Passat V5 2.3 Petrol Owners – Please Help

[jamespearson]

I have a cherished year 2000 V5 estate 114k miles.
It has developed a misfire and lost substantial power.
Much £ already spent on investigation, testing by reputable workshop including new coil packs but unfortunately the misfire / no power issue persists
Has anyone experience of this ?
I’d be very grateful to receive news of a solution.
Thanks for your consideration.
James.

[rfsteel]

What fault codes do you have? I have a MK4 V5 Golf with 185k, the only issue I have suffered is a flat spot around 4200k 4pm.

Edited by rfsteel on Sunday 26th August 01:55

[rfsteel]

Also if its a 2000 V5, then it's more likely to be the 150 bhp with a single coil pack and not the 170 bhp with 5 coil packs.

What 4pm does the misfire occur and does it only do it when the engine is under load?

[jamespearson]

Thank you for your feedback, the update is very much appreciated !

WORK CARRIED OUT | WORKSHOP APPRAISAL
Long Life service carried out.
Tested spark plugs and checked coil packs, all ok.
Removed, cleaned and adapted throttle body.
Checked engine compression, all good.
Supplied and fitted new coil igniter pack as required.

TEMORARY FIX
Once the new coil igniter pack was fitted there was a notable reduction to the misfire, the power returned and only the slightest hesitation notable in the engine.

BODYSHOP | FLAT BATTERY JUMP
When at Bodyshop (dents being removed) battery ran flat which was jumped with a pack.
Unfortunately the misfire and loss of power returned worse than ever !

FAULT CODES
I’ll have to check with Deutchtek (workshop) on which codes showed up.
No warning lights visible on dash now.

MISSFIRE | CONDITIONS
On Start Up. Starts perfectly, unfortunately idles like a Harley Davidson.
Misfires under load.
Overtaking now not possible.

Your thoughts ?

[rfsteel]

Sounds like a fueling or ignition problem.

From your description, you have the 150 bhp V5, with HT leads and a single coil pack.

Personally I would be looking at the HT leads or fuel pump/ fuel pressure, ideally you'd want access to someone with VCDS or VagCom to log some data channels so you can rule out potential the causes.

Here are some similar threads to your problem;

https://uk-mkivs.net/topic/11293-23-v5-miss-fire/
http://www.vwaudiforum.co.uk/forum/showthread.php/...

Which also highlight the possibility that your timing chain could have slipped, do you know had rattling your chain has been/is ?

Other simple options to try, would be to disconnect your MAF sensor to see if this has any impact on the misfire.

You also mention that a flat battery has made the problem worse, have you tried disconnecting the battery to reset the ECU to see if this has any positive results ?

To reset the ECU:

1 Disconnect neg. terminal of battery for about 10 minutes.
2 Reconnect battery
3 Open driver's door and leave open (important!)
4 Turn ignition key to ON (don't start car) and leave it there for 3 minutes.

https://www.passatworld.com/forums/volkswagen-pass...

[rfsteel]

https://www.youtube.com/watch?v=1vlbXtpImaw

worth a watch also

[jamespearson]

Thanks for being so generous with your time, update, links and valued technical expertise.

This week the car is scheduled for a return to Deutchtek - http://www.deutschtek.co.uk
I’ll be sharing the headlines you’ve listed and discussing your recommendations before agreeing next steps.

I’d prefer the recommencement of trouble shooting to start with the less costly exploration.
Would you like to suggest an order in which the investigation should continue ?

Thanks for your consideration.

James.

[rfsteel]

No problem, cheapest and easiest option would be to use the VCDS diagnostics software to see where the issue lies.

https://www.ross-tech.com/vag-com/m_blocks/010-019...
https://www.clubgti.com/forums/index.php?threads/m...

I'd be looking at fuel, injectors and timing if I were you.

[jamespearson]

Apologies for delayed reply.
Thanks for another great update, much appreciated.

I'll update you once I've been to Deutchtek.

[Herr Bouff]

Had a similar problem with my Bora with the 10 valve V5 engine. Sounded like it was running on 4 cylinders.

Replaced the ignition amplifier and all has been fine ever since.

[jamespearson]

Thanks for the update, apologies for my delayed reply.

Issue with the ignition amplifier has been suggested as a possible cause.

It's great to know that replacing it was the solution for your Bora.

I'll speak with the workshop asap.

[Herr Bouff]

jamespearson said:

Thanks for the update, apologies for my delayed reply.

Issue with the ignition amplifier has been suggested as a possible cause.

It's great to know that replacing it was the solution for your Bora.

I'll speak with the workshop asap.

The ignition amplifier was an easy fix. A 5 minute DIY as it's on the bulkhead and easy to replace even with a basic tool kit.

My V5 is up to 160k miles now. Mega reliable engine. Only other problem I had was random cutting out which was cured with a new crank sensor. Hope you find the fault as there aren't many left in captivity now.....!!