Spark plugs/wires changed and upstream o2 sensors changed and misfires and knocking
12-08-2023, 09:46 AM
#1
Spark plugs/wires changed and upstream o2 sensors changed and misfires and knocking
Long story short only mods on it are intake/cam/catch can, changed spark plug and wires and let me tell u I spent 4 hours just changeing spark plugs and wires that **** would not come off glued on there. Anyway changed spark plugs/wires, and upstream o2 sensors because I’ve been going through gas like crazy lately even though car is showing 18 mpg so I changed those thinking those are the problem, well after installing everything turned the car on it was running fine idling, then I take it for a drive get the new spark plugs warmed up a bit and check engine light flashing po300 open the hood and hearing a terrible knocking noise coming from the motor, not like a metallic knock but more like air somewhere. Took the wires out got different ones thinking maybe I just got a bad set and made sure they clicked in I go for another drive and check engine light turned off for maybe 5 minutes and the car is jerking back and forth exhaust is popping like I have 2 step on permanently car won’t accelerate. My thinking is the coil packs don’t like the new spark plugs because well they are old and can’t provide a good spark and since I bought ones with a bigger gap it’s running like it’s only on 4 cylinders. Could this be coil packs being old and not supplying a good spark or does the car just not like the spark plugs since it’s throwing off codes. And why would the motor be like knocking because of it? Possible that fuel injectors are going bad as well? Idk it’s interesting to me how changing spark plugs and wires ruined how the car runs I fixed the excessive fuel consumption though from o2 sensors being bad so ig that’s a good sign but a new thing has arised any help would be great, don’t want to take it to a mechanic all charging 149 an hour just to look over my car figure out what is up also should mention I went from the AC delco .040 gap to the NGK tr55-Ix with a .059 gap, shouldn’t be an issue right? Also I have a vacuum leak somewhere po171 po174 comes on could that cause any misfires in cylinders with the new spark plugs
Last edited by C5samuelt; 12-08-2023 at 09:58 AM.
12-08-2023, 11:51 AM
#2
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Moved to C5 Tech for some comments.
12-08-2023, 05:12 PM
#3
Melting Slicks
Is "NGK tr55-Ix" a transcription error by chance? Correct NGK is TR5IX, which does indeed have .5mm less gap. That said, I find it hard to imagine that would cause the problems you've described, particularly immediately after changing parts. When I changed my plugs the originals had huge gaps from platinum pads having fallen off -- in excess of 2mm. The big gaps caused a bad idle, but it ran well otherwise.
You changed the O2 sensors because of perceived low gas mileage? Did you do any analysis on the sensors via the OBD port prior to the change -- and do you still have the original O2 sensors? Have you looked into verifying the O2s are reading properly?
Almost never see coils listed as much of an issue, and never in groups.
You changed the O2 sensors because of perceived low gas mileage? Did you do any analysis on the sensors via the OBD port prior to the change -- and do you still have the original O2 sensors? Have you looked into verifying the O2s are reading properly?
Almost never see coils listed as much of an issue, and never in groups.
12-08-2023, 07:45 PM
#4
Is "NGK tr55-Ix" a transcription error by chance? Correct NGK is TR5IX, which does indeed have .5mm less gap. That said, I find it hard to imagine that would cause the problems you've described, particularly immediately after changing parts. When I changed my plugs the originals had huge gaps from platinum pads having fallen off -- in excess of 2mm. The big gaps caused a bad idle, but it ran well otherwise.
You changed the O2 sensors because of perceived low gas mileage? Did you do any analysis on the sensors via the OBD port prior to the change -- and do you still have the original O2 sensors? Have you looked into verifying the O2s are reading properly?
Almost never see coils listed as much of an issue, and never in groups.
You changed the O2 sensors because of perceived low gas mileage? Did you do any analysis on the sensors via the OBD port prior to the change -- and do you still have the original O2 sensors? Have you looked into verifying the O2s are reading properly?
Almost never see coils listed as much of an issue, and never in groups.
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Dads2kconvertible (12-09-2023)
12-09-2023, 05:20 PM
#7
fuel leak and the car caught on fire it didn’t burn to the ground my everything on the top, wire harness, injectors intake, coils completely just melted I went in the hospital “first degree burn” so I’m lucky #1 and I also have blurry vision in my right eye from the heat
12-09-2023, 05:22 PM
#8
true, I actually spent all day rebuilding the top of the motor to the point where it runs new intake manifold found a wiring harness at a junkyard, bought new MSD ignition coils, fuel injectors, elderbrock spark plug wires, rails so now it runs but still nothing good idling like it wants to kill itself misfiring so I’m changing out spark plugs with some ac delco iridium’s from the tr55-ix and see if any changes
12-11-2023, 08:37 PM
#10
Melting Slicks
First things first: has the blurred vision cleared?So on the morning of the 8th the car ran well but had poor gas mileage. On the 8th you replaced the plugs, wires, AnD the front O2 sensors, leading to the car running very poorly. You then tried another set of wires, verifying both ends of each wire are securely connected to coil and plug. You had codes po300, po171, and po174, car ran ran poorly but gas mileage was good, at least until the engine caught fire and you ended up in the hospital — correct so far?
On the 9th, you obtained and installed a used harness, another intake manifold, another set of wires, what sounds like aftermarket fuel rails, new aftermarket coils — but not plugs. Am I still on the track?
The car is running, but poorly. I have to repeat an earlier question, do you still have the original O2 sensors? When you installed the manifold, did you verify the vacuum lines are connected and good? Did you verify the injectors were good before installation?
On the 9th, you obtained and installed a used harness, another intake manifold, another set of wires, what sounds like aftermarket fuel rails, new aftermarket coils — but not plugs. Am I still on the track?
The car is running, but poorly. I have to repeat an earlier question, do you still have the original O2 sensors? When you installed the manifold, did you verify the vacuum lines are connected and good? Did you verify the injectors were good before installation?