Suspected MAF Failure

Hi All,

Only just got my baby back on the road and she develops another fault 😞

Shes a 1998 Disco with the 3.9 V8, when I start up from cold, the engine has no power then it will find some then drop again, when sat still in neutral the idling is crazy, there is also a smell of petrol from somewhere.

It does this until the engine starts to warm up then it isn't as bad and runs better but then I flick over to LPG and she doesn't miss a beat.

I have done some research and these are symptoms of a failing MAF sensor.

I ordered a cheap one last night on ebay not sure if cheap was the right way to go but hey ho, wondered if anyone had any other idea's.

The MAF sensor should be delivered tomorrow so I will fit it and post how she runs.

Cheers

John

Smell of petrol never inspires confidence.
Check the condition of the fuel lines.
They are steel running along the offside chassis rail.
I remember having a rotten fuel filler neck and could smell it doing 40.
It had me convinced it was coming from under the bonnet

John-Ellis said:

there is also a smell of petrol from somewhere.

Click to expand...

Check the fuel pipes at the back, it is a common issue the pipes corrode between the tank and the fuel filter on the chassis rail. Look on the chassis behind the offside rear wheel.

The other place to check you don't have a leak is the fuel injectors. Look carefully at the connectors on the injectors which are only ppush fit and sealed with "o" rings - if the rubber has perished or gone hard there could be a fuel leak.

If you suspect your MAF, get handy with a multi meter and check the CO trim and air flow signals. If you do a search you should find the values you need to be looking for but check you use the right ones if you have cats, CO trim is normally 1.8v (IIRC), if the O2 sensors are failing it might also cause mixture problems. HTH.

Hi Guys

The new MAF sensor come today so fitted that just now, I had a good look round the injectors and could not see sign of leaks, I know the fuel lines were replaced a couple of years ago.

One scary thing happened tonight though, i started engine to warm it up before switching over to gas and there really was no power at all, it reved plenty but it was like it was only firing on 4 cylinders. So switched over to LPG and a load of unburned petrol come out of the exhaust, i mean it stunk and it was thick, after a couple of minutes it cleared but I definitely notices the fuel needle drop.

As I say I will know for certain when I do a cold start in the morning.

Really really hope this has solved the problem, she sounds and runs perfect for on LPG.

John

Started this morning nicely, couldn't smell petrol in the exhaust and in general she is running a lot better. I have ordered a set of o2 sensors for good measure.

Thanks everyone for there replies.

John

It's safe to put this one to bed, she ran perfect on both petrol and LPG from start to finish he he I am one happy boy 😃

out of interest after fitting your new MAF did you have to disconect the battery for a while to reset the engine ECU
After reading stuff on here a faulty engine sensor wot the ECU takes info from will put the ecu into limp mode , which yours may have been in with it over fueling

I haven't got an EFi or even worked on one just being nosey