I have been experiencing an intermittent fault which causes my car to stop suddenly. The local main dealer has tested it extensively (and expensively!), and eliminated everything but the ECU. The ECU was sent away to a specialist who tested it and found nothing wrong. However he did resolder whatever it is you solder in an ECU. It now seems to be performing better, but twice yesterday the car seemed to lose all power for a split second before picking up again, and I fear all is not entirely well. Does anyone know of a real ECU whizz to whom I could take the car for another check up, ideally somewhere locally - I live in Bury St Edmunds.
The car is a 94 Bentley Turbo R.
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Can't help with an ECU whizz, Topaktas, but please read the thread I posted a couple of days ago about "doing it yourself" in the Discussion Area.
The theme is similar.
I truly believe that the root cause of your problem will not be in the ECU.
Let us know how things develop.
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Try motorsport developments near blackpool (they have a web site)
but I agree with the other thread that the problem may well lay in another part of the engine system
Good luck
K2
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topaktas,
all ECUs do basically the same job in an electronic sense.
Some have their own individual quirks and faults, but on the whole they are pretty reliable.
If the specialist who previously checked it out didn't find anything wrong but did some resoldering then he probably suspected a dry joint, (which can be almost impossible to find), and did the right thing.
As long as the board was resprayed afterwards to protect the resoldered joints then it sounds as if he was a conciencious and competant tradesman.
Alot of suspected ECU problems are actually due to the sensors they use to gather data or the actuators they control.
Eg. Throttle-position sensor, MAF or crankshaft sensors, fuel injectors and emmission control valves.
The environment they operate in is pretty hostile and after a while they do suffer from mechanical wear or chemical contamination.
By looking more closely at the symptoms you can often narrow the problem down to a particular function.
On that basis, can you give as much detail as possible ?
When does the problem occur ?
Constant throttle or when accelerating ?
After braking or not ?
At any particular speed or RPM ?
Warm or cold ?
Before/during/after gearshifts ?
Kevin...
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Is it at all possible to 'borrow' another ECU via the main dealer and drive it for a week or so to see if the problems persist?
If they do then the fault is probably wiring. If they dont then I would say there my be another dry joint or a broken track on the loom.
H
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Thanks to all for your interest in helping to solve this problem. I have since done another journey, about 45 miles, this time without any problems - but that's the thing about intermittent faults! Let me quote from the main dealer's invoice, so you can get an idea about what has happened so far:
"Carry out checks on complete engine management system. Check every component, associated wiring circuits input and output circuits. Check ignition circuits, fuel circuits, fuel system components and fuel system pressure. Carry out numerous road tests with multi meters and pressure gauges in situ aiding the diagnosis process. Fit breakout looms to main harness in order to check signals at different points of engine load. Diagnose fault in engine management ECU. Fit loan ECU to prove. Send owner's ECU for testing and repair. Refit to car and test. Fault no longer apparent. Fit new engine management sensor during process as this was showing a poor signal.
Note: as explained, although we have proved the problem to be with the ECU, a new one has not been fitted, and best efforts have been made to rework exisitng unit."
Kevin: in answer to your questions, the fault occurred on deceleration - entering a speed limit, leaving a motorway, and entering my own drive!
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Topaktas,
I bet I'm not the only one, dying to know.
"Let me quote from the main dealer's invoice,"
What was the bottom line, please?
What did they charge for this sort of work on a Bentley?
(Yes, I'm a Yorkshireman)
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£1462 (of which labour was £1299) + VAT = £1719 - painful, even for a non-Yorkshireman.
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topaktas,
sounds like the work on the ECU fixed the problem with sudden stopping so I'd get the specialists name from your dealer and make a note of it. You never know if you might need him again.
For the intermittent loss of power when decelerating, my first guess would be a worn throttle position sensor or a possible vacuum leak.
When the problem occurs, have you released the throttle completely, just 'backed-off' or braked ?
Have you noticed what happens to engine RPM ? Does it drop straight to idle or lower as if it's about to stall, and then recover ?
Does the engine recover immediately you press the throttle again or is there a significant delay ?
BTW. A new TPS shouldn't be too expensive and your dealer may even feel obliged to loan you one for a week or two FOC.
Kevin...
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