2002 F250 diesel - discovery and build thread.

[Curious Hound]

Does it get cold enough down there to need to do that? A block heater always did my father well with his diesels, even on the coldest mornings.

II think you misunderstood. The truck normally uses the glow plug cycle during startup. It just always cycles them when the key goes to “run” during startup. It’s NOT normally needed. I am having intermittent starting issues. I was told that if the glow plugs heat up while I’m using ether to start the engine, that could be dangerous and damage the engine. So I installed a switch that allows me to DISABLE the glow plug relay if I don’t need it or when using ether during starting.

 

[Blmpkn]

II think you misunderstood. The truck normally uses the glow plug cycle during startup. It just always cycles them when the key goes to “run” during startup. It’s NOT normally needed. I am having intermittent starting issues. I was told that if the glow plugs heat up while I’m using ether to start the engine, that could be dangerous and damage the engine. So I installed a switch that allows me to DISABLE the glow plug relay if I don’t need it or when using ether during starting.

Aah alright.. starting issues. I thought you were doing all that for winter

 

[scotts90ranger]

Are you sure your glow plugs are working? I've gone through two glow plug relays in the last decade... and one neat thing to do is get a '03 starter, they're bigger and bolt right on... I just sent the '97 starter back as the core...

For injectors, it's a spendy thing and I've been putting it off for years, mine aren't working like they should, you can get modified injectors for the same price as stock so I was just going to go with stage 1 so I can get a little power bump and get a tuner to go with them, I think I was looking at full force diesel for that, last I looked it was about $1600 for the injectors and $450 for a tuner... in my case I need a higher flow HPOP since the '94-97 is behind the later ones in flow... I've been putting all that off since I don't have an intercooler, I should really make this my winter project...

 

[Curious Hound]

Are you sure your glow plugs are working? I've gone through two glow plug relays in the last decade... and one neat thing to do is get a '03 starter, they're bigger and bolt right on... I just sent the '97 starter back as the core...

For injectors, it's a spendy thing and I've been putting it off for years, mine aren't working like they should, you can get modified injectors for the same price as stock so I was just going to go with stage 1 so I can get a little power bump and get a tuner to go with them, I think I was looking at full force diesel for that, last I looked it was about $1600 for the injectors and $450 for a tuner... in my case I need a higher flow HPOP since the '94-97 is behind the later ones in flow... I've been putting all that off since I don't have an intercooler, I should really make this my winter project...

Starts the same with or without the glow plugs. It runs rough for a while after starting, as if it’s missing. Shouldn’t need glow plugs to start in this weather.

Check out Irate Diesel for parts. Our member, @Mattman347 is their rep in Nashville, TN. He was there Sunday morning and got me going.

 

[Roert42]

Why does it seems like diesel guys are always talking about issues with their injectors and you almost never hear about injectors on gas engines causing issues?

 

[scotts90ranger]

Because in the rust belt a 250-350k mile gas engine has the vehicle rusted in half before the injectors have an issue... on the 7.3L the injectors are known to last about 250k before they gum up and start being an issue...

I'll have to check that out, for my uses I need to be over 300hp and will need injectors, HPOP and tuner to get there no matter what...

 

[Curious Hound]

Why does it seems like diesel guys are always talking about issues with their injectors and you almost never hear about injectors on gas engines causing issues?

Probably a bunch of reasons.

1. many car owners never know they have injector problems. They often think they need a tuneup. Take it to a mechanic. He cleans the injectors, installs fresh plugs and sends them on their way.

2. many diesels see rougher service, dirty fuel and neglected maintenance due to drivers who don’t own the truck. They“just drive it”. So, when it finally gets some attention, injectors are a common problem. Can’t be spark plugs.

3. Gas engines have spark plugs to initiate combustion. That may mask some injector problems.

4. Some diesels have a more complicated system, such as using an electric solenoid to admit high pressure oil as a hydraulic fluid to actually open the injectors.There are higher pressures and forces involved. So, dirty oil, weak solenoid. Wear in the injectors, etc. add up to more problems.

I don’t know. Just throwing out ideas. If you’re around racers, you will hear more about injectors on gas cars. They get picky about orifices, orifice sizes, flow matching, etc.

 

[sgtsandman]

They also aren’t high pressure like they are on a diesel. Exception, the direct injection engines have a pretty high pressure. So, they might break before the truck rusts out.

 

[Curious Hound]

Because in the rust belt a 250-350k mile gas engine has the vehicle rusted in half before the injectors have an issue... on the 7.3L the injectors are known to last about 250k before they gum up and start being an issue...

I'll have to check that out, for my uses I need to be over 300hp and will need injectors, HPOP and tuner to get there no matter what...

274k miles on this engine. It lived most of its life being neglected by a landscaping crew.

 

[Roert42]

Is diesel injected at high pressure like gas? Like 40psi +?

 

[sgtsandman]

Is diesel injected at high pressure like gas? Like 40psi +?

The newer ones are. They have been direct injection for a while.

 

[Curious Hound]

Is diesel injected at high pressure like gas? Like 40psi +?

I think it’s higher, at least in some diesels. That’s why the high pressure oil is needed to overcome higher closing spring pressure to open the needle (I think they call it a Pintle). I’ve been meaning to hook up the scanner and see if I can check fuel pressure and the HPOP output oil pressure.

 

[Roert42]

Interesting, I thought it may have been low pressure system like old carb stuff.
Figured that might be causing the injections to get clogged easy with the low pressure.

 

[Snoranger]

Is diesel injected at high pressure like gas? Like 40psi +?

The 7.3 Powerstroke can see 20k psi injection pressure or slightly higher. That’s before modifying everything.

 

[scotts90ranger]

As sno said, diesel pressure is high, it's injected directly into the cylinder during compression and the ignition is set by the timing of the injection instead of the spark like gasoline, diesel is a variable air fuel ratio unlike gas which is most efficient at a fixed air fuel ratio that is why a diesel engine is easier to regulate speed than gas, with no throttle a diesel gets all the air it can use but you are varying the fuel which is not compressible where air is compressible so there is a time delay...