• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Glow Plug relay

dieselkidd04 said:
Ok how was it again you can tell if it's a cali emissions or fed?
Click to expand...

The easiest way is to look in at the glow plugs. If it has individual wires going to each glow plug then it's a CALIFORNIA emissions truck, if it has a bus bar connecting them together it is a federal emissions. Also teh cali truck will have an EGR valve on it most of the time.
 
I REALLY doubt it a Cali emissions truck. It was originally ordered in Aurora, Il by Coffman's and they would have NO reason to order it that way.
Do the wires go direct from the GP to the relay or to a terminal is the question I have.
 
THEFERMANATOR said:
This is on the 04.5+ glow plugs, LB7's used a regular 12 volt plug. Another reason why we need to know what you have to tell you how to test it. Also need to know if it is a federal or california emissions truck if it is an LB7.
Click to expand...

Whoops... my error.
 
dieselkidd04 said:
Ten-4 it does have individual wires going to the glow plugs
So I guess we're dealing with a Cali emissions unit, now does this also pertain
To lly engines?
Click to expand...


The LLY also uses individual wires going to each glow plug, but they do not use 12 volt glow plugs, they use 4.7 volt pulse width modulated plugs. There are 2 differrent glow plug systems for LB7's, and then the 04.5+ style. Post up a picture of the engine so we can see if your dealing with a cali emissions truck. I know we've asked earlier, but thisd is in fact an LB7 with injectors under the valve cover right? If it is an LLY you will not get 12 volts to a working glow plug, but bad ones will show high voltage if your checking at the glow plug. Also the cali emssions glow plug controller is pretty pricey at well over $300, but they rarely fail as it is 8 individual relays inside of it. We need to narrow down exactly what you have first, then you need to do an in depth code check as a cali emissions or lLY controller will tell you individual glow plug codes normally.
 
Definately a CALI emissions controller there. First thing to do is to do a scan and check and see if there are any other codes. That controller checks each glow plug individually, so you will normally get a code for which glow plug is bad. Let me saee if I can dig up a diagnostic chart on it as my stuff is all for federal emissions systems.
 
dieselkidd04 said:
View attachment 31686
Click to expand...

I did a little digging, and it seems that the LB7's even with the CALI emissions system seems to only throw a P0380 code for a bad glow plug or a failed controller. First thing to do is unplug the 2 plugs on top that power the glow plugs(they are the outer ones with 4 wires in them I believe). Check the pins inside to see if there is any corrosion or if they are bent or loose as there seems to be problems with loose connections in the plugs causing the P0380 code on the CALI trucks. Next get an ohm meter and hook one end to ground, then take teh other lead and check the resistance of each glow plug at the plugs for the controller. The resistance should be fairly low if they are cold(around 1-10 ohms). If you have one that is open, then you need to leave those plugs unhooked and do the same test at the glow plugs to see which one is bad. If they all have low resistance, clean up the connectors really good and plug them back in. Recheck to see if the code is still present. If you still get teh P0380 and you don't have power at all of teh plugs, then it sounds like your controller is bad. Fair warning though, that controller is hard to come by and expensive. You may also want to check with a dealership if it has less than 200K miles on it as the CALIFORNIA emssions system has a 10 year 200K mile extended policy on the glow plugs(not sure about the north east package though).
 
Ok will do, thanks for the help, my dad did get a price on a controller from gm its
$125.00, ill check the connections and ohm out the wires when i get home from work
And ill keep this thread updated
 
dieselkidd04 said:
Ok will do, thanks for the help, my dad did get a price on a controller from gm its
$125.00, ill check the connections and ohm out the wires when i get home from work
And ill keep this thread updated
Click to expand...

Make sure this is for the cali emssions trucks, the federal emissions controller is MUCH cheaper but will not directly swap into yours. Give them the VIN number before you order anything for it.
 
Well i checked the pins at the control module connectors, no corrosion or damaged pins ,
Had two wires that were out of spec, left the connectors unplugged and ohmed out the plugs
#2 and #7 had 42.2 k ohms all others were at 2.5 ohms.
 
Check the loom that goes to the whole circuit. Gotta be a wire with the insulation rubbed through.
Or it just could be 2 bad GPs.
 
NVW said:
Those 2 GP's are bad, 1-2 ohms is good, 2.5 should be OK.
Click to expand...

What he said, 1-2 at the plug, but up to 4 or 5 is borderline at the plug for teh glow plug module. Anything more than 5 for a LB7 plug cold is bad. SO keep in mind if it has been ran the readings WILL change.
 
Well i with the help of pb blaster and a little luck i swapped out both suspected plugs with no problems at all, cleared fault and nothing returned, i really appreciate all the help guys if you have any questions about big rigs/ cummins, cat, kenworths let me know haha.
 
You must log in or register to reply here.
Back
Top