Resistors overheating?

[ALEXAKOS]

I know those are supposed to get hot... But this seems to be too hot.

When I turn the ignition to the battery supply with the engine off still, after 5 minutes it smells like hot wiring. The resistor is terribly hot and so are the wires.

I took a photo in case you spot a wire connected the wrong ay to create that.

Mind you the engine starts and I don't really have any thing that U.S. Not functioning.
http://i821.photobucket.com/albums/zz135/alex-akos/delo%20resto/0711F410-C0D1-4DB9-ADA2-FEA5A05B43E5_zps6lzexzmp.jpg (http://s821.photobucket.com/user/alex-akos/media/delo%20resto/0711F410-C0D1-4DB9-ADA2-FEA5A05B43E5_zps6lzexzmp.jpg.html)

[DMCMW Dave]

I know those are supposed to get hot... But this seems to be too hot.

When I turn the ignition to the battery supply with the engine off still, after 5 minutes it smells like hot wiring. The resistor is terribly hot and so are the wires.

I took a photo in case you spot a wire connected the wrong ay to create that.

Mind you the engine starts and I don't really have any thing that U.S. Not functioning.


With the engine not running you're probably pulling 100% available current through the resistor (normally it is pulsing the coil). Probably not a huge difference, but if the normal duty cycle is 50% then you are pulling 2x the average. It may be much less than 50% at idle so you are really at the extreme.

So it's not a valid test. And not good for the parts either.

BTW - on a running car it is still hot enough to blister your finger.

[Bitsyncmaster]

Like Dave said....Engine not running is the highest power. I think at cruse RPM the power would be 10 to 20% less then what you have found (not much). The duty is more like 60% but with the engine running your getting more voltage.

You do not want to touch those resistors or have any wires routed to close to them.....you and the wires will burn.

[David T]

Like Dave said....Engine not running is the highest power. I think at cruse RPM the power would be 10 to 20% less then what you have found (not much). The duty is more like 60% but with the engine running your getting more voltage.

You do not want to touch those resistors or have any wires routed to close to them.....you and the wires will burn.

Not that it matters but the white wires belong on the top and the yellow on the bottom. More importantly, you do not have the bypass relay installed. Leaving the ignition key on with the motor not running that resistor will get hot but more importantly so will the ignition coil. Not good and you can kill the battery besides damaging the coil, the resistor is made to take the heat just don't touch it! If you don't have a working RPM relay installed the fuel pump is also running and the heater in the CPR. The aux relays are on too. Bottom line, it is not a good thing to leave the key on with the motor not running. if you do it for testing purposes you should try to have the key on for as short a time as possible.

[ALEXAKOS]

Not that it matters but the white wires belong on the top and the yellow on the bottom. More importantly, you do not have the bypass relay installed. Leaving the ignition key on with the motor not running that resistor will get hot but more importantly so will the ignition coil. Not good and you can kill the battery besides damaging the coil, the resistor is made to take the heat just don't touch it! If you don't have a working RPM relay installed the fuel pump is also running and the heater in the CPR. The aux relays are on too. Bottom line, it is not a good thing to leave the key on with the motor not running. if you do it for testing purposes you should try to have the key on for as short a time as possible.

Three Dave's to the rescue.! Thank you. The finger blister example gives me a good idea of how hot that can get.

David.
-How do you know that I don't have an rpm relay? Where would that be located?

- I do get a constant light buzzing sound from the resistors...

- My pump is not working constantly. It only makes a buzz for about 3 seconds upon turning the key and then stops.

- the wiring is exactly set as it was when I bought it. Off course that should not mean anything.

Also please notice the two grousing wires I screwed on the lower fastening bolt. Would that interfere with the smooth operation of the resistor?

Thank you in advance :)

[Kherns]

Buzzing is from the idle speed motor if I aint wrong.
I had the same thoughts.....resistor is passive and logically can not buzz.
Fuel pump noise priming depends on rpm relay you have. So this is good sign.

