FIXED: Just take and burn it... after ive taken my mods off

[mtj2k]

Hi all,

Firstly before I get blasted   - i know its not a GTI but its a mk5 and this is the only place where ppl give friendly, helpful advice ;)

I've been getting misfires for a few months now and I've tried so much stuff I'm tempted to just get rid of it for whatever someone will give me. Symptoms are: misfires shown (mainly on cyl 2, but a bit random) between 4000 and 5000 rev range, very jerky accel and EML light flashing. Worse with the remap on but still there without it. It's a MY07 1.4 TSI (140bhp) and I've tried: *swapping coils and spark plugs *2x Archoil AR6400 *New injectors *Compression test shows all cyl. OK

Has anyone got any ideas to what could be causing this??

My local VW specialist now wants to "take the head off to have a look" at the cost of £600-£800  

If this doesn't get resolved soon - there will be a lot of things on the "For Sale" section.

Thanks all

 

EDIT: one thing i should note (not sure if this is related or not). When i disconnected the fuel lines from the fuel pump to replace the injectors, i was expecting some high pressure fuel to escape. Hardly any did - just sort of dribbled out.

EDIT: Problem now sorted http://www.mk5golfgti.co.uk/forum/index.php/topic,84284.msg882060.html#msg882060

[omeydz]

Id point to the electrics mate.. Iv heard 1.4tsi with ECU issues and ? wiring also.

Cheaper way would be to swap out the wiring before trying to do the ECU.


The 170 TDI had a recall on injectors and their wiring so its not entirely implausable. They used to have jerky acceleration and misfire readouts.

Hope thats of some help.

[anorganix]

I'd also have a look at the injectors before opening the head.

[mtj2k]

Id point to the electrics mate.. Iv heard 1.4tsi with ECU issues and ? wiring also.

Cheaper way would be to swap out the wiring before trying to do the ECU.


The 170 TDI had a recall on injectors and their wiring so its not entirely implausable. They used to have jerky acceleration and misfire readouts.

Hope thats of some help.

Thanks - I'd hoped this wasn't the issue because the wiring looks so complicated to replace. I've mapped and unmapped my ECU about 20+ times, can that cause damage?

[mtj2k]

I'd also have a look at the injectors before opening the head.

I just spent this bank holiday weekend replacing all 4 injectors which made no difference 

[omeydz]

Mapping and unmapping with things like bluefin shouldnt cause this imo particularly if the car was initially fine with the map.

My guess is there is a dodgy connection or some corroded wiring. (does happen with time) VW warrenties dont cover wiring either so maybe a reason why?

it is possible to order certain portions of the engine wiring loom from the dealers and essentially plug and play for the most part.

Thing with this sort of thing is that you need to swap things as a final resort to finding the culprit.

but before you do this: Is the spark plug on cylinder 2 clogged with soot? Are all injectors spraying equal amounts of fuel? ( I know you replaced the injectors, but if one is still jamming no matter if you swap them on cyl 2 then its the injector wiring for example.)

[OSB]

Really sorry to hear your probs. SO frustrating.
Just a couple of thoughts - you say you swapped the coil packs and plugs. Did you just swap them round (accepted practice to see if the misfire moves to another cylinder, but does not always work) or did you swap all for known good ones ? Might be worth trying as you then definitely eliminate them.
Have you replaced the fuel filter? It solved rough running and misfire on a friends Ford a short while ago. When he cut it open the filter element was quiet dirty - doing its job - but had also come part loose and would block the outlet. Fairly cheap and simple to do I believe.
I doubt the head needs to come off, especially as the compressions are good and the misfire is intermittent. A burnt valve would be constant.

[D_Philli_82]

If you do return to stock I'll take your HIDS from you (shameless  )

[mtj2k]

Thanks for everyone's advice - my next stop was the fuel filter - relatively cheap and never replaced AFAIK

I should also note that it only happens at max boost (actual boost reading over 2300mb). This is what's leaning me toward some sort of leak on cyl 2 only at max pressure. Doing a compression test only runs at atmospheric.

@omeydz - can you log specific fuel injection quantities in VCDS? I haven't seen it under "Measuring Blocks"

@OSB - only swapped them around although i might as well order a new set of sparkies

@D_Philli_82 - noted lol watch this space

[omeydz]

Dont think injection quantity can be logged. Maybe the injection rate possibly. Check measuring blocks or control module map it.

Best way to do it visually is to remove the injectors and put into clean plastic bottles of the same size/type. Try starting the car for 10-15 seconds intervals until enough fuel is visible and see if the quantities of fuel expelled are the same.

If one is different swap injectors round to different position and run the test again and see if the problem migrates with a particular injector or just on 1 cylinder.

If its just staying on 1 cylinders injector wiring then question injector wiring.

If its on just 1 injector then injector is faulty.

If changing wiring does not fix it then Id point to the ECU as that is what ultimately is telling injector when to fire and how much. And before replacing ECU, ask VW if there are any ECU updates and software glitch might be an issue. Shouldnt charge you to update software if there is a update.

(Also if fuel filter was clogged, wouldnt misfire happen on any cylinder randomly?)

Good luck man!!!

[mtj2k]

For the sake of £50 I've ordered a set of spark plugs and fuel filter.. Will fit tonight and report back 

[greygti]

Hope you get it sorted mate

[Wooosh]

Good luck mate.

[J400uk]

If they offer a reasonable price I'd suggest just chucking it of to WBAC or similar after removing the mods. The early 1.4 TSI was a great concept but can be somewhat problematic.

[SurreyED30]

For the sake of £50 I've ordered a set of spark plugs and fuel filter.. Will fit tonight and report back 

Any news mate?