Lacking usefull spark on trailing plugs
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Lacking usefull spark on trailing plugs
I have been working on an issue with spark on my trailing plugs. The car is difficult to start (must floor the throttle to get it to start) and the trailing plugs foul all the time. I have tested the spark on the trailing plugs and it is a weak orange spark.
The compression is good on both rotors. I've tried some old plugs (IRE01-27's) that have a smaller gap, this helped it start easier than the new plugs but the spark is still weak.
The plugs are new 7's and 9's, the plug wires are new. The ohms on the coils are within the FSM specs. I have also tried a known working ignitor. None of these new parts have made a difference.
The ground on the upper intake is good and so is the one on the coils. The wiring to the coils looks good visually (no hard/cracked plastic etc..)
I had thought it wasn't an issue with the coils because it would be unlikely for both coils to fail at the same time. I also don't think its the ground as it is shared with all three coils and the leading plugs are firing properly.
At this point the only other testing I can think of is power to the coils and verifying the ground is adequate. Is there an additional test that can be performed on the coils to verify they are not faulty? What could be causing a weak spark on both trailing plugs?
The compression is good on both rotors. I've tried some old plugs (IRE01-27's) that have a smaller gap, this helped it start easier than the new plugs but the spark is still weak.
The plugs are new 7's and 9's, the plug wires are new. The ohms on the coils are within the FSM specs. I have also tried a known working ignitor. None of these new parts have made a difference.
The ground on the upper intake is good and so is the one on the coils. The wiring to the coils looks good visually (no hard/cracked plastic etc..)
I had thought it wasn't an issue with the coils because it would be unlikely for both coils to fail at the same time. I also don't think its the ground as it is shared with all three coils and the leading plugs are firing properly.
At this point the only other testing I can think of is power to the coils and verifying the ground is adequate. Is there an additional test that can be performed on the coils to verify they are not faulty? What could be causing a weak spark on both trailing plugs?
Make sure your battery connection is free of corrosion. Make sure all of your grounding straps are free of corrosion and in place.
Check your compression regarding a hard start. Your injectors may be dirty or malfunctioning as well to foul the plugs so badly. I am worried about your compression in particular. Even if the trailing plugs were toast it would start easily. Trailing plugs are mostly for emissions purposes and also to squeeze every last bit of flame out of an elongated combustion chamber.
Your plugs could very easily be fouled by the presence of too much fuel, or poorly dispersed fuel(hence the injectors).
But, consider this: If your compression(the seal) is bad on the engine it would draw in less air and compress that air less, requiring substantially less fuel than the ecu is hardmapped to deliver at idle. That would foul the plugs pretty well.
Do you have a boost gauge? Have you modified your car in any way? What kind of vacuum are you pulling at idle? What rpm does the engine idle at? We need details!
Check your compression regarding a hard start. Your injectors may be dirty or malfunctioning as well to foul the plugs so badly. I am worried about your compression in particular. Even if the trailing plugs were toast it would start easily. Trailing plugs are mostly for emissions purposes and also to squeeze every last bit of flame out of an elongated combustion chamber.
Your plugs could very easily be fouled by the presence of too much fuel, or poorly dispersed fuel(hence the injectors).
But, consider this: If your compression(the seal) is bad on the engine it would draw in less air and compress that air less, requiring substantially less fuel than the ecu is hardmapped to deliver at idle. That would foul the plugs pretty well.
Do you have a boost gauge? Have you modified your car in any way? What kind of vacuum are you pulling at idle? What rpm does the engine idle at? We need details!
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ZaqAtaq
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Sep 5, 2015 08:57 PM