Misfire when hot, replaced everything I could think of... |
Misfire when hot, replaced everything I could think of... |
Oct 16, 2007 - 4:47 PM |
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Enthusiast Joined Sep 21, '07 From FL Currently Offline Reputation: 0 (0%) |
OK, been chasing a misfire for quite some time. The car runs great first thing in the AM but misfires once normal operating temp is reached. Misfires at idle and while driving. First, I have replaced all fuel and ignition components and all vacuum lines. I decarbonized the combustion chamber (MOPAR CC Cleaner, good stuff!). I have replaced the MAP sensor, O2 sensor, and some various wires that looked corroded. Stock 5s-fe.
The engine bay seems to be getting extremley hot! (but not overheating). Yesterday I pulled the plugs to see if they show any evident signs of wear and I was confused by what I saw. The firing end looked great (brown to grayish color), however the insulator on top of the plug was brown and blistered (burnt)?! Anyone ever see this? They are NGK plugs with the factory heat range. Also (not sure if this has to do with the misfire) but every now and then I hear a pop come from my gas tank. Is the "pop" just releasing pressure from the tank? Is it supposed to do that? Sorry so long, I am just truly stumped!! List of parts replaced: Fuel Pump, Filter, Pressure Reg, Charcoal Canister, EGR Valve, and injectors Brand new distributor, wires, plugs, igniter, O2 sensor, MAP sensor, and even the ECU! Could this be a bad cat causing the heat? Cracked head? Thanks for input... This post has been edited by cv7713: Nov 9, 2007 - 11:21 AM |
Oct 24, 2007 - 8:48 PM |
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Enthusiast Joined Aug 31, '02 From Philadelphia, PA Currently Offline Reputation: 8 (100%) |
yeah thats your problem then. it sounds like either the gasket for the header is leaking, or the cheap header cracked.
make sure you get a brand new gasket from toyota. not those cheap silver mesh gaskets they give you. -------------------- 15PSI - 30MPG - Megasquirt Tuned
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Oct 25, 2007 - 2:51 PM |
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Enthusiast Joined Feb 7, '07 From Portland, Oregon Currently Offline Reputation: 67 (96%) |
QUOTE(lagos @ Oct 24, 2007 - 6:48 PM) [snapback]608118[/snapback] yeah thats your problem then. it sounds like either the gasket for the header is leaking, or the cheap header cracked. make sure you get a brand new gasket from toyota. not those cheap silver mesh gaskets they give you. Could a leaking header gasket cause the same problem only when the engine is cold, too? I'm having the exact same problem, but it goes away when the engine warms up. I noticed a leak coming from the header somewhere when I ran Seafoam through the vacuum yesterday. -------------------- |
Oct 25, 2007 - 9:06 PM |
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Enthusiast Joined Mar 11, '06 From Way South Chicago Currently Offline Reputation: 0 (0%) |
QUOTE(GriffGirl @ Oct 25, 2007 - 2:51 PM) [snapback]608365[/snapback] QUOTE(lagos @ Oct 24, 2007 - 6:48 PM) [snapback]608118[/snapback] yeah thats your problem then. it sounds like either the gasket for the header is leaking, or the cheap header cracked. make sure you get a brand new gasket from toyota. not those cheap silver mesh gaskets they give you. Could a leaking header gasket cause the same problem only when the engine is cold, too? I'm having the exact same problem, but it goes away when the engine warms up. I noticed a leak coming from the header somewhere when I ran Seafoam through the vacuum yesterday. yes, things heat - expand - and then seal. very common for an exhaust leak to only make noise on a cold engine, then go away when hot, however it will get worse to where it'll do it when hot as well. -------------------- |
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