Truck doesn't start.

[amishtrucker]

Here is one reason I am so 'hot' on this cold timing advance solenoid. Besides setting the timing ahead for cold starting (which it would NOT if it didn't function, or was not getting the right voltage), another forum says <<The cold advance solenoid also aids in purging air from the injection pump.>>

This being the case, there could be air in my IP if the solenoid does not work right. I know some say neither that CTA solenoid nor the High Idle solenoid matter that much, but I wonder?

 

[turbodiesel94]

With the engine running and warmed up take a test light from battery + to the cold advance terminal on the IP, if its working you should hear a slight difference in engine noise.

 

[amishtrucker]

ok, burt is here, we just checked the voltages both to the glow plugs AND the cold timing advance. as the relay for the GPs clicks, the voltages to both oscillate WILDLY from 0 to 12 volts.

remember, the truck starts when it has been plugged into the block heater for 4 hrs....stands to reason that if neither the GPs of the COLD timing advance are receiving the proper voltage, that it won't start cold...and only with difficulty when plugged in. Also, the engine coolant temperature switch tests good, but NO voltage is getting to it. This controls both CTA and GPs.

Summary: GPs getting 10.5V to 11.5V, initially, but after 3 seconds, voltage to both GPs and CTA oscillate wildly, so, there is an electrical problem BEFORE the engine coolant temp switch and BEFORE the GPs. GPS all new Bosch. GP controller/relay/solenoid/timer new motorcraft.

Any ideas about the wiring? Anyone have schematic for wiring?

(If I cycle GPs manually for testing purposes, how many seconds on and off?)

 

[amishtrucker]

OK, we speculated that the new GP controller had bad electronics inside, making it click up and down and oscillate the voltage erratically, so we shorted the fat terminals for 8 seconds on, 4 seconds off, 4x. The engine did rattle, like it does when the heater is on, but didn't start, without the block heater.

Any ideas?

 

[OLDBULL8]

To rule out the operation of the solenoids, IP fuel solenoid, cold advance solenoid, glow plug controller.

WITH A COLD ENGINE
1st--Disconnect the Black ground wire on the GP controller. GP controller should not operate.
2nd--Turn the key on. Check for 12VDC at the IP fuel solenoid, Got 12VDC good. Pull the connector off of it, touch connector back on, should hear a click as the solenoid energizes, do several times to assure clicking. NO clicking, solenoid is bad.
3rd--Same thing on the cold advance solenoid.
TURN THE KEY OFF
4th--Reconnect the black ground wire on the GP controller. Turn key back on. Controller should stay on for 4 to 15 seconds depending on the ambient temperature, then cycle ON/OFF up to 90 seconds depending if engine is started quickly after WTS lite goes off. Truck should start if turning over fast enough, about 500 RPM. Not fast enough, WEAK batteries.

If all that checks out correctly, then you have a fuel problem.

Replace the IP return line with a clear line, look for air bubbles in the line while cranking, got bubbles, check for air intrusion from lift pump to IP.

With the engine starting when hot, I would guess you have weak or bad batteries, as the engine will turn over much easier/faster when hot.

 

[BioFarmer93]

A-T & Burt-
I'm kind of surprised no one has asked this yet, but rough starting after four hours on the block heater in this weather (Live Oak, - right?) makes me wonder if it's spinning fast enough. My cold start solenoid is not even installed, but my GP's work properly and my starter spins ridiculously fast. A couple mornings ago when it was in the high 40's I cycled the plugs, gave zero throttle and bumped the key and it's running. Not bragging, just illustrating starter cranking speed influence on the situation. You said it is getting fuel, right? -And you can cycle the plugs manually. I'm racking my brain, but the only thing that keeps coming back is cranking speed...

 

[amishtrucker]

OldBull, turbo, fixall, biofarmer, thank you too. burt just left for home before sabbath. So, we couldn't even start it with ether. It did rock and rattle a bit, but no start. Block heater not on long enough. Sunday, I will try testing the solenoids.

