LEARNED A BIG LESSON TODAY!! - Problems that I have been having with cold starting are all from a bad Glow Plug Wiring Harness wire. Lost the whole bank on one side and just blindly replaced all of my glow plugs without looking into why the whole bank went. Found out that when the wire went bad it was sending all of my voltage to one side of my glow plugs - that's why it was taking 30 seconds to heat up - looked up in the Chilton manual and it runs until the amperage is at a certain level before kicking off - Unfortuneately now I have fried all of my Glow plugs again. Short of rewiring the whole truck, I am now in the process of hard wiring the glow plugs to bypass the bad wire in the harness, Gonna have to cut the wires if I ever need to take the engine out. Hope this fixes everything - Thanks Guys.

 

The wire to each bank has a fusible link on it, check with a navistar parts department to see if you can get the parts for them before hard wiring it.

 

If you have lots of white smoke after long cranking it could be from your fuel lift pump leaking and draining into the crankcase. When you are cranking you are pumping the fuel back into the system. Fuel pump is about 30bucks. INjector pump I know is about 200$.

 

I rewired my glow plugs to a manual switch to bypass that damned relay.

 

I checked all the glow plugs with the test light and they all lit it up. Looks like I will be doing the same as above. :beer:

 

try to replace the temp- sensor to the plugs, worked like a champ in mine.

Goodluck- Chris

 

Check out this link for glow plug , controllers, relays and harness for your truck...
http://www.shopdiesel.com/index.cfm/...uct_id/593.htm

 

Does your glow plug contorller make a clicking sound after the wait to start light goes off? Check for power at your cold idle solenoid on the left of the injection pump. If it has power and is working check. If it does not have power check to make sure the coolent temp switch is connected. I have seen where the wires came off the switch and then there was no power to the cold idle solenoid. The fuel return valve on the fuel filter tower. Its a one way check valve and when it goes bad the fuel keeps draining back down when your cranking thus hard start.


An easy way to check your glow plug controller is to take a wire test light. If you look at the controller behind the air cleaner and take the black cover off of it you will see what looks like a starter solenoid. You should have power at the big terminal ( right rear ) all the time. Turn the key on and check for power at the other big terminal kitty corner to the other one. When you turn the key on does left terminal have power? Now with the key still on check for power at the first terminal again. with the key on both should have power do they?


let me know i know that was confusing and its really hard to explain by typing it. Let me know if you have questions i will look for a picture that may help

 

I'll take a look. But there is something missing on the intake, looks like something was bolted there and I dont think the cold idle sol is even there either. I'll go down and take a pic. Any reason to get out of me cubicle LOL

 

Thanks for all the great info. I see I'm not the only one with glow plug problems. My wait to start light stays on about 2 seconds and then my gp relay clicks on and off very quickly (which I've already replaced). I going to check my glow plugs next. Thanks again, Adan

 

I just checked ours and had 3 burnt out, so I "borrowed" them from the other one, all is well now.

 

easy way to check your glow plugs is to take a wire test light and connect your clip to the possitive batt terminal or the hot terminal on the controller and remove the wire harness connectors off of all the glow plugs then touch your test light on the tip of the glow plug. if the test light does not light up then your glow plug is bad. usually you should replace them all and when you do brush a little anti-sieze on the threads to make them easier to do the next time.



let me know if you have any more questions

 

I have a '86 f250 with the 6.9. I have had problems with cold starting here in the UP of Mich. I have replaced the glow plugs after finding that the light test isn't accurate. I've had several bad glow plugs short or change to a lower resistance and not open like usual. Typical resistance for a good aftermarket plug I've found to be about 2 ohms, where the shorted ones are about .8 to 1 ohm. It takes a good meter to find these. After replacing the plugs a second time in 6 months, I found that the power Relay on the inner fender was bad. It would pass 12volts to the plugs but would not supply enough current to operate them correctly, the light test showed ok. Sometimes the relay would evidently stick on burning out the new plugs. After replacing the relay, it cycles quicker and it'll start even below zero. one other note, the controller on the back of the intake was replaced on mine before I bought it so I eliminated that part as the problem at the time. The controller doesn't route the power for the plugs through it, it only controls the power relay on the inner fender.I put a override switch to the hot side of power relay fed with 12 volts when I was trying to find the problem, this allowed me to at least manually cycle the plugs.

 

I can't remember of O have ever mentioned this but for anyone who wants to controll thier glowplugs manually, you can go get a set for a 5.7 Chev and they are said to be a direct fit. All that is needed it st swap the connectors on the harness to the spade terminals. In a manually controlled setup the 12 volt chev plugs are better the the 9 volt Ford ones.

 

I should have clarified and said that the switch was a momentary action push button and was only held long enough to start. Usually only a few seconds. DO NOT hold the button for more than maybe 10 seconds as you will burn out the plugs. Since the relay has been replaced, I haven't needed to use the switch. As an electronic tech for 25 years, I have seen the problem with relays developing high resistance in the contacts when under load so many times that it is one of the first things to suspect. It has sent me on wild goose chases more the once when relying on continuity checks only.