4th Cyl Misfire
02-29-2004, 03:30 PM
#1
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Location: Seattle, Washington
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4th Cyl Misfire
Okay, Now I've been through this before with the 5th Cylendar. We went through a full tuneup, brand new wires (they were said to come with bootprotectors, is this true?), brand new plugs less than 2K miles on them infact. and we replaced the first two ignition coils. It turned out the first coil fixxed the 5TH cylendar misfire. Car ran fine for two weeks then out of nowere when I was making a left turn, I hit the accelerator and bam, started running like crap, misfires are back. I got it scanned at Autozone, they said it was the 4th cylendar this time. I decide okay, I havn't changed that last coil in the back. I change it and the 4th cylendar was linked to that coil. The coil was corroded and needed to be changed badly. After replacing it, It still runs like crap and misfires. SES light is also on. The plugs are pretty much brand new!!! I can't pay another $200 for another tuneup. What could be the cause of this? how can I finally rid of this? Boot Protectors were said to have come with the new wires (I can't tell, I've never seen one and they look like normal wires to me). It's hard reaching these plugs aswell so I can't clean them either. Any ideas as to what this could be?
03-02-2004, 04:33 AM
#3
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Join Date: Oct 2000
Location: Honolulu, Hawaii, USA
Posts: 8
Need4Camaro,
Check out my "great misfire mystery" post. I'm not sure what type of wires you got, but here's some thoughts:
1) With the heat generated by our engines (cast iron block/heads retain heat more than aluminum), and since the engine is nestled underneath the dash, you definitely want to use good wires. GM was replacing the stock wires because they were causing misfires. I changed mine to MSD Superconductor. I have heard great things about them, and even my mechanic (who used to race cars) highly recommended them. My MSD wires have over 50,000 miles on them and work fine.
2) What year is your car? Mine is a 1997, and did not come with boot protectors. I think the 1999 and up came with these, but I'm not sure. Nevertheless, the factory boot protectors are metal, and sometimes the heat will cause a cheap wire boot to crack and then the wire will arc on the boot protector. I recommend using boots protectors like those by Design Engineering. They'll completely cover the boot and protect it, and because these are heavy cloth-like, no arcing [if the boot ever cracks, which it shouldn't with these protectors].
3) Use heat sheathing over the wires, especially where they go under the manifolds. Except where they go into the wire looms, I have heat sheathing over all my wires.
To check if you got boot protectors, you'll have to put the car on ramps (be sure they are steady before you go underneath the car, and be sure to block the wheels) and check, especially wire #6 (passenger side, closest to firewall).
Believe me, I had this same problem that would not go away until I put the heat sheathing and boot protectors on, along with high-quality MSD wires. Good luck!
Check out my "great misfire mystery" post. I'm not sure what type of wires you got, but here's some thoughts:
1) With the heat generated by our engines (cast iron block/heads retain heat more than aluminum), and since the engine is nestled underneath the dash, you definitely want to use good wires. GM was replacing the stock wires because they were causing misfires. I changed mine to MSD Superconductor. I have heard great things about them, and even my mechanic (who used to race cars) highly recommended them. My MSD wires have over 50,000 miles on them and work fine.
2) What year is your car? Mine is a 1997, and did not come with boot protectors. I think the 1999 and up came with these, but I'm not sure. Nevertheless, the factory boot protectors are metal, and sometimes the heat will cause a cheap wire boot to crack and then the wire will arc on the boot protector. I recommend using boots protectors like those by Design Engineering. They'll completely cover the boot and protect it, and because these are heavy cloth-like, no arcing [if the boot ever cracks, which it shouldn't with these protectors].
3) Use heat sheathing over the wires, especially where they go under the manifolds. Except where they go into the wire looms, I have heat sheathing over all my wires.
To check if you got boot protectors, you'll have to put the car on ramps (be sure they are steady before you go underneath the car, and be sure to block the wheels) and check, especially wire #6 (passenger side, closest to firewall).
Believe me, I had this same problem that would not go away until I put the heat sheathing and boot protectors on, along with high-quality MSD wires. Good luck!
03-03-2004, 02:24 PM
#4
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Join Date: Dec 2003
Location: Seattle, Washington
Posts: 1,459
Okay, I fixxed the misfire problem! Turns out a plugwire was loose. There's one or two wires that go around behind the engine, they said they wouldn't recommend putting heat sheathing around that wire because it would melt due to it beeing right on the engine and firewall. If it's THAT hot then wouldn't the wire just fry right away?...
03-04-2004, 04:44 AM
#5
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Join Date: Oct 2000
Location: Honolulu, Hawaii, USA
Posts: 8
Need4Camaro,
I think the heat sheathing they are talking about is the thin plastic hose-type that is used in an engine compartment to route electrical wires. In the back of the engine, driver's side, our cars came with this, as well as where they route in back of the alternator. This does dry out, and if used near the exhaust manifold it will melt.
The heat sheathing I'm talking about is the one from Napa, that is specifically used for spark plug wires. It withstands heat of 500 degrees directly, or 1200 degrees or so indirectly. [Design Engineering makes similar products also, check it out at http://www.designengineering.com/products.html.]
These heat sheathing products will not melt or burn, trust me. I used this for all wires on the passenger side, since it was these that I had problems with. On the driver's side, I used it for the 1 and 3 cylinder wires, as they are routed near the exhaust manifold.
As for mechanic's advice these days, I take it with a grain of salt. No mechanic solved my misfire mystery, I did with a little research. All my mechanics had me do was replace parts that didn't need replacing, without ever fixing the root cause.
Anyway, just be sure you use high quality plugs, wires, and heat sheathing. It will pay dividends in the end.
I think the heat sheathing they are talking about is the thin plastic hose-type that is used in an engine compartment to route electrical wires. In the back of the engine, driver's side, our cars came with this, as well as where they route in back of the alternator. This does dry out, and if used near the exhaust manifold it will melt.
The heat sheathing I'm talking about is the one from Napa, that is specifically used for spark plug wires. It withstands heat of 500 degrees directly, or 1200 degrees or so indirectly. [Design Engineering makes similar products also, check it out at http://www.designengineering.com/products.html.]
These heat sheathing products will not melt or burn, trust me. I used this for all wires on the passenger side, since it was these that I had problems with. On the driver's side, I used it for the 1 and 3 cylinder wires, as they are routed near the exhaust manifold.
As for mechanic's advice these days, I take it with a grain of salt. No mechanic solved my misfire mystery, I did with a little research. All my mechanics had me do was replace parts that didn't need replacing, without ever fixing the root cause.
Anyway, just be sure you use high quality plugs, wires, and heat sheathing. It will pay dividends in the end.
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