Griff's running lumpy occasionally
Discussion
Had a recurring problem with the Griff, two or three times recently I have filled up at my local Shell station with fuel. Soon after when putting my foot right down the car coughs, splutters, backfires and judders. When I take my foot of the gas, it seems to tick over fine. Everything on the ignition side is new. Could I be right in thinking that this could be ECU related? Would I be wasting my money getting the ECU chipped and a RR session? On one occasion that this happened the car completely cut out and the AA man disconnected the ECU, re-connected it, and all was fine apart from tickover being slightly higher than normal. After 100 or so miles tickover was back to normal and we drove 500 miles with no issues, until I filled up with fuel again from the same garage. Am I paranoid or could this be related?
Any help or advice greatly appreciated.
Dean
Any help or advice greatly appreciated.
Dean
Hi Dean,
I see where due to go on the Carbon Offset run but your P&J intervened.
I note from your fault description that the fault has only occured when you have filled up. Have you noticed if, when releasing the fuel filler cap if there is any hissing noise?
The symptom you describe sounds like a blocked fuel filler/tank breather. I have come across this in other makes of vehicle. Basically a vacumm is created which the fuel pump may not be able to overcome( most pumps have a stall pressure to prevent damage), think, if you drain a radiator by releasing a hose the water will run out quicker if you undo the radiator cap...sorry if that sounds elementry.
I cannot see how the ECU could be affected by the amount of fuel in the tank & there are certainly no sensors that I am aware of that are fitted to a TVR which would monitor the fuel temperature.
Another possibility is if there fuel vapourisation occuring at the inlet manifold, was the engine very hot? In theory this would occur irrespective of the tank level but if you are only filling tank to tank you would not know. When I had my 400se on the road that used to suffer from vapourisation & would give the same symptoms you describe, I used to have to let the engine cool or, as at Le Mans, pour Evian over the inlet manifold! The way I cured it was to increase the fuel pressure which meant the fuel circulated back to the tank much faster & therefore did not have enough time to vapourise.
Hope this helps
I see where due to go on the Carbon Offset run but your P&J intervened.
I note from your fault description that the fault has only occured when you have filled up. Have you noticed if, when releasing the fuel filler cap if there is any hissing noise?
The symptom you describe sounds like a blocked fuel filler/tank breather. I have come across this in other makes of vehicle. Basically a vacumm is created which the fuel pump may not be able to overcome( most pumps have a stall pressure to prevent damage), think, if you drain a radiator by releasing a hose the water will run out quicker if you undo the radiator cap...sorry if that sounds elementry.
I cannot see how the ECU could be affected by the amount of fuel in the tank & there are certainly no sensors that I am aware of that are fitted to a TVR which would monitor the fuel temperature.
Another possibility is if there fuel vapourisation occuring at the inlet manifold, was the engine very hot? In theory this would occur irrespective of the tank level but if you are only filling tank to tank you would not know. When I had my 400se on the road that used to suffer from vapourisation & would give the same symptoms you describe, I used to have to let the engine cool or, as at Le Mans, pour Evian over the inlet manifold! The way I cured it was to increase the fuel pressure which meant the fuel circulated back to the tank much faster & therefore did not have enough time to vapourise.
Hope this helps
Try opening the bonnet the moment you stop to fill-up. The heat soak is tremendous! The coil gets very hot and there is also the risk of fuel vapourisation. You mention you have changed ignition components, don't forget the HT leads. New, good quality HT leads are a worthwhile investment and will cost around £100. Hope this is helpful! Good luck!
I've had a similar problem with my 500.
Lots of new parts plugs, leads, dizzy cap, rotor arm etc etc. didnt cure it and eventually traced the fault to the big connector on top of the AFM.
The AFM is fitted so high on the wing that the bonnet - and particularly the bonnet stay - pushes the connector plug slightly skew in its socket and disturbs the electrical connectors
Its so bad that when I go over a big bump the engine will completely cut out as the bonnet rattles around.
I WILL
cure the fault over the winter by cutting the old plug off and soldering in an line connector straight on to the AFM socket.
I would have thought that this could be a fault on a lot of Griffs as the bonnet is so tight against the AFM
Good luck - Andy
Lots of new parts plugs, leads, dizzy cap, rotor arm etc etc. didnt cure it and eventually traced the fault to the big connector on top of the AFM.
The AFM is fitted so high on the wing that the bonnet - and particularly the bonnet stay - pushes the connector plug slightly skew in its socket and disturbs the electrical connectors
Its so bad that when I go over a big bump the engine will completely cut out as the bonnet rattles around.
I WILL
cure the fault over the winter by cutting the old plug off and soldering in an line connector straight on to the AFM socket.I would have thought that this could be a fault on a lot of Griffs as the bonnet is so tight against the AFM
Good luck - Andy
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