Lly knock on cylinder 2, tried everything..

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,492
472
83
Central OH
I know its time consuming, but did you swap injectors with another cylinder?

And don't worry too much about the orings, just there to keep dirt out, they don't hold pressure.
 

Mwaterman1

New member
Oct 30, 2014
54
0
0
pittsfield maine
Yeah I sprayed with electromotive cleaner and blew out, no noticeably messed up pins but I've run in to some generators that will not carry amperage through a pin connector this afternoon I'm going to pin out the wires and see what I can make of it, I really appreciate the help guys, this thing is plaguing me, after adjusting the valves yesterday im fairly confident now it's not mechanical, I need to string out the wires, and if everything checks out then I have to watch the injector pulse and see what it's doing


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kidturbo

Piston Tester
Jul 21, 2010
2,537
1,363
113
Somewhere On The Ohio
www.marinemods.us
I first replaced the injector the oring was almost completely gone, pulled the valve cover and the intake and exhaust valves were out of adjustment .008 but I can't imagine that would make the noise, haven't checked compression,

Return where you left off above.. Verify compression on that bank first. You know it's not an injector since you switched them out, correct? So leaves 2 possible causes, compression or electrical.

My money is on low compression, that +3.6 is not super high like a bad electrical miss. A blown copper you can hear easy, and if ya spray soapy water around the injector base it will change sound or blow bubbles up at ya.

I had the electromagnet ring come loose on a LLY injector, fuel knocked hard at part throttle, then went away on acceleration. My balance rate was like a +13 on that cyl.
 

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
I highly doubt it's low compression causing a knock, and the balance rate isn't that far off... I would swap a known good injector say 5 or 7 with 2 and see if the problem stays or switches holes.
 

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
But the thing is, I've swapped two brand new not reman injectors to that cylinder


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Pretty sure you said used or old earlier... But that changes things. Forget swapping the injectors.

I would change the tune back to bone stock and verify the issue and recheck for codes, sometimes tuners will shut certain things off. Check the wiring for #2 from the injector to the Ficm back to the ecm.

If you have a buddy that has the same engine see if he will let you swap Ficms, ecms. If you swap the ecm be prepared to do a vats relearn, there is a tutorial on it somewhere on here.
 

Mwaterman1

New member
Oct 30, 2014
54
0
0
pittsfield maine
Just quickly redid the connectors for the injector, I originally used heat shrink connectors but found when I ohmed it out high at 12 ohms through the connector


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Mwaterman1

New member
Oct 30, 2014
54
0
0
pittsfield maine
Got to troubleshoot a little more today, pulled the glow plug for #2 and took the compression kit I bought apart and rigged it up to my leak down tester, put it to top dead of #2 and put 175psi in the cylinder, measured 80% leakage, took my stethoscope and checked all over, can hear air clear as day at the y bridge, nothing in the pan or crankcase breather, is it odd this makes me happy???


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Mwaterman1

New member
Oct 30, 2014
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0
0
pittsfield maine
bb07f63783b14b83de4d0bbed666f710.jpg



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Mwaterman1

New member
Oct 30, 2014
54
0
0
pittsfield maine
Found the issue, wrist pin bushing, built up so much carbon valve wouldn't seat properly, what are the odds or just swapping one piston and rod?


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