BASHTHEBISHOP Posted March 24, 2008 Share Posted March 24, 2008 I originally posted this about 3 months ago where i was only seeing a slight stutter at high speeds when flooring it.It was also only intermittent. Now this stutter is alot more pronounced and i am seeing it from speeds of 60mph +. Up until this speed i get full boost and the car accelerates as it always has(gives me hope the turbos arent knackered:blink:). Basically i get surge,cut,surge,cut and so on. If i gently apply the pedal and not all the way to the floor all is fine and it accelerates ok. So am i looking at a dodgy FCD? or problems with second turbo? or what?. I have checked all fluid levels and have always had them regularly changed.They are all ok. The only one i dont know how to check is for the diff but this was not done that long ago(about a year). I have tried to visually check for split hoses etc but all seem ok. My technical knowledge is about the same as your average saxo driver so please try & give a very basic guide as how to diagnose this. Thanks Mark Quote Link to comment Share on other sites More sharing options...
SupraShaun Posted March 24, 2008 Share Posted March 24, 2008 Spark plugs maybe, by stutter do you mean hesitation? http://www.mkivsupra.net/vbb/showthread.php?t=35931&highlight=hesitation Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted March 24, 2008 Author Share Posted March 24, 2008 Thanks for that but i do have colder plugs fitted (denso IK24's). However from reading that i would say this is the most accurate desc of my symptoms... 3c - massive overfuelling - you will get a drop in power harsher than 3b but less harsh than 2a. The engine pretty much won't get past the load site, it will just keep cutting out, so acceleration is lost. If you have a BOV, it will fire rapidly as power comes on and off. But still with a big lacking in technical knowledge i dont know. Could my walbro pump be knackered? Quote Link to comment Share on other sites More sharing options...
hodge Posted March 24, 2008 Share Posted March 24, 2008 Ah the spluttering gremlin. Do an error code check first mate if your FCD is dodgy you will probs get a code 31 which is map sensor. if its all clear I would check or change your plugs and go from there mate. Good luck Quote Link to comment Share on other sites More sharing options...
bondango Posted March 24, 2008 Share Posted March 24, 2008 Did you Check for codes? what boost are you running, and at what boost is the problem occouring? Could be the coil packs breaking down under load, bad coil pack connectors, bad plugs as it sounds like an ignition problem under load, i.e. if you ease the car on to boost the problem dos'nt occur. Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted March 24, 2008 Author Share Posted March 24, 2008 Ah the spluttering gremlin. I take it this one is not uncommon or you have had it before lol. Thanks for your help. Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted March 24, 2008 Author Share Posted March 24, 2008 Did you Check for codes? what boost are you running, and at what boost is the problem occouring? Could be the coil packs breaking down under load, bad coil pack connectors, bad plugs as it sounds like an ignition problem under load, i.e. if you ease the car on to boost the problem dos'nt occur. Am only running stock boost and only ever have. Will check for codes now but what you are saying on coil packs makes sense so thanks. Quote Link to comment Share on other sites More sharing options...
Sean1933 Posted March 24, 2008 Share Posted March 24, 2008 I know you say you changed the plugs but did you gap them correctly? How recent were they done? If its not plugs then check ignition coil pack clips, could also be your coilpacks. Does it do it only on boost, past a certain pressure...ie in the high load points. Or would it do it above 60mph say at cruise? I doubt its mass overfuelling, expecially on the stock ecu (you are using the stock ecu?). Also, your would see nice clouds of sooty black smoke out the back if it was! Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted March 24, 2008 Author Share Posted March 24, 2008 I know you say you changed the plugs but did you gap them correctly? How recent were they done? If its not plugs then check ignition coil pack clips, could also be your coilpacks. Does it do it only on boost, past a certain pressure...ie in the high load points. Or would it do it above 60mph say at cruise? I doubt its mass overfuelling, expecially on the stock ecu (you are using the stock ecu?). Also, your would see nice clouds of sooty black smoke out the back if it was! Plugs were done about 10k ago iirc and fitted by interpro and it was fine for 9 months or so. Only does it at high boost above 60mph its fine at cruise. Its only on stock ecu and no smoke so overfuelling is hopefully fine. Quote Link to comment Share on other sites More sharing options...
colsoop Posted March 24, 2008 Share Posted March 24, 2008 Ik24's are probably overkill for a stock boosted supra. How much fuel is in the car ? I used to get a missfire when i accidently went below empty, due to picking up the dregs at the bottom of the tank. Quote Link to comment Share on other sites More sharing options...
Nic Posted March 24, 2008 Share Posted March 24, 2008 Usual culprits are either plugs or broken connectors to the coil packs. Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted March 24, 2008 Author Share Posted March 24, 2008 Usual culprits are either plugs or broken connectors to the coil packs. I did an error code check and its not showing any. I will have the plugs swopped and then look to swop the coil pack connectors. How much are the connectors and how many do i need? Thanks Quote Link to comment Share on other sites More sharing options...
jevansio Posted March 24, 2008 Share Posted March 24, 2008 Are you running an aftermarket gauge to prove what boost you're running? Could cold weather not be contributing to you "just" seeing fuel cut? PS when I say "just" I'm not be-littling the problem , I mean you're seeing just enough boost for fuel cut to register PPS the only reason I ask is that it sounds sooo much like fuel cut, and you garage says BPU (does that mean you've been decatted???) Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted March 24, 2008 Author Share Posted March 24, 2008 Are you running an aftermarket gauge to prove what boost you're running? Could cold weather not be contributing to you "just" seeing fuel cut? I have been running the same mods since i bought the car nearly two years ago and have only seen this problem recently. It does have an FCD fitted. I dont have a boost guage fitted so probably need to do this to gain more understanding as to whats happening. Quote Link to comment Share on other sites More sharing options...
jevansio Posted March 24, 2008 Share Posted March 24, 2008 IMHO you need to know what boost you're running, you could spend a lot of time & money tracking this problem through the ignition system. If I were tracking this I'd want to know exactly what boost the car is running & what level the FCD is set at. I'm not saying it's the problem but there are some basics you need to eliminate first IMHO. Quote Link to comment Share on other sites More sharing options...
BASHTHEBISHOP Posted March 24, 2008 Author Share Posted March 24, 2008 IMHO you need to know what boost you're running, you could spend a lot of time & money tracking this problem through the ignition system. If I were tracking this I'd want to know exactly what boost the car is running & what level the FCD is set at. I'm not saying it's the problem but there are some basics you need to eliminate first IMHO. Agreed & Thanks:) The odd thing is it flies to 60ish but a month or 2 back that was 90ish before i saw the same symptoms. Quote Link to comment Share on other sites More sharing options...
Sean1933 Posted March 24, 2008 Share Posted March 24, 2008 Does sound a bit like fuel cut, but the gradual breakdown says no. Personally this points straight at coilpacks as once they start to go they get progressively worse quite quickly. Change the clips 1st though as you may be lucky! Quote Link to comment Share on other sites More sharing options...
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