Hi Guys
How's it going with this problem Gibbo?
There's similarities with mine which is well documented elsewhere here.
I'm convinced my fuel trim codes aren't down to the MAF itself. But could be the result of a cross wire, lose connection or even excessive cooling when reaching 91 degrees.
I also get P0100 which is MAF heater circuit.
Got a MAF off Steve who assured me it came of a well running car....it didn't work.
Got a Chinese MAF from Autosensors on ebay...EML switched off imeadiately...then came back on after awhile. Got them to refund and send me another. Same thing happened.
Reset the codes, disconnect the battery over night...EML off but back on again. This is all the same with any of the 4 MAF's I now have.
Recently had the Chinese MAF's in...car going fine but...EML and codes back after making a sharp right hand turn with one in. Then with the other, car going well MPG improving all the time (but strangely only round town, not on a long run), then go up a road with evil speed bumps...EML and codes back after a particularly nasty bump.
Much to Kevin's dismay I tested all the MAF's with an Ohm meter...Standard Bosch MAF's had similar readings (which indicates that if nothing was wrong with my original MAF then the one I got of Steve was ok too...or both are bad and there's a different problem) and though completely different the Chinese MAF's had similar readings to each other. There is no change in any readings wether the EML and codes are registered or not.
Which tells me that as there is no change with any MAF how can the problem be the MAF sensor?
I recently had reason to start the car from cold and drive it straight away, rather than wait for it to warm up, whilst it was barely running i.e. the rough starting/no tick over but it drove...then YIKES at the 1st junction....no brakes!!!! indicating a vacum (i know spell check, I know) problem. When the rough starting stops and tick over is normal I have brakes. When warm tick over increases if I pump the brakes! Is this normal???
When I've been under the bonnet inspecting the rough starting/barely ticking over problem, I've heard a solenoid suddenly click and hey presto...ticks over sweetly. This solenoid sound comes from behind the Plenum.
I noticed that the coolant barely got above 80, so changed the thermostat...thanks OOF for the guidance. Has there ever been such a stupid design that puts so much work just in to changing a thermostat??? Crazy...poxy B bolt lol. I'm adapting my old housing to come up vertical and bend through the "V" behind the throttle body and then to the top of the rad.
Anyway, when filling up with coolant, I put so much in then ran the car to get warm with my fingers crossed (which actually worked this time...no leaks). Then as I was topping up the expansion tank the sound of the engine and tick over changed as the cold coolant was being taken in. Struck me as being a bit odd. What does anyone think???
Also, now the coolant is getting up to temperature the cooling fans are switching on. The problem is now the temperature yo yo's between 91 and 80. I've notice that the consumption on the MID drops after the 3 fans have been on and the temperature is 80-85. When it builds back up to 91, just before the fans come on the consumption doesn't drop and in fact gets better.
I've also not got the rough starting anymore from cold but do have it when the engine is warm. For instance after filling up with fuel or nipping in to Sainsburys then restarting the car. Is the something, a sensor of some kind that operate in higher or lower ambiant temperatures. When the weathers cold I get rough starting from cold but when it's only a few degrees warmer i.e. above 0, no rough starting from cold but rough starting when engine is warm?
Now 64,000 dollar question:-
Could the yo yo of the coolant temperature create a situation of confusion in the ECU and cause it to throw up fuel trim codes? I.E. when the coolant reaches 91 it feeds less fuel and when the coolant drops to 80 after the fans come on it feeds more fuel. This would cause havoc to the long term fuel trims surely and the codes disguise the real problem?
No. 64,001
Could a bad/lose connection that runs the MAF heater circuit throw up a P0100 code rather than the actual circuit within the MAF itself? As there is no change in the resistance in the MAF's I have. The ECU wouldn't know any different and just assumes it's at the MAF. Where on earth are the wires that connect to the MAF, specifically the MAF heater circuit, where do they go? Is there an earth for the MAF heater circuit or is it part of the general earthing of the car? I've noticed that the dash and MID alumination changes quite alot. Could a bad earth cause there to be too much volts in the circuit and confuse the ECU?
Sorry Guy's I know this is a long one but I'm as inquisitive as a child.
Cheers.
Dave
Author
Topic: Omega 2.6 v6 engine management light on. Car running rough at idle speed (Read 5631 times)