Jump to content
SAU Community

Recommended Posts

hey guys

tonight whilst driving my 32 i noticed that once it comes on boost it starts hesitating/ misfiring abit and a cloud of black smoke out the back. I put $20 of BP 98 in it before hand and thats when i started noticing it and thats the first time it happened, the night before i went on the Antilag cruise and again put fuel in before hand and it had no problems came on power fine and smooth.

the car has splitfire coil packs with standard BOSCH plugs, forward facing plenum with saard injectors and a 35R turbo with 44mm gate

im thinking it could be a bad batch of fuel?? possible coil pack?? and maybe the standard plugs have given up on life and thats causing the drama

it idles fine, drives fine with no misfire but as soon as it creeps up to about 4-4.5rpm as the power comes on thats when it starts to hesitate and misfire, sometimes its not bad then some other times its pretty bad any suggestions????

cheers

Link to comment
https://www.sau.com.au/forums/topic/398853-32-misfiring-hesitating/
Share on other sites

ill try gets some plugs with that size gap, and thats what i though but drove till warning light was on went to a different servo and still the same result.

I put a set of platinum plugs in it this morning that i had sitting around, so i put them in and drove it the hesitation is gone but still has abit of a misfire i looked inside each coil pack when i changed plugs and cylinder 1 coil had a white powdery resedue and the little coil spring inside is like gone and all other coils are clean and have no pwdery stuff in it, and the top of the old plug was powdery and all crapped up, so i have a feeling its a combination of shit plugs which are failing when hot? and a crapped out cylinder one coil pack? i think the connection between the plug and coil is not good and spark has to jum further hence why still has abit of a miss??

ok so i swapped a whole coil pack assembly for all 6 cylinders and the harness from my mrs's car to mine and took it for a spin, still the same result, like a popping, misfiring sound, doesnt really seem to miss i think i can rule out its a coilpack if mine runs the same with 2 different harnesses, i even swapped the dud looking one with the white shit in it to her car and took hers for a drive and hers ran nicely no miss or hesitation, im going down the lines that the pooping/ miss sound is maybe from the screamer pipe under abit of heavy acceleration??, it doesnt do it all the time when on boost just sometimes through the rev range, might even pay to get plugs with a .8mm gap??

well the plug from cylinder 1, the terminal had like a white powdery substance all over it and same with the inside of the coil all the rest where fine but on some the insulator had like brown burnt marks on the bototm of it and around the centre electrode its all black with carbon build up, could this mean anything towards it having a misfire on boost??

took it for a drive with my original splitfires in and new platinum plugs and its the same on boost seems to have like a misfire/ backfire/ popping effect could this be tune related?? is it best i take it to a tuner to run on a dyno to see if they can spot any bugs??

could a air leak cause it to wanna miss on boost??

whats got me stumped is that i changed plugs and the hesitation had gone but still it seems to have a misfire/ popping/ backfire affect i changed the coil pack loom and coil packs over and no difference i even put mine on my gf's car and hers still ran nice and smooth with good power delivery.

so that kinda pulled me away from it being a coil pack issue, im even thinking it could just be it backfiring out of the screamer pipe, the car still goes hard, i was thinking even maybe a air leak in cooler piping or vac lines? its been raining here in perth and my AFM is in cooler piping so maybe water could of stuffed it up causing it to make the tune out of whack whilst i was driving it through puddles etc?

could be something as simple as i just need to get plugs with a .8mm gap?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
    • AHHHH gotchaa, I'll do that once I am home again. I tried doing the harness with the multimeter but it seems the car needed a jump, there was no power when it was in the "ON" position. Not sure if I should use car battery jump starter or if its because the stuff that has been disconnect the car just does send power.
    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
×
×
  • Create New...