6.9 cranking but no start

[rhkcommander]

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.

How much fuel are we talking, A dribble while cranking?

Here's an easy test. On top of your IP is a wire, unplug it, turn the key to on, and tap the wire to the post. Should be some sparks, and a click from the IP. If you don't have a click the FSS is stuck shut not letting fuel flow. You can either tap it gently with a wooden handle to try to liberate it, or look up how to remove the top and clean it.

Another simple test - there is a schrader valve on the fuel filter you can see if fuel comes out while cranking: either setup a switch/alligator clamp to manually trigger the starter relay, or find a helper, and crank the engine over. while cranking, push the schrader valve in, you should see fuel dribble out reliably. Hear hissing? It isn't primed up, you have air intrusion or fuel leaking back. Neither? The lift pump is clogged/blocked up or you have an issue in the fuel tanks like a broken fuel pickup or similar. Try switching tanks or adding 5 gallons of fuel. My old fuel switch takes a few tries before it willingly goes to the other tank too.

Check the fuel filter, see if it's gunked up. Or just get a new one and fill it with ATF or diesel.

 

[dreed86]

How much fuel are we talking, A dribble while cranking?

Here's an easy test. On top of your IP is a wire, unplug it, turn the key to on, and tap the wire to the post. Should be some sparks, and a click from the IP. If you don't have a click the FSS is stuck shut not letting fuel flow. You can either tap it gently with a wooden handle to try to liberate it, or look up how to remove the top and clean it.

Another simple test - there is a schrader valve on the fuel filter you can see if fuel comes out while cranking: either setup a switch/alligator clamp to manually trigger the starter relay, or find a helper, and crank the engine over. while cranking, push the schrader valve in, you should see fuel dribble out reliably. Hear hissing? It isn't primed up, you have air intrusion or fuel leaking back. Neither? The lift pump is clogged/blocked up or you have an issue in the fuel tanks like a broken fuel pickup or similar. Try switching tanks or adding 5 gallons of fuel. My old fuel switch takes a few tries before it willingly goes to the other tank too.

Check the fuel filter, see if it's gunked up. Or just get a new one and fill it with ATF or diesel.

@rhkcommander, I have removed that wire before and run a line from the battery to the FSS. I hear a audible click from it. Also have tried the schrader valve on the filter while cranking and fuel comes out at a good pace. Im wondering since im not getting any exhaust smoke from the pipe either the glow plugs are bad or the injectors aren't working. I have a feeling its not the injectors because I smell fuel. I have used a test light on the glow plugs and they do show a light when touching the tops. I have never removed them to inspect what they look like

 

[rhkcommander]

@rhkcommanderIm wondering since im not getting any exhaust smoke from the pipe either the glow plugs are bad or the injectors aren't working. I have a feeling its not the injectors because I smell fuel. I have used a test light on the glow plugs and they do show a light when touching the tops. I have never removed them to inspect what they look like

You'll get smoke without glowplugs if you have fuel flowing out from the injectors, it'll be whitish.

The only thing glowplugs do is warm up the engine for several seconds, then turn off. It's not like spark plugs on a gas engine. You can run these engines without glowplugs, some guys use ether if they delete the glowplug system. DONT USE ETHER with glowplugs, you can blow stuff up. If you unhook the controller or the relay or each plug, you could. Point is, all they do is turn on for a few seconds to warm things up. If you don't have fuel it doesn't matter how well your glowplugs work.

You can tell a lot about these engines based on exhaust alone. No smoke = no fuel in the engine. White smoke means you've got fuel. It might take 10 seconds of cranking to start chuffing out some from the exhaust, depending on your fuel systems' prime and such. Just a scientific wild ass guess on that number, I can't remember the last time I tried starting my IDI while watching the tail pipe.

Injector pop pressure is north of 1500 psi. These engines will run with bad injectors all day, but if the fuel is restricted to the IP by algae/rust/contaminates then it won't build enough pressure to pop them. Failed injectors would be stuck open, I've never heard of them stuck shut. You'd have white fuel exhaust with open injectors. I've heard of guys running with theirs stuck open, because they are getting fuel. Side note on that - you can tell if one is stuck open because the line to it will get hotter from the combustion going against the open injector pintle.

