Eng Sens Fuse popping
10-07-2013, 05:28 PM
#1
Eng Sens Fuse popping Ok so last week I finally popped the ENG SENS fuse. At first I thought it was because of wiring to the reverse lockout (which I have had problems with before) but I am starting to lean towards o2 wiring. I know the fuse blowing will take out CAGS, reverse lockout, o2s and MAF but it has raised some odd questions:
1. I replaced the fuse and went on a roughly 30 minute drive. Logging with HPTuners shows that the MAF never read above .96ish lb/min during the entire drive and that reading was very early on in the drive. The remaining 25+ minutes it read like .30 lb/min. This would say to me the fuse blew basically as soon as I started the car. Read on..
2. The o2s both read fine for most of the drive. Halfway through the passenger side leveled off and stopped reading. It stayed at about 600ish right until the end. The driver side fluctuated all over the place like it has since I got the car. At the end of the drive I parked and let it idle and the passenger side dropped down to about 180ish, came back up to 600 and then dropped again a few seconds before I shut off the engine. Both sensors reading as long as they did tells me that the fuse didn't blow till about half way through the drive which is when I would have guessed based on part throttle driving and exhaust smell at idle.
So would these log details show that my fuse blew halfway through the drive and that I also have a bad MAF sensor? Or did the fuse blow right after I started it and the o2 sensors read via black magic or something?
1. I replaced the fuse and went on a roughly 30 minute drive. Logging with HPTuners shows that the MAF never read above .96ish lb/min during the entire drive and that reading was very early on in the drive. The remaining 25+ minutes it read like .30 lb/min. This would say to me the fuse blew basically as soon as I started the car. Read on..
2. The o2s both read fine for most of the drive. Halfway through the passenger side leveled off and stopped reading. It stayed at about 600ish right until the end. The driver side fluctuated all over the place like it has since I got the car. At the end of the drive I parked and let it idle and the passenger side dropped down to about 180ish, came back up to 600 and then dropped again a few seconds before I shut off the engine. Both sensors reading as long as they did tells me that the fuse didn't blow till about half way through the drive which is when I would have guessed based on part throttle driving and exhaust smell at idle.
So would these log details show that my fuse blew halfway through the drive and that I also have a bad MAF sensor? Or did the fuse blow right after I started it and the o2 sensors read via black magic or something?
10-07-2013, 05:31 PM
#2
Also, as a related question. What should I be looking for when it comes to o2 sensor readings? My car with long tubes and a stock tune (when reading correctly) bounce all over the place. My truck with a stock tune and long tubes hold steady at around 5-600. The truck only has 1 sensor installed because of the terrible job TSP did on the bung placement. So if both sensors aren't hooked up, does the computer default to not using either one? If so, why would my car not react the same as my truck when the passenger side sensor stops reading?
10-09-2013, 07:32 AM
#5
I have had the same issue for some time now, and I still haven't located the source of the short. Very similar symptoms to yours. What I did is unplug everything on that circuit and replace the fuse. Started the car and it still popped. Obviously, it is something in the harness somewhere. I then unplugged the harness leading from the engine bay to the PCM, and replaced the fuse. It didn't pop at that point, so that tells me its in the harness downstream from the engine bay. Still haven't been able to find it though. The good news is that it only seems to make the car run a tad rich, and I haven't really noticed any major loss in gas mileage or performance.
10-10-2013, 09:26 PM
#7
Ok so I went for another drive after pulling the blown fuse. MAF still obviously doesn't work but both o2 sensors read as "normal". I say it like that because they constantly fluctuate up and down while driving but I have readings from both sensors and no fuse plugged in at all??
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10-19-2013, 06:10 AM
#11
Yea, the P0102 is suspicious: http://www.obd-codes.com/p0102
If you have a fault in the MAF or the MAF wiring, it could be causing the code and the problem.
Have you tried driving with the MAF unplugged?
Also, the other codes are for solenoids on your transmission. Have you checked the wiring down there? Have you installed any exhaust/headers lately?
If you have a fault in the MAF or the MAF wiring, it could be causing the code and the problem.
Have you tried driving with the MAF unplugged?
Also, the other codes are for solenoids on your transmission. Have you checked the wiring down there? Have you installed any exhaust/headers lately?
10-20-2013, 07:44 PM
#12
I haven't had a chance to get some fuses to replace that yet. All I have at home are physically to big. The plan is to grab a new fuse and unplug the MAF just as you said.
I bought the car with all the mods in my sig done to it in March. Randomly I have had issues with the reverse lockout allowing me into reverse while moving forward but I never could reproduce the problem to track it down. The car also had a large oil leak which at some point coated the bottom of the car so I had assumed the wiring to be the cause of reverse lockout problem. I checked all the wiring to the transmission and it all looked fine (dirty but fine). I checked the passenger o2 harness as well but it looked fine.
I am hoping my issue is with the MAF and plan to check that ASAP. This winter I plan to pull the engine and trans to clean up all the oil, and all the terrible the previous owner(s) have done to it so if I need to I can check over all the wiring at that point.
I bought the car with all the mods in my sig done to it in March. Randomly I have had issues with the reverse lockout allowing me into reverse while moving forward but I never could reproduce the problem to track it down. The car also had a large oil leak which at some point coated the bottom of the car so I had assumed the wiring to be the cause of reverse lockout problem. I checked all the wiring to the transmission and it all looked fine (dirty but fine). I checked the passenger o2 harness as well but it looked fine.
I am hoping my issue is with the MAF and plan to check that ASAP. This winter I plan to pull the engine and trans to clean up all the oil, and all the terrible the previous owner(s) have done to it so if I need to I can check over all the wiring at that point.
10-21-2013, 12:11 PM
#13
Since I had an engine sensor fuse problem I will post my tidbit.
One of my header pipes was too close to the starter power wire on the back of the starter. They had a decent gap between them but the current would arc under the right circumstances and leave me stranded. I had to wrap the power wire with electrical tape because the old rubber insulation cracked off from the brass fitting on the power wire
One of my header pipes was too close to the starter power wire on the back of the starter. They had a decent gap between them but the current would arc under the right circumstances and leave me stranded. I had to wrap the power wire with electrical tape because the old rubber insulation cracked off from the brass fitting on the power wire
