I'm have a very frustrating and weird problem
My 15a ecu fuse under the steering wheel keeps blowing, and it's not immediate. It's happened once a week but twice today.
This is my daily so I need to figure it out ASAP.
I have not messed with the workin under the dash.
I have a 98 civic that was automatic.
Now it has an h22a manual swap in it with a hasport wiring harness and an s300 p28.

 

There are several 15A fuses in the dash fuse box. Which one?

 

It's fuse number 13 on that chart. My SRs light is on btw... It just came on randomly though..

 

Currently, if you turn the key from off to ON(II) several times, does fuse 13 eventually blow?

 

Well, it only blows while I'm driving it, but I'll try that and tell you.

 

If you get fuse 13 to blow the way I mentioned, you will be able to pinpoint the short. Otherwise, I'll mention that a common cause of fuse 13 blowing is a bad fuel pump.

 

The fuse didn't blow when I did it repeatedly for like 5 mins lol.
And literally a month old walbro 255 :/

 

It could be the main relay or a bad wire, but my bet would be on the fuel pump.

 

I can't imagine it being a bad wire, I haven't messed with anything under the dash.
I'll replace the main relay soon.
If its the fuel pump will it happen more frequently till it fails all together?
When the fuse goes out it doesn't power my ecu, I didn't know it was affected by the fuel pump.

 

Fuse 13 does not directly power the ECU. As shown in the diagram below, fuse 13 provides voltage directly to the fuel pump.

 

Ok so when the fuel pump doesn't come on neither does the ecu?
I can tell because the s300 lights don't come on

 

This could possibly indicate a main relay problem.

 

That's what I'll replace next. It's blowing instantly now and I'll probably have it trailered home. When I put another one in it, the walbro primes like normal but when I start to move the car just quits and ecu shuts off.

 

I missed this^

Jump the service connector to pull the SRS code (see FAQs sticky). What code is thrown?

Then unplug the SRS control unit to see whether this prevents fuse 13 from blowing.

 

I'll do this as soon as I can get the car home and let you know what happens.

 

happened to me .. ended up being a wire on the downstream 02 sensor rubbed on the exhaust heatshield and grounded out