Can i run wires direct from the battery to the glow plugs for 8 seconds or so?
Can i run wires directly to the cold timing advance solenoid directly from accessory that will feed when the key is turned, in order to test my theory?

Thanks to Burt for all your help all day.

 

[Diesel JD]

You can always run a hot wire direct to the cold timing advance or fast idle. No risk in it. If you really want to put direct voltage to the glow plugs I think that's pretty safe you just need to be aware of the possibility that you could fry them. I don't want to insult your intelligence by any means but if you do use ether, make sure the glow plugs are completely disconnected. Glow plugs and ether will do bad things. Ether by itself in very small amounts is ok with these engines, but the safest way is a tiny sniff in the air intake while the engine is being turned over.

 

[turbodiesel94]

Run a jumper wire to the cold advance while the engine is running and warm, if its working you should hear a difference in the engine noise and that will eliminate the advance.

 

[icanfixall]

Well the electrical issues might be the ignition switch or the engine main wireing harness disconnect plug. The connection plug is found usually on the passenger side fender well. Usually the yellow two wires feeding power to the glow plug controller gets corrosion in it. then it melts the plastic causing the symtoms you post about. a bad ignition switch will do the same thing. Running a jumper wire to the controller and the injection pump fuel shutoff solenoid will bypass the ignition switch. May just prove whats going on...

 

[burtcheca]

Gary,

I fed the controller with a wire directly from the battery trying to do manually few glowplug cycles and it did the same crazy thing. When I put the wire from the battery in the relay coil terminal it gives you 4 sec. on and then start on and off very quickly. I thought maybe a problem in the glowplugs harness could be the culprit for the controller craziness and I checked one by one all the harness wires with a live test on each to get the 10.5v before the controller got in the intermittent mode, then put it back on each glowplug. That's why I said to my brother to change the controller, even when he says is new. After that I jump the two fat ones to give few cycles to the glowplugs and tried (even with some ether puff) and I brought my van close and added my batteries (that are fresh and 100% good) to his batteries because I thought those batteries may be weak already after so many tests; and we couldn't started it. It rattled and I thought at one time that it was going to start but nop.

My brother thinks the starter may be weak or with some gunk inside because there was a fuel leak right on top of it that spilled a lot of the oil mix on it for some time.

At this time, I think there is more than just the glowplug circuit problem. I think we are dealing with more than one problem at the same time. The glowplug problem plus weak batteries/starter problem.

If it were my truck I will get a new starter, a new controller and new batteries. If my brother can get convinced to get this parts I'll get him to town later or tomorrow but he hates to waste money on parts he's not 100% sure. In that matter I'm different, I hate uncertainty; I don't mind to go and get some parts and change stuff until I get it running, even if I end up with few spare parts that were good but I changed them. They will go to the spare part shelves in my shop and if I never have to use them that's good because that means that I didn't have a problem with neither of my two 6.9 engines.
Thank you all for your help. I'll keep you posted later.

Burt.

 

[dmaxjoe]

When you say the controller clicks.........is it clicking on and off ? Or is it clicking on for 15 or so seconds then off?

 

[Diesel JD]

Well I think it's very likely that you're right about more than 1 problem. You could pull the batteries and have them load tested at any good auto parts store. The starter is perhaps down to a difference in philosophy between you and your brother because it is very hard to know for sure that it is bad until you replace it. Now with the glow plug controller, was there a difference in cycling time when you jumped voltage directly to the plugs versus just to the relay itself? If so and the controller only leaves them on 4 seconds but you can go longer manually I would assume he's got a dead glow plug. It would be worth checking them all even though they are new. Short cycling usually means a dead glow plug on a solid state controller.

 

[dmaxjoe]

Thats what I was thinking JD.

 

[OLDBULL8]

I would bet my right arm it's not the GP's or controller. It's the batteries, one almost new and one old just don't work, even when jumpering from another vehicle. Amen.