SiH

Right, to cut a long story short:
Car has been off the road 18 months. Took her for the MOT (roadworthiness inspection) and on the way there is a biiiig hesitation coming on to boost. If you 'push through' then she seems to pick up and go, but not at full pelt, however, sometimes she just holds back. Issue is worse around 3-4k under full throttle - worse with most load, if you gently accelerate no issues at all.
Idles fine, hot and cold.
Cruises with no issues.
When you blip the throttle there is a definite misfire/pop.

Took out the plugs today to be greeted by this:


So I'm assuming either ignition issues (which is what it 'feels' like) or chronic overfuelling.

I have replaced the plugs, and the issue is still there.

I have checked the following:
- Sensor check on PFC
- Grounds
- Fuel pressure
- Checked MAP sensor is connected

In the time she's been off the road, I have:
- Removed and replaced coils
- Relocated fuse box (but the reality of what I did was very minor)
- Drained the tank and refilled before driving
- Had the UIM off
- Regularly put a bit of 2 stroke in and turned over.

Car is a GT35r running PFC. Ignition stock save for a Twin Power. Was 100% fine before coming off the road.

Any suggestions?

Was mapped about 500 miles before coming off the road, and all was completely fine.
HP Fuel filter has done about 7k, but is 5 years old. LP fuel filter about 1k, <3 years old.

New leading coil about 2 years ago, has done about 500 miles. Leads are newish Magnecors.

Fresh fuel and 2 stroke mix in there.

Coils are wired with relay so direct 12v from battery (have checked voltage with a multimeter)

Tem120

iTrader: (5)

Did you rewire your fuelpump when relocating the fuse box ? or anything to do with the fuel pump

I know atleast for my car rewiring the fuel pump made a big deal with howmuch fuel was going into the engine , so IF you did . the increased fuel pressure could be drowning spark how are your AFR's when the hesistation / missfire happen

SiH

It's been rewired, but only in the sense that the fuse box has been moved - it was running off a direct wired 12v relay before, and still is now. The car is also running an Aeromotive FPR which should keep a reliable lid on the pressure (although obviously not if the pump is now under performing)

I don't have a wideband so can't measure AFRs unfortunately.

Tem120

iTrader: (5)

did you change the wires as well as the plugs ? , and what condition were the coilpacks?

SiH

Nope, wires have about 1k on them, trailing coils are original, leading coil is about 500 miles and 2 years old.

It's pretty difficult to make out, but you can kind of almost hear some of the misfires here:


When the throttle is blipped, it misfires a bit before revving - but really hard to make out on that.

And here - you can hear the 'pop' when I hit the throttle at the start.

It's almost like the TPS is out of whack, but it's within spec, and hasn't been touched.

s2kguy17

iTrader: (5)

My car was doing the same thing really bad and found out it was actually the tune. Did you try to drive it when the car was cold just to see if it transition over to boost better?

FD3Cam

My car is doing something very similar at WOT past 3000RPM or so

Let me know what you find!

SiH

Well, it's fixed.

A shiny penny (Quarter? ) to anyone that can see the issue.

adam c

iTrader: (2)

Plug wire not fully on.

IRPerformance

iTrader: (41)

Coils look to be in the wrong order. Those wires look to be in very poor condition. I would replace them with a set of NGK wires asap. In the future don't try to accelerate through breakup. Doing so skyrockets egts and you can warp seals.

SiH

Ping! Shiny quarter being sent your way over the internet!
I had the coils off during the lay up time, and didn't properly label them...
Leading coil was receiving the signal for the T2. Strangely, that made it run a bit odd.
I can rewire and rebuild an entire FD, yet I can't get three plugs in the right order.

Regarding the leads: It's an optical illusion They are 500 mile old Magnecors, but wrapped in black self amalgamating tape to hide the horrible red colour Where it's ropey looking is as a result of the amalgamating tape being pulled apart from it's neighbour that it had bonded with!
I wasn't doing repeated runs through breakup -those were brief test runs to see if the issue was still present after swapping out the plugs I'm not a complete fool.