Sounds like your problem is somewhere right after the fuel filter up to the IP. How much fuel comes out of an injector line when cranking? A couple drops doesn't mean anything. We don't want bubbles, We want it gushing/spurting. You could need to purge the air out by cracking all 8 lines until they are gushing, I've never had to do that, I usually just floor it and crank and that seems to purge it just fine... If you never get gushing, it's probably the IP based on your description. My guess would be the metering valve is stuck shut. There is an inlet filter on the IP that could be gunked up too, but that's kind of involved for a beginner...

Do you feel any airflow when cranking from the muffler? Maybe your tailpipe is disconnected? You'd still see exhaust coming from somewhere though so that might be a dumb question.


Here's a source on some related info https://www.nickpisca.com/diesel/fu...and-purge-air-on-a-6-9-7-3-idi-diesel-engine/

 

[dreed86]

You'll get smoke without glowplugs if you have fuel flowing out from the injectors, it'll be whitish.

The only thing glowplugs do is warm up the engine for several seconds, then turn off. It's not like spark plugs on a gas engine. You can run these engines without glowplugs, some guys use ether if they delete the glowplug system. DONT USE ETHER with glowplugs, you can blow stuff up. If you unhook the controller or the relay or each plug, you could. Point is, all they do is turn on for a few seconds to warm things up. If you don't have fuel it doesn't matter how well your glowplugs work.

You can tell a lot about these engines based on exhaust alone. No smoke = no fuel in the engine. White smoke means you've got fuel. It might take 10 seconds of cranking to start chuffing out some from the exhaust, depending on your fuel systems' prime and such. Just a scientific wild ass guess on that number, I can't remember the last time I tried starting my IDI while watching the tail pipe.

Injector pop pressure is north of 1500 psi. These engines will run with bad injectors all day, but if the fuel is restricted to the IP by algae/rust/contaminates then it won't build enough pressure to pop them. Failed injectors would be stuck open, I've never heard of them stuck shut. You'd have white fuel exhaust with open injectors. I've heard of guys running with theirs stuck open, because they are getting fuel. Side note on that - you can tell if one is stuck open because the line to it will get hotter from the combustion going against the open injector pintle.

Sounds like your problem is somewhere right after the fuel filter up to the IP. How much fuel comes out of an injector line when cranking? A couple drops doesn't mean anything. We don't want bubbles, We want it gushing/spurting. You could need to purge the air out by cracking all 8 lines until they are gushing, I've never had to do that, I usually just floor it and crank and that seems to purge it just fine... If you never get gushing, it's probably the IP based on your description. My guess would be the metering valve is stuck shut. There is an inlet filter on the IP that could be gunked up too, but that's kind of involved for a beginner...

Do you feel any airflow when cranking from the muffler? Maybe your tailpipe is disconnected? You'd still see exhaust coming from somewhere though so that might be a dumb question.


Here's a source on some related info https://www.nickpisca.com/diesel/fu...and-purge-air-on-a-6-9-7-3-idi-diesel-engine/

@rhkcommander, This information is awesome thanks a bunch. I will get started with checking this out. Side question for you. would timing by chance cause the same issue?

 

[rhkcommander]

@rhkcommander, This information is awesome thanks a bunch. I will get started with checking this out. Side question for you. would timing by chance cause the same issue?

Happy to help, we all gotta start somewhere

Not likely to be timing. No matter how advanced or retarded, it would still be injecting fuel at some point into the heads. Indirect injection isn't as picky by nature. Usually it'll clatter like hell if its too far one way or the other when running. It should smoke, it could able to start regardless of the timing or glow plugs (if its warm enough like a hot day, block heater, or ether if plugs are disabled) and run like crap.

You only need fuel, compression, rotation, air, and heat for a diesel to run. Take away any of those and it won't. No signs of fuel coming from the exhaust is a big red flag in my opinion. No point chasing other leads until you know fuel is flowing into the cylinders/heads precups.

And to check that, see how much if any fuel comes out when you loosen an injector and crank. Bubbles means airs in the line. You want a good gush coming out all around the injector nut to prove you have fuel flowing to the injectors. If you do, we can rule out the fuel system. But there's no way you are getting fuel if you have no signs of it in the exhaust...


