Hello,

I am new to the group so please be patient.

We purchased a Bentley Continental GT 2005 which went to a garage in London for a remap. The power was reportedly increased from the standard 552bhp to around 612bhp.

This is where the problems started. The Bentley would drive fine upto 3-4k rpm, however if on full throttle the power would hesitate and be delivered in waves, hard to describe but the power wasn't constant and strong. I also noticed a faint smell of coolant at high speed - 80mph plus.

So we took it to a local garage, they found a lamber sensor with water contamination. This was cleaned and returned with a £200 bill.

The misfire was still present.

Took the Bentley to a specialist, he said we need two new ECU's @ £1500 +vat and labour.

We decided to take the Bentley back to London and remove the remap and put back to standard. There was one fault code detected:

16455 - Sensor - Ambient Air Temp (Fault code P0071-004)

Once the remap was removed the car drove ok, no more misfire!! we thought great its fixed. Returned from London 200 mile trip, all good.

One week later, same misfire experienced and again it only happens on full throttle and boost.

I would really like to reach out to you guys for any similar experiences and known fixes. I am even tempted to buy a VAS 5054A diagnostic interface.

Please help!

Thanks.

 

Hi.

I can't help with the misfire but wondered who you took the car to in Cheshire.
Not the one in Knutsford I hope!

Les.

 

Thanks for the reply Les.
I took the car to a very helpful and knowledgable specialist in Crewe - GT Services Cheshire.

Which garage in Knutsford are you referring to? Bentley Manchester...

 

Hi.

Yes, the main dealer is not a place I could recommend I'm sorry to say.
Ivor in Crewe however is a top chap. He taught the rest of the world about the GT when it was first introduced and he was Bentleys flying doctor when problems arose.
He has sorted my GT out a couple of times after the main dealer tried to rip me off.
For example, a job they wanted nearly 4 grand for was fixed by Ivor for a couple of hundred quid. Big difference!
I honestly have total faith in him as do some of my mates, so if he says it needs ECU's, it probably does.
It makes me wonder why the have failed though. Could it have been the tune?
Also, you could perhaps ask Ivor if he could source second hand ones from a scrapper, there are a few about, Ebay, etc.

Good luck with it anyway.

Regards. Les.

 

You either have a spark plug or coil pack breaking down, I had exactly the same issue when I mapped mine, the extra load highlights the issue. I changed all plugs and coils which resolved the issue completely.

 

Makes sense as Bentley did have a bad 'batch' of coils years ago. If you're not sure when the coils/sparks have been changed this would be good time to have that sorted.

 

PS, If you need to go down the ECU route which i personally dont think you do then I have a spare pair of ECU's available.

 

Thanks for all your very helpful replies guys, much appreciated.

I have the Bentley booked in with Ivan (GT Services Cheshire) on Wednesday next week so I will ask him to replace all the spark plugs and coil packs. I guess genuine parts is the only option?

Wes, I will definitely be in touch about your ECU's if the spark plug and coil pack replacement doesnt fix the misfire.

I cleaned the Bentley today and noticed the left hand side exhaust had significantly more carbon deposits on the tail pipes, took me ages to clean it!

Can't wait to have her back to full health and running smoothly.

 

From your post regarding the carbon deposits that's 99% confirmed it for me, incomplete combustion on that side of the engine so you have the choice of changing that side out with new plugs and coil packs or do all, I did all as you never know how long the others will last. You can cross ref the coils with VW Audi parts and buy a lot cheaper and the plugs are also available from euro car parts and eBay for about half the price, labour wise it's about an hours job. Hope you can get the map put back on as it really brings the car to life! Regards Westy

 

Thanks for your comments Westy, it's a massive relief to hear the problem could be fixed by spark plugs and coil packs. Any idea as to whether the repair could be done "diy"? I've spent years fixing new(ish) and old cars, changing engines, brakes, etc. But tinkering with a Bentley just seems wrong...

 

Easy DIY job if you're used to tinkering! Remove airboxes, disconnect a couple of plugs on the MAF's and hoses and unbolt the inlet manifold, I didn't remove it from the car just tilted it up gently and propped it up, from there it's fairly easy access but the right tools are essential, extensions and plug socket etc. I can get you the part numbers of plugs and coils if you need them?

 

Installed a pair of BMC filters whilst I was at it, they compliment the map well.

 

Thanks for the reply, they are great pictures too! I would appreciate the part numbers for the spark plugs and coil packs. Should I order the parts from Bentley directly or would Volkswagen stock them?

 

Ok, I will get the part numbers on here asap for you, I would order from VW or Audi as prices will be a lot cheaper for exact same parts.

 

Very true! I think Toyota lost a big lawsuit for doing that years ago with their parts.