MiL light - Wet Weather running - Sorted, you decide ?
Discussion
A quick question for the assembled masses ... .. .
I have had since Le Mans last year an issue where the car in pouring rain, when I slow/brake the MiL light comes on and the car run's liek shite. Th mixture is richened to the point that on the way to Le Mans last year I managed a whole 8mpg.
Without a fault code reader I have chased a number of issues around the car nd we now think we have sorted it ...
Last Sunday I came home from Silverstone WSB in the pouring rain, nearly home when the MiL light comes on. Come back the car a week later, reset the ECU to cancel MiL light ad unusually it stays on. Fuse box out, not wet, WD40 for good measure. No difference.
All connections in engine bay off nd WD40'd, no change.
Take AFM out and water comes out of it, strange as it's been undercover for over a week.
Inside quite corroded.
For those not familiar with the inside of their AFM, there is a small hole at the bottom of the AFM, where 2 x Hot Wires sit in a small tunnel. There is a chamber in front of it and one to the rear and the measurement of resistance across these wires when heated and cooled in the air flow gives you air temp and density etc . . .
Now, going back to the issue, the car runs shite in the really wet conditions, and then whe I brake /slow the MiL light comes on and it's game over, some times won't even run.
My theory therefore being that when driving along, open throttle the sheer volume of air passing through the AFM help to keep the Hot Wires at least a little clear of water.
When I slow/brake, I am off the throttle, therefore no vacuum effect and any water will fall to the bottom of the AFM and collect in the chambers where the wires are, then I can not clear the problem with out re-setting the ECU.
Once we had cleared the AFM out, properly, by splitting it open and clearing the crud etc, MiL has not come back on . . . .
The real cause of the problem is the old foam panel air filter which once checked appears dry, and lacking any oily residure, therefore letting a lot more water pass through it than it should, hence the AFM getting soaked etc etc . . . .
Ordered a new air filter form Tim this morning and we'll go from there, but I am interested in peoples views ?
I have had since Le Mans last year an issue where the car in pouring rain, when I slow/brake the MiL light comes on and the car run's liek shite. Th mixture is richened to the point that on the way to Le Mans last year I managed a whole 8mpg.
Without a fault code reader I have chased a number of issues around the car nd we now think we have sorted it ...
Last Sunday I came home from Silverstone WSB in the pouring rain, nearly home when the MiL light comes on. Come back the car a week later, reset the ECU to cancel MiL light ad unusually it stays on. Fuse box out, not wet, WD40 for good measure. No difference.
All connections in engine bay off nd WD40'd, no change.
Take AFM out and water comes out of it, strange as it's been undercover for over a week.
Inside quite corroded.
For those not familiar with the inside of their AFM, there is a small hole at the bottom of the AFM, where 2 x Hot Wires sit in a small tunnel. There is a chamber in front of it and one to the rear and the measurement of resistance across these wires when heated and cooled in the air flow gives you air temp and density etc . . .
Now, going back to the issue, the car runs shite in the really wet conditions, and then whe I brake /slow the MiL light comes on and it's game over, some times won't even run.
My theory therefore being that when driving along, open throttle the sheer volume of air passing through the AFM help to keep the Hot Wires at least a little clear of water.
When I slow/brake, I am off the throttle, therefore no vacuum effect and any water will fall to the bottom of the AFM and collect in the chambers where the wires are, then I can not clear the problem with out re-setting the ECU.
Once we had cleared the AFM out, properly, by splitting it open and clearing the crud etc, MiL has not come back on . . . .
The real cause of the problem is the old foam panel air filter which once checked appears dry, and lacking any oily residure, therefore letting a lot more water pass through it than it should, hence the AFM getting soaked etc etc . . . .
Ordered a new air filter form Tim this morning and we'll go from there, but I am interested in peoples views ?
spend said:
Sounds dubious to me, I would expect water off inner wing or road wheel spray to be more likely.
Dave
Well, I believe I'm right . . . Dave
Having driven 2500 miles in the last 2 weeks, in torrential rain to Le Mans and in the UK, I have not had the MiL light come on once . . . .Plus the car uns far better than it was in the dry as well.
Nothing else has changed other than the air filter and cleaning the AFM and there has not been a single issue since.
It's taken 12mths and a lot of cursing and swearing but it appears that the new K&N filter has stopped the amount of water coming into the AFM, and therefore once off the thottle there in't the water in the induction hoses to pool on to the hotwire . . .
Chuffed, as I love driving in the rain in the TVR and this meant it was a nightmare . . .
so sorry The old foam type gther curd over the surface and this got cleaned off, removing what I'd conidered blocked the air flow. Actually probably took too much.
Additionally, the car has now done 60k miles with the same air filter, as to my knowledge it has never ever been changed.
Therefore having removed some fo the oilly crud, and with time the oil would get washed out etc, it has then gone enough to allow too much water through . . .
The K&N filters are in fact fabric and come pre-oiled form the factory generally, and I prefered this option to re-oiling the last one.
Additionally, the car has now done 60k miles with the same air filter, as to my knowledge it has never ever been changed.
Therefore having removed some fo the oilly crud, and with time the oil would get washed out etc, it has then gone enough to allow too much water through . . .
The K&N filters are in fact fabric and come pre-oiled form the factory generally, and I prefered this option to re-oiling the last one.
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