when things arrive and I make any progress.

[Henry]

Having taken DogWagens advice and watched the video and the follow up on fuel pressure I am now totally confused. Connected up the fuel pressure kit switched on to run pump and I get 3.4 bar pressure, good, after 5 minutes it’s at 3 bar and after an hour it’s still at 3 bar. So I’m thinking there’s no issue with the pump or FPR and injectors aren’t leaking. As a final check I start the engine which runs fine BUT the fuel pressure has dropped to 2 bar and remains there even at revs or idle. Any thoughts appreciated.