Quote:
Originally Posted by 1slow370
The fsm sucks when it comes to coils. It should just say "replace all coils with known good ones, and check to see if the light goes out. Our misfire detection sucks, and there is no way to determine if a self ignited coil has a bad winding. It can only be checked for a shorted, burned out ignitor, good luck it's probably not the coils any way see other sections"
|
The FSM is written for a tech to be as fast as possible and in the process, if more parts can be sold, that is good for the dealer. Years ago my friend had to replace all 6 coils on his 95 Maxima as the dealer couldn't figure out which one was bad.
As for the coil testing, there are a few tests the FSM doesn't mention...
They do require a scope (mine is a $125 Pico 2204) and you simply view the primary current and voltage waveform of the common ground for all 6 coils. Since you see all 6 coils in operation, you can see the weak one.
For the misfires, the fuel trims can help narrow it down to a specific bank, and the mode $06 misfire counters can help you narrow it down further...
Then scoping the fuel injector current (not easy to do on the VQ37) can how how well they are working and even when the fuel injector is actually opened. (google pintle bump)
The VQ37 is a fairly simple engine, and deeper troubleshooting requires special tools, or take it to a shop with the required skills and tools.
Bonus Tip
You can also use a scope to measure fuel pump RPM!
For a Nissan/Infiniti simply measure the ripple voltage frequency and multiply it by 7.5.
My pump runs at 6200 RPM at idle