Injector Question
Posting Guru
Joined: Dec 2009
Posts: 2,265
Likes: 2
From: Garden City, KS
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.
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.
I've never heard of the check valve being mentioned... someone wanna expand on that for me?
Post Fiend
Joined: May 2009
Posts: 5,470
Likes: 3
From: Pea Ridge, AR
I do not have oil in my fuel bowl, however after sitting for a little while, now when I start it I get blue smoke for a few minutes while "warming up". Could this be injector o-rings? Or pointing more to Turbo seals, no play in and out or striking in my turbo? Oil cap checking for blow by is good, No smoke while on throttle after engine is up to operating temps. I'm thinking of replacing O-rings anyway before injectors, since My truck runs fine. Any thoughts would be appreciated.
Posting Guru
Joined: Dec 2009
Posts: 2,265
Likes: 2
From: Garden City, KS
Glow plugs will do that... I remember when mine weren't even there (all but two were completely burned out) it's smoke like crazy and idle rough and loud. As soon as it was warm, it all cleared up and was fine. After I changed the glow plugs, it wouldn't smoke at all when cold and ran like it was warmed up! Unreal... also, as your motor and injectors age, light white smoke is normal... O-rings might be the problem, but I think it'd be more obvious. Do you have AE?
Post Fiend
Joined: Jun 2004
Posts: 9,293
Likes: 10
From: Parker, CO
If you are wondering if it's injectors blowing oil past the poppets or o-rings, there is a simple test. You can remove the valve covers, crank the engine, and let it idle. If an injector is bad, you'll see it spraying oil all over the place. It's unmistakable.... trust me, I've been there before. Nothing like blowing oil past the poppets.
Thread
Thread Starter
Forum
Replies
Last Post
