higher atomization should help with cold starting shouldn't it?
i kinda wonder if good atomization in the precup is actually a bad thing?
the way i picture it, it is shooting very hot gases at the piston in a certain spot everytime it fires, also putting more heat into the head (thermal loss).
more heat in the head, more heat on the injector tip as well as more pressure in the precup(from the flow out of the cup).

 

Good atomization in the pre-cup isnt a bad thing, its just moot. All it does is increase the burn rate and out flow of the combustion...You can get the same effect with increased static timing, even with poor atomization... Only limiter is raw fuel droplets, those hurt, crappy injectors can cause that... However, good stock injectors atomize the fuel well enough to not make a difference...

 

I pop tested 7 brand new DPS injector and they all spray a stream of fuel at about 1400PSI. They are junk. I thought I posted a thread about them but I can't find it. I'm not surprised yours have scored tips. The needle was probably open the whole time the engine was running. I have come to the conclusion that if you want a good IDI injector, you need to build it yourself.

 

well if you start a thread on how to do it i have a spare set of nasty ones i would love to try it on. any idea on where to get parts to rebuild injectors?

this is the set i pulled out a couple weeks ago pretty bad...........
http://i978.photobucket.com/albums/a...I/DSC_0411.jpg

 

i just put a little fine river silt in there and spin the valve (in this case the pintal).
basically lapping it with dust

no, i have never done this to any critical valve just some junk lawn mower engines, although i will say it made a perfect fit.

 

Those are pretty nasty. I have not yet found a good place to get Ford IDI injector parts. It's on my list of things to keep an eye out for. Once I do, I will post videos of how to rebuild them. I guess I could take apart an old one and reassemble it but you wouldn't see the results of the new nozzle. Torquing the halves correctly is probably the hardest part.

 

i saw a thread on rebuilding VW mercedes injectors, since the ol lady drives a 300sd now. it didnt look too hard. and ebay has pop testers for around 200 bucks! i really thought about getting one. if i could rebuild my own injectors the pop tester would pay for its self. i also work on my buddies 6.2. sadly i know more about diesels then he does... well i have the internet as well and do alot of searching...lol

P.S. you should do the disassembly and reassembly video, would make me feel safer pulling one apart. maybe i should start a thread and people who can find parts can post what they know. ill do some digging myself.

 

Taking them apart and putting them back together is not hard at all as long as you get all the parts back in the right order. I have found the hard part is adjusting the torque on the lower half of the injector to get the pop pressure right. I'm on vacation this week, so I couldn't make a video until next week some time. I'll be glad to do it, though.

 

well its on page 2 now but i started a thread on rebuilding injectors. im looking into injector parts, i think i might have a line on them but she hasnt gotten back to me yet.

 

I am halfway through my Pop-tester build as of tonight. As soon as I rebuild my spare set of injectors, and get them in my truck, Ill pop the DPS sticks and we can see what they look like after ~20k. Ill get a vid of both sets for comparisons sake.

 

How are you planning to rebuild them? do you have a parts supplier? or are you just going to clean everything up really good and put them back together? i dont know how to adjust the popping pressure. i think someone said it was by the torque of the nozzle? maybe? if i read that right?

 

The shops that "rebuild" them, simply clean the parts (Ultrasonic generally, which is my plan), inspect them, set pop pressure, and pop test them for leaks. If the pintle and seat is bad, it gets tossed in a pile and another injector is used.

Setting the pop pressure is as simple shimming the spring inside until the desired pop pressure is reached. As said above, cap torque can be used to "fine tune" if need be.

You have to be absolutely completely clean (Think clean room...Gloves, work area, etc.) be cause one little spec of crap can make these things leak.

 

i cannot remember where i saw it at, maby Northern tools book, but they had a small ultrasonic parts cleaner that would be perfict for cleaning injector parts in.

 

harbor freight has one as well.

do you not regrind the seat and pental with lapping compound or anything?
or are they just case hardened?

 

The only thing I would trust in "regrinding" a pintle and seat would be a super fine diamond compound, and its probably not necessary. If the seat is so worn that you would need to grind it, its probably not worth using anyway. Im not sure if they are case hardened or through, but either way, they are hard, Im thinking they are through hardened though.