2G Eclipse GSX Cylinder one misfire.

[Bensont]

So I just got a 98 GSX and shortly after driving it the check engine light came on. I got it scanned and it was a cylinder 1 misfire. The engine was tuned up just a month ago new plugs, new wires and all of that.

So having said that are my only other options a compression issue or a issue with the injectors?

The car still runs fine and after clearing the code it took almost 27 Miles for the check light to come back on. So I am thinking that it could also be a Random misfire.

Any thoughts?

 

[Insane20]

Take the spark plug from cylinder 1 and switch it with 2, then see if it says cylinder 2 misfire. If that doesn't work switch the injectors around, if that doesn't work switch the plug wire around. Hopefully when switching one of those things it switches the miss to another cylinder then you will know what exactly is wrong.

 

[Bensont]

Take the spark plug from cylinder 1 and switch it with 2, then see if it says cylinder 2 misfire. If that doesn't work switch the injectors around, if that doesn't work switch the plug wire around. Hopefully when switching one of those things it switches the miss to another cylinder then you will know what exactly is wrong.

Thanks ill try that, If it is not one of those what could it be?

 

[PlanZero]

I had a misfire code for the last year. Mind you, on dsms a blinking light means active misfire, while a steady light means misfire detected. Mine only blinks at idle, and as soon as I move it stops,. Got a compression test done (that's your best bet), and cyl 3 is only at 50, 80 wet. However, she runs great. Leakdown showed that my valves and HG were good, so it must be the ring, but no one can explain to me why it's running so well and only blinking at idle. Welcome to the mysterious world of dsms.
Oh, I forgot to mention, the light went off for a couple days after I changed the.plugs. go figure.

 

[Bensont]

I had a misfire code for the last year. Mind you, on dsms a blinking light means active misfire, while a steady light means misfire detected. Mine only blinks at idle, and as soon as I move it stops,. Got a compression test done (that's your best bet), and cyl 3 is only at 50, 80 wet. However, she runs great. Leakdown showed that my valves and HG were good, so it must be the ring, but no one can explain to me why it's running so well and only blinking at idle. Welcome to the mysterious world of dsms.
Oh, I forgot to mention, the light went off for a couple days after I changed the.plugs. go figure.

So because I have a steady light it means that it misfired at one point but it is not doing it on every stoke?

 

[boost97gst]

I had a misfire that was so confusing. Intermittently would run on 3 cylinders. Rare and soon as i cycled the key it would be fine. In a blink.... So i thought injector wiring. Nope. Ended up changing coil pack and it went away.

The really weird thing was: It was saying cylinder 3. In reality it was cylinder 2. The ecu is not always right. come to find out a terrible thing much like planzero said: 95psi on #2 cylinder. FML. Still runs great and you couldnt tell, doesnt smoke or anything.

edit: Planzero, i cant believe your running even half way decent with 50psi comp number!! Thats a 420a, shouldnt normal stock compression be about 215?

 

[PlanZero]

Cyl 1,2, and 4 are at about 180 which is about right. Supposedly I'm running on 3.5 cylinders. This is my third 420a and it runs no different. I also changed coil pack. No difference in cel . Baffled.

 

[delta448]

Ask to see the code numbers next time.

P0300 or P0301?

If you have a constant every-cycle misfire, you will get P0170 or P0171 along with P0301. You have to drive it long enough in learn mode to max out the fuel trims though. -The misfire dumps unburnt oxygen into the exhaust and pegs the front O2 sensor full lean even with the fuel trims adding all the extra fuel they can.

http://www.dsmtuners.com/forums/1594853-post15.html

 

[jbeaton9292]

i had a misfire on my 98 gst and i found after it was to late that it was my coil pack as i tryed to use it on another car and it did it again. you could look into the coil and see the connection was all corroded. that car lasted me 2 day and then it got a bad knock i was so sad it was my first 2g.

 

[delta448]

About 99.9% of the time, when a coil fails on a DSM that still has the factory ignition setup, you'll drop 2 cylinders and not just 1.

With a waste spark ignition, the spark voltage is created between the 2 secondary poles (what your plug wires attach to) of the coil. When it discharges, the coil's electrical potential actually jumps from one pole through 2 spark plug gaps to reach the other secondary pole.

The neat thing about that setup is that the vast majority of the energy is always used on the cylinder undergoing compression while the cylinder on exhaust always uses up very little.