Hi all. I bought this truck last week 92 f250 xlt 4x4 xcab 7.3 NA.
At purchase = smokes a ton. smells like raw fuel. runs real rough.
I replaced the fuel injectors, glow plugs, and return fuel lines. Now it smokes a little bit on start. Then smokes much more (too much to drive down the street without heads turning) when warm. Still has an obvious miss but not as bad as before.
Thinking low compression causing the fuel not to burn??
Or possibly the timing retarded on the injection pump causing the fuel to be squirted after compression.
Fuel temperature sensor was disconnected. How big of a difference does this make on an IDI? Napa said a new one is $344

 

For starters, there is no "fuel temperature sensor"

So what color is the smoke?

Where did you purchase your replacement injectors?

What is the condition of your IP (injection pump)?

Could be timing, depending on color of smoke.

 

The smoke is a very pale blue almost white smells like unburnt fuel not like oil. There's almost no black smoke. just a puff occasionally when revved.
The Injector pump was the newest thing on the engine, but, doesn't mean it's good as the truck itself has 337k. All other components were still covered in factory grey including the injectors.

the sensor/Item I'm talking about is between the injector and the fuel line on the first cylinder under the fuel filter.

 

OK, that is your timing adapter. If that is missing, that cylinder will not fire when it is supposed to. That could be your miss right there. "they say" the line off the vans with the IDI is the right one, as the vans had the timing adapter on cylinder #4.

I would lean toward timing causing the smoke. Get it timed by someone who knows these engines, if you can find such a one.

The question you did not answer is where did you get your replacement injectors?

 

Ok thanks, the adapter is there. Is it supposed to to have a wire coming out of it? because it has solder on the top of it at the brass ring.

I got the injectors from Accurate Diesel in Bitely Michigan

 

I have another thought. I took the check valve off the top of the injector pump. It looked like brand new in there there was only like one drop of fuel in there. Maybe there isn't enough pressure in there? shouldn't the pump be constantly flowing excess pressure to the return lines?
My main concern right now is there is internal engine damage like broken rings or hole in piston causing not enough compression to ignite the fuel.
Is there something I can do today to attempt to turn that white smoke to black? That way I would know I,m getting enough compression, right?

I'm researching this probably more than I should. If I spent my time looking for work I could pay someone to fix it. LOL

 

Ill about bet my paycheck that whoever put the injector pump on, did it wrong. Most likely you are a tooth off. Refer to the FAQ threads and have fun and good luck.

 

x2 on that one, loosen the IP, mark where it was and give it a moove to the passenger side, I bet it will help. If u find it is better but still not good u have timing skipped a tooth.

 

I turned it about 3/32 if I went past that it knocked real hard. I pulled the dipstick while running and steady puffs of smoke came out. If I can see it is that cause for alarm internally? I'm leaning toward lack of compression. would cracked pistons or rings cause the injected fuel not to burn then be sent out to the exhaust as whitish blue smoke. I may just build an adapter out of an old glow plug to check the compression. does anyone know the procedure and pressures I should see. I haven't checked compression on anything in 20 yrs. never on a diesel.

 

That check-valve is the "housing pressure regulator valve" and yes, there should be fuel coming out of it all the time the engine is running. It maintains an internal pressure usually around 4-5 PSI. When "off" the injection pump should always be full of fuel

I learned something new today after reading some posts here. I had no idea there as a "timing adapter" on any of my injector lines. But to my defense - since my 6.9 and 7.3s have been so good - I never had to take any of them apart. What I do NOT understand is how can a $30 adapter cost $300 and also how it can effect how the truck runs? The pump is mechanical and not electronically controlled during normal running conditions. I've got several timing adapters that were made by Ferret Company that I use to check timing advance on many diesels. All the adapter is (at least from Ferret) - is a Piezo microphone transducer. It "hears" injector pulses and turns them into an electrical signal so it can be hooked to a conventional gas engine timing light. I have the full set of factory service manuals for my 1994 F250. I guess I'll have to read up on this adapter. I did not know it existed until today.

 

Here is the Ferret diesel timing adapter. Holy cow prices have gone up. $130. I paid $30 for the last one I got maybe 6-7 years ago.

 

This youtube video shows the blow by at the dipstick. and the smoke out the tailpipe. Is that to much blow by? also, I must be getting air intrusion before the IP if the pressure relief cavity wasn't full of fuel?

 

JDemaris. The ford adapter threads in-between the fuel line and injector. So the #1 injector line is shorter without it. Different length of fuel line changes the timing on that cylinder. I cant watch vids on this computer, but IDIs have alot of blowby, just how they were designed.

 

Changing the length of an injector line on any mechanically injected diesel changes the timing-lag but it is very small amount. If it was changed by an inch or so, you and the engine would never know the difference.

 

That's what I always thought too. Never removed the adapter and tried it, though.
I did measure a bunch of the lines a few years ago because I didn't believe they were all the same length, and lo and behold, they are. About 19" IIRC

But we know this, IH went to the trouble of making sure they were all exactly the same instead of saving steel and making the short runs shorter.

I have the same ferret adapter, even at $130 or whatever it's way cheaper than the old snap-on timing setups. Probably more accurate too.