Electric Load Mod

[comp_engineer]

Non 4Runner related question - but having been on this forum for a while I'm confident I'll get good advice from the frequent posters here (@rigtec [MENTION=65614]Antman[/MENTION]).

My father in law has a 2006 GMC diesel pickup - he tows excavation equipment with it. It's not the stereotypical lifted, coal rolling, truck nuts hanging, brodozer that people now associate with diesel pickups.

He had a bad glow plug - shop tried to removed it and snapped it at the base of the cylinder head. Shop claims engine needs to come out to get heads off to remove the remnants of the glow plug in the head - to the tune of $4k.
Truck runs fine, but has a CEL due to the glow plug resistance circuit being interrupted.

I'd like to rig an electric component with the same resistance as the glow plug, to trick the ECU into thinking the plug is operational.

My question to you is what I should use for a load. The glow plug is 120W, therefore 10Amps at 12V = 1.2 ohm resistance.

I bought another glow plug and plugged it into the harness so that I could get it inspected, but don't like the idea of a super-hot element under the hood at startup - so that's not a viable long term solution.
I was thinking a couple 55W headlight bulbs wired in series, but still need to fabricate brackets to mount them. Can you think of a cheap, easy to install, load I can use to trick the ECU?

Thanks for your help!

 

[Jetboy]

My guess is the measurement isn't very complex. Either it sense open circuit, closed circuit, or a short circuit. I'd try just putting a high ohm resistor in line and seeing if that works without the need of spoofing an actual load on that circuit. One alternative method would be to just splice the wire into another glow plug wire. I doubt the ECU could tell the difference.

Edit: a little review looks like I was wrong. Maybe you do need an actual load on the one branch of the wiring.

 

[rigtec]

Non 4Runner related question - but having been on this forum for a while I'm confident I'll get good advice from the frequent posters here (@rigtec [MENTION=65614]Antman[/MENTION]).

My father in law has a 2006 GMC diesel pickup - he tows excavation equipment with it. It's not the stereotypical lifted, coal rolling, truck nuts hanging, brodozer that people now associate with diesel pickups.

He had a bad glow plug - shop tried to removed it and snapped it at the base of the cylinder head. Shop claims engine needs to come out to get heads off to remove the remnants of the glow plug in the head - to the tune of $4k.
Truck runs fine, but has a CEL due to the glow plug resistance circuit being interrupted.

I'd like to rig an electric component with the same resistance as the glow plug, to trick the ECU into thinking the plug is operational.

My question to you is what I should use for a load. The glow plug is 120W, therefore 10Amps at 12V = 1.2 ohm resistance.

I bought another glow plug and plugged it into the harness so that I could get it inspected, but don't like the idea of a super-hot element under the hood at startup - so that's not a viable long term solution.
I was thinking a couple 55W headlight bulbs wired in series, but still need to fabricate brackets to mount them. Can you think of a cheap, easy to install, load I can use to trick the ECU?

Thanks for your help!

Hi comp_engineer,

What I would do first is measure the glow plug's resistance across the terminals, and note it. Then connect the glow plug 'as you did before' and measure the current draw; there may be a feed-back circuit that tells the ECU that everything checks out based on resistance AND current! Once you know those parameters you can likely imitate it with a device that can be built with parts from Radio Shack!

You can buy a Dummy load resistor which mimics an actual load; like if a guitar player wants to use his Marshal tube amplifier head's pre-amp out to feed another input but has to give the amplifier section's output somewhere to go... he'll use an 8ohm dummy load resistor so the tube amplifier will think it's driving a speaker load to prevent damage to the amp! I don't know what else to tell but...GOOD LUCK lol!

rig

 

[comp_engineer]

Thanks for the tip - 100W 2ohm dummy resistor on Amazon for $8 seems like a good place to start.

 

[flyrv9]

I agree with the resistor approach. I have been involved with both A/C and D/C loadbanks on flight test aircraft. The D/C ones are simple large resistors connected in such a way as to equal the load desired. All had some sort of cooling system to help dissipate the heat generated; usually fans controlled by a thermostat or just running constantly. So, the heat generated along with moisture protection would be my concerns.

