Check engine light conundrum!

[Silver Fox]

Any advice on this problem would be really appreciated as I'm really struggling where to look next

1.Check engine warning light on
2.P1074 & P1071 codes weak mixture banks 1 & 2
3. MPG at motorway speeds 40+
4.Smoke test passed
5.PCV valve changed
6. Brake Servo pipe changed
7. MAF cleaned
8. DISA valve checked
9. CEL comes on after approx 30 miles driving

E85 2004 2.5 litre 90k miles

 

[Argyll Andy]

Hello and welcome, a few more detail about your car may help with responses like , engine, model, age

 

[Silver Fox]

Thank you Andy thread updated

 

[enuff_zed]

Morning, welcome to the madhouse.
Hopefully we can help you out here.
Simple stuff first, have you checked the inlet pipe to the throttle housing? There's a smaller convoluted pipe on the top of that which is notorious for splitting and letting in unmetered air.

The fact you have codes for both sides points to something upstream that then affects the whole engine.

 

[Silver Fox]

I'm in the right place then!
Yes I've checked the inlet pipe and had it smoke tested all apparently ok

 

[enuff_zed]

I'm in the right place then!
Yes I've checked the inlet pipe and had it smoke tested all apparently ok

Yup, it was something I suspected you would have done.
So are you sure the MAF is good? I know you've cleaned it, but it could still be iffy. Any chance you could substitute another one to check?
Whereabouts are you, as there is a slight possibility there may be someone nearby with a spare?

 

[enuff_zed]

I just stuck those codes in the 'search on here'.
Comes back with either that hose which you've already checked, or MAF.
Someone had the same issue some time back. Fitting a new MAF cured it.

 

[enuff_zed]

More searching (quiet day in the home office )
Double check that hose isn't split - look underneath it too.
I had a problem once where I replaced that pipe but one of the jubilee clips didn't quite locate properly and forced the pipe to have a small open section on the lip. Triple check all the connections.
Also found one person who had those codes because the oil filler cap wasn't seated correctly.
Then I still think it's back to substituting another MAF.

 

[bigwinn]

is it running poorly- youve not said actual symptoms?

e.g. misfire, low power, hesitant or flat spots

If youve done all that I would start to think fuel starvation and looking at the fuel pump efficacy

 

[Silver Fox]

Seems to be running ok certainly no hesitation or flat spots

 

[colb]

Looked at a 3.0l today with EML lit up and a couple of codes for low Maf, smoke tested it and no leaks found, took a look at Long term fuel trims and they were in excess of 20% so it thinks its running lean and adding fuel at the injectors. Disconnected the Maf and that didn't make any difference they remained high. It certainly looks like the Maf is the cause, the one fitted is a used replacement of unknown quality or brand. Bosch or Siemens brands eye wateringly expensive, other brands available on Autodoc at various prices, probably worth a punt on Hella or Delphi brands for sub £100.

 

[Silver Fox]

Thank you I'll give that a go

 

[enuff_zed]

[ref]Silver Fox[/ref], you never said where you were?
For instance, if you were close to me in Norfolk I have a project 3.0i on the drive. If the MAF is the same I would happily let you swap it over as a diagnostic check.

 

[Silver Fox]

Hi I’m in Canterbury

 

[enuff_zed]

Hi I’m in Canterbury

Ah, not quite close enough to help, sorry.
Hopefully another member may pop up though.