george.bryant Posted October 5, 2007 Share Posted October 5, 2007 I've attached this video to try and simlify my awful problem description. Hey all, after trying to narrow down the problem of my misfire i'm getting rather confused. I just changed the spark plugs and air flow meter. I'm lost as to what next. Motor idles great and accelerates averagely. Once around 2400rpm is reached the motor starts to misfire really bad. SOrry to not be really descriptive at the moment but i've been working on it for the last couple of hours and ive got myself in alot of confusion. Quote Link to comment Share on other sites More sharing options...
DREW RBZ Posted October 5, 2007 Share Posted October 5, 2007 Ill throw out one thing to check.. My misfire on my RB26 was cured checking the plug gap...could be many more things though Quote Link to comment Share on other sites More sharing options...
george.bryant Posted October 5, 2007 Author Share Posted October 5, 2007 My father gapped the plugs b4 I put them in. This motor is a L20et by the way. Quote Link to comment Share on other sites More sharing options...
george.bryant Posted October 5, 2007 Author Share Posted October 5, 2007 BUMP. Seems No one wants to help me out? Thats fairly sad, cmon guys! I've Tried a different Fuel Pump, Fuel Pressure Regulator, Coil, Ignition module, Dizzy, AFM, leads, spark plugs, ecu. The AFM was the only thing that made any difference in running. For about 10 minutes it would run good, then it misfires like ♥♥♥♥ over 2400rpm. So Stagefumer and me think its the AFM but any more ideas??? Quote Link to comment Share on other sites More sharing options...
big-phil Posted October 6, 2007 Share Posted October 6, 2007 does it get worse as it warms up? I don't know anything about an L20et but thinking as if it were an L28et I'd also check the head temp sensor, clean the plugs on the ECU, put a long screw driver on each injector (while the motor is running) then put the screw driver next to your ear pressed against your head (temple area) to make sure they are all ticking. Take each plug out after running it and read them, are any of them wet? check the resistance of each plug wire. clean rotor surface under dizzy cap???? Quote Link to comment Share on other sites More sharing options...
Zraced... Posted October 6, 2007 Share Posted October 6, 2007 Hmmm did you try it without the air filter connected and see if there is improvement? Is the AFM new or rebuilt? After running a while do your plugs look OK? Quote Link to comment Share on other sites More sharing options...
george.bryant Posted October 6, 2007 Author Share Posted October 6, 2007 big-phil: Yeh it does get worst as it warms up. The L20et and L28et are pretty much exactly the same setup. Except for the obvious 2l opposed to 2.8l. I've checked head temp sensor and it seems to be working because when I unplug it the motor dies on throttle but runs fine with it plugged in (but i'm not sure to be honest, how can I check?). I'll Clean the ECU pins and rotor cap and check injectors now. As for the resistance of the leads; my multi meter is dead ZRaced: I havn't ran a filter on the AFM at all whilst trying to first get it running properly. The AFM isn't new. I've tried 3 now. My good L20et AFM that got drowned when the headgasket blew, a L28e AFM and a Z18et. Plugs look fine to me. I'll pull them again and double check Quote Link to comment Share on other sites More sharing options...
GLENN280ZX Posted October 8, 2007 Share Posted October 8, 2007 Have you taken a look at the small sceen located in your feul pump? It's on the outlet side of the pump behind the hose barb adaptor. This happened to me and had the same symtom as you are discribing, cause's a lean condition. Found my problem after I fuel up and noticed that the stations pump was operating very slow (i got the bottom of their tank).It took me about a week to find it. Also did a feul pressure check while riding down the road when misfire was occurring, noticed drop to about 10pounds. Quote Link to comment Share on other sites More sharing options...
george.bryant Posted October 8, 2007 Author Share Posted October 8, 2007 Thtas a good Point. Totaly forgot about that. The car had been sitting for a few months and had ran outta gas where it was sitting so you may be right! I wish I had a fuel pressure gauge.. Quote Link to comment Share on other sites More sharing options...
Daeron Posted October 8, 2007 Share Posted October 8, 2007 what kind of throttle switch does this vehicle have?? Switch type, like the L28E FI, or potentiometer type? Just a SWAG, really, but I thought I would throw it out there. Quote Link to comment Share on other sites More sharing options...
george.bryant Posted October 8, 2007 Author Share Posted October 8, 2007 TPS is the Same as L28E FI Quote Link to comment Share on other sites More sharing options...
Daeron Posted October 9, 2007 Share Posted October 9, 2007 i couldn't pick up too much of your hesitation on the video, but try taking the cover off the tps and making sure the thing is working properly.. find Blue's techtips page for the EFI bible if you don't know how. Its another thing to check, at least. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted October 12, 2007 Share Posted October 12, 2007 I have experienced a bad misfire on a Z before and it turned out to be a cracked ditributor cap. Double check the cap. GL Quote Link to comment Share on other sites More sharing options...
george.bryant Posted October 16, 2007 Author Share Posted October 16, 2007 It was the igniton coil. Warning to all, do not use Bosch GT40T Coil. It burns out after ignition being on for short periods of time. I've put my L20et coil back on and it runs amazingly!! Quote Link to comment Share on other sites More sharing options...
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