I just got my new motor in my truck everytime i start it it smokes alot untile warm. motor had 75000 on it. I have to plug it in to start it glow plugs arnt working. i check voltage on the relay and batery side its 12.8 and glow plug side its 9.6 volts. i ohmed out each glow plug they are all within specs of .8-1.5 ohms i take the plugin out of the valve cover and plug it into my extra valvcover gasket and hook up my glow plugs out of the other motoe that have aobut 15000 miles on them and worked good when motor went. They dont even get warm cycling the key. i checked the wolts in the plug for the glow plug and its .031v seems realy low i looked at the wireing scematic and it shows the wires going strait from the relay to the glow plugs with out any resisters. Does anybody have any ideas. I used the same wiring harness by moving from motor to motor could the wires inside broke. anyone ever hear about that. i did the ohm test for continuity and from the realy to the plug ins i get the beep. but from thr realy to the glow plug plug in under the valve cover it dont get the beep but the voltage does change from nothign to .031 when i cycle the key. My plan is to ripe out the wiring harness and tear into it looking for bad wires.

3 questions.

is the relay only supost to have 9.6v on the glow plug side and 12.2 on the batery side.

how much volts are supost to be to the glow plugs when they are on.

any ideas anybody.

the truck is throwing the glow plug code 0380 0603 0541
i took the o541 air intake heater out and disconected it havent got around to making a teaser wire yet thats what the code is from but glow plug and batery pcm disconected codes not sure one.
thanks

 

the first thing i did is check the realys and the glow plug and the air intake heater both show 12.2 on one side and 9.6 on the other thought that was low went to napa got the new realy and that one is doing the same thing 12.2 and 9.6.

 

I just went out and put a DVM to my GPR. Volts coming in are 11.2 (my batts are low, haven't started truck in a week) but I am getting 11.0 volts out to the GPs. Only losing .2 volts. I have a one year old OEM GPR.

 

To isolate where you are losing that voltage remove the connection going to your GPs and then see what the difference is coming in and going out. It will tell you if the trouble is toward the GPs or toward the GPR. I suspect the trouble is toward the GPs. If there is a minimal loss of voltage with the GPs isolated from the GPR then the GPR is likely good.

 

IIRC there are wires for each side of the motor to the glow plugs - could check with one side, and then the other. Would at least help isolate to one side.

 

That is, wires from the GPR to each side of the motor. Could also check voltage from the harness connector at the valve cover, unpluged from the UVC connector. That would rule out the harness. Could also try wiggling wires, they have broken inside without the insulation being damaged. Essentially, start at the battery, and work your way to the GPs - gotta be in there someplace

 

Rich - You do recall correctly. There are to wires. One to each bank, right?

 

Damn, you type to fast. You're one step ahead of me.

 

[QUOTE=millermanbg

is the relay only supost to have 9.6v on the glow plug side and 12.2 on the batery side.
Nope, should be identical and will pull the battery voltage down.

how much volts are supost to be to the glow plugs when they are on.
Should be same as battery voltage but if it pulls it below 10.5, you won't start.

any ideas anybody. How old are your batteries?

the truck is throwing the glow plug code 0380 0603 0541
i took the o541 air intake heater out and disconected it havent got around to making a teaser wire yet thats what the code is from but glow plug and batery pcm disconected codes not sure one.
thanks[/QUOTE]What I said above.

 

Batteries are new 1000ccamp im going to go do some more test on the wire harness then probly pull it off the motor also unhook the gp side of the gpr and see it the voltage drop leaves if thats the case something is wrong with the wireing harness since i have booth valve covers unpluged and gettign the voltage drop ill keep you all informed thanks for the info.

 

any one hav an ohm reading for the wireing harness from say gpr to end of the plug in for each glow plug is that a posible way to test it or will i get the same reading in all the plug ports. sorry if thats a dump question i know enough to get my self introuble on the wiring side of things.

 

The ohm reading from the output of the GPR to the end of the harness where it plugs into the valve cover should be as close to zero as possible. I don't have a number, but since it is just a wire, with no resistors, it should be really low.