on full throttle runs im getting a popping, I think its coming from the exhaust. it goes from around 4500rpm upward, doesn't always do it. :S just worried its dett but from my experience that tends to sound like a ticking in in the engine high up. any ideas? I don't think its shooting flames.

sounds like a missfire

Questions:

Spec of car?

What map are you running?

How much boost are you running?

What plugs are you running? (If copper, what's the gap?)

Have you got access to a wideband lambda sensor?

 

Recommendations: No more WOT until you are sure exactly what is going on :)

 

Audible detonation sounds like an empty crisp packet being scrumpled up in a hand. Crackly.

I have been in steves z It sounds similar to a limiter stumble pop, bang

 

Its strange as the car is smooth as otherwise

Yeah thats right gaz that what I thought it was at first, then looked down and v8 was like oh not on full revs :s stock everything really just full decatt 360 degree stock tubs, stock boost. Il recheck the gaps tomos.

also no wideband unfortunately...

what should the spark plugs be gapped at? I think mine are 0.8 atm

what plugs are they?

Just the stock ngk jobbies.

might be worth trying a new set in there, when were they changed last?

In honesty, not within my ownership, so god knows.

Mine did this and turned out to be the plugs. I think stock gap is 1.1 or .2 then when you up the boost drop them down to 0.8

Im currently on stock boost, I think replacement is prob wise.

new ngkpfr-11cs ordered. hopefully that will do the job.

plugs are here so il fit and test Saturday and come back to report. im fairly confident now that this is an issue with missfire due to ignition related sources, hopefully its just the plugs but im expanding my mind to coilpacks, connectors ptu cas connection. trouble is diagnosis wise im pretty well limited to the whole try and listen method.

right pulled the plugs this morning, the looked normal, slight yellow orange colour to the electrode, otherwise clean no heavy deposits etc. the gap was 1mm and they were ngk pfr6b-11 that's it no a b or c rating? so ive replaced them with pfr6b-11c which ive gapped to 0.8 as that most of the forum posts seem to recommend. I am however still on 9psi and a stock ecu, but ive got full freeflow exhaust full decat etc, and 360 degree tubs. its raining atm so I'm not going to test it till it drys up, as I don't fancy ending up in a hedge backwards, but after letting it warm up on the drive and reving it a little the engine feels chunkier, more solid, I can feel the engine rock slightly in its mounts which is new, and the rev needle goes through the celing post 4k, it actually sounds more solid aswel. Of corse those things could all be in my head.

fired her up tonight, had a little check over the bay before I began you know usual checked the oil and coolant levels, let it idle for a minute and popped each coilpack connector just to double check it was firing on all cylinders(yes I'm a paranoid fella) anyways all good, so I progressed over the other usual suspects... temp sensors etc, and hello whats this my cas connection is half hanging off! that may have something to do with it. Anyways im happy to report my car now pulls right through the rev range to redline with just a note of wheel hop at the top of second, it is only 5 degrees c outside today, so cold roads and tyres. Didn't get a go at a 3rd gear pull through the higher revs as it was nearing rush hour and the road was never er... suitable for it lol that's the way im going to choose to put it. Anyho, looks like its done it, and its corrected the low speed juttering on pull away and its less poppy on overrun. overall it seems to have made a bit of a difference.

nice one steve glad the beast is sorted ;)

lol get a 1000 mile son it and I can finally boost it up, ohhh that's gonna be so much fun! still undecided how much boost to run and how to do it :devil2: 19psi outta do it hahaha!

Great stuff, just ensure base timing is set to 15° BTDC when fully warmed up.

I think and gaz might be able to say that weve done that, it was set few weeks back.

yes we did check base timing, but only takes 5 mins to double check it with the strobe, i know how paranoid steve is!