M1008 Electrical Question

I have a 1984 M1008. I has been parked for 1 year and I got it running this weekend. I had to replaced the glow plug solenoid with an old one taken from a junk truck because it would not activate. The problem is that the glow plug solenoid is making a chattering sound when I turn the key on. My Dad has a M1008 also and the top of his solenoid is pointing to the passenger side. Mine is pointing to the driver side. Could this be a part of the problem? I have yet to measure the voltage to the bottom of the solenoid when the key is turned on. I will try that tonight or tomorrow. All help appreciated.

Gary

Was the junk truck an M1008 or M1009? The relay has to have a coil that is NOT grounded by the mounting bolts.

It was off of a M1009. I am not sure if I was very clear in my first post so just to make it clear I am refering to the silver can mounted on the firewall to the left of the brake booster. It has 4 studs.

I don't think it matters what position it's mounted for proper relay function. Since it's mounted "sideways" to begin with.

Chattering relays are usually an indication of a bad connection or low voltage.

If I want to test the solenoid by grounding the post with the small blue wire should I remove the card first? This is assuming that the card is good.

There is no need to unplug the card. You can safely jumper the blue wire on the relay terminal, to a good ground, while it is all assembled.

Thanks for the assistance so far. I did some checking this morning and found that I have 25.8? volts to the top stud (comming from the resistor)of the solenoid. On the bottom side (going to the glow plugs) I only had around 4 to 6 volts. The meter jumped around a lot. This reading was with the key in the run position right after turning it on. Temp outside around 70. The solinoid chattered again approximately 2 seconds after I turned the key to the run position. I also ohmed all the glow plugs and they all had reading from 0.9 to 1.4 ohms. Most were 1.3 ohms. The vehicle has two brand new batteries and all of the battery cables were cleaned with a brush prior to battery install. The connectors are on their last leg but they are holding tight for right now.

hmm, You should have seen about 12.5 volts on the bottom, instead of 4-6. Glow plugs sound ok(0-3 ohms is good). If you use a jumper wire and ground the light blue wire on the relay, to ground, does your relay hold on, or still chatter?

I am going to check that tomorrow. I will report back.

Ok, I connected a DVM to a good ground and the bottom (orange wire) of the solenoid. Turned on the key and the solenoid chattered. Jumped an extra wire from the small post with blue wire to a good ground. Solenoid stopped chattering and made a positive click sound. DVM read 2.8 volts. Is the solenoid bad? If the top side is getting 25 volts and the bottom is only getting 2.8 volts I would think the solenoid is bad. I have a brand new ST85. I have not installed it yet because I did not want to mess it up if there was another problem.

2nd question - Does anyone have a good source for new battery cables (really well made). I also need the rubber covers that go over the larger studs on the GP solenoid and the back side of the alternators. They look loke a 90 degree elbo that protects the stud from grounding out if metal touches it. All four of mine are dry rotted.

Thanks again.

I would suggest you either have a bad relay or a dead short on the glow plug wiring(relay to glow plugs) or your battery cables are shot.

It also sounds like your controller card may not functioning correctly.(not sure yet)

One more test you could do easily is, measure the input voltage on the relay, while manually grounding the blue wire. The input and output voltages should match and they should go from 25 down to 12.5ish, rapidly(2-4 seconds). If they are not the same, then your relay must be bad.

I would correct the faulty battery cables, before proceeding(they may be the cause of your glow-plug troubles).

I have seen a seller on ebay that sells nos cables for the cucv. I don't recall their name though, sorry

Ok, so I need to connect a DVM to the top post, red wire, and manually ground the small blue wire stud with the key in the run position. If the volts on the top do not drop to 12 or so the the relay or solenoid is bad. I hope I got that right. I try that tonight after work.

You need to see the same voltage on the top as the bottom, after a couple seconds. They will both drop from 24(or whatever you have) down to 12.5 ish,. while the relay is activated.

If they dont match, then the relay is bad. If they do match, but are not in the 12.5v area, you have glow plug issues.

Pm me your number, and we can try to get this straight over the phone.

IN the past few days I have installed a new NAPA ST85 GP solenoid, cleaned some ground wire attachment points, put new ends on the glow plug wires and cleaned the battery terminals. I then removed the glow plug resistors from the firewall. I used one of the wires and routed it to the top of the GP solenoid and then to the 12 volt block next to the solenoid.

Now when I turn the key to the start position I have the following: hear a click sound immediately, 12.8 volts to the top of the solenoid, 11 or so volts to the bottom of the solenoid, 10 or so volts at the glow plug and 9 to 10 volts at the fast idle plunger solenoid. The glow plugs get voltage for approximately 20 to 25 seconds when it is cold. 70 degrees outside temp. The truck cranks pretty good but I am concerned that the glow plugs are staying on to long. I have 13g in it right now. One other thing is that the GP light on the dash does not ever light up. I tested the bulb with a power probe and the bulb lights up. Does any of these readings or times appear to be out of the norm? Thanks for all help.

You can get some really well built cables made at your local batt supply house. Take the old harness with you and they should be able use the old harness as a template.

Well I drove the truck this morning for the first time since all of the new parts. As soon as I turned the key to the run position I heard a click. The solenoid appeared to be working properly. After about 8 seconds the solenoid began to chatter. I cranked the truck and the chattering quit. I let the engine run for approximately 2 minutes and then drove down the road. Approximately 4 minutes after starting the solenoid began to chatter again while I was driving. Other than replacing the two terminal ends on the two small wires that connect to the solenoid I am at a loss. Anyone ever had a glow plug solenoid chatter. Almost sounds like a grinding noise. I am positive it is comming from the glow plug solenoid. One note is: When I use a seperate ground wire to ground the solenoid it works fine as far as I can tell.

Tonight I replaced the ring terminal ends on the two small wires (blue and pink) at the GP solenoid and added a ground wire to the small lug with the blue wire on it. The ground wire goes through a switch then to a ground. The solenoid acted fine after this. Strange thing is now the seatbelt buzzer started working. It never worked before. Who knows.

Glow Plug Relay Question

New to the site so forgive me if I am not in the correct "new post" order. Can't seem to find the "new Post" button. Anyway, Just got a CUCV in great shape but had cold starting issues. Replace GP's (some were mushroomed or wet) and replaced GP relay. Truck starts immediately now but I hear the relay click one & sometimes two more times right after the truck has started. Does this mean the GP's are getting additional shots of voltage to them while truck is running & is this normal?
Thanks, Tom

Welcome, usss7

try this, for some answers on using the site. http://www.steelsoldiers.com/faq.php , also in the top menu bar)

And yes, that sounds normal.