01-17-2018, 01:09 AM | #1 |
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Join Date: Mar 2007
Location: Farmington, MN
Posts: 928
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Spark knock?
I put a used engine in my '92 K1500 a few months ago and the engine had been running great. I think the engine has about 150K on it. Over the last couple weeks my gas mileage has been getting worse, about 10 mpg, but I figured this was because the temps have been below zero. The truck started idling a little rough yesterday and this afternoon I noticed the coolant temp was bouncing around between -32 and 190 degrees. About the time the DTC for the coolant temp sensor was set I noticed the engine knocking. I replaced the coolant temp sensor and the pigtail tonight, but now I have a knock that gets progressively worse while accelerating and during highway driving. If I shift into neutral and rev the engine its not there. I checked the timing and that seems fine. What else should I be looking at? Ignition module? Thank you for the help.
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01-17-2018, 09:59 AM | #2 |
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Join Date: May 2006
Location: Santa Maria, Calif.
Posts: 781
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Re: Spark knock?
You know where the knock sensor is? It's screwed into the middle of the block right by the starter. Check that first.
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1989 K1500 Chev. EC Original owner; some of the aftermarket parts I've installed are Borla headers, Hypertech chip, Edelbrock water pump, and a Stillen rear disc brake conversion kit. 2009 Hummer H3T 3.7L 5M (sold) 1997 K2500 Chev. EC 7.4L/ 4L80E 2018 Dodge Ram 2500 HD R/C |
01-17-2018, 04:51 PM | #3 |
driving is in my blood
Join Date: Dec 1999
Location: Mesa AZ
Posts: 5,687
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Re: Spark knock?
Make sure its an engine knock as well. I thought I had one...flexplate was about to come all the way apart via the half way threw crack that had started
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-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me. |
01-17-2018, 08:53 PM | #4 |
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Join Date: Mar 2007
Location: Farmington, MN
Posts: 928
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Re: Spark knock?
I'm going to try the knock sensor tonight and see if that helps. I put the engine in in August and didn't see any cracks then, but that does mean it hasn't happened since then.
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I can still count my vehicles on two... wait three hands. |
01-18-2018, 12:14 AM | #5 |
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Join Date: Mar 2007
Location: Farmington, MN
Posts: 928
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Re: Spark knock?
No luck with the knock sensor. I ran across a thread by Ackattack where he was having similar issues and his problem was a blown head gasket. After the knock sensor I decided to check compression on a couple cylinders be fore spending too much time swapping parts. Checked cyl.3 and got about 150 psi, cyl. 4 not so good. I have about 50 psi so it looks like I'm doing head gaskets this weekend. Thank you for the help guys.
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I can still count my vehicles on two... wait three hands. |
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