| Random knock | |
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CrashMaster
Posts : 190 Join date : 2011-12-05
| Subject: Random knock Tue Jul 03, 2012 7:50 pm | |
| My 72k mile lt1 has started doing some random knocking. Sometimes it can go weeks without doing it and when it does I usually just let it idle in drive a little and it stops. However I think it stops because it's retarding the timing because I have noticed a serious lack of power at times.
My first question is this. The egr valve used to throw a code every once in a while when I first got it (sometimes on for weeks somtimes it would clear itself the same day) but it hasn't come on in a very long time. Is that most likely the problem?
Could it be as simple as plugs and wires? I think no since the knock rarely happens but does anyone think otherwise?
I have put 23k miles on it in the year I have owned it and it's a fairly recent problem.
Any help lt1 gurus? | |
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Ironfistdog
Posts : 2141 Join date : 2011-01-11 Age : 42 Location : Warren, MA
| Subject: Re: Random knock Tue Jul 03, 2012 9:16 pm | |
| Take the egr valve tube off the intake side and see if that hole is plugged up solid. | |
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CrashMaster
Posts : 190 Join date : 2011-12-05
| Subject: Re: Random knock Tue Jul 03, 2012 10:22 pm | |
| I will check that soon. Thanks for the reply.
To add more info...... There is no ryme or rythem to the knocking. Hot or cold that is. It's never at idle though. Always under throttle. Also it has been hard to start alot in the mornings lately which is probably related. | |
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Ironfistdog
Posts : 2141 Join date : 2011-01-11 Age : 42 Location : Warren, MA
| Subject: Re: Random knock Tue Jul 03, 2012 11:08 pm | |
| What year lt1? Any codes or CEL? IAC been replaced? clean the MAF?
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CrashMaster
Posts : 190 Join date : 2011-12-05
| Subject: Re: Random knock Tue Jul 03, 2012 11:31 pm | |
| 96. IAC? Not familiar. Never cleaned the MAF.... Heard that can cause more harm than good. No dash lights. | |
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IMPALADAKID Admin
Posts : 1525 Join date : 2009-01-17 Age : 55
| Subject: Re: Random knock Wed Jul 04, 2012 6:54 am | |
| - CrashMaster wrote:
- 96. IAC? Not familiar. Never cleaned the MAF.... Heard that can cause more harm than good. No dash lights.
Just because there is no light does not mean there are no codes. If you don't have a code reader, bring it to autozone. The one near me uses a scanner that can see past codes, and soft codes. To clean a MAF safely, and gently. Remove it from the car, hold it in your hand with the engine side pointed at you. Take a couple Q-tips saturated with rubbing alcohol on them and reach in and wipe the three diodes. You have to be very gentle. Bend the Q-tip so you can get the back side of the diode. Let the alcohol do the work. I have cleaned MAFs this way for over 20 years with great results. | |
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SPCS
Posts : 122 Join date : 2012-02-17 Age : 46 Location : Stuttgart, Germany
| Subject: Re: Random knock Thu Jul 05, 2012 12:15 pm | |
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CrashMaster
Posts : 190 Join date : 2011-12-05
| Subject: Re: Random knock Thu Jul 05, 2012 2:15 pm | |
| No codes at auto zone. Egr replaced, pcv valve replaced. Still no luck.
Are you serious about it being the opti? Would it be an intermittent issue like this if it were the opti?
Trying plugs tonight..... | |
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SPCS
Posts : 122 Join date : 2012-02-17 Age : 46 Location : Stuttgart, Germany
| Subject: Re: Random knock Fri Jul 06, 2012 2:04 pm | |
| At this stage, the Opti really isn't more likely to be the source of the problem than a lot of other things. It just always ends up actually being the source, for me, anyways.
It certainly can fail in the most bizarre, intermittent, coming-and-going ways. Never had a MAF do that to me - but in any case, cleaning the MAF is a better place to start than replacing the distributor. | |
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IMPALADAKID Admin
Posts : 1525 Join date : 2009-01-17 Age : 55
| Subject: Re: Random knock Fri Jul 06, 2012 2:16 pm | |
| If you are getting a random knock and a loss of power, it might be that you need to do an engine flush and replace with fresh oil and filter after. The knock sensors will detect knock, and the PCM will pull timing. This might be the loss of power you feel. If you do a motor flush and oil change, and the knock continues, you might try and find a LT4 knock module. I don't like them on a stock valve train motor, but in your case it may be an idea. | |
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