Mainsubject

hey guys, the car is a 97 civic EX with a JDM B18C swap. I had a problem of the #15 fuse under the dash blowing, losing speedo, and alternator charge. Did some test and research, found the ground wire on the VSS harness connector was pulled out some. all of the lock tabs no longer work. I figured that was building resistance and arcing causing the fuse to blow. Anyways i played with the plug, pluged it in and pushed all of the wires into the plug and i was good to go. got about 500miles and it blew again. retraced my steps, and did this test on the VSS harness plug.

1) Insert the black meter plug into the "com" hole and the red meter probe into the "V, Ohms, mA" hole not the "DC 10A" hole.

2) Turn the meter dial to measure continuity (white sound symbol on lower right side). If you touch the red and black meter probes together, you should hear a beeping or buzzing continuity sound.

3) Unplug the VSS connector and inspect the wires and connector terminals. Do you see any corrosion or damage?

4a) Turn key OFF. Touch any meter probe to the thermostat housing and the other meter probe to the black wire terminal in the VSS connector. Does the meter make the continuity sound?

4b) Dial the meter to measure DCV (red). Turn key to ON(II). Touch the black meter probe to the thermostat housing and the red meter probe to the Blk/Yel wire terminal in the VSS connector. What voltage do you read?
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i have continuity, but AS SOON as you cycle the key to ON 2 you can actually watch the fuse blow. so i can't do test 4b. However i'm thinking with the VSS unplugged that the VSS is not the problem this time. I'm going to jack the car up tomorrow, look at the harness, check and clean all ground wires. Anything else i can check that may cause the #15 to pop once you turn the key?

BTW running OBD1. P28 chipped ECU "Richtuned" and the O2S were cancelled out.

any input would be great, Hoping to hear of a place to look for a quick test & fix. thanks ahead guys!

Former User

Does unplugging the alternator 4P connector and the large white alternator wire attached to the hood fuse box prevent fuse 15 from blowing?

mimog3

O2 Sensor, Alternator, and VSS all share fuse 15, check and see if your o2 sensor wire or connector is touching anything. i once stripped the o2 sensor wire and it touched the metal body and it blew fuse 15 and caused the speedo to stop working, alternator didn't work and threw a code for an o2 sensor. i noticed you said that you "deleted" the o2 sensor so i thought maybe this is something you should check.

Mainsubject

I'll have to find some more 7.5a fuses and try that, and yes the PO who i bought the motor swap from gave this ECU with the car, and told me he had that done. The O2 on the exhaust manifold isn't plugged in, however the post-cat O2 from the OBD2 motor was never unplugged. So i'll be unplugging that today as well. I'll try these things and get back to the thread with results, thanks guys.

slobalt716

iTrader: (1)

I had the same problem, but on my d series motor. The harness was rubbing on the intake manifold bracket causing it to short out.

Mainsubject

yeah ive read that all over, I never had the issue when the D series was in the car. and i got 2000 miles on the B series with no issue until the wire backed out of the VSS plug. It could be a wire worn through but i wouldn't think so since the harness sits different on the B series with how i laid it. Still need to check after work though.

Mainsubject

turns out it was the O2 wire rubbed on the heat sheild which cut the insulator. glad it was a simple fix, generally with my luck it's always replacing something these days.

mimog3

Glad you figured it out. I know how much of a pain in the *** it is. I ended up stripping the O2 sensor wire when I was trying to swap my subframe with the exhaust and O2 hanging while connected. When I put everything back together I had a CEL, car shifted like crap, speedo didn't work, alternator wasn't charging and many other things. Couldn't figure it out until I retraced my steps and saw that the fuse for the VSS/Alternator was blown and when I replaced it all my problems went away. That's how I found out the o2 sensor shares the same fuse and caused all my issues

Happy for you man cause when it happened to me I was freaking out haha.