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Bank 1 missfire vq25det

Inxlusion

By Inxlusion,
in Wagoneers

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Inxlusion Explorer

Inxlusion

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Posted

So I drove someone elses m35 last week and realised mine was seriously underpowered. I ordered a new set of ignition coils, sparkplugs and brought a boost gauge. When I hooked up the boost gauge I was only making peak of 8psi. I put a boost tee in and managed to push it back up to the standard 14psi. Drove it around like that for a few days while waiting on the ignition coils to come in and had no issues.

Ignition coils arrived so next up was the coils and plugs. Pulled the intake piping and plenum off and pulled the coils to find all the drivers side spark plug tubes were full to the brim with oil. Sucked the oil out of them, pulled the covers and threw some silicone on the seals as a temp fix while I wait on the new valve covers to come in.

While I had it all apart I decided to get the injectors tested and cleaned. Just got them back from the shop today, they said injector 3&4 were ~5% down compared to the rest but are now flowing the same.

Threw everything back together and started the car up and it was missing. Double checked I had connected everything back up and had all hoses on and secure. Everything looked good. Jumped on the forums and read that the connectors for coils 4&6 and 3&5 are commonly put on wrong. Swapped the connectors to 4&6 started it up to find the misfire had gotten worse, swapped them back around and repeated the process on the other side with connectors 3&5. When I started it this time it had no effect. I have left it there for today and will dive back into it after work tomorrow.

My thoughts, the fact that changing the connectors between 3&5 had no effect makes me think that whole bank is not firing. I will check the ignition grounding on that side but it is there anything else I should check before I pull everything back off?

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GTSBoy Grand Master

GTSBoy

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Posted

Since when is stock boost on a VQ 14 psi?

Look to the health or otherwise of the coil looms. They can die, taking one or more coils out. Disassembling something in that state can make it go from barely working to not working at all.

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