I reinstalled my built GSR motor back into my '00 GSR over a month ago. I have 950 miles on it right now. I broke it in NA and have not installed the turbo yet. It is tuned with AEM EMS by myself. All stock sensors except for a wideband, oil gauge and injectors.

Everything has been great for a month until recently I started blowing the ECU fuse. At first I thought it was just a fluke but then I saw a pattern. Everytime I blew the fuse it was during a hard right hand turn.

Its the 15amp EMS/FI fuse under the hood. Can anyone tell me what else is powered by that fuse besides the ECU?

Naturally I thought it must be an open wire or short somewhere that was grounded when I cornered hard. The engine harness is stock and untouched. All grounds are intact. I inspected the entire engine harness when I cleaned the engine bay and reinstalled the engine over a month ago. There were no shorts or wears on the harness sleeve. The only open wires I had under the hood were from some quick gauge installs I did but they are powered from the accessory and ignition sources in the cabin so I dont think they are related. I taped them all up with electrical tape anyways but Im still blowing fuses. Ive spent hours looking over my engine harness and I dont see any bare wires or anything strange.

I have no idea what else to look for. I also noticed its not just sharp right hand corners it seems to blow right at the end of the sharp corner when I step back on the gas. When it blows the car just dies of course. I cannot blow the fuse from sharp left turns, only right turns. Im stumpted. Im blowing this fuse out every other day.

Any ideas?

 

Did you change your injector clips or resistor box?

 

I am having this same problem in my 1990 Accord f22. Only blows on sharp right turns. I figure their is a wiring short that connects or disconnects when I turn sharp. I have learned to not take right turns very quick.

 

The injectors are new RC 550 Saturated injectors. No resistor box needed. OBD1 clips are soldered on and securely taped. They have been installed for nearly 6 months without issue so I doubt they are the problem.

I blew 3 fuses today. First one was this morning pulling out of a gas station while on the throttle maybe 50% during a slight right hander. Second was sitting at an intersection taking a right, it blew was starting off in 1st under normal acceleration. It was on a slight hill so I rolled down the hill maybe 10 feet to get it out of the road, changed the fuse right there, and attempted to make the turn again. Car was running for 30 secs fine then I took the very same corner again this time very carefully. I got 10 feet further and the fuse blew.

This time I grabbed a 30amp fuse and threw it in. I know this isnt the smartest thing to do but I needed to get back to work. While driving back to work there is this one particular right hander thats also slightly up hill, where the fuse normally blows. I took the corner very slow and when i got back on the gas hard, the whole system bucks like the fuse blew but then kept going. So I think what ever happends, occured but it wasnt enough to over take the 30amp fuse.

After I got back to work I did my own auto-cross in the back without any cones. I flogged the car extremely hard left and right, with and without throttle. Full braking and full acceleration but not even a flinch with the electrical system. I dont get it.

Ive been forced to carry around a bunch of fuses and some pliers to do emergency fuse changes lol

<u>What else is on that damn fuse?!</u>

 

From the underhood fuse box, Fuse 44 (FI E/M, 15A) - follow the Yel/Wht wire which leads to the Main Relay (pin 7)

After the Main Relay (pin 6), there appears to be a cluster of Yel/Blk wires. Two of them go to the ECU (B9, B1). A thrid wire then feeds another juntion connector which powers the fuel injectors, IACV, and the EVAP purge solenoid and the primary O2 sensor heater section. A 4th wire then feed the immobilizer unit.

That is all there is hanging off of Fuse 44.

 

Thanks for the input chris.

How do I trace a wire through a harness? Id have to cut off the outer sleeving wouldn't I? A continuity test wont tell me what I need to know.

 

I had that same issue with my car. It ran fine for a long time. Then that damn fuse kept blowing. Turns out a yel/blk wire on my injector was reversed. Shouldn't matter because of the circuitry of an injector, but never the less, it was still blowing. Some where a yel/blk wire in your harness is grounding out. If you have the service manual you can see the power schematic and follow all the yel/blk wires.

 

I suck at reading wiring schematics.

Your right Ive heard injector polarity doesnt matter too, however I kept the polarity the same when I wired in my new injectors just in case.

This morning I started the car up and I jiggled every harness and connector I could get my hands on. I poked a screw drive into wire looms that were open near the connectors. Without ripping stuff apart I inspected everything major that was in plain sight. I could not recreate the problem.

 

I was not able to do it either. It only happend when I was putting the car under a load. And when you turn right, the harness or sensor that has this issue is getting strained just enough.

 

Correct. Only problem is tracking that one wire or component down. Needle in a hay stack.

 

In the meantime cut b9 and b1 from the ecu and run them to a switched 12v source.

 

Whats your logic? B1 and B9 are the 12v power sources for the ECU.

 

Basically - isolate each circuit that is powered by this fuse.

So cut B1 and B9 and run a seperate, but fused, wire to those pins.

Same thing goes for the O2, IACV, injectors, etc until you find who is the culprit.

And if the case comes to be that you have run all seperate power wires for each of these things and your NOT blowing any fuses for these new power wires, you can conclude that your original wiring harness is indeed the culprit.

 

I didnt really want to hack up my engine harness.

Could a bad ground cause this?

 

Could there be any way that your o2 sensor wires are touching the header/exhaust manifold? My brother's car did this same thing.

Worth a shot ....

 

Clean'em, tighten'em, make sure they aren't dropping some excessive voltage across them and thats all you can do with respect to the grounds.

So without answering yes/no - just do it to be sure.

 

At least you car starts I have been trying to find my problem with no luck.

Keep taking components off that circuit until you find the one causing the problem then trace the wires to and from it. Good luck.