hi all, recently done some upgrades to my car and have a question. my tuner is telling me when he tries to boost turbos (gt675s) that my car starts to misfire/ that there isn't enough spark to boost any higher - any ideas what this could be? he seems to think it may be ignitor pack or something to that effect? or coil packs.... sound about right?? any help appreciated.... thanks, gypo
Old PTU, coil packs, dirty connectors and old or incorrect spark plugs can all affect spark. Get a S2 PTU, clean connectors and test coil packs as per FSM, for starters.
Possibly coilpacks. How much boost are you running? What spark plugs have you got? Maybe try a set of coppers first.
Possible it's blowing out the spark. Most likely the wrong plugs, or if coppers, wrongly gapped. I don't think that a PTU (ignitor) in working order would supply diminished voltage, althoug it is a bunch of transistors, anythings posisble. STD coilpack's have been happily used in high boost applications, but again could be an issue. If your wanting to rule out spark issue, replace it all. S2 PTU, splitfire coils and some correct plugs.
Im gonna go with one of Andy's suggestions , incorect gap on the plugs, should be no more than 0.8 on a big boost motor.
Put in a fresh set of plugs of the correct type and range, not iridiums. If you cant get these easily put coppers in. Check the gap before install. Check coils for any cracks or burn marks. The burning looks kind of like a grey dust on the plastic parts of the coil. A 675 kit will not make enough cylinder pressure to overcome the voltage or EMF at the plug.
i was blowing out spark on my zed under 12 psi !!! untill we gapped the plugs to 0.7mm and thats with s2 ptu, splitfire coils, extra earths and a few other goodies
Just as a side note, not having a go at you Andy or Wattzed. The spark doesn't get blown out as commonly thought or stated, The cylinder pressure can get high enough to overcome the amperage (electrical pressure) of the ignition system. If the plugs are gapped too wide, the energy consumed for the spark to jump the gap will cause slow/cold flame propagation in the combustion chamber. It is this flame that will peter out giving the missfire. A plug that is too cold can also cause a missfire as the tip of the plug can not get hot enough to burn of combustion deposits, this leads to fouling and then a missfire. Generally speaking, engines running high boost or making more than 30% of thier factory rating should use a plug 1 number cooler. The standard TT plugs are PFR5B, going to a PFR6B would be a colder plug. Also gapping from the standard 1.1mm to 0.8mm will help alot. Often overlooked but there is alot to be learned in reading the plugs after a good hard pull on the road or dyno. Alot of engines could be saved from failing on the dyno or while being driven hard by simply pulling the plugs and looking at the electrodes and insulation. Sometimes sensors or tuners cant see eveything that is happening. This is how it was done before efi and most drag motorsport crew's still use this method.
brk7's @ 0.8 + x6 ignition box + bosch coils = fun! IMO, splitfires dont really give much extra spark and the s2 ptu is just a non fault prone nissan upgrade.
hey all, thanks for suggestions!!!! we changed the plugs before tuning. we put in ngk bcpr7es spark plugs. is that right or wrong????? sorry i'm still learning!!!!! we hit spark problems at about 18 pounds and im not sure if its related, but its pulling sh!t power.... after all these mods im not happy at all with the power and only had small gains after some fairly substantial mods.... hopefully fixing this spark problem will help with the power? thanks in advanced for your help!!!!! gypo
I would be doing what Bolts has suggested and go over all the earthing points. I was running split fires and the engine ran like poo. I think it may have had something to do with some of the coils going under water. Put the stock coil packs back in and it runs 20PSI and 300+RWKW no probs at all. Just for reference using NGK BCPR6ES plugs gapped at .8mm.
A CDI system is what most race cars use, with a coil per cylinder it will fire any turbo motor no matter how high the boost. Mine is run in conjunction with a aftermarket ECU, MoTec M600, I'm not sure if one can be run with the Z32 ECU. Do a Google on 'cd ignition', 'MW ignition' to learn more.
ok guys - replaced spark plugs to 0.8m changes PTU to a series 2, checked earth points - all good. Where to from here???? HELLPPP!!!!!
