Question: Engine problem

kenny

kennydiesel
Mar 5, 2009
319
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washington state
fuel balance rates

OK, I got the fuel balance rates recorded.
MIN AVG MAX
#1 -3.36 -2.9 -2.39
#2 -1.09 -0.8 -1.88
#3 -2.78 -2.25 -1.23
#4 -1.06 -0.70 -0.98
#5 -1.75 -1.13 -0.45
#6 -1.95 -1.58 -0.13
#7 -2.08 -2.54 -2.66
#8 -4.09 -4.64 -5.28
This data was taken with the engine temperature just above 160*. Looks like #8 is toast.
 

Cougar281

Well-known member
Sep 11, 2006
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St Louis, MO
OK, I got the fuel balance rates recorded.
MIN AVG MAX
#1 -3.36 -2.9 -2.39
#2 -1.09 -0.8 -1.88
#3 -2.78 -2.25 -1.23
#4 -1.06 -0.70 -0.98
#5 -1.75 -1.13 -0.45
#6 -1.95 -1.58 -0.13
#7 -2.08 -2.54 -2.66
#8 -4.09 -4.64 -5.28
This data was taken with the engine temperature just above 160*. Looks like #8 is toast.

Yes, #8 is higher than the others, but it's not that far out of whack....
 

the4wheeler

--->(Something Funny)<---
May 4, 2008
254
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Ventura County SoCal
x2 balance rated dont look to horable. for s*It and giggles take the intake tube off the front of the turbo and see how it spins.. any slop in the shaft... ect.
 
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LBZ

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Jul 2, 2007
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I would do a compression test to confirm if it is an injector or cylinder issue before you start ripping and tearing.

Just my two bits of advice!:D
 

Cougar281

Well-known member
Sep 11, 2006
1,806
249
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St Louis, MO
I would do a compression test to confirm if it is an injector or cylinder issue before you start ripping and tearing.

Just my two bits of advice!:D

Agreed; I have an injector on my truck that gets over +7 in park on occasion (it's the injector causing it), so 5 or 6 isn't that bad; A Compression test would tell you for sure if you have a blown piston (or HG), but I think when a piston goes, you usually see a balance rate in the 15 range because the ECM is trying to max the injector out to compensate for the blown piston.
 
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SteveFord

What's Next?
May 8, 2008
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If you fell comfortable doing this I would get the motor warmer than that. My rates are always higher than when it's fully warmed up. That much blow by is a sighn of either burnt/cracked piston or damaged rings in my opinion. If your running alot of timming and pulse width your spraying the fuel all over the piston and cylinder wall when your rail starts to drop and at higher rpms and can result in cooking a piston. Maybe not though.
 

JoshH

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A bad piston should show balance rates of +12 on an LBZ. Negative balance rates indicate a piston is making too much power, and it is trying to pull fuel. I would recommend you doing a compression check if you can.
 

JoshH

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What do you do about that?


Compression check would be the best.....Even just pulling the glow plug
Could be several different things. I'm no expert, but my guess would be injectors more than anything. If you're really worried you can move the injector and see if the balance rate problem moves or stays in the same cylinder.

Kenny's problem is weird because of all the blowby but not a lot of smoke coming out of the exhaust. My truck smoked like hell when I killed a piston. Looked like I was fogging mosquitoes.
 

JoshH

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Where would it be coming from, Henry? I thought since they moved the injectors out from under the valve cover they didn't dump fuel into the oil pan when the injectors went bad.
 

ripmf666

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Sep 20, 2006
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Where would it be coming from, Henry? I thought since they moved the injectors out from under the valve cover they didn't dump fuel into the oil pan when the injectors went bad.


If its a bad ring it could be running past just a thought.Kinda werd no codes for miss fire and like you said not smoking out the exhaust heavy. My injector balance rates were less then his when I cracked #6
 
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LBZ

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Even if it wasn't smoking but was knocking because it was pumping in so much fuel it couldn't fire, you will see fuel in the oil either visibly, or with an oil sample analysis.