Gti6 Misfire

[evojay71 0]

I've just finished my conversion but it seems to have a slight misfire, coilpacks changed and checked, new spark plugs put in so I'm pretty sure I can discount those.

 

The car revs very clean at stand still and seems to rev clean in first gear to the red line fine but the misfire starts from second gear on. the misfire is very intermitant throughout the rev range though. I know it's hard to diagnose on a forum but do any of you guys have any ideas on what to check??

 

Thanks in advance

Jay

[Richie-Van-GTi 70 2 Cars]

Crank sensor and cam sensor also earth points are clean and healthy. Does it get worse the further up the gears you go? Is it more frequent at higher rpm? I had an 8v start with a similar misfire at top end high gears which gradually got worse spreading into lower gears and lower RPM. Then the fuel pump failed. Problem found lol.

[evojay71 0]

Just a quick update, I had to nurse the car last night, again seems fine in first gear then starts missing all through the rev range in all gears after that but seems better when accelerating very slowly though. Around 10 miles from the end of the event the misfire strangely disappeared, got back to the finish, parked the car up for around 11/2 hours but as soon as we left for home the misfire returned again. I'm maybe thinking it could be the fuel pump maybe or coil packs but would a coil pack problem clear like it did???

[ORB 227 1 Cars]

Fuel filter?

[evojay71 0]

Fuel filter's brand new, I'm going to put an uprated pump in it and see if it sorts things out and then on to the coil packs.

Edited March 3, 2013 by evojay71

[Jemehan 3 1 Cars]

I'd go coil paks before fuel pump tbh... You got a voltmeter on it yet? Do you have or know anyone with fuel pressure tester. It's very unlikely the pump... Can you hear it prime etc?

[evojay71 0]

Yeah the pumps priming, most of the time, the odd occasion I've noticed it doesn't but still starts fine. I'm wondering if it's a pressure problem?? Going to change both anyway tbh.

[mikeygulley 19 1 Cars]

My fuel pump primed everytime but it wasn't packing the punch it should of when I was in the higher rev range.

I changed sensors etc then the pump last of al!!!

[evojay71 0]

My fuel pump primed everytime but it wasn't packing the punch it should of when I was in the higher rev range.

I changed sensors etc then the pump last of al!!!

 

Did yours show the same sort of problems that I have??

[mikeygulley 19 1 Cars]

Yes they were similar symptoms. Would rev cleanly at a stand still but was hestitant under load at higher revs.

[evojay71 0]

Hi all, it's been almost 3 months since I started this thread so I thought I'd share with you the cause of my misfire woes and it's something that I would've never thought of checking out.

After wasting money and time changing the fuel pump and ECU coolant temp sensor and not curing the problem I booked a trip to the road road before I went any further, when it was hooked up thoughts were the alternator was knackered.

It was only supplying the battery with 3 amps max so the ECU wasn't getting the power it needed to work properly when the car was under load.

 

I fitted new alterntor today, not a job I'd look forward to doing again but the cars now running like it should, problem sorted

I hope this helps some of you guys in the future.

 

Cheers

Jay

[Jemehan 3 1 Cars]

Wish mine was that easy, my alternator died and replaced it. Still bogging down, mines at lower revvs, trying iridium core spark plugs next... Thanks for updating though, I hope that will help someone else in the future...

[welshpug 1,623]

W, trying iridium core spark plugs next.

 

 

dont waste your money, standard NGK are perfectly fine.