BigDaddyRich

Well just when I thought I had it all figured out... The 15amp Ignition fuse in the upper right corner of dash fuse box keeps blowing. This has been the trouble spot for me. I noticed the GSR's use a 20amp fuse here? WHY?

I need to know from anyone who has pulled out an LS motor swap or is good with wiring on an LS, about what I can look for as a root cause.

This 15amp fuse feeds the MAIN RELAY's power supply.
Does anyone have a good diagram of the route of this particular wire from power to ground?
I think Im gonna have to trace this wire end to end to find the issue.

What would cause this circuit to short out? could it be a bad MAIN RELAY? a bad Ingition Control Module, Distributor? Has anyone else experienced this?

This is beginning to **** me off.


https://honda-tech.com/zerothread?id=325949
This guy is describing my problem exactly.


Modified by BigDaddyRich at 3:27 PM 4/2/2005

BigDaddyRich

Bump for any suggestions..... Anyone else every have this problem?

BigDaddyRich

Thanks to EE_Chris, I have narrowed down what is controlled by this 15a fuse.

Cruise Control
Main Relay - Fuel Pump - ECU
VSS sensor
Electric Load Detector
SRS unit
Alternator


Im thinkin of getting one of those add a circuits and moving The MAIN RELAY to a different circuit. this way if something blows.... the car can stil get power and drive?

this way I can narrow down if the NEW ADD-A-Circuit blew (Which involves the MAIN RELAY - ECU - FUEL PUMP) or if the old 15a fuse blows next which still points the problem to something else.


Modified by BigDaddyRich at 5:55 PM 4/3/2005

W C L

i beleive tha fuse powers the ecu, and main relay to the fuel pump...

what kidna car do u have?

anyting plugged up like a vafc??

any kinda of wiring done lately???

BigDaddyRich

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Big Will &raquo;</TD></TR><TR><TD CLASS="quote">i beleive tha fuse powers the ecu, and main relay to the fuel pump...

what kidna car do u have?

anyting plugged up like a vafc??

any kinda of wiring done lately???</TD></TR></TABLE>

Actually fom what I learned, that fuse powers the main relay.... which in turn powers the Fuel Pump and ECU. so miving that main realy power supply should move the powersupply for ECU and Fuel Pump as well.

I installed a new CD radio 2 weeks ago. Car ran well for a week after radio install.

I mean it was a standard install.... using factory speakers and such. Only think I can think of that was not used was the illumination wire. (red./blue) or something. but I taped that up pretty well?

I have been doing radio installs for over 15yrs and I've never had any wires get exposed on me. and short anything???

For kicks, Im gonna remove the radio. If the radio was grounding out somewhere, why doesnt the radio fuse blow?

BigDaddyRich

Well I did some inspection...
I found two broken right headlight housing tabs (headlight is completely loose in bumper) The right headlight plastic wire loom was pinched between coolant expansion tank and metal frame. I removed coolant tank, freed wire loom but could not find any frayed wires. I jiggled the right headlight to death while lights were on and car was idling... couldnt pop the fuse.

I also found what seems to be a pinched sensor wire coming from AC Compressor where the ground screw attaches to housing and sensor wire is kept in place with metal clip. I tugged on that wire a few times as well, but I cant seem to pop fuse.... I didnt remember if the AC or heater has to be on. I'll test some more engine harness stuff tomorrow and possibly retape a few things

EGallmotorEG

if u got a alarm installed try removing it...we had a customer that had that kinda of trouble...after removing it, car started up fine and didnt blow any fuses

EGallmotorEG

if u got a alarm installed try removing it...we had a customer that had that kinda of trouble...after removing it, car started up fine and didnt blow any fuses

EGallmotorEG

if u got a alarm installed try removing it...we had a customer that had that kinda of trouble...after removing it, car started up fine and didnt blow any fuses

BigDaddyRich

actually there is no alarm. car is 100% stock. just recently changed the radio. I am going to disconnect the VSS for a week. see if that causes any issues. it seems to happen when car is moving. it will idle until the gas runs out as it stands. no matter what I jiggle or rock or poke at.

BigDaddyRich

I bought a circuit breaker at AutoZone and replaced the fuse. car died twice today, but was jolted back to life when the circuit breaker automatically reset.

I finally got the car to throw a CEL that I could diagnose to help solve the problem.

code P0141 - Fuel Tank Pressure System

was thrown. At least I know this now has to do with the fuel pump.

My question is: Can the fuel pump short internally, due to possible low fuel?

JimBlake

That code isn't about the fuel pump. There's a pressure sensor in the tank, it's part of the EVAP system.

The pump CAN short internally, but low fuel doesn't have to be the reason. And that would blow the fuel pump fuse, it shouldn't blow the ignition fuse. As long as it doesn't run dry, the gasoline cools & lubricates the pump.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BigDaddyRich &raquo;</TD></TR><TR><TD CLASS="quote">Thanks to EE_Chris, I have narrowed down what is controlled by this 15a fuse.

