I could do another one but last time the numbers weren’t really off enough to tell me much. I know it’s not rings because every time I reinstall the injectors, the blowby stops for a day or two.
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Injector blowby LB7
- Thread starter Jdherron
- Start date
I could do another one but last time the numbers weren’t really off enough to tell me much. I know it’s not rings because every time I reinstall the injectors, the blowby stops for a day or two.
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Ohhh good idea. I can get the adapter from the compression tester and hook a compressor to it
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Okay, another update: my blowby isn’t from the injectors. We tore it down, replaced the return lines, never touched the injectors, and the blowby completely stopped. However, it’s been two days and my crankcase is already full of diesel again and blowing by again. I’m thinking maybe it’s the high pressure lines leaking? I’m praying it’s not a cracked injector.
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I’m gonna get dye and try that, in the meantime I pulled a vacuum on both my fuel rails and they held a perfect vacuum so I think I can rule out hp lines. I’m at a total loss. Can I tell if an injector is cracked using efi live?
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I didn’t have time to pull my valve covers tonight but I drained the oil and refilled it, as well as checking my balance rates and pulse width. I figured out the blowby was a result of an overfull crankcase, it went away after I changed the oil. Here are the results of my balance and pulse tests, everything looks good but let me know if you see anything
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Those numbers look pretty good.
If you don't see anything from the injectors when you pull the covers, maybe the shaft seal on the CP3
Did you vacuum test the returns on each bank of injectors?
If you don't see anything from the injectors when you pull the covers, maybe the shaft seal on the CP3
Did you vacuum test the returns on each bank of injectors?
I'm still confused. You seem to be doing everything against what people tell you to do for testing.
If the crankcase is filling up you have a leak somewhere. Realistically it'll come from cracked injector bodies, sticking injectors bleeding off after shut down, leaking high pressure line, leaking return line, or leaking CP3 shaft seal.
You need to find the source of your fuel leak, that's critical. Until then you're just wasting time.
I'm not trying to be hard or harsh, I'm trying to save you from building a motor by constantly letting it fill up with fuel over and over again.
If the crankcase is filling up you have a leak somewhere. Realistically it'll come from cracked injector bodies, sticking injectors bleeding off after shut down, leaking high pressure line, leaking return line, or leaking CP3 shaft seal.
You need to find the source of your fuel leak, that's critical. Until then you're just wasting time.
I'm not trying to be hard or harsh, I'm trying to save you from building a motor by constantly letting it fill up with fuel over and over again.
Man I’m trying but really the only time I can put a lot of time into testing is on Sunday afternoons. I don’t really have time on an evening to pull valve covers or do anything super invasive so I try to just to the quick easy stuff on weeknights. I ran it with no valve covers today
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I dyed the fuel with a UV and ran it without valve covers, it looks like it’s coming from around where the hp line meets the injector but it’s hard to tell with all the oil also now having the dye in it. I replaced the hp lines, nothing changed. I went through efi live and commanded higher fuel rail pressure but it didn’t spray out from anywhere. Would a cracked injector spray under high fuel rail pressure, or are there instances where it wouldn’t spray?
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Injectors when cracked, will usually crack at the lower portion that is only exposed to the high pressure fuel. Si if it's cracked then raising the pressure should make it leak more. Not exactly the same injector but close enough
Is it leaking near where the feed fitting meets the body? If so, that injector needs to be replaced. This "typically" occurs when a high pressure line is overtightened as the fitting rotates/moves then leaks.