T4 2.5 petrol drama

[Golf Loon]

Did you change the 30 relay?

How about the coil?

[Jmac]

Mate i would probably disregard the knock sensor as it is doing its job, if you are saying you are having fuel dramas the system might be leaning off and causing it to ping , knock sensor can only retard the ign so far. Like the guys are saying try 30 relay this only needs to drop a volt or fluctuate voltage and it causes dramas - if you connetc a scanner you can actually watch it doing this.
Jmac

[Transporter]

Yep tried all things suggested including second hand computer but it still runs like a slug intermittently????? Someone suggested cranck angle senor?? This is about the only thing not tried at this stage..what are you thoughts???

Cheers

Slugger

How did you go with VW mechanic?
Was it the fuel pump?
If not did he check fuel flow and fuel pressure. Fuel flow is as important as fuel pressure. You can have a good fuel pressure and bad flow.
How old is the fuel filter? Partly blocked fuel filter would give you good fuel pressure reading but not enough flow your engine would start missing and even stall. And at the same time knock sensor would retard the ignition timing.
To diagnose the fuel system your mechanic should have Inter-Ject fuel flow and pressure measuring equipment or similar.

[slugger95]

Still working on a solution, will get it back to him this coming week hopefully, fingers crossed..............will update you all when we find the gremlin

Ta

Slugger

[slugger95]

Tried everything suggested and more. Mech suggests it may be tension leads??? Cant see why that would stop motor from running completely on the odd occasion??? Running out of options now. It really should not be that hard should it, the mech is very knowledgable but even he is getting more and more frustrated..

Slugger

[Bodhi]

Hi i'm new to the forum (from the UK). Check out the Technical section our UK T4 forum, there might someone on there who has had a similar problem and maybe able to help you.

www.vwt4forum.co.uk

[slugger95]

Cheers buddy, I will have a gander....

[Jmac]

Mate you say your mech is pulling his hair out what has he done /checked???? have you tried a substitute coil in it???????? IMO it is electrical mate. Coils are bad on these , give us a run down on what has been done /checked
Jmac

[slugger95]

Geez, where do I start...

We have replaced the following:
Coil
Fuel pump
air flow sensor
air intake boot(hose)
computer(used)
fuel filter
number 30 relay
and these are the things I can remember.....I think thats about it..

Symtoms:
Slight rough idle at times hot and cold
under powered at times hot and cold, feels abit fluffy if that makes sense when on the go-pedal.
does not seem to want to rev out when under power and taking off from lights etc (periodic).
periodic non start after driving both long and short distances. Leave for 10 mins then hay presto it starts again.
periodic cut out of motor for 1 second when driving at any speed.
Finally had it stop in traffic and had to have it towed, when we got to the other end and the mechanic tried to start it fired up first thing.
On 1 ocassion and on a hot day the motor lost power and it seemed to go back to a half idle but could not move off due to lack of power and it sounded reallt strange almost light a pre ignition type of sounds, you know when it runs on after being turned off but on this occasion it was on???

That's it in a nutshell..........

The guys trying to fix it are from the Volks Shop in O'connor just off South street, really nice guys and helpful but I am feeling guilty as it is taking up so much of their time when I keep taking it back so often..

Cheers

Slugger

[gregozedobe]

A few more suggestions:

Lack of fuel (some of your symptoms remind me of a fuel vapourisation problem I had with an ancient (petrol) corolla I once had - it really disliked hot weather.

Poor earth(s).

Corrosion in connector/s (has any water gotten into somewhere it shouldn't have)

Broken wire (with the insulation surrounding it still intact).

Focus on electrical things that move with the motor (to fit in with the intermittent nature of the faults).

It is possible that you have more than 1 fault.

Carry a multi-meter with you so next time it won't start you can check for a lack of power when the fault actually exists. Even if you don't know what actually causes it this will be very valuable diagnostic info.

Take it to someone else who is good at tricky diagnostics but don't tell them what has been done ie a fresh set of eyes and minds looking at the problem, let them go back to basics.

Hope you solve it, and let us know what the problem was when you do finally fix it.