Cruise Control
Main Relay - Fuel Pump - ECU
VSS sensor
Electric Load Detector
SRS unit
Alternator
</TD></TR></TABLE>Does this fuse actually supply the fuelpump power, or only the main relay? I thought the fuelpump is switched by the main relay, but it has it's own fuse. Actually, I really need wiring drawing in order to talk intelligently about this level of detail.

edit... check your other post
https://honda-tech.com/zero...14751



Modified by JimBlake at 7:49 AM 4/7/2005

BigDaddyRich

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">That code isn't about the fuel pump. There's a pressure sensor in the tank, it's part of the EVAP system.

The pump CAN short internally, but low fuel doesn't have to be the reason. And that would blow the fuel pump fuse, it shouldn't blow the ignition fuse. As long as it doesn't run dry, the gasoline cools & lubricates the pump.

Does this fuse actually supply the fuelpump power, or only the main relay? I thought the fuelpump is switched by the main relay, but it has it's own fuse. Actually, I really need wiring drawing in order to talk intelligently about this level of detail.

edit... check your other post
https://honda-tech.com/zero...14751

Modified by JimBlake at 7:49 AM 4/7/2005</TD></TR></TABLE>

I know the code doesnt match, but when I cut the two Pin#5 wires on the MR which power the VSS and Fuel Pumps systems: a VSS code and this "Fuel tank Pressure system" was thrown. (which puzzles me, as I really doubt by cutting that wire it directly affected the o2 sensor - which iP0141 is doc'd as being) To my knowledge a bad or missing o2 sensor will not stall or stop your car from starting, it would simply just run like crap?

Correct FP is switched by MR, but Fuel Pump does not have its own fuse per say. (At least I didnt see one noted on the fuse panel covers (engine or dash) When I supplied fuel pump with an alternate power supply it worked. (used an add-a-circuit from Autozone) but due to exposed cut end of wire, also threw the "Fuel Tank Pressure System" code although fuel pump was being powered by an alternate source.

JimBlake

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BigDaddyRich &raquo;</TD></TR><TR><TD CLASS="quote">I know the code doesnt match, but when I cut the two Pin#5 wires on the MR which power the VSS and Fuel Pumps systems: a VSS code and this "Fuel tank Pressure system" was thrown. (which puzzles me, as I really doubt by cutting that wire it directly affected the o2 sensor - which iP0141 is doc'd as being) To my knowledge a bad or missing o2 sensor will not stall or stop your car from starting, it would simply just run like crap?</TD></TR></TABLE>O2 sensor won't keep the car from starting. Especially the 2ndary one, it doesn't even have any control authority. It's ONLY job is to tell the ECU whether your cat is working.

Whatever else is powered by that wiring doesn't get power. That sensor heater code doesn't mean the actual sensor signal, all it means is the sensor preheater circuit isn't working. VSS or any other sensor that needs power from that circuit will also throw a code.

Remember, the fuel tank pressure measurement has nothing to do with the fuel pump. It measures the vapor pressure inside the tank, not the pressurized feed line going to the engine.

BigDaddyRich

Hmmmm then I'll have to look at more wiring this weekend under car and around evaporator canister and such. I dont wanna give up on this car as I kinda like it and I think it has lots of potential. Im bankin that this is being caused by something really stupid.

Just to rule out any fuel pump ideas, I have a compatible working fuel pump from a 2001 car that Im gonna swap in tonight and test out. It cant hurt cause I dont have to purchase it to test... its just sitting in a ziploc baggie since my Walbro255 upgrade

JimBlake

You need a Helm book... I don't know what's different from my cars!

On my '98 Accord, the fuel tank pressure sensor is on top of the tank, nowhere near the EVAP canister. You have to drop the tank to get it...

Any reason to suspect pinched wires up there? Mice eating the insulation?

Go ahead & try the pump since that's free (unless you pay yourself labor...) I bet that's not it, but maybe you can look around for a wiring harness leading up towards the top of the tank??.

BigDaddyRich

I have a PDF version of the manual I'll look at it I'll also look for the pinched wires under back seat.

BigDaddyRich

Well, I looked under the car and sure enough the O2 sensor #2 was pinching between top of CC and underbody of car. I think its been rubbing for a while as the paint around where the sensor was rubbing is completely gone. and sure enough one of the black wires going to the sensor, the insulation is broken and about 3/16" of an inch of wire is exposed and in direct contact with the bare metal spot on body.

I disconnected the o2 sensor from the location on shifter tunnel right behind center console on the floor where the sensor grommet plugs.

I'll run the car for a week and see how it goes while I decide if I should buy an O2 Sim or buy a new o2 sensor to replace the sensor.