I made a switch for cranking the engine while under the hood. I just took a big ring terminal, a little ring terminal, a toggle switch, and a bit of wire and crimped it all up. Big ring to 12v positive on starter relay, little ring to the sense/switch whatever post. Done. Now you can crank under the hood. Its a life saver. You can do the same with a wire if you don't wanna buy the supplies, just get a solid piece of copper, bend it around the two posts and rip it loose, or get a wire with two alligator clips. Just watch out for shorting if you do it those ways!

 

[IDIBRONCO]

Dreed86 what part of Texas are you in?

 

[dreed86]

Dreed86 what part of Texas are you in?

San antonio

 

[IDIBRONCO]

If you want, I could stop by Friday evening and take a look at your truck since I'll be there on Friday. PM me if you want to.

 

[dreed86]

If you want, I could stop by Friday evening and take a look at your truck since I'll be there on Friday. PM me if you want to.

I'll dm you

 

[Selahdoor]

If you want, I could stop by Friday evening and take a look at your truck since I'll be there on Friday. PM me if you want to.

Thank you for your service to the community!!!

 

[david85]

I had a lift pump fail on my a while back. No white mist and it wouldn't move fuel out from the filter. When I tore open the old pump I found one of the check valves was not doing it's job. Cranking with the schrader valve open should be able to detect this.

 

[dreed86]

Happy to help, we all gotta start somewhere

Not likely to be timing. No matter how advanced or retarded, it would still be injecting fuel at some point into the heads. Indirect injection isn't as picky by nature. Usually it'll clatter like hell if its too far one way or the other when running. It should smoke, it could able to start regardless of the timing or glow plugs (if its warm enough like a hot day, block heater, or ether if plugs are disabled) and run like crap.

You only need fuel, compression, rotation, air, and heat for a diesel to run. Take away any of those and it won't. No signs of fuel coming from the exhaust is a big red flag in my opinion. No point chasing other leads until you know fuel is flowing into the cylinders/heads precups.

And to check that, see how much if any fuel comes out when you loosen an injector and crank. Bubbles means airs in the line. You want a good gush coming out all around the injector nut to prove you have fuel flowing to the injectors. If you do, we can rule out the fuel system. But there's no way you are getting fuel if you have no signs of it in the exhaust...


I made a switch for cranking the engine while under the hood. I just took a big ring terminal, a little ring terminal, a toggle switch, and a bit of wire and crimped it all up. Big ring to 12v positive on starter relay, little ring to the sense/switch whatever post. Done. Now you can crank under the hood. Its a life saver. You can do the same with a wire if you don't wanna buy the supplies, just get a solid piece of copper, bend it around the two posts and rip it loose, or get a wire with two alligator clips. Just watch out for shorting if you do it those ways!

@rhkcommander I was wondering about the Injection pump. Is it possible to have some fuel coming out of the injection pump and not be bad? If so does that mean its clogged and needs cleaning or if its a little bit. If as you say your supposed to get 1500psi and be gushing out. When I originally cracked 2 lines i didnt try to bleed the lines just kinda checked to see if fuel was coming out. I am hoping to bleed those lines like you suggested on friday.

 

[IDIBRONCO]

I am hoping to bleed those lines like you suggested on friday.

We should be able to do that if you haven't got it done beforehand.

 

[Selahdoor]

@IDIBRONCO Will help you get it started.

Pay close attention to what he does. Ask him questions about WHY he does what he does.

While it is important to know what to do, and so know what he does... It is more important to know the 'whys', than the whats.

The whats will give you a knowledge of what parts to replace. But the whys will give you a knowledge to diagnose more than just the one problem.

 

[dreed86]

So I wanted to come on here and give a quick update on what @IDIBRONCO and I tested and found out tonight. @IDIBRONCO first started at the lift pump to verify pressure. This was good. Then checked at the Schrader valve. Again good. Then to injection pump. Finally he cracked 7 of the 8 fuel lines at the top of the injectors. Found there is enough fuel pressure to hit the top of the open hood. We attempted several times trying to start it but unfortunately no good. @IDIBRONCO did mention that he thought the starter did sound like it might be getting a little tired but that he still believes it would be enough to start with.

Next we removed a glow plug and found that the glow plug was not ohming out at all. Also it appears that the previous owner put in AC Delco glow plugs previously. So I am going to start by removing the rest of the glow plugs and testing them. Weather seems to be a factor currently. Pretty sure Ill replace the glow plugs with Motorcraft brand.