What is air in fuel doing to our injectors?

[hoot]

I created this topic not as a continuance of the others but to be specific. Please do not post anything here except answers to the following....

No guessing please ;)

Will somebody please explain what the air from the original equipment fuel system setup is doing to our injectors.

Please be specific as to exactly what is happening inside the injector as this 23000 psi fuel is being metered through it. Where is the air and in what state is it in inside the injectors and how is it effecting longevity?

[mackin]

Not to many takers .... :confused:

[NWDmax]

Hoot :D id you ever get ahold of a Bosch tech yet?
I thought it was you who was trying to talk to one of their engineers about these questions.

[rcarbs]

No guessing???? That's how we solve problems, someone offers an idea or theory and everyone else try's to prove it wrong. If not proved wrong then it's probably correct. I think it is because.................. smile.gif

[hoot]

I say no guessing cause that's pretty much what all this air in fuel/filter hub-bub is all about. Guessing but no definitive edumicated facts.

Would stink if Bosch came out and said the injectors were designed to work properly with a certain amount of natural dissolved air and if you remove it you create a problem.

[chuntag95]

Hoot,
Working on your proof. First step was proving that the air/vapor comes out of the fuel under heat and vacuum. (check)
I guess for a living. Sometimes multi-million dollar guesses and then I test them to see if they are right. I am applying the same methodology here. I am trying to fully understand the system based on physics, chemistry, etc. If I can do that, then I can answer your question. Just need some more time. :cool:

[pinehill]

hoot,

Although there was some mention of potential problems with injectors due to air earlier in this lengthy discussion, more recently the concerns seem to have been centered on what large amounts of air might do to the low pressure side of the injector pump.

I would agree that Bosch probably took into account in their pump design the minor outgassing caused by the vacuum their pump creates, but they may not have realized that GM was going to add a lot of heat to the fuel via the FICM and the placement of the fuel filter. They also may not have expected GM to use crappy fuel line connectors that create air leaks.

I'm not terribly concerned about the effect of air on the injectors. But with the high cost of injector pump replacement, I am willing to make an effort to reduce the amount of air the pump will see.

[ 05-22-2003: Message edited by: pinehill ]</p>

[a bear]

Hoot,
With the amount of these trucks sold you will probably never here the general admit to any design short falls. Their biggest concern is probably that you reach that 100K miles. It's a shame that with near 1/2 billion dollars worth of trucks sold just through our membership alone we can't get a simple nod. It would appear to me that if things were OK it would be simple to tell us so. I would like to know if the LP pump housing desigh sends the free air back to the return to separate but can't get a answer. It's just a shame that were left hanging here to speculate on what is best for our trucks. I guess all we can do is what we think/hope is best for our fuel system untill the only possible answer becomes available. THE FUTURE FUEL SYSTEM DESIGN.

PS I guess I broke the rules. Sorry! :eek: :eek:

[hoot]

The other problem is once somebody has confirmed that they eliminated free air, what will the long term effects be? Will it make a significant difference in component durability? Unless a bunch of people get on board and we track failures with/without the mods, it will be some time before we would know if themods make a difference.

On the other hand, I think the addition of extra filtering has already proved itself over the years in diesel systems.

Chris and everybody else working the issue, you are all doing a great job. The more we know the better.

I didn't want to come off as rejecting this stuff, just pulling all you guys out to have another look at the justifcation of it all.

[a bear]

Good point. I'm a strong believer that joint efforts and a good data base is the way to go for measurable results.

[svpdiesel]

I think it's unlikely that we will hear anything from GM about this. If they admit that air is bad, then they will have to fix all sold units. If they say air is OK, and problems resulting from air become common, then they will have to fix it. So, I don't think they are gonna give us any help. They will just quietely fix anything that pops up, and say nothing about it- in hopes that we all run past our warranty... Personally, I own a lot of machines with hydraulic systems onboard, and anything that cleans up the fluid and eliminates air is GOOD. So, hats off to all the folks doing good work here, cause I think we are on our own...