diagnosing misfire

SlipAngle · 08-31-2008, 11:39 AM

So I'm working on a friends Daewoo Nubira. I know...its a horrible car. But its got D-Tec yo.

I scanned it, got po300, random misfire. Then cleared the code, then ran it. CEL came on again and I got only po304, cyl 4 misfire. I had tested the EGR valve, its fine.

So I unplugged the #4 plug wire. Car ran exactly the same, no other codes.

So is it safe to say this could be a coil pack problem, or a plug wire problem? It has a single coil pack.

eMKay (BFLO) · 09-02-2008, 07:19 PM

tpierce · 09-03-2008, 04:44 PM

have it running, get a spray bottle with water in it. Spray the coil pack and see if you see sparks and can hear it misfire. If not, go to the wires. Also, if it's just the one cylinder, switch plug wires with another cylinder and see if it changes.

SlipAngle · 09-14-2008, 12:34 PM

as I had initially assumed that was the problem, due to the plugs in a couple cylinders looking very lean.

Turns out 2 injectors were functioning at half flow. They got cleaned/balanced, I put them back in, and ran the car. It fired right up and ran 10x better than before. It seems to have the normal amount of power, no more CEL's, but this is real weird. The car will just bounce off the rev limiter at 4000rpm while revving the car in park. I know this thing can rev more than 4000rpm.

UrbanAssaultAudi · 12-06-2008, 03:45 PM

09-02-2008, 07:19 PM	#2
eMKay (BFLO) AudiWorld Uber User Garage is empty, add now Join Date: Jun 2000 Posts: 35,554	Check the plugs first __________________ President - AWOT Minivan BT '02 Honda Odyssey '03 Subaru Forester '92 NX2000 (borrowed racecar, SCCA ITA) '80 Hunter 27 '96 Hobie Wave '71 Piper Cherokee 140 '76 Cessna 172M '76 Piper Archer II '77 Piper Archer II

09-03-2008, 04:44 PM	#3
tpierce AudiWorld Super User Garage is empty, add now Join Date: Feb 2002 Posts: 17,033	single coil pack for all cylinders? have it running, get a spray bottle with water in it. Spray the coil pack and see if you see sparks and can hear it misfire. If not, go to the wires. Also, if it's just the one cylinder, switch plug wires with another cylinder and see if it changes. __________________ ----------------------------------- aim: tmpierce0000

12-06-2008, 03:45 PM	#5
UrbanAssaultAudi AudiWorld Super User 1988 Audi 90 Join Date: Dec 2006 Location: Auburn Posts: 4,523	not unless it sees road speed.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Welcome to AudiWorld!
		Welcome to AudiWorld.com. You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join AudiWorld.com today!

09-14-2008, 12:34 PM	#4
SlipAngle AudiWorld Member Garage is empty, add now Join Date: Jun 2003 Posts: 466	I sent the injectors out to get cleaned and balanced.... as I had initially assumed that was the problem, due to the plugs in a couple cylinders looking very lean. Turns out 2 injectors were functioning at half flow. They got cleaned/balanced, I put them back in, and ran the car. It fired right up and ran 10x better than before. It seems to have the normal amount of power, no more CEL's, but this is real weird. The car will just bounce off the rev limiter at 4000rpm while revving the car in park. I know this thing can rev more than 4000rpm. __________________ -Signature Space For Rent-