Chasing an electrical gremlin
Thread Starter
Teching In
Joined: Apr 2002
Posts: 25
Likes: 5
From: South Florida
Chasing an electrical gremlin Driving me crazy, Engine sensor fuse keeps blowing. codes at first were bank 1 and bank 2 sensors # 2 on both sides, Maf (I put a new one in) After replacing both oxygen sensors and the Maf I thought must be an open wire touching somewhere. I followed bank 1 sensor 1 wiring and noticed the coolant temp sensor on the driver's side head was broken previous owner had the connector barely on wrapped with aluminum foil 
I replaced the sensor I figured that was it. Put a new 20 amp fuse and as soon as I turned the key there went the fuse again. I read on this forum after doing a search one guy had the same problem and after searching for a bit he said it was his bank 1 # 2 oxygen senor, He was getting all kinds of crazy codes like me. Should I replace the remaining 2 oxygen sensors? Bank 1 and bank 2 # 1 sensors on both sides?
I replaced the sensor I figured that was it. Put a new 20 amp fuse and as soon as I turned the key there went the fuse again. I read on this forum after doing a search one guy had the same problem and after searching for a bit he said it was his bank 1 # 2 oxygen senor, He was getting all kinds of crazy codes like me. Should I replace the remaining 2 oxygen sensors? Bank 1 and bank 2 # 1 sensors on both sides? 
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
Likes: 265
From: Bossier City, Louisiana
I'd run a temporary junk yard harness to each sensor first before buying new sensors. Diagnostically, I might even screw in a set of inexpensive "looks good enough" junk yard O2 sensors so as to not waste money on unneeded new O2 sensors.
Yea, I know - I'm a cheap tight wad for money.
Rick
Yea, I know - I'm a cheap tight wad for money.
Rick
Thread Starter
Teching In
Joined: Apr 2002
Posts: 25
Likes: 5
From: South Florida
Well in case anyone is curious, I couldn't find any burnt wires. I found a broken Engine temp sensor on the driver's side head that was held together with aluminum foil 
I thought that must be it but it wasn't. I then had my 2 pre cat oxygen sensors replaced when Nick at DS Motorsports in South Florida installed my springs and new shocks, I had already changed the after cat sensors myself. Low and behold! no more blown Engine sensor fuse, no codes and everything is working as it should. Hope this helps anyone with the same problem.
I thought that must be it but it wasn't. I then had my 2 pre cat oxygen sensors replaced when Nick at DS Motorsports in South Florida installed my springs and new shocks, I had already changed the after cat sensors myself. Low and behold! no more blown Engine sensor fuse, no codes and everything is working as it should. Hope this helps anyone with the same problem. 
Teching In
Joined: Nov 2019
Posts: 21
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O2s trashed my engine? OK I changed the oil and noticed a few things. Keep in mind that the engine may have only 45-60 min total run time but I've been told I fuel washed the cylinders due to the wrong O2's causing the injectors to pump massive fuel:
1. The oil was very dark. It was Penn Grade break in oil and was green. Pretty dirty.
2. The magnet in the drain plug was coated with a good 1/8" metal paste (filings?) No actual chips or splinters but you could rub it between your fingers and it was like paste (not gritty). I figured a little of this is normal for a new engine.
3. The drained oil seemed less than the 6 qts I originally put into the engine. I could be wrong but such a short time shouldn't burn any oil....right?
4. I scoped the no 2 cylinder and I can see vertical lines (scratches?) in the cylinder walls. I've been told you should never see vertical lines in the cylinder walls.....correct?
5. The spark plug was wet with what looked like oil but could it be fuel? I think we corrected the rich fueling.
6. I'm getting smoke when I get into the throttle and it takes a few minutes of easy driving to clear.
7. No detectable pressure or vacuum at the oil cap or the dip stick when running so no serious blow-by.
I'm just looking for some experience to comment here. This idea of a rich condition trashing an engine in such a short time is new to me. Before I tear the entire thing down I'd like some comments from people who have been a victim of this.
1. The oil was very dark. It was Penn Grade break in oil and was green. Pretty dirty.
2. The magnet in the drain plug was coated with a good 1/8" metal paste (filings?) No actual chips or splinters but you could rub it between your fingers and it was like paste (not gritty). I figured a little of this is normal for a new engine.
3. The drained oil seemed less than the 6 qts I originally put into the engine. I could be wrong but such a short time shouldn't burn any oil....right?
4. I scoped the no 2 cylinder and I can see vertical lines (scratches?) in the cylinder walls. I've been told you should never see vertical lines in the cylinder walls.....correct?
5. The spark plug was wet with what looked like oil but could it be fuel? I think we corrected the rich fueling.
6. I'm getting smoke when I get into the throttle and it takes a few minutes of easy driving to clear.
7. No detectable pressure or vacuum at the oil cap or the dip stick when running so no serious blow-by.
I'm just looking for some experience to comment here. This idea of a rich condition trashing an engine in such a short time is new to me. Before I tear the entire thing down I'd like some comments from people who have been a victim of this.
