Fuse sizing?

[Dan_Austin]

I ended up buying a house instead of working on my sequencer install, but I am
about a two weeks out from the actual install. I have been working on stub
harnesses and planning the wiring layout and documentation.

One design element I have not finalized is the ignition and injector fuse sizing.
I've been reviewing the quickstart guide, megamanual and other installs, and
the majority, OK all that I found, are based on non-sequential installs.

I am working on a six cylinder with six lo-z injectors, six LS2 coils. Can I use
one 7.5A fuse for the injectors and a 10A for the coil and nissan CAS? Or should
I plan to install multiple fused circuits for the injectors and the coils?

[Bernard Fife]

Dan,

I think your plan is sound and is the way I have wired mine (one fuse for the injectors, one for the coils). Any short to ground will blow either fuse, so you are protected. as well, there is the practical problem of have to install a dozen (or more) of fuses if you fused them individually. Finally, if an individual injector or coil has a problem, I personally would rather have the engine stop so I can check it out rather than have it limp along running less than optimally (on the highway, for example, you might not even notice this for many miles).

Lance.

[Dan_Austin]

The 7.5A fuse for the injectors proved to be too small. I managed to blow
it during a hard pull through first and second getting on freeway. This was
the first fuse issue in eight weeks of normal use, less two weeks of break-in
for the the new engine.

I have had a couple moderate pulls after the break-in, but this was the longest
sustained full throttle run. I checked my injector specs sheet, and they are
all tested at 2.2 Ohms. Simple math indicates I need over a 30A fuse for six
injectors, so I doubt I have my simple math right. For now I have stepped up
to a 15A fuse, but wonder if it might be a step too far.

[ca434sbc4]

Fuses typically blow at 150% of the rated value. Check the manufactures spec's.