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Author Topic: Loss of power, no fault codes....  (Read 343 times)

Offline Greeno

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Loss of power, no fault codes....
« on: May 31, 2021, 01:21:35 pm »
Hi, I’m new to the forum and could do with some help!

I have a 2007 GTi which as the subject says has a loss of power and no fault codes. There are no “strange” noises from the engine bay but the power loss is such that even on a slight incline the car will not accelerate in 6th gear.

Any help would be greatly appreciated.

Thanks in advance Greeno

Offline Hypertuned

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Re: Loss of power, no fault codes....
« Reply #1 on: June 01, 2021, 05:53:52 am »
Hi, I’m new to the forum and could do with some help!

I have a 2007 GTi which as the subject says has a loss of power and no fault codes. There are no “strange” noises from the engine bay but the power loss is such that even on a slight incline the car will not accelerate in 6th gear.

Any help would be greatly appreciated.

Thanks in advance Greeno
When you say strange noise from the engine bay, please help us help you by describing where in the engine bay it seems to come from and under what conditions.
When you say power is down to the point where the car won't go up an incline in 6th gear, are you sat at 1500rpm (outside the torque band) or 3500rpm (within the torque band) & how steep is the incline?

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Offline Greeno

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Re: Loss of power, no fault codes....
« Reply #2 on: June 01, 2021, 07:19:01 am »
Hi Hypertuned, thanks for your reply.

Unfortunately there are no strange noises, the car sounds normal.

I’d say that I would be doing approximately 55-60mph in 6th and the car won’t accelerate, before it would, now it’s completely flat, the incline in question can’t be much more than 2%

Offline DBXdarkangel

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Re: Loss of power, no fault codes....
« Reply #3 on: June 01, 2021, 02:30:26 pm »
I would check your injectors on vcds and check for any miss fires on vcds too. Missfires don't always throw up a fault code but you can check different blocks to test for it.

Also maybe your HPFP isn't working as it should?

Offline Pudding

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Re: Loss of power, no fault codes....
« Reply #4 on: June 05, 2021, 04:07:00 pm »
VCDS is invaluable for troubleshooting stuff that doesn't throw a CEL/fault code.   You can data log up to 12 sensors and review the data when you get home.

Things to look for are the actual and requested values meeting their targets.  On a turbo engine with variable cams, all manner of fuel controls, electronic boost control and god knows what else, you simply cannot guess as to what it might be.  You need to review hard data.

There are a few common things you can check physically though.  PCV, boost pipe O rings, diverter valve, spark plug condition etc and also MPG.  MPG usually plummets when there's a significant problem.  If that hasn't changed, then investing in VCDS is probably wise.  It's a wise purchase on any VAG car to be fair.

Not much does actually throw a CEL.  Usually just a bad cat and dead O2 as they are required for emissions compliance, so MUST throw a CEL by law.  Things running sub-optimally don't generally put the engine light on.  As for fault codes, the problem has to be repetitive in order to store a code.  If the ECU gets over itself within a preset time frame, it won't code.

One thing that is VERY commonly over looked is dragging brakes, especially the rears.  That often explains sluggish performance, but you'll also get a small hit in mpg.
« Last Edit: June 05, 2021, 04:09:48 pm by Pudding »


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