Miss fire at WOT - even when out of gear.

[kaeolian]

I have got a good 96-02 Harness piece of you want to rule it out as long as you pay postage both ways, I don’t mind you trying it out

That would be super helpful dude ill PM you my address.

 

[JagKing]

That's what Pete at Boston Rotary told me, it's running a bit rich lower down as well as it pops whenever you blip the throttle and if you put your foot down and let off it makes a massive bang, everything apart from the back box is standard so I guess it shouldn't be doing that!.

The vast majority of popping and backfiring is actually caused by lean conditions not rich. If it is going rich you'll smell it.
I'd say test/clean the secondary injectors (and primaries while you are at it), fuel pump and fuel filter as well as check none of the fuel lines have perished. All good reliability actions and even if they aren't the cause any money spent won't be wasted.

 

[jdmr_neil]

Fuel

The vast majority of popping and backfiring is actually caused by lean conditions not rich. If it is going rich you'll smell it.
I'd say test/clean the secondary injectors (and primaries while you are at it), fuel pump and fuel filter as well as check none of the fuel lines have perished. All good reliability actions and even if they aren't the cause any money spent won't be wasted.

Fuel filter is a great shout

 

[Spendyrx]

After reading all that I bet it'd be the fuel filter!

 

[Paulm]

I was going to say fuel filter, but doesnt really fit with boosting in higher gears. I dont know a lot about the twins setup, i would guess a solenoid is not holding pressure. To get to the bottom i wpuld start by checking (i would replace) all the vac lines and check the plastic connecting points, the one way valves and then look at the solenoids

 

[jdmr_neil]

See

I was going to say fuel filter, but doesnt really fit with boosting in higher gears. I dont know a lot about the twins setup, i would guess a solenoid is not holding pressure. To get to the bottom i wpuld start by checking (i would replace) all the vac lines and check the plastic connecting points, the one way valves and then look at the solenoids

See now I've never seen a solenoid or vac/pressure issue cause a misfire. Lose boost and shit idle yes but not misfire. Misfire is usually fuel/ign/map, timing etc.

Only way I can see solenoids causing it was overboosting and running lean. This leads me on to, if it is overboosting even a little the oem ecu will retard timing to save lunching your engine. Could this be what your experiencing?

Edit, this couldn't happen without load though so if it does it on idle its not that.

 

[MightyCondor]

Mine delayed similar symptoms during the never ending single build. It was suspected that I had fuel contamination, but it took a few fuel filters and tanks of fresh fuel until that issue went away. Would certainly try changing yours.

 

[kaeolian]

Fuel filter has been done gents, I did that a couple of weekends ago thinking the same thing. Didn't fix it, unfortunately.

Once the cable Jit is sending me arrives im going to get fuel pressures tested as well, can anyone tell me if there are any testing valves on the fuel rails etc?

And how would I go about testing pressure from the pump? Im thinking if I can test before and after the FPR then only problem fuel wise it would be after all that is a knackered injector.

 

[jdmr_neil]

Would I not be right in thinking of you open the fpr right up that figure will be base pump pressure. As you close the regulator the pressure will rise due to the regulated flow. Hence you get both sets of figures

 

[kaeolian]

Would I not be right in thinking of you open the fpr right up that figure will be base pump pressure. As you close the regulator the pressure will rise due to the regulated flow. Hence you get both sets of figures

Absolutely no clue bud.

 

[kaeolian]

Small update, many thanks to Jit for lending me a cable to swap out. No change unfortunately so another thing ruled out at least.

 

[Wolfie1]

How much do you want to bet it is the engine harness to coil wiring harness junction? This part was bad on mine when I bought the car and needed replacing before it could be mapped as it was bad and causing random misfires.

https://www.atkinsrotary.com/store/...Coil-Wiring-Harness-Junction-N3A3-18-05Z.html

View attachment 6251

Thats exactly what i would try next

 

[Spendyrx]

Doesn't matter now! Is sold

 

[kaeolian]

Doesn't matter now! Is sold

Ha it doesnt matter to me but the new owner is on here so would probably appreciate all the help as well!

 

[Spendyrx]

Well show yourself new owner! Stop hiding in the shadows and make sure you post the result

 

[kaeolian]

Nickmms94 where are you

 

[Nickmms94]

Hey guys ive tested FPR as well as the fuel pump both ok ive got injectors out and going to send them off for cleaning/refurb. found a crack on the secondary rail where the two feet bolt to the engine so looking for a new rail. it wouldn't effect fuel flow at all but don't want the foot cracking right through as then it probably would effect how the injector sits.

 

[Paulm]

Im sure ive seen one on facebook, ill have a check later, may mot have even been on uk