How do i know its the injectors?

[greenthunder7.3]

i have a 96 7.3 with high miles as a work truck and it won't start unless you give it a little spray ( yea yea i unhooked the glow plugs) i have been reading up and trying diff things. it passes click test and they all sound good. passes cylinder contribution test. glow plugs all work but one and its hotter then hell so it shouldn't even need them. i pulled the injectors and resealed them. watched on my ae while cranking and it starts building icp right away and will go up to about 3000psi and 45 percent duty cycle. 45 psi fuel pressure once it starts. every once in awhile if you have been driving it for a couple days it will start on its on. it smoke white like crazy while cranking and for about the first coouple minutes of running. i don't have a compression tester but i did a differential pressure test on the cylinders and all seemed good. one was a little less then the others. the level in the resivor in the moring is probly between 1/4 and 1/2 inch from the bottom of the plug. with it building such good icp pressure i would'nt think that would be the problem or the injectors poppets rushing oil out. is something messed up with the fuel side of my injectors or am i missing something. it has been doing this for sometime but i don't drive it very often but i'm wanting to get this figured out. any ideas would be appreciated.

 

[neverkickn]

If you are hitting and holding 3kpsi off the bat then ice isn't the problem. If you had a poppet issue that was causing a no start then you wouldn't be able to make that kind of pressure.

 

[greenthunder7.3]

could somethin be messed up with the fuel side of the injector causing this?

 

[neverkickn]

Yes. I can't help you with how to determine the definite cause. I would think that if you had a no start problem due to compression then you would be getting some pretty nasty blowby. If the crankcase pressure looks normal then I would guess you have an injector or fuel pressure problem. You said that it is making 45psi of fuel pressure, that should start the truck fine. Do you know how fast it ramps up to that?

 

[ghohouston]

My bet is worn injectors. I would also vefify fuel pressure at w.o.t.

 

[greenthunder7.3]

it takes a little bit but not to terribley lone to get to that. also i for got to state above it cranks at 150rpm so the engine is spinning over good.

 

[greenthunder7.3]

its probley due for them its got 320k on it and as far as i know 7 of the injectors are original. i just hate to throw a bunch of money in a truck that is beat.

 

[ghohouston]

I'd do a compression test. If compression is good, either buy a set of injectors or get yours rebuilt. But with 320k, theyre gonna be pretty worn out

 

[greenthunder7.3]

i have a good set of early 99 injectors that are good. i believe they are ad's but i could be wrong. might put those in it. i believe they will work the superduty split shot is run by the computer isn't it? or will i have to get a chip to run them in here since obs are single shot?

 

[ghohouston]

You would need a chip, and e99's had ab codes. 120cc's iirc.

 

[greenthunder7.3]

k when i get a chance i think i'll throw those in it and see what happens

 

[lincolnlocker]

what are the compression numbers?
live life full throttle

 

[greenthunder7.3]

i didn't have an actual compression tester i used a pressure differential guage set up. not sure if that was the right thing to do or not. one cylinder was a little lower then the rest. i will try to get the sheet and put the numbers on here. i have been messin with the truck whenever i get time over about a 6 month span.