6.9 cranking but no start

[dreed86]

Hey everyone,

I'm new to diesel engines and I recently bought an 1986 f250 with a 6.9 idi non turbo from an old farmer. My father had one of these when I was younger. The man said he had last had the engine running 2 years ago but was too old to figure out what was wrong with the truck. Didn't care to try anymore. So he says. Anyways I had the truck towed home. Where it sits now.

I was under the impression that diesel engines needed 1. Heat 2. Fuel and air to essentially run. I picked up some new batteries installed them. Went inside the truck turned the key expecting to hear the wait to start buzzer, but it never came. Did do some research after that and thought I should check the glow plugs. Used a test light from positive to each glow plug all 8 seemed to work. More research pointed to possibly the glow plug controller having failed. Now this is where I start noticing the harness looks all jacked up. Traced the lines back to the glow plug relay and realized someone used speaker wire to attempt to bypass the controller. On the glow plug relay the speaker wire went from the switch along the firewall down to the floors boards. Where a momentary switch was installed above the bright lights. Tested the switch found it had failed to. Went to the store picked up new wire and a new switch. Installed them. Looks much better on the dash to the left of the steering wheel. Anyways still don't get any power across the relay switch with ignition turned on and button pressed.

I've also checked to see if I'm getting fuel to the injectors. Loosened the fuel line and got fuel out of the the furthest fuel line.

I did completely removed the old glow plug harness and I'm the middle of repairing it.

I was hoping someone could pass some advise as to what else I could do. Oh and FYI the truck does crank gets to about 500 rpms. Just doesn't start yet. Thanks again

 

[CDX825]

Plug in the block heater for an hour or so and it should start without the glow plugs provided the fuel system is functioning.

If its been sitting awhile you might have to bleed air out of the fuel system at the schrader valve on the fuel filter.

 

[dreed86]

I started to do that the other day. Left it plugged in for 2 hours came out and had left the keys in the on position. Thus coming back out to a Dead battery. Haven't tried it again since. So I will try again

 

[MtnHaul]

Be careful leaving the keys in the "On" position because it activates the injection pump fuel shutoff solenoid which is cooled by fuel and can burn out if left on. So make sure that when you turn the key to the "On" position you hear an audible click at the IP. No click=nofuel to IP.

 

[dreed86]

So I was wondering when attempting to bypass the glow plug controller. Are you supposed to disconnect the controller from the harness? I have the one that screws into the back of the block.

 

[CDX825]

I never bothered to unhook mine when I did my manual glow plug setup. I just unhooked the trigger wire from the glow plug solenoid and hooked it to a push button.

 

[IDIBRONCO]

So I was wondering when attempting to bypass the glow plug controller. Are you supposed to disconnect the controller from the harness? I have the one that screws into the back of the block.

I would just to be safe. I have my glow plugs on manual control and I don't even have a controller in mine. If you've redone the wiring and the put in a new switch and still don't have power going across the relay, I would guess that the relay itself is bad. You can test this out before you buy a new one to install. First finish repairing your glow plug harness and reinstall it. Leave one glow plug that's easy to get to unplugged. Push the pointed test light lead into the plug that goes onto the glow plug and clip the lead on the other end onto the glow plug (you do know that they aren't burned out, right?). Then take a heavy wire or a flat tip screwdriver and short across the two big terminals on the relay while watching the test light. No need to do this for very long, just a few seconds. The test light should now light up. If it does, then you know that the relay isn't working when you use your manual control switch.

 

[dreed86]

So I have reinstalled my glow plug harness was able to activate the glow plugs. Heard a definite click on the relay. And a first I also got the glow plug light on the dash to activate. YAY. Of coarse its cold and I need to charge up the batteries. But definitely a glimmer of hope! I did completely disconnect the Controller and just left the connector sitting near by.

 

[IDIBRONCO]

I like to disconnect them (6.9 style) because if you leave it hooked up, it's possible that it could still try to activate your glow plugs. This style of controller has a nasty reputation of liking to fail in the "on" position and burning out your glow plugs. If it's not hooked up, it can't burn them out.

 

[dreed86]

So this weekend I've had some time to test a few things. Unfortunately still not starting. I ran a wire from positive terminal to the injection pump and heard an audible click as suggested also flipping the key to ignition I also hear a click on the injection pump. I've disconnected two injectors at the top rail and found I do get fuel to the injectors. I believe the glow plugs to be working properly did the manual bypass seems good now also here the click on the relay when engaging. So now the only thing I can think of could possibly be fouled injectors? I also removed two belts one to the AC unit and power steering just to loosen up the demand for power when starting. Any other thoughts on what could be?

 

[rhkcommander]

I personally would:

crank it with the pedal floored. See smoke out the exhaust? No smoke means no fuel trying to burn. White means cold/unburnt fuel, black means its igniting. Blue means ignition with motor oil, engines probably well worn.

Then I'd bypass the gp relay, with a screwdriver you don't care about, jumping only the two fat posts only. Its a spark show unless you dig it in good. About 8 Mississippi. At your own risk if you try that.

You'll want white/black. No smoke, id keep cranking it till you get some. If you never do it could be the lift pump, ip, or clogged fuel system. Try swapping tanks or adding fuel. Sometimes the tanks fail inside with the pickup / hose and you can have half a tank but get no fuel. Sometimes my tank switch acts up too... you hear clicking on the FSS so that's good.

 

[dreed86]

This afternoon I tried to crank the engine over as i did before foot to the floor. Again no start. I did check to see if there was smoke of any color coming from the exhaust tip. Not producing smoke. Im thinking I might try replacing all the glow plugs this time. Since I have never removed them from the engine. Also what are the chances that even though fuel is getting to the injectors what if they are not spraying? Also could timing cause the engine to not work either?

 

[miles1400]

@dreed86 next time you go to your truck take of the fuel filter and see if there is fuel. if there is any in it you are in the right direction. if there is non try filling it up then putting it on. if you can get fuel down to thru the IP then you should be able to get it to the injectors so it will be more likely to run. you may have been told this before, but DO NOT use ether starting fluid on these engines

 

[rhkcommander]

No smoke, no fuel in the cylinders...

 

[dreed86]

No smoke, no fuel in the cylinders...

So even though I am getting fuel to the top of the injectors nothing is getting into the cylinders? Like I mentioned previously I did crack the hard lines on top of the injectors and get fuel coming out of the top. Does this mean I need to replace the injectors?

Again sorry for this I'm literally learning how all this works as I go along.