calvin280zxt Posted April 8, 2011 Share Posted April 8, 2011 my 82 turbo ran great in the fall. now a few months later it seems to lose spark at 45-4800 rpm like a ghetto rev limiter. its not fuel cause it shoots crazy flames out. any ideas Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted April 8, 2011 Share Posted April 8, 2011 Check your plug gap and electrode condition. Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted April 8, 2011 Author Share Posted April 8, 2011 plugs are brand new and properly gapped Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted April 8, 2011 Author Share Posted April 8, 2011 plugs are brand new and properly gapped Quote Link to comment Share on other sites More sharing options...
tec280zx Posted April 8, 2011 Share Posted April 8, 2011 (edited) What condition is your coil in? Ignitor, wireset? You should do an ohm check on your wires even if they look to be in good condition. Edited April 8, 2011 by tec280zx Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted April 9, 2011 Author Share Posted April 9, 2011 wires and coil are new. butt looking at the coil its to small the p/o just clamped the top part in. might pull the coil out of my parts car and test that out Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted April 12, 2011 Share Posted April 12, 2011 What about the dizzy cap and rotor? my ZX was acting strange at around 5000rpm my old rotor was missing a piece , and the dizzy cap had copper buildup. Put the new rotor and cap on and took it to 6500rpm down the block. Also bought a new coil and wires(couldn't hurt to have them instead of the decade old crap). Quote Link to comment Share on other sites More sharing options...
YeaJimi Posted April 12, 2011 Share Posted April 12, 2011 What gap are you running btw? Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted April 12, 2011 Author Share Posted April 12, 2011 i think thats what ill do. its well over a decade old its only ran 2 of the last 12 years. dont rwmember the gap. its stock spec though Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted April 13, 2011 Author Share Posted April 13, 2011 cleaned rotor and cap different coil made zero difference Quote Link to comment Share on other sites More sharing options...
aarang Posted April 14, 2011 Share Posted April 14, 2011 Clean all of the engine harness plugs including at the ECU. Remove the plugs, get some electro contact cleaner, spray them, reinstall. I would highly recommend getting some Caig Deoxit for all of the connectors as well or some dielectric grease. They help with the oxidation that builds up on these old connectors. Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted October 8, 2011 Author Share Posted October 8, 2011 Problem Found!! weak spring in the fpr couldnt support 9psi boost 8 psi takes it to 6500, fpr is bumped to top of wishlist. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted October 8, 2011 Share Posted October 8, 2011 Strange. You said you were shooting flames out the back so it sounds like you ran out of spark not fuel. If you can't get enough fuel you should be running lean not rich enough to shoot flames. Sounded more like a week spark - are you sure it's not blowing it out at the higher PSI? Does it rev past 4.5K at low boost? Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted October 8, 2011 Author Share Posted October 8, 2011 (edited) must be enough fuel to burn in the exhaust i guess, it wasnt just flames it was like a violent rev limiter with no fuel cut,was a big bang out the exhaust. revs right up to 6500 at less than 9 psi, the more boost the lower the "violent rev limiter" could be a spark problem that shows its face at high boost/rpm i suppose. spark plugs not meant for boosted applications maybe?? eom spark plugs- bpr6es 11 in car - bpr6ey 11 Edited October 8, 2011 by calvin280zxt Quote Link to comment Share on other sites More sharing options...
FricFrac Posted October 9, 2011 Share Posted October 9, 2011 I had some nasty backfire when I got into the throttle when one of my spark plug connectors modified itself from a 90 degree to a 180 degree connector on the dizzy.... There was enough fuel from the one cylinder that wasn't firing to get into the exhaust system to cause it to backfire. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 10, 2011 Share Posted October 10, 2011 Sounds like a fuel-flow problem to me...like possibly a clogged fuel filter making the pump's internal bypass lift! Check the fuel pressure UPSTREAM of your fuel filter. The conditions you describe are EXACTLY what happened to JeffP at the Jim Wolf Dyno Run. Car was fine to 5500 rpms, and then at 5525 WHAM like a rev limiter. Everybody was puzzled and then the car just stopped. Pulled the dissy cap and found the rotor 180 out! Jim says "Well, we know it didn't drive down here like that!" and the search was on: drive gear on dissy shaft was spinning when we hit the 'rev limiter' Eventually it was traced to a combination of two things. The Nissan ECU switched from two shots to one at 5525, so at lower flows the injectors were passing the fuel no problem. But when it went to a single BIG shot, there was cellulose fibers from a collapsed fuel filter which were allowing the lower 'two shot' flow through unimpeded, but when it switched to the 'big shot' the engine was starved for fuel. I suspect you may have a filter which is partially clogging, and the pressure upstream is getting to bypass point on the fuel pump. When this happens it's the same situation: you have all the flow in the world right up to the point of the valve lifting, then the engine falls flat on it's face. We went through plug gap and took it down to 0.020", all that stuff. We weren't shooting flames though... Biggest caveat: We NEVER heard a SINGLE detonation. Nonetheless 5 of 6 JE Forged Slugs sunk their rings on that run! This was at 8.39PSI on a calibrated, precision MAP Gauge set up on the manifold to independently register boost pressure. I'd do some testing, as well as check your compression and do a leakdown test. If you have done this several times and it IS fuel going lean....chances are high something is on the way out. We did it THREE times. We made THREE passes till the engine slipped 180. We re-timed it, and made a 'soft' pass where it 'hit the limiter' and the timing slipped 7 degrees---so that was it for the day. You may have a combination of both a misfire, AND insufficient fuel flow. I'd verify that upstream pressure on the fuel filter and see what you have, as well as possibly dropping the gap 0.005" at a time until it gets better or your noticing idle quality degradation. Good Luck, be careful...you're treading on "BOOM Ground" Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted October 10, 2011 Author Share Posted October 10, 2011 thanks guys, the fuel filter is almost new, but i have a spare so ill try that who knows whats in that gas tank. And its for sure not just one cylinder it loses all power. going to check fuel pressure when i get a chance. plugs dont look lean but who knows. this all started after sitting for the winter Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 14, 2011 Share Posted October 14, 2011 The ZX does have a pressure restricting mesh screen susceptible to restriction of fuel flow on the front end of the pump as well, down in the tank! Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted October 16, 2011 Author Share Posted October 16, 2011 ill have to troubleshoot it in the spring, sounds like a good excuse to install a wideband afr. narrow it to spark or fuel atleast Quote Link to comment Share on other sites More sharing options...
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