Hi Guys and Girls,

I keep getting a check engine light coming on every few days. I clear it and then a few days later it comes back. Today I captured some of the data to see if that gave me a hint. A few things I noticed :
- MAF absolute pressure was around 37 kPa while atmospheric was 101 (no units but assume it is also kPa)
- Long term fuel trim bank 1 (left ?) is around -2.94
- Long term fuel trim bank 2 (right ?) is around -1.28
- Short term fuel trims both 0
- O2 sensors are 0.69 Volts and 0.74 Volts, difference stays the same

Can anyone give me hints / tips on what could be causing this ?? I have an Excel sheets with all the values and an AVI clip showing the numbers while running.

I would really appreciate your help.

Cheers,

Eugene MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

I cant help you with specific suggestions, however; lean or rich codes can be symptoms of the following (in order of likelyhood):
Vacuum Leak (allows unmetered air)
Dirty MAF (incorrect fuel/air mix)
Failing MAF (as above)
Failing spark plug (unclean burn) 

I had same errors and it turned out to be perished inlet manifold pipe, 2 were pretty bad, so replaced for £25 ish and reset, never been since cheers
bogie

Thanks for the suggestions guys, I will start on them in the next few days.

After posting I got hold of some surgical spirit and cleaned the MAF. Lot of dirt came out and when I put it in it seemed like the ECU had to re-learn how to run it. Hope to know more when I take it for a test drive tomorrow. After the test drive I will do another data capture and see if the numbers have changed.

The spark plugs are new and the old ones didn't look too bad when they came out bit "sooty" so a bit rich already. Thing with this car is, it sat still in the hot African climate with two rainy seasons for two years so it could be just fouling of the MAF sensor. The original air filter was still in and it was full of crap, now it has a K&N filter.

Will definitely check the vacuum pipes, although when I disconnected a vacuum hose while doing the spark plugs, it let in quite a bit of air, indicating that at least that part of the system still maintains vacuum quite well.

Anyway, will keep you posted here !! MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Hi Ebajema. How did you get on with this issue.....Dirty MAF?

Fraser

Hi Fraser,

Nope, it wasn't the MAF. It is most likely the crappy petrol from our "main" fuel station plus two years of sitting still in Lagos (causing the petrol to gum).

After cleaning the MAF and changing the oxygen sensors on that side, it still didn't go away. So I started running injector cleaner in the fuel. Helped a bit but still not perfect. Then we had to use another fuel station for a bit and the problem went away. So now I hardly ever have a problem (CEL is on now but that is probably because my driver filled it up at the "old" fuel station, I need to check and tell him not to go there).

Seems the S/C is a bit sensitive to bad petrol.

Cheers,

Eugene MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Rive gauche trop riche? Paris?









sorry
 
RRC 2Dr, RRC 4Dr,
P38, and 2 L322s
(wife thinks I'm nuts - prob right, too)

@Steve

Current batch of lousy petrol is throwing up a new one : Left bank too rich, right bank too lean  MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!