For an A/C loadbank you can use small electric space heaters connected as required as long as your system is 60HZ.

 

[nevada]

Non 4Runner related question - but having been on this forum for a while I'm confident I'll get good advice from the frequent posters here (@rigtec @Antman).

My father in law has a 2006 GMC diesel pickup - he tows excavation equipment with it. It's not the stereotypical lifted, coal rolling, truck nuts hanging, brodozer that people now associate with diesel pickups.

He had a bad glow plug - shop tried to removed it and snapped it at the base of the cylinder head. Shop claims engine needs to come out to get heads off to remove the remnants of the glow plug in the head - to the tune of $4k.
Truck runs fine, but has a CEL due to the glow plug resistance circuit being interrupted.

I'd like to rig an electric component with the same resistance as the glow plug, to trick the ECU into thinking the plug is operational.

My question to you is what I should use for a load. The glow plug is 120W, therefore 10Amps at 12V = 1.2 ohm resistance.

I bought another glow plug and plugged it into the harness so that I could get it inspected, but don't like the idea of a super-hot element under the hood at startup - so that's not a viable long term solution.
I was thinking a couple 55W headlight bulbs wired in series, but still need to fabricate brackets to mount them. Can you think of a cheap, easy to install, load I can use to trick the ECU?

Thanks for your help!

forgive my ignorance on the subject, but wont any load you put in its place heat up as well? if it has to draw that same current to trick the ecu, its going to produce heat, yes?

if think it if were me, I would insulate/isolate the dummy plug, and run it as is.

 

[MisplacedTexan]

forgive my ignorance on the subject, but wont any load you put in its place heat up as well? if it has to draw that same current to trick the ecu, its going to produce heat, yes?

.

Yea, It'll generate heat, but most of the resistors you'll find for that will be able to be mounted to something (metal) and shouldn't get nearly as hot as the glow plug.


Think Op's on the right track of just putting that Amazon resistor in there, making sure it won't touch anything while it's hot, and letting it ride.

 

[adaml]

Call me crazy but unless the CEL is causing the truck to operate in some other mode than normal, why bother at all? I would rather have a CEL on than have something rigged up that I have to make sure doesn't touch anything when it's hot. Maybe that's just me though

 

[1engineer]

Non 4Runner related question - but having been on this forum for a while I'm confident I'll get good advice from the frequent posters here (@rigtec [MENTION=65614]Antman[/MENTION]).

My father in law has a 2006 GMC diesel pickup - he tows excavation equipment with it. It's not the stereotypical lifted, coal rolling, truck nuts hanging, brodozer that people now associate with diesel pickups.

He had a bad glow plug - shop tried to removed it and snapped it at the base of the cylinder head. Shop claims engine needs to come out to get heads off to remove the remnants of the glow plug in the head - to the tune of $4k.
Truck runs fine, but has a CEL due to the glow plug resistance circuit being interrupted.

I'd like to rig an electric component with the same resistance as the glow plug, to trick the ECU into thinking the plug is operational.

My question to you is what I should use for a load. The glow plug is 120W, therefore 10Amps at 12V = 1.2 ohm resistance.

I bought another glow plug and plugged it into the harness so that I could get it inspected, but don't like the idea of a super-hot element under the hood at startup - so that's not a viable long term solution.
I was thinking a couple 55W headlight bulbs wired in series, but still need to fabricate brackets to mount them. Can you think of a cheap, easy to install, load I can use to trick the ECU?

Thanks for your help!

Moved to proper sub forum.
-mod-

 

[rigtec]

forgive my ignorance on the subject, but wont any load you put in its place heat up as well? if it has to draw that same current to trick the ecu, its going to produce heat, yes?

if think it if were me, I would insulate/isolate the dummy plug, and run it as is.

Hi nevada,

A 'Dummy load resistor' is just a 'convection cooled' carbon pile, having heat sinks (dependent upon it's size), and enough surface area to safely transfer the heat produced by the load carrying resistor away from the device! The amount of heat is measured (in BTU's) and then an ample amount of surface area is calculated and implemented to the UL safety standard! Hope this helps,

rig, 'Best'