all instructions for carrying out the o2 sensor test on a standard ecu say with each sensor test it should blink over 5 times in 10 seconds but on mine, each sensor test flashed the light on for 15 seconds then off for 5 seconds then repeated, is this just a different result due to it not being the standard ecu and if so does that flashing pattern mean its all good?

If you mean the light stays on for 15 secs then off for 5 it suggests the o2 sensors have failed the test, however the built in diagnostic is very limited and it could be they are a bit lazy at idle but ok when on the road, try again with a higher revs see if they react better, to be honest a true diagnostic via a live data system such as ConZult is a better idea.

 

Jeff TT

thanks jeff, can you advise on the rest of my diagnostic?

 

carried out a diagnostic and got code 12 and 13

 

when i disconnect the maf the revs pick up, is this showing that the connection is ok but likely a faulty unit?

 

also the coolant temp sensor, when i disconnect it, the front fan kicks in then goes off when reconnected, does this show that the connections are ok but possibly faulty sensor?

 

hopefully the 2 ecu problems are the reason behind my slightly rough idle.

if replacing the maf and temp sensor, do i have to disconnect the battery for at least 20 mins to get the ecu reset and clear of the old codes or will testing it with a new maf and temp sensor show all clear if i havent disconnected the battery to reset?

 

also could these 2 problems stop the o2 sensors working properly or make them lazy?

Are you sure the codes are not old, try a battery disconnection over night.

 

The afm been disconnected will raise the revs as it runs on a default map which includes a raised tickover to prevent stalling and of course a 2,5k rev limit.

 

The temp switch sounds to be working ok when disconected the fan runs and then when reconnected the fan stops.

 

The running issue is very likely a matter of cleaning throttle bodies adn setting up things such as timing, tps and base idle.What plugs are fitted and what condition are they?

 

One other thing to consider is wiring faults thar can give errors that do not follow the usual diagnostic route,as I said before once you get to a certain point in fault finding you need better equipment, do a battery disconnect as I said and when reconnected and before starting the engine do a code check again, should be clear, then start up run up to temp and then shut down and do the test again.

 

Let me know how you get on.

 

Jeff TT

disconnected over night then done another diagnostic in the morning, all clear then started up and went for a drive and all clear after that too. also both o2 sensors were fine when i gave them a few more revs like you said. it seems to be running fine and sits at 1k revs in gear and 7-800 in neutral but is a little up and down in neutral, maybe its just a case of tweaking some settings as you say, had the throttle valves cleaned and new ngk iridium plugs in a couple of weeks ago. henstead motorsport are only 5 minutes away and have datascan i think so will probably pay them a visit over the week and see what it says. thanks for your advice.