Missing/no power

[bigrigr]

Yes, bad batteries, and dirty connections on the cables at "both" ends, can cause these trucks to do some crazy things sometimes. If the batteries check o.k. per the above instructions, and the alt checks out, then make sure the cables are in good shape as well. Good luck

 

[BDJack]

Thanks Bigrigr and Dave. I was under the impression that if block heater was engaged, it was a way to "troubleshoot" gpr because gpr would not need to be used, bypassing it sorta. I have seen that said on several different threads, am I wrong?

 

[BIG JOE]

Not to High-Jack but there may be a misunderstanding between the two components ?


Block Heater:

The Block Heater is a 120 volt, A/C (House Current), heating system that is completely independent of all other systems on our trucks.

When & If, we plug it in to "House Current", It can be used to provide [a little] heat to the block by powering up a Heating Element in the coolant jacket, and warms the Coolant (through convection).... at temps of say... 40*, or colder, to a temp that is warm-ER than outside temps. It Does Not.. heat the block to operating temperature. It's simply an "Owner Controlled" AID.. for cold weather starts. If it's not plugged in (?) it doesn't work. The longer it's plugged in (depending on how cold it is), the more Time/EFFECT it will have to warm More of the block (Iron), more evenly.

Example of effect: On a 7.3 the heating element is on the D-side of the block. It's 20* out. If it were plugged in for say, 2 hours, the D-side bank may be Warm-ER than the P-side bank. Fire it up ? It may shudder'n shake.. blow some smoke.. Because the P-side cylinders only got preheated by the Glow plugs.... which may not.. have been enough HEAT to >achieve< good >detonation< in a couple of the P-side cylinders.

Make any sence ?

Glow Plugs*:

They, on the other hand, when the key is turned on, are controlled completely..by the 12 volt D/C, powered, PCM. From in-puts from sensors like.. Air, Oil and Coolant Temperatures, (to mention just a few).... that tell the PCM wether or not, systems are Not at, Near, or Are At.. operating temps. Cold start ? The Gp's heat the cylinder air.. PCM controlled.

(*They operate Just like the Glow Plugs on RC Airplanes & Cars. They "Glow" dang near red hot to provide the Heated Air needed.. to provied the >Initial< detonation (flash point) temprature, of Diesel fuel. The only dif is.. They are controlled by a timed (WTS light).. Glow Plug Relay.. so we don't have to jerk the wire(s) off the cylinder heads, with our fingers)

Combine the two ? They compliment each other, in creating Warm-ER Temps, for cold weather start-ups.







Again.. "DUH" to some.. But maybe.. enlighteng to others ??

 

[DaveBen]

Any thing you can add to this topic is welcome, Joe.

Dave

 

[dachshund]

(They operate Just like the Glow Plugs on RC Airplanes & Cars. They "Glow" to provide the Heat needed.. to proved the >Initial< detonation of the fuel. The only dif is.. They are controlled by a timed.. Glow Plug Relay.. se we don't have to jerk the wire(s) off the cylinder heads)

Very good analogy Joe.

 

[dachshund]

PS, I always check the switched power on the small terminal on top too just to make sure the relay is being energized.

Which relay is it?[/QUOTE]

Rear one, maybe this will help:

 

[BDJack]

Thanks daschund, I gotta wait til next week to use my buddies multimeter.

I figured I didnt have a spare cps anyway, and wanted to feel like I was making some forward progress, so I put in a new one, no luck.

Found the bad cell, put in a new battery, just the one until payday, but no luck. Turns over like it is really trying and almost catches, but nothing.

Have right amount of oil, is fairly new, no sludge.

Harness going into valve covers is not frayed or damaged/no arcs.

 

[BDJack]

Thanks Joe, that was my 90% understanding, but I was 10% unsure, based on what I had read if there was/was not some way to troubleshoot relay using block heater.
Appreciate the clarification!

Buying a napa special pending multimeter results! Is this correct way to check gpr?

To check the Glow Plug Relay (GPR)
· Be sure the engine is cold, so that the PCM will tell the GPR to turn on. If the engine is hot, you won’t have as much time to check.
· Locate the GPR – Its behind the fuel filter on top of the engine, a little bit toward the passenger side of the valley. There may be two relays there. If so, the rear one is the GPR. It will have two fairly large wires (yellow and brown) connected to one of the large posts.
· With your multitmeter set to DC volts, and 15 V range (if not autoranging), clip the positive (red) lead to the output terminal (with yellow and brown wires connected), and the negative (black) lead to a good ground point (like the battery ground terminal or someplace metal directly on the engine block.)
· Turn the key to ON (do not start)
· If your GPR is good, it should click, and you’ll see 11 volts or so on your meter, then, depending on temperature, it will click off up to 2 minutes later. You should do this a couple of times to make sure it consistently makes the connection.
· If you don’t get voltage with this test, confirm by retesting as follows.
· Remove the two small wires from the smaller two of the four GPR terminals.
· With jumper wires, apply voltage from the battery across the two small terminals. If your voltmeter now reads voltage on the output terminal, your GPR is OK, and your problem is in the PCM circuit that tells the GPR to activate.

 

[BIG JOE]

While yer waiting on other things.. you might go All Around, under the hood and back-off & re-tighten the many Ground wires that are under there.

Once you start looking.. yul see many components that are individually/specifically Grounded. Over time, miles and use (4X4'n), Grounds can get loose/corroded.. as bad as Positive connections can. Even worse at times.... in my experience's

Give all the Connector plugs a unplug/plug/twist/tweak too.

Could be the things yer troubleshooting but.... Ya never know.

Joe

 

[BDJack]

Not a bad idea! I decided to just go ahead and swap a napa cheapie in tomorrow, rather than wait til next weekend for a multimeter. I will buy a stancor down the road, for when the cheapie breaks.

22 bucks is worth having my truck running sooner rather than later.

Thanks again big joe.