miller cycle engine misfire and knock
#1
05-16-2012, 04:27 AM
miller cycle engine misfire and knock
I'm a recent mazda owner (99' Eunos with millercycle engine). Right hand cyl on front bank is misfiring. Have changed the plugs and replaced the coil, fuel is getting in as plug gets wet - anyone any ideas? In addition I have a knocking noise from the supercharger (blows no smoke). Ideas welcome!
#2
05-16-2012, 08:47 AM
Leaking fuel injector seals?
A consistent, single-cylinder misfire at idle and possibly higher in the rpm range can indicate a leaking or stuck injector. The constant stream of fuel leaking into one cylinder throws the air/fuel ratio completely out of whack, making fuel ignition for that cylinder impossible. Note that a leaking injector will only affect its host cylinder; if you detect multiple or random cylinder misfires, the problem probably lies in your ignition system. Read more: Leaky Injector Symptoms | eHow.com Leaky Injector Symptoms | eHow.com
The worse case scenario is a fuel injector that has failed in the open position. This will immediately flood the cylinder with fuel, disabling the spark plug and allowing raw fuel to flow into the exhaust system. This can be a dangerous situation since, in severe cases, raw fuel may pour out of the exhaust with the engine running. It will also destroy the catalytic converter in short order. In a less severe situation, the fuel economy will take a dive.Another problem common with fuel injectors is a leaking injector body or a leak at the o-ring on the top inlet port on the injector where it plugs into the fuel rail. This can be seen with the engine running and a strong smell of gas will be present.
A broken lower o-ring will cause an air vacuum leak at the manifold. Depending on the severity of the leak, a misfire will occur and a conflict with the computer with respect to the fuel mixture which is now unmanageable within the correct parameters.
A broken lower o-ring will cause an air vacuum leak at the manifold. Depending on the severity of the leak, a misfire will occur and a conflict with the computer with respect to the fuel mixture which is now unmanageable within the correct parameters.
I'm surprised it's not smoking: "As you can see the supercharger's oil seals are completely FUBAR, causing the spark plugs to foul and the car misfire like crazy. This is a common problem with these cars that should have been recalled, however this reman supercharger has better than oem seals". From: http://www.youtube.com/watch?v=9sxejOXWmE4 At near end if you listen to supercharger, you can hear knockin
Last edited by UseYourNoggin; 05-16-2012 at 08:57 AM. Reason: knockin
#3
05-16-2012, 11:59 AM
there are several cases recently of bad fuel injectors on the 2.3. we had one on our black 99 about 4 years ago, i could not believe an injector would go bad. it was cyl 5, the worst one to get to. i changed plugs and coils, and it was still there. when cold, the car would start and run fine, for about 10 minutes. then it would start to miss, and it would throw a cyl 5 misfire code. when i ohm'd the injectors, 5 showed bad. i was able to find a used set on ebay, and i took a chance and installed the whole rail on the right bank, even reused the seals, and it has been fine since. on the other forum, mazdaworld.org, there are a few posts where others have also had the same problem. we are right now organizing a fuel injection cleaning, trying to get 10 people, and one of the members is going to do the cleaning at a deep discount. if you have a eunos, you probably are not in the us, so this cant help. however, there is also a post on how to ohm your injectors by using the pins at the connector end of each rail, and this will show you if any of the injectors are dead, way better than pulling the rail and checking it. also, a word of caution, if you do need to change the injector, be very careful when removing the rail. get a good air nozzle, and blow away all the dirt around the seal where the injector sits, there will be plenty. and that seal btwn the injector and the head is pricey, about 12 bucks each. you can get a nice set of the other seals and silicone pad for the top of the injector from rock auto, about 3 bucks per set. dunno if this will work, but here is the set, beck arnley, 1580890.
http://www.rockauto.com/catalog/raframecatalog.php
you will still need the main seal in the head, KL02-13-257. you will also need some copper crush rings, these go on the crossover fuel feed line between the rails. to get to the injectors, you have to pull the intake, not a hard job, but a lengthy one. and if i were going to pull the intake(which i have, too many times), i would also change out the vacuum line system, at least 21 ft of vacuum line(i like the silicon line) and replace the plastic tees with brass. i would also change the plugs, and swap the right(rear) bank coils with the front ones. the rear bank gets way more heat than the front, and the rear coils are way more prone to fail. if the car has lotsa miles, now would be the time to do the valve cover gaskets, a job that will test your mettle. with the intake off the car, it is easy to get at the rear motor mount, and i can guarantee you it needs to be changed. make sure you get the factory mount, it is liquid filled, and the buttco aftermarket ones from india are not, and they just dont work. are we having fun yet?
http://www.rockauto.com/catalog/raframecatalog.php
you will still need the main seal in the head, KL02-13-257. you will also need some copper crush rings, these go on the crossover fuel feed line between the rails. to get to the injectors, you have to pull the intake, not a hard job, but a lengthy one. and if i were going to pull the intake(which i have, too many times), i would also change out the vacuum line system, at least 21 ft of vacuum line(i like the silicon line) and replace the plastic tees with brass. i would also change the plugs, and swap the right(rear) bank coils with the front ones. the rear bank gets way more heat than the front, and the rear coils are way more prone to fail. if the car has lotsa miles, now would be the time to do the valve cover gaskets, a job that will test your mettle. with the intake off the car, it is easy to get at the rear motor mount, and i can guarantee you it needs to be changed. make sure you get the factory mount, it is liquid filled, and the buttco aftermarket ones from india are not, and they just dont work. are we having fun yet?
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