the problem I had at the Atom training day
Discussion
Meyrick and others you remember the problem I had at the day with Rob Gravett - a fuel starvation type issue. Well its back again, the factory have looked at it and can't find a problem. As last time, yesterday it ran perfectly at Mallory for several hours, seeing off everything but a radical. Then mid afternoon it started to miss at constant revs. Coming back down the M40 and A34 was a nightmare, with the car totally reluctant to run at constant revs, missing and coughing & slowing down/ speeding up. In the end I had to leave the main roads and poodle along B roads.......so it needs several hours of reasonably hard driving to produce this effect, its not crap fuel, its all clean in terms of fuel filters ( main service 300 miles ago). Help. what is going on!
Hi Ian
I know you'll get a lot of suggestions to solve the problem but I'll kick off as I had a similar problem with a car I once owned.
Short journeys were fine but longer runs produced the symptoms you're experiencing.
It was eventually traced to a blocked fuel tank breather pipe. This resulted in fuel starvation as a partial vacuum was building up in the tank.
Something easy to check I guess.
JC
I know you'll get a lot of suggestions to solve the problem but I'll kick off as I had a similar problem with a car I once owned.
Short journeys were fine but longer runs produced the symptoms you're experiencing.
It was eventually traced to a blocked fuel tank breather pipe. This resulted in fuel starvation as a partial vacuum was building up in the tank.
Something easy to check I guess.
JC
We had this exact problem with our 220, we spend loads of time (and money) to try and cure it, new injectors, fuel filter, coils, etc, etc.
We thought it was a dodgy tank of fuel.
Eventualy Tom (Ariel) just disconected the Lambda sensor altogether and the car ran perfect from then on, something to do with no Cat and B**locks.
The car was almost undriveable on part throttle, it would clear when you pushed it very hard, but would almost stall on normal driving.
Badge
We thought it was a dodgy tank of fuel.
Eventualy Tom (Ariel) just disconected the Lambda sensor altogether and the car ran perfect from then on, something to do with no Cat and B**locks.
The car was almost undriveable on part throttle, it would clear when you pushed it very hard, but would almost stall on normal driving.
Badge
No idea about Atom specific problems but a few ideas of things which have produced similar symptoms.
1. Filter over the end of the pickup pipe in a fuel tank. It had been pushed on so hard that the pipe was blocked by the gauze filter where it was folded over and stitched.
In that case the symptoms were more severe - it would hardly run at all over 40mph no matter how much fuel was on board.
If the fuel line was disconnected on the engine side of the pump the flow looked OK visually - but was not when under load.
2. Earth strap.
Read about this a few years ago. Vaux Carlton. Would run OK and then suddenly cut out then start a gain. Problem would come and then go for weeks at a time. Many garage visits. Eventually it managed to fail at start up on the owner's driveway. Turned out to be a broken braided earth strap from the engine to the chassis but the intermittent break was dependent on engine movement and hidden frmo view by the plastic sheathing over the braid!
2. HT leads.
This is a bit of a long shot really since once they go they go so for something to appear and disappear seems odd. I had this one night heading up the M1. Forst 25 miles on the M25 were fine but then a misfire developed and got worse and worse. After a few miles any attempt at using the throttle had the opposite effect to that expected.
I managed to keep going, just and subsequently discovered that the only smoothi running speed happend to co-incide with 70 on the motorway and worked as long as it was flat. Hills were a problem. So I could accelerate very gently to 70 and switch on the cruise control (which provided better throttle control than my foot) and made it home. Turned out one of the two HT leads was breaking down. Had both changed of course - partly 'cos the labour cost was the same to do one or both!
So, your problem will not be any of these but you never know what thoughts might occur to you as you consider them.
I guess the final thought would be some water in the fuel. Can happen if you get a fill from the bottom of a tank - or at lest it used to years ago.
1. Filter over the end of the pickup pipe in a fuel tank. It had been pushed on so hard that the pipe was blocked by the gauze filter where it was folded over and stitched.
In that case the symptoms were more severe - it would hardly run at all over 40mph no matter how much fuel was on board.
If the fuel line was disconnected on the engine side of the pump the flow looked OK visually - but was not when under load.
2. Earth strap.
Read about this a few years ago. Vaux Carlton. Would run OK and then suddenly cut out then start a gain. Problem would come and then go for weeks at a time. Many garage visits. Eventually it managed to fail at start up on the owner's driveway. Turned out to be a broken braided earth strap from the engine to the chassis but the intermittent break was dependent on engine movement and hidden frmo view by the plastic sheathing over the braid!
2. HT leads.
This is a bit of a long shot really since once they go they go so for something to appear and disappear seems odd. I had this one night heading up the M1. Forst 25 miles on the M25 were fine but then a misfire developed and got worse and worse. After a few miles any attempt at using the throttle had the opposite effect to that expected.
I managed to keep going, just and subsequently discovered that the only smoothi running speed happend to co-incide with 70 on the motorway and worked as long as it was flat. Hills were a problem. So I could accelerate very gently to 70 and switch on the cruise control (which provided better throttle control than my foot) and made it home. Turned out one of the two HT leads was breaking down. Had both changed of course - partly 'cos the labour cost was the same to do one or both!
So, your problem will not be any of these but you never know what thoughts might occur to you as you consider them.
I guess the final thought would be some water in the fuel. Can happen if you get a fill from the bottom of a tank - or at lest it used to years ago.
Just like Badge70, we had the same problem (was a nightmare on the M42 on the way back from Donnington), and the fix was to disconnect the O2/lambda sensor. We've subsequently had a new sensor fitted (seemed to run a bit rich without). Takes 5secs to pull the plug, got to be worth a go?
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