[Tillsy]

Or frequency valve...

[ALEXAKOS]

Buzzing is from the idle speed motor if I aint wrong.
I had the same thoughts.....resistor is passive and logically can not buzz.
Fuel pump noise priming depends on rpm relay you have. So this is good sign.

Sorry to insist, I know where a buzz comes from and it was the resistors.
After all I did not have an idle speed motor installed yet at that time.
The buzzing sounded like a starter on fluorescent lights. That slight.








PS I bought a cross over idle speed motor from a Renault Williams. Much smaller and efficient. 12 years younger in design.

[Elvis]

Shouldn't the resistor stay cool when motor stopped running ?
I haven't tested it on my car, but I thought that's the fun behind eletronic ignition
that it won't stay on 100%.
At least the 123 Ignition for my roadster does that.

I'll measure it, the ignition ECU is so reliable that I haven't had the need to repaire one yet.
But I started to draw the schematic years ago. Time to finish it ?


A buzzing resistor is new to me, but I'm only an electronics guy for ~25 years...and
still learning :-D
And if the current would really make it buzz, then it would turn the coil on and off
which means a constantly sparking coil. so watch your fingers :-)

[ALEXAKOS]

My point exactly Elvis! That thing gets so damn hot it feels almost abnormal.
Okay maybe the word buzz is not correct.. Would the description "zzzzzzzzzzzzzzz" like a fly is trapped inside it, make it more natural of a resistor sound. You know like when you hear power lines make that slight hissing noise?

Okay I am known to hear things that I shouldn't. Like the
"peaping" of those mouse/ rat repellent high tone equipment the human ear is not supposed to hear...

[ALEXAKOS]

Okay I'll make. A video of it... Be back I a giffie ;)

Edit... Tried it... Stopped buzzing :( or should I say zzzzzzzzzzzz-ing

[Elvis]

... Would the description "zzzzzzzzzzzzzzz" like a fly is trapped inside it, make it more natural of a resistor sound. You know like when you hear power lines make that slight hissing noise?
...


LOL resistor sound ? LOL

maybe too much Ouzo last night ? :-D

Power lines have 50 Hz on the, while we have a DC current at the resistor when the engine is off.
Even if you could hear a resistor working - no frequency - no noise !

Sorry for being a wise ass, but this is too heavy :-D

:clown:

[ALEXAKOS]

Ha, no. Don't like ouzo...
I'll get the bottom of this conspiracy... Hihi

[Bitsyncmaster]

Yes the ignition ECU keeps the coil powered (DC current) when the engine is not running with the key on. Not a good thing to keep that powered for to long so I would pull the white wire off the resistors if you need to test a long time.

The stock idle ECU keeps running the idle motor running at 100 Hz all the time also with the engine off and the key on. That is probably what you are hearing buzz. Just pull the connector off the idle motor when testing. My idle ECU will not run the idle motor with the engine not running.

[ALEXAKOS]

Thank you. Dave for the reassurance.
All I wanted to make sure I have not hot wired that thing somehow creating it to overheat and fail eventually. That is why I added the photo.

So me attaching those grounds the on the lower bolt is no issue right?

[Bitsyncmaster]

Thank you. Dave for the reassurance.
All I wanted to make sure I have not hot wired that thing somehow creating it to overheat and fail eventually. That is why I added the photo.

So me attaching those grounds the on the lower bolt is no issue right?

The resistor plate does not need to be grounded but it is grounded just so they could use it for a place to join the multiple ground wires. Using that for a ground is stock configuration.

I don't ground my resistor plate but that is only because I prefer to have wire connections crimped and soldered.

[ALEXAKOS]

Issue sorted!

Thanx Dave, Dave, David and Elvis;)

Bottom line, resistors get VERY hot instantly and overheat with the engine off.
Oh and they can't buzz, huzz, zzzz etc