I am having some starting issues with my early 99' with AB injectors. My son has a good set of AD out of his 2000. Will these work with my early 99? What kind of issues would they might cause?

 

They are both split shot injectors so no retuning would be required I believe you will flow more fuel 30cc more IIRC which I dont think would be a big issue personally. Might benefit from some retuning though, to use them fully.

 

Ive heard that ab's actually flow 135cc not the advertised 120cc and the ad's 135-140cc.

 

Ok, whatever it may be, I believe you will not have any issues with swapping them.

 

What leads you to believe your starting problem is injector-related? It can be alot of things... if you're lucky, it's just a stuck IPR or bad ICP. Both are a ton cheaper than injectors and are an easy fix compared to an injector swap. More info would be appreciated... I have an e99 as well.

 

My truck starts fine when cold, but when hot it gets harder to start and eventually won't start. If you let it cool it will start fine or give it a little starting fluid.

I have replaced both the IPR & ICP without any change. I am getting SES light. P1211 Injector control pressure sensor above / below desired level. I watch the duty cycle as I drove and it runs around 65% when I believe is should be in the 40s. That has lead me to believe I have an oil bypass issue. My son has the injectors sitting on a shelf, so it would be just the time needed to replace them with mine.

 

Well, if you've got the injectors sitting on the shelf, then I'd go for it. However, it sounds like the tell-tale sign of a bad injector O-ring... the theory behind it is since the oil is thicker when cold, the O-ring doesn't leak as bad and allows the truck to run once started. But when hot, the oil is thinner and it leaks worse and doesn't allow enough pressure to build up to start the truck. If you had AutoEnginuity or knew someone nearby who could hook up and read your data, you could tell.

 

Sounds like an IPR or the IPR o-ring to me? Same theory with the oil just not allowing pressure to build in the HPOP allowing it to bleed by

 

That's the thing, though... I would think a 7.3L would run without an injector. But then again, a leaking injector O-ring would affect the whole set of injectors on that head since it's the same oil rail that feeds all four in that head. The OP stated he replaced his IPR and ICP... both come with new O-rings I believe. HPOP failiure is VERY rare with these trucks so I doubt that's even an issue, but you never know.

 

It's NOT an injector problem, unless you're finding oil in the fuel, then it would be related to injector o-rings.

Hot start problems like what you're having, along with a P1211 code, are oil related. The fact that your IPR duty cycle is maxed out (stock programming maxes out at 65%) tells me that there's probably a bad check valve. Seeing that you've already replaced the IPR and ICP sensor also says it's a bad check valve.

 

Where is the check valve you are referring?

 

I don't think so. The check valve on the 7.3 don't really do a whole lot.

He's likely got an injector O-ring leaking. I'd get a new set of o-rings from dieselorings.com and put the late injectors in.

 

Pocket is correct, if you have o-rings going south the oil will be going somewhere like your fuel. Unfortunately I think he knows this from his own experiences and diag.

 

The oil can go into the fuel, but it usually just goes back into the crankcase. Crank it with the valve covers off and you will probably see one squirting ALOT of oil out of it.

It effects both banks in my experience. Because the pressure will find the easiest way out, it keeps pumping into the leaking side and neither build enough pressure to start.

 

I shouldn't have capitalized the "NOT" part to put so much emphasis on it. I'm just doubting there's an injector problem at this time.

Problems with hot starts are always related to a problem building oil pressure from the HPOP. Warm oil is thinner than cold oil, so there is something allowing oil to excessively bleed out when the oil is thinned out, preventing proper oil pressure from being built.

The thing is, it starts fine when cold. This indicates that the oil is not bleeding down when the engine is off.

Now, injector o-rings that fail on the oil ports typically dump oil into the fuel. However, there are times when they don't.... the thing is here... oil bleeds down when this happens, as a bad o-ring will weep oil when the engine is off if there's nothing holding the oil back... such as fuel sitting in the way.

So the main thing is something is preventing oil pressure from building, yet not causing leak-down issues when the engine sits. Meaning something leaks when in use, not just leaking all the time.

It means there's an internal problem somewhere in the HPOP system (IPR, check valve, etc). This is usually something that happens overnight. One day the truck cranks fine, the next it doesn't, and you have a recurring problem from then on out.

It can also mean that the injector poppets are leaking oil. However, this is something that slowly gets worse over time, as one injector by itself won't leak enough oil past the poppets during cranking to cause pressure issues. It takes several injectors bleeding past the poppet before the truck won't crank when hot. However, as more injectors fail, there are more and more signs of hard starting while cranking and the problem slowly gets worse with time.

So if this is something that has been slowly getting worse over time, I would believe it's an injector problem. But if this is something that recently happened, and came on suddenly, I would start looking into the HPOP system first.

I guess I should have explained myself better first time around.