Dash lights blow at 3000rpm, like clockwork?!
07-15-13, 02:18 AM
#1
10-8-10-8
Thread Starter
Dash lights blow at 3000rpm, like clockwork?!
I've got a really weird one here.
Friend's FD is a 1992 JDM same as mine, but manual trans and single turbo/PFC, etc.
Car runs fine, except that accelerating medium speed, with load, when it gets to 3000rpm, it blows the 15 amp instrument cluster fuse, down in the fuse block under the dash.
Replace 15A fuse. Go for another drive round the block.
Soon as it gets near 3000rpm, dash lights dim and then go out. Fuse blows again.
We can replicate this over and over. 6 fuses later, and still we dont know what component on this circuit is causing this to happen.
Car is stock in the wiring. Not monkeyed with..
Anyone ever had this happen? :s Things we should be checking/replacing?
Friend's FD is a 1992 JDM same as mine, but manual trans and single turbo/PFC, etc.
Car runs fine, except that accelerating medium speed, with load, when it gets to 3000rpm, it blows the 15 amp instrument cluster fuse, down in the fuse block under the dash.
Replace 15A fuse. Go for another drive round the block.
Soon as it gets near 3000rpm, dash lights dim and then go out. Fuse blows again.
We can replicate this over and over. 6 fuses later, and still we dont know what component on this circuit is causing this to happen.
Car is stock in the wiring. Not monkeyed with..
Anyone ever had this happen? :s Things we should be checking/replacing?
07-15-13, 10:57 PM
#2
Rotary Freak
In attempt to assist you, I've been looking to the factory service manual.
A few things happen above 2500 RPM.
Nothing seems to trigger at 3000 RPM.
My guess is that once you get past 2500 RPM this new "thing"kicks in, and by the time you're 3000 RPM it has heated the fuse to the point where it finally blows.
The first thing I want you to look at that I found the manual has to do with the trailing coils.
After 2500 RPM the trailing coils change behavior or kick in, one or the other. I can't tell.
More to come...
P.s.
Have you pulled the codes on the engine yet?
This has to have left a code, no?
A few things happen above 2500 RPM.
Nothing seems to trigger at 3000 RPM.
My guess is that once you get past 2500 RPM this new "thing"kicks in, and by the time you're 3000 RPM it has heated the fuse to the point where it finally blows.
The first thing I want you to look at that I found the manual has to do with the trailing coils.
After 2500 RPM the trailing coils change behavior or kick in, one or the other. I can't tell.
More to come...
P.s.
Have you pulled the codes on the engine yet?
This has to have left a code, no?
07-15-13, 11:36 PM
#3
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Alternator is going to put out VOLTAGE if battery does not absorb it body will.
1 make sure battery posts and grounds are 100% clean.
2 Test voltage output. Volts blow fuses not amps.
3 have battery load/voltage capacity tested-also is battery in stock location?
4 check blown fuse for proper contact.
5 check voltage at suspect fuse with lights on 3000rpm.
My 5cents.
1 make sure battery posts and grounds are 100% clean.
2 Test voltage output. Volts blow fuses not amps.
3 have battery load/voltage capacity tested-also is battery in stock location?
4 check blown fuse for proper contact.
5 check voltage at suspect fuse with lights on 3000rpm.
My 5cents.
07-15-13, 11:53 PM
#4
Rotary Freak
Alternator is going to put out VOLTAGE if battery does not absorb it body will.
1 make sure battery posts and grounds are 100% clean.
2 Test voltage output. Volts blow fuses not amps.
3 have battery load/voltage capacity tested-also is battery in stock location?
4 check blown fuse for proper contact.
5 check voltage at suspect fuse with lights on 3000rpm.
My 5cents.
1 make sure battery posts and grounds are 100% clean.
2 Test voltage output. Volts blow fuses not amps.
3 have battery load/voltage capacity tested-also is battery in stock location?
4 check blown fuse for proper contact.
5 check voltage at suspect fuse with lights on 3000rpm.
My 5cents.
No.
I don't dispute that he needs to check to see if his battery terminals and ground points are making good contact, your understanding of how the alternator works when power is being generated, but not being used, in addition to how fuses operate is completely wrong.
You can put 10,000 V through a 40 amp fuse – no problem.
Amps blow fuses – not volts.
The clue that this is true comes from the fact that fuses are rated in amps.
Another example is a Tazer.
This device produces thousands of volts, and sends it over wires at a fraction of the wire found in a 30 amp fuse.
Anyway,
You should still check his Crownpoint some battery terminals but not because the body is absorbing the power that's not being used by the alternator.
Alternators these days including the ones in the FD, are self excited/self regulated and only output the amount of current necessary based on the amount of demand requested of them.
07-16-13, 01:40 AM
#5
10-8-10-8
Thread Starter
Alternator checks out fine. We found the source of the problem.
The alloy intercooler piping runs behind the front turn signal lamp in the stock bumper. It runs so close, that the lamp wires are rubbing the intercooler pipe.
At 3000rpm, when there is just enough movement in the intercooler pipes and just enough boost to move them forwards an tiny amount, the wires contact the alloy pipe and get pinched hard up on the pipe, and the fuse blows.
Who would have thought??
Thanks guys
The alloy intercooler piping runs behind the front turn signal lamp in the stock bumper. It runs so close, that the lamp wires are rubbing the intercooler pipe.
At 3000rpm, when there is just enough movement in the intercooler pipes and just enough boost to move them forwards an tiny amount, the wires contact the alloy pipe and get pinched hard up on the pipe, and the fuse blows.
Who would have thought??
Thanks guys
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