Misfire problem? HELPPPPPPPPPP
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From: Overland Park KS... Car: Stock 95 Coupe
Misfire problem? HELPPPPPPPPPP
I have a 95 LT1 Auto Coupe
OK, so I am loosing my mind with a what I thought was a misfire problem. About 6 months ago I replaced the opti wires, plugs and O2's and all was well. The car ran great. I recently took the car on a 200 mile trip and at the end of the trip the car started misfiring or what I thought was misfiring.
I checked all the plugs as well as disconnecting them one at a time while running looking for the dead cylinder. Each time I disconnected one the car started ran like crap. I also disconnected each injector one at a time and each time the cylinder died.
So now I am at a loss with what is going on. The roughness does not seem to be related to an individual cylinder.
The weird part is the car will run good sometimes then run like crap. Mostly like crap. :-)
The plugs seem to be all sooted up and the intake seems to be dirty and gooey as well.
Any thoughts?
OK, so I am loosing my mind with a what I thought was a misfire problem. About 6 months ago I replaced the opti wires, plugs and O2's and all was well. The car ran great. I recently took the car on a 200 mile trip and at the end of the trip the car started misfiring or what I thought was misfiring.
I checked all the plugs as well as disconnecting them one at a time while running looking for the dead cylinder. Each time I disconnected one the car started ran like crap. I also disconnected each injector one at a time and each time the cylinder died.
So now I am at a loss with what is going on. The roughness does not seem to be related to an individual cylinder.
The weird part is the car will run good sometimes then run like crap. Mostly like crap. :-)
The plugs seem to be all sooted up and the intake seems to be dirty and gooey as well.
Any thoughts?
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From: Overland Park KS... Car: Stock 95 Coupe
I just OHM'd out the injectors and they all come back as 13.5 ohms. I also removed the IAC and it was clean. BUT when I was looking at the throttle body I noticed that it was all oily. This happened a while ago and I replaced the PCV and seafomed the intake and it was great. The oil is getting in to the throttle body through the crankcase breather on the passenger side. There is no valve on that side just a breather pipe that goes from the valve cover to the intake.
I saw that the PCV valve is on the driver side of the intake. What is the purpose of the other breather pipe with no valve in it just sucking up oil?
Would it be safe to remove it and plug up the holes?
I saw that the PCV valve is on the driver side of the intake. What is the purpose of the other breather pipe with no valve in it just sucking up oil?
Would it be safe to remove it and plug up the holes?
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Joined: Mar 2001
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From: Cincinnati, Oh USA
Sooty plugs indicates running rich. Check for vacuum leak. Missing, check at night with the hood light fuse pulled engine idling, look along each plug wire for sparks. Wire looms must be in good condition and no plug wires touching metal.
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Get a timing light and use that to track down misfires.I use them all the time on all my EFI cars,even they dont use distributors.
Hook the light lead up to one wire at a time and watch the flashes as you rev the engine at the Throttle.If theres alot of pauses between the flashes,you found a possible miss area.It should be about the same for all wires,the flashes from the light speed up and down with the rpms.I just aim the light at a spot I can see it well.
When you have a miss and use a timing light,if its secondary ignition problem,you WILL see it with the light right away.It will flash alot differently than the others that arent missing.
Hook the light lead up to one wire at a time and watch the flashes as you rev the engine at the Throttle.If theres alot of pauses between the flashes,you found a possible miss area.It should be about the same for all wires,the flashes from the light speed up and down with the rpms.I just aim the light at a spot I can see it well.
When you have a miss and use a timing light,if its secondary ignition problem,you WILL see it with the light right away.It will flash alot differently than the others that arent missing.
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From: Overland Park KS... Car: Stock 95 Coupe
Yeah, its a weird problem. I hooked the car up to my laptop and the O2 sensors are both working fluctuating up and down from 200mv-800mv.
TPS is at .55 volts.
No codes at all on any sensors.
That freaking valve cover vent tube on the passenger side is letting all kinds of oil in the intake making it a pile of goo. Could that soot up the plugs?
I will do the timing light thing tonight.
It is defiantly running on the rich/oily side.
Any suggestions would be great.
TPS is at .55 volts.
No codes at all on any sensors.
That freaking valve cover vent tube on the passenger side is letting all kinds of oil in the intake making it a pile of goo. Could that soot up the plugs?
I will do the timing light thing tonight.
It is defiantly running on the rich/oily side.
Any suggestions would be great.
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Check your coil wire, too. I'll bet you've got electrical arcing along one or more of your ignition wires.
Check them at night or in a darkened garage. They can be kind of hard to spot visually unless you examine closely.
Check them at night or in a darkened garage. They can be kind of hard to spot visually unless you examine closely.
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From: Overland Park KS... Car: Stock 95 Coupe
I am getting black soot on the plugs on the passanger side only not on the drivers side. The drivers side plugs look like new.
The O2 sensors seem to be fine.
What would cause only one bank of plugs to soot up?
The O2 sensors seem to be fine.
What would cause only one bank of plugs to soot up?
Team Owner
Joined: Mar 2001
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From: Cincinnati, Oh USA
One or more injectors on that side leaks causing a rich mixture only on that bank. Measure the fuel pressure on the shrader valve on the end of the fuel rail and turn the ignition on for more than 2 seconds and turn it off. If the pressure drops rapidly, you likely have one or more leaky injector/s .
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From: Overland Park KS... Car: Stock 95 Coupe
I wanted to use the car this weekend so I replaced the plugs and that bought me a little time to have some fun. I tried the Bosch quad fire plugs because I was told they reduce fouling. I need to address the richness this week and see what is causing it.
Thanks for all of your tips I will use them this week.
Thanks for all of your tips I will use them this week.
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From: Fort Knox, KY
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I have the NGK TR-55 Double Platinums in my LT1 and have never had a fouling problem with them. They're an excellent plug for use in the stock heat ranges.
