A rattle when driving

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SquareRoot

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Buy a Duramax. You will forget all about the rattle. What, don't like the rattle? LS swap. Drink beer, carry on.
 

91v2500

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a scanner will let you see what the ECM sees at each sensor, monitor fuel trims, watch knock counts, etc.

you could run through the diagnostics on the Knock sensor, but I'd expect it to set a code if the module or the sensor went bad. but I guess if it were that easy, there wouldn't be a diagnostic procedure.

it only performs the self test 1 time per start. so if you my hear it multiple times on the same drive, it isn't doing a self test. it could be actual knock. knocking sounds like a fast rattle to me.

if it is knocking, all the ESC does is retard timing. it doesn't set a code when it detects knock.

i am assuming your check engine light works?
Ok and yes my check engine light works
 

Ricko1966

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Thanks for bringing me into this thread @Ricko1966

There is a LOT of information on the ESC system used on the carbureted rigs 305 mostly a few 350's got the system too. If @91v2500 wants to see that thread it is here >> https://www.gmsquarebody.com/thread...-knows-more-about-esc-system-than-i-do.33216/ << If you go to the last page post #168 has the stuff @AuroraGirl posted. BUT keep in mind that info is geared towards the carbureted trucks.

With that said Korey, I haven't a clue if your noise is pinging, a rod knock, a loose fender or something entirely different and neither do the rest of the guys because we can't hear it from here. Could you please take the truck out for a drive and record some audio of the noise. You can just use your phone and take video doesn't matter what we see it's what we hear. Pinging is a pretty unique sound and I'm sure anyone of us could tell that from say a cat rattle in a recording. Once you have captured the video upload it to youtube and link it to the sight.
Yeah, I wasn't thinking,we've been battling your esc. So long now everything is an 84 305. Even VW GTI it will get an esc controller a gm knock sensor and I have no idea how I'll get the hei to fit. Lol
 
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SirRobyn0

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Yeah, I wasn't thinking,we've been battling your esc. So long now everything is an 84 305. Even VW GTI it will get an esc controller a hm knock sensor and I have no idea how I'll get the hei to fit. Lol
Well that just requires the right drilling equipment and gear to go on the camshaft. Bonus points if the cap and coil are outside the hood!
 

91v2500

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Did you see my message? It would be helpful if you could upload some audio of the noise. A simple video would probably be easiest and then we could all hear what you are hearing. Thanks.
Sorry I missed that I’ll try to post one tomorrow
 

91v2500

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does this noise happen if you are in park/neutral and you ramp up the revs? if you coast in neutral while rattling (So while moving) does it go away?
Only while in drive and my foot on the gas if I take my foot off it would stop
 

91v2500

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Number: 93-03-6D
Section: 6D
Date: AUGUST 1992
Corporate Bulletin No.: 166001R
ASE No.: Al, A6, A8

Subject:
NEW DESIGN SPARK PLUGS

Model and Yew:
1991-93 ALL PASSENGER CARS AND TRUCKS WITH GASOLINE ENGINES

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO., 91-234A-OB, DATED JULY 1992. THE 1992 AND 1993 MODEL YEARS HAVE BEEN ADDED. ALL COPIES OF 91-234A-OB SHOULD BE DISCARDED.

In 1991 GM introduced a new design spark plug for use in all trucks equipped with gas engines. These new design spark plugs have a ceramic insulator which is approximately 1/8 inch longer than the insulator used in previous model years.

The longer length spark plugs, which conform to S.A.E. and I.S.O. Engineering guidelines, magnify the problem of cracked insulators because currently, most spark plug sockets are not of sufficient length to properly engage the shell hex. If the spark plug shell hex is not fully engaged in the spark plug socket wrench, the socket may **** at an angle and cause insulator cracking and/or breakage during plug installation or removal.

When servicing these new design spark plugs, make sure that the spark plug socket being used is deep enough to accommodate the longer length insulator. The spark plug socket wrench should conform to the proposed S.A.E. and I.S.O. world standards for spark plug socket wrenches. Spark plug socket wrenches that conform to these standards are designed to accept the lengthened spark plugs and allow full engagement of the hex nut on the shell of the spark plug.

Use of a spark plug socket which is NOT deep enough may result in the ceramic insulator becoming cracked above the spark plug shell.

Note:

SOME CRACKS IN THE INSULATOR M" NOT BE VISIBLE. SUCH CRACKS MAY LATER CAUSE A SPARK PLUG TO MISFIRE. SPARK PLUG MISFIRES ARE OFTEN MISDIAGNOSED AS A SLIPPING TRANSMISSION, DEFECTIVE TORQUE CONVERTER CLUTCH, ENGINE IMBALANCE, OR MALFUNCTIONING FUEL SYSTEM.

Number:91-375-10

Section:10

Date:JULY 1991

Corporate Bulletin No.: 161602


Subject:
RATTLE FROM "B" PILLAR CAB MOUNT CUSHION AREA


Model and Year:
1991 C/K TRUCKS

FIGURE 1
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FIGURE 2
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Some 1991 C/K trucks may experience a rattle from "B" pillar cab mount cushion area.

SERVICE PROCEDURE:

To correct this condition it is necessary to increase torque on the cab body and radiator support mounts to the following revised torque specifications.

1.Body mount bolt (P/N 15611432) from 60-90 N-m. (44-66 lