Hey all,

I know some of you are gonna recognize my post, I just got done putting in glowplugs and injector orings, and got a lot of info from everybody.
I started the truck about 2 dozen times since then, even in the chilly weather with no problems at all. Until this AM, when it wouldnt fire even after 4 cycles of the glow plugs. It did throw white smoke, and I had to use (gulp) a tiny bit of go-juice to get it running. I replaced the solenoid about 5 months ago, and am wondering if the solenoid may have crack, or there is something else like a connection I am missing. I did get voltage across the solenoid when I tried to troubleshoot before replacing the plugs.

Any ideas?

thanks, Digger

 

You're right on track with no glow plugs. Get a test light and start testing for power at the solinoid posts on a cold morning. It should come on bright on the glow plug side. I am not sure on the small posts, but I think one of them has power all the time when the key is turned on and the solinoid is activated when the ECU completes the circuit to ground. That would make both small posts light the test light when the glow plugs are OFF. And one on and one off when the glow plugs are ON.
But please don't quote me on this, as I am unsure. If someone knows how it works, please jump in and either verify or correct me here.

 

With key off you should have battery voltage to one large terminal and nothing to the other large or either of the small terminals.

With key on for the first two minutes or so you should have battery voltage to both large and one small terminal. The other small terminal should show ground. This shows the relay active.

With the key on and after the glow plug cycle has finished you should have battery voltage to one large and both small terminals. The computer activates the relay by grounding the second small terminal thus activating the relay.

It is possible to have battery voltage to both large terminals when the relay is active and still have a bad relay. If the contacts inside are pitted or corroded you may have low amp voltage passing through it but not enough power to actually run the glow plugs.

If you want to check the relay and what controls it take a jumper cable and jump between the two large terminals on the relay (WATCH FOR SPARKS!!) for 60 seconds. Disconnect and start. If it starts like it should either the relay or what controls it is the problem. I agree with Kwick - probably the relay.

Dave / Believer45

 

Would that be responsible for the intermittent part of it? I havent jumped it yet, but did get voltage on the one side, and did get 12V on the other side, but I didnt try that this AM, had to get to work. I dont think there is too much more to the system is there? The idiot light still works, and seems like the right amount of time. The only other thing I could think of was the connections at the valve covers, but I cant believe they would loosen up already, but I will check them this afternoon.

 

Hey all, tested the relay posts, and the first time, the relay clicked, but I didnt get any voltage on the 2nd big post at all. The small ones showed the back one at .5 volts, and the front one at 12.
The second time I did get voltage at the big lug, but after the first time, I think I will replace it. Kinda miffed about replacing it again after 5-6 months, but oh well.

Kwik, I did find something I have never seen before, my oil plug's copper gasket was crushed to the point where it wouldnt seal completely...Replaced and my oil leak completely vanished!

 

Great. Two repairs in one post! Glad it worked out.

 

Thanks Kwik!