Vibration/shudder from engine - The 1947 - Present Chevrolet & GMC Truck Message Board Network

philobeddoe · 01-06-2016, 09:47 AM

Under load, like going up a hill or just plain accelerating, I feel a vibrate/shudder coming from engine. I can also feel it in park when I give it gas. No matter how fast going down the road, if foot is off the gas it is very smooth. It is also smooth at idle.

I'm stumped! Plugs and wires were changed when I had valve seals done back in Sept. Could it still be a bad plug or firing order, I guess I would have noticed before then? Maybe a plug got bad since? Timing, hoses??

I'm stumped! Thanks for all help.

jjmorrse · 01-06-2016, 12:20 PM

Did the row of black widow bikes you knocked over damage the harmonic balancer? Did Clyde check the accelerator pump? That is all I have, sorry.

Matt Man · 01-06-2016, 12:31 PM

How are the condition of the motor mounts?

Dead Parrot · 01-06-2016, 01:13 PM

Check your plugs. They should all look similar. If one or more are different, those are your suspect cylinders. Did you replace the cap with the wires? Could be the cap, rotor or the button in the cap.

An almost plugged fuel filter will cause cutouts under load.

To eliminate accessories, remove all the belts and do a brief retest in park. If the vibration goes away, one of the accessories is suspect. Keep in mind, no belts, no water flow so keep the tests under a few minutes.

philobeddoe · 01-06-2016, 03:41 PM

I will start with the plugs, and try it without belts. We did replace cap and wires. Thanks.

Oh, i bet the black widows messed with it! Lol, any which way but loose!

mMad Dawg · 01-06-2016, 04:09 PM

Did you do a compression test. You may have a low cylinder. Did it start to miss after you did the plugs. You may have a bad wire that got damaged when you pulled them off the plugs. Did you check the wires with an ohmmeter.

Zach079xxx · 01-06-2016, 06:42 PM

Check your fuel filter, maybe it's not getting the fuel it needs at high RPM. Air cleaner nice and clean? What about your plug wires? and engine mounts ok? Hmmm.. what's the story behind the black widow bikes? Or am I missing the joke lol

philobeddoe · 01-06-2016, 07:01 PM

Quote:

Originally Posted by Zach079xxx

Check your fuel filter, maybe it's not getting the fuel it needs at high RPM. Air cleaner nice and clean? What about your plug wires? and engine mounts ok? Hmmm.. what's the story behind the black widow bikes? Or am I missing the joke lol

The black widow thing is the gang in the two clint eastwood movies, "anyway which way but loose" and "any which way you can". Philo beddoe was clints character.

Plugs are good, wires are good. Will check fuel filtr, but i dont think thats it. It does not skip or hesitate at all.

Question, should the harmonic balancer be "pin" straight? I can see a little movement in mine.

jjmorrse · 01-07-2016, 06:19 PM

This thread has several obscure things that might be worth checking.

http://www.jalopyjournal.com/forum/t...ration.836151/

philobeddoe · 01-07-2016, 08:16 PM

Yeah, that's a good thread, I have a good mechanic taking a look at it, a lot is pointing to the h. balancer. Will certainly post results.

01-06-2016, 09:47 AM	#1
philobeddoe Registered User Join Date: Mar 2015 Location: Brimfield, MA Posts: 91	Vibration/shudder from engine Under load, like going up a hill or just plain accelerating, I feel a vibrate/shudder coming from engine. I can also feel it in park when I give it gas. No matter how fast going down the road, if foot is off the gas it is very smooth. It is also smooth at idle. I'm stumped! Plugs and wires were changed when I had valve seals done back in Sept. Could it still be a bad plug or firing order, I guess I would have noticed before then? Maybe a plug got bad since? Timing, hoses?? I'm stumped! Thanks for all help. __________________ Philippians 4:8, Victory through pure thoughts.

01-06-2016, 12:20 PM	#2
jjmorrse Registered User Join Date: Aug 2010 Location: east tx Posts: 128	Re: Vibration/shudder from engine Did the row of black widow bikes you knocked over damage the harmonic balancer? Did Clyde check the accelerator pump? That is all I have, sorry. __________________ jjmorrse 86 C30 crewcab big dooley. 454- 400

01-06-2016, 12:31 PM	#3
Matt Man Registered User Join Date: Oct 2009 Location: Buhl, Idaho Posts: 1,438	Re: Vibration/shudder from engine How are the condition of the motor mounts? __________________ 86 c30 crew cab dually 454/400 4/6 drop SOLD 1-8-11 1981 chevy K10 short Bed Scottsdale SOLD 10-26-2020 67 GMC Stepside Straight six/3 on the tree "The Peach" 2020 Silverado Double Cab LT Z71 5.3 8 speed Daily Driver K10 build http://67-72chevytrucks.com/vboard/s...d.php?t=671934 The Peach build http://67-72chevytrucks.com/vboard/s...d.php?t=733903

01-06-2016, 01:13 PM	#4
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,611	Re: Vibration/shudder from engine Check your plugs. They should all look similar. If one or more are different, those are your suspect cylinders. Did you replace the cap with the wires? Could be the cap, rotor or the button in the cap. An almost plugged fuel filter will cause cutouts under load. To eliminate accessories, remove all the belts and do a brief retest in park. If the vibration goes away, one of the accessories is suspect. Keep in mind, no belts, no water flow so keep the tests under a few minutes.

01-06-2016, 03:41 PM	#5
philobeddoe Registered User Join Date: Mar 2015 Location: Brimfield, MA Posts: 91	Re: Vibration/shudder from engine I will start with the plugs, and try it without belts. We did replace cap and wires. Thanks. Oh, i bet the black widows messed with it! Lol, any which way but loose! __________________ Philippians 4:8, Victory through pure thoughts.

01-06-2016, 04:09 PM	#6
mMad Dawg Registered User Join Date: Jun 2009 Location: Calgary AB. Posts: 88	Re: Vibration/shudder from engine Did you do a compression test. You may have a low cylinder. Did it start to miss after you did the plugs. You may have a bad wire that got damaged when you pulled them off the plugs. Did you check the wires with an ohmmeter.

01-06-2016, 06:42 PM	#7
Zach079xxx Registered User Join Date: Apr 2015 Location: Shenandoah Valley, Virginia Posts: 332	Re: Vibration/shudder from engine Check your fuel filter, maybe it's not getting the fuel it needs at high RPM. Air cleaner nice and clean? What about your plug wires? and engine mounts ok? Hmmm.. what's the story behind the black widow bikes? Or am I missing the joke lol __________________ 85' GMC Sierra Classic Built 350; Weiand intake, Holley 600, Thumpr Cam Built 350 turbo with shift kit & 2500 Stall Thumpin' away

01-07-2016, 06:19 PM	#9
jjmorrse Registered User Join Date: Aug 2010 Location: east tx Posts: 128	Re: Vibration/shudder from engine This thread has several obscure things that might be worth checking. http://www.jalopyjournal.com/forum/t...ration.836151/ __________________ jjmorrse 86 C30 crewcab big dooley. 454- 400

01-07-2016, 08:16 PM	#10
philobeddoe Registered User Join Date: Mar 2015 Location: Brimfield, MA Posts: 91	Re: Vibration/shudder from engine Yeah, that's a good thread, I have a good mechanic taking a look at it, a lot is pointing to the h. balancer. Will certainly post results. __________________ Philippians 4:8, Victory through pure thoughts.



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