Glow plugs drivin me crazy

[dyoung14]

So i have confirmed that i have all 8 working(BERU) glow plugs, i have swapped in a knowgood glowplug controller, and a glow plug relay, and i turn the switch on and i might get a hole second of glow light then it goes out, and wont start, so what the heck is going on????? its ,aking me crazy

This is on the 89 by the way

 

[Goofyexponent]

David, I am JUST sitting down to watch the movie "Get him to the Greek", but when it's over I will come back and see what we can't come up with.

What are the wires from the controller to the plugs like? Good contacts?

Can you get us a picture of how it is wired just for kicks....it might be something as a bad wire.

 

[dyoung14]

David, I am JUST sitting down to watch the movie "Get him to the Greek", but when it's over I will come back and see what we can't come up with.

What are the wires from the controller to the plugs like? Good contacts?

Can you get us a picture of how it is wired just for kicks....it might be something as a bad wire.

I have no way of pics at the moment, but i saw a picture of how its supose to be wired, and its exactly how its supose to be wired, and its exactly like my other truck, but the damn thing will not heat the plugs, with the other relay and controller it would let the glow plug light do like normal, but wouldnt heat them, now with this know good one it just flashes the light for about a second, then nothing, all the connections look good as far as i can tell

 

[Agnem]

Have you done the contactor test yet? Place a test light across the heavy lugs on the relay.... should light when truck is off, and should go out COMPLETELY when relay is energized.

 

[dyoung14]

Have you done the contactor test yet? Place a test light across the heavy lugs on the relay.... should light when truck is off, and should go out COMPLETELY when relay is energized.

Which lug do i test?

 

[dyoung14]

Heres the rap,

To start with, when i first messed with the truck the light would cycle normal, but wont draw voltage and wont heat plugs so i swapped a known good relay in, still same thing so i then swapped a know good controller in and now it short cycles, like 1 sec, sometimes 3 sec maybe, but doesnt draw any voltage, im getting so tired of messing with them,

The big 2 yellow wires have constant power, the red wire gets power when the switch is turned on, the Z strip never gets any power

 

[LCAM-01XA]

With the ignition on and after verifying there is 12V on the small terminal of the relay where the red wire is, run a manual ground between the other small terminal on the relay where the single white wire is and say the intake manifold, the relay should click and the Z-strip should get power. If no click then relay is done for, if click and happy go-glowy action then you have controller problems.

 

[Goofyexponent]

If you are not getting power to the strip it sounds like a bad ground. The ground (I am sure you already know) is the whire wire....directly opposite of the red ignition wire. REALLY clean the grounding area (I think mine is grounded to a bolt that holds a lifting lug to the engine) and make sure the bolt is tight.

This should let power though the relay. If this is not the case, make sure you have 12 volt to the red wire at the relay. Using a test light is one thing, but try it with a light bulb...nothing big, just 1157 or something like that. Volts is one thing, but if there are not enough amps (even though it is a small load to close the loop to that relay) it might not be enough to make a proper connection.

Now that you are sure you have a good 12 volt supply AND ground to that relay, try testing it again.

That controller has a ground as well...IIRC it's the BROWN wire. Make sure this has a good solid ground. I think mine grounds to the bolt that holds the controller down...but I can't remember.

This is about all I can remember without seeing a GP relay and wiring.

If all this checks out, I would pop another relay in there (test it on the batteries first) and see what happens. It sounds like the relay might not be any good.

This is why I considered moving my GP relay and comtroller to the inner passenger side fender.....that way you aren't leaning over the engine for hours at a time diagnosing problems.

That might be a this summer project....lol

 

[dyoung14]

The relay works, if i touch a ground to were the white wire is hooked then you can here it click, the controller was working great on my 86 the other day, there is no way it went bad in a day

 

[Goofyexponent]

The relay works, if i touch a ground to were the white wire is hooked then you can here it click, the controller was working great on my 86 the other day, there is no way it went bad in a day

I've seen stranger things happen, but a controller going bad unprovoked would top that list lol.

If the relay is doing it's job you should be getting power to the "zig zag" piece of steel...the resistor....I think it reduces voltage or something.

If you put 12 bolts directly to this does it power up the GP's? Don't hold it there for long, just long enough to verify that you are getting power from there.

A diagram is coming in my next post.

 

[Goofyexponent]

You must be registered for see images attach

The big yellow wires from the battery would be the first thing I toss.

I would put a 1/0 cable in place of them that runs from the live side of the passenger side fender solenoid to the terminal on the relay which now houses the two yellow wires.

Check the white wire on the relay, and the black wire on the controller for a silod, concrete gound.

Also, make sure that the red wire is giving you a SOLID 12 volt.....with enough amps to hold that relay open allowing current to flow.

The two smaller wires that go to either side of the resistor...are they reversed maybe? Giving it a false reading and causing the controller to think the plugs are heated already?

I made this diagram from a little research, but I have not checked it to what I have done to my truck...so if it is off, please forgive me.

Could there be a dead short in the GP harness from the resistor out to the GP's somewheres?

This is a relatively simple system, but it sure is screwing with us!

 

[LCAM-01XA]

The relay works, if i touch a ground to were the white wire is hooked then you can here it click, the controller was working great on my 86 the other day, there is no way it went bad in a day

Well, if the relay is good, and the only thing that triggers the relay is the controller, you tell me where you think the problem is - sure as heck ain't gonna be in the flux capacitor Goofy is right on the controller ground tho, that one needs to be attached and nice and clean for the whole thing to work properly - what I don't know is how having no ground would affect the controller, I now a poor ground makes it glow the plugs till kingdom come, but no ground at all I dunno, never felt brave enough to try it. My controller grounded to the bolt that also holds the return lines brass T-ee at the rear of the engine.

 

[dennis]

The relay works, if i touch a ground to were the white wire is hooked then you can here it click, the controller was working great on my 86 the other day, there is no way it went bad in a day
__________________
~David~

this is the ground wire. ground it.

 

[dyoung14]

The relay works, if i touch a ground to were the white wire is hooked then you can here it click, the controller was working great on my 86 the other day, there is no way it went bad in a day
__________________
~David~

this is the ground wire. ground it.

So a solid ground on the white terminal? Sorry I'm not typin much response I'm on a damn I pod touch lol

 

[Black dawg]

the controller will do nothing without a ground.