Mechanics

MULTIPLE MISFIRES

2003 Kia Spectra

Engine Performance problem
2003 Kia Spectra 4 cyl Front Wheel Drive Manual 54000 miles

I have a 2003 kia spectra with misfires on cylinder 1, 2 and 3. DTC codes P0300, P0301, P0302, P0303. I have replaced plugs (properly gapped), wires, coil packs, fuel filter, fuel injectors. No effect.

Noid light shows pulse signal at fuel injectors. Compression check shows 140 on cyl #1, 150 on cyl #2-4

Thanks for your help!
Avatar
Gfspectra
April 15, 2009.




What is the fuel pressure reading? And, can you describe how it's driving going down the road? Please advise.

Tiny
James W.
Apr 15, 2009.
Bought a gauge to check fuel pressure, but the reading was erratic and fuel accumulated inside the gauge. I assume the gauge was faulty, so I don't have an accurate pressure reading right now.

When cold, the car will start but then die immediately. If I press the gas, I can keep it running, and then it will idle (very rough) once it warms up for about a minute.

When I try to drive it, it stumbles up to about 2500 rpm. Above 2500 it seems smoother and accelerates decently.

Tiny
Gfspectra
Apr 15, 2009.
Well, if it were a fuel pressure problem, the symptoms would be the other way around. Good performance at low revs and poor at higher revs under load.
I'm assuming you have not had a "check engine light". A problem with the cam sensor will usually trip the CEL, but many times a bad throttle position sensor won't. I'll see if I can find the TPS test specs and attach them to this post. I now sounds like the TPS may have a dead spot in it.


http://www.2carpros.com/forum/automotive_pictures/248092_03_Kia_1.jpg



http://www.2carpros.com/forum/automotive_pictures/248092_03_Kia_1_1.jpg



http://www.2carpros.com/forum/automotive_pictures/248092_03_Kia_2_1.jpg


Tiny
James W.
Apr 15, 2009.
I do have CEL, codes P0300, P0301, P0302, P0303. Just misfire codes. Would a bad TPS cause misfires like that? Thanks for the spec sheet, I'll test the TPS as soon as I get some daylight.

Tiny
Gfspectra
Apr 15, 2009.
The term " miltiple missfires" mean that a given cylinder is not firing. This isn't just limited to spark. A lean condition can also cause a misfire. And, a possible cause of this could be the TPS. Let me know what you find.
AND, what do you mean, " get some daylight", it's still daylight here. Pardon my twisted humor.

Tiny
James W.
Apr 15, 2009.
Sounds good, I'll check it out. My work schedule doesn't allow me much daylight : )

I'll post my findings.

Tiny
Gfspectra
Apr 16, 2009.
Ok, TPS was slightly off the numbers you posted. I replaced it and cleared DTC codes. Started it up and it ran (didn't stall immediately like usual), but still very rough. After a couple minutes the misfire codes came back (cyl 1 & 3)

Side note, I can hear what sounds like sparks arcing to the block intermittently. It will do it for 30 seconds, then stop for a minute, etc. I started the car in the dark and couldn't see any arcing.

Tiny
Gfspectra
Apr 22, 2009.
Did you ever find the problem? I'm having a misfire on my car and figured your solution may help me if you could just post the result.

Thanks!
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Tiny
Kingrock
Aug 11, 2009.

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