And again

[foresterdj]

Same symptom as earlier this month (well, almost the same, no WIF light issue this time)
http://www.oilburners.net/forums/showthread.php?56400-5-months-good-now-nothing

This morning, hop in, turn key, WTS light flashes on, then off, try starting, spins like crazy, no start.

Check schraeder valve, lots of fuel.
check power at fuel shut off solenoid, it has juice
spin it over more, some puffs of white smoke at exhaust
check glow plug with switch on, NO juice; and engine is cold, and it is 50+ degrees.

Figure I will plug in block heater for an hour.

When I go back, turn key and *&^%$#%%^&&*, now WTS comes on and stays on, I do not even wait for it to go out, hit switch and it is running instantly.

So we can figure it has had fuel, spins good, starts fast once warmed a bit, but the big question remains.....

Why was the WTS flashing on then off before, and why does it stay on like it should later, and how is this affecting the starting (not starting) of the truck? I am thinking some kind of electrical intermittent problem? But what is going on? Glow plug relay was new in October 2011.

 

[Hydro-idi]

The same thing was going on with my pickup earlier this year. My truck would sometimes start great, and other times, the WTS light would flicker on for one second and it wouldnt cycle glowplugs properly. Glowplugs were only a year old so I knew that wasnt the problem. I put a brand new $90 glow plug controller and it still occasionally acted up. So i went to kragen and bought a $20 glow plug relay (passenger side fender under hood) and that fixed it! Even though the glow plug controller and relay can check ok, they can act up sometimes. Mine also checked out ok when I tested them. Also, if the WTS light stays on longer than usual, it is more than likely a faulty glow plug controller.....and when this happens.....time for new glow plugs because they will burn up after approx. 30 seconds of glow time. Hope this helps

 

[Shadetreemechanic]

Check all your connections at the glow plug controller and in the harness. Something is loose. The glow plug controller senses resistance across the glow plug circuit, as the plugs warm their resistance increases. 8 glow plugs warming is what times the WTS light. If fewer plugs are connected, cycle is shorter, if you have a bad connection in the harness it is shorter still. Cycling on and off is a sure sign off poor connection since a burned out glow plug would cause short cycle of the WTS light all the time.

 

[foresterdj]

Stupid truck started fine and normal today. None-the-less, I checked the connections on the top of the controller, all seem snug and checked voltage across the big studs of the solenoid on top of the controller had 13v key off and 0 v. key on. But, what did I expect, since today it started normally.

Have it in the shop now and will be cleaning it up on the top side, in preparation for a new IP and injectors this weekend. Will test harness while I am at it.

 

[foresterdj]

While working on the IP and new injector install, I tested the GPC system (harness, the controller voltages, connections and ground, etc.). The day I tested stuff, it all tested fine, but as before, it was acting fine at that time. But then Murphy made a tactical error and caused the system to act up when I was ready to start the truck after my install work, and I had volt meter at the ready. I am convinced now that it is a malfunction in the electronics of the 6 month old GPC. So now I just need to decide if I replace the GPC or just wire in a manual switch.

 

[Hydro-idi]

I was debating the same thing when I was having issues with the glow plugs. I chose not to put a manual glow plug switch in because I was afraid I would be accidentally burning out my glow plugs......especially if somebody else were to drive my rig. Instead, I bought a GPC from autozone for about 90 bucks..........best part is that it has a lifetime warranty so I wont be spending that money again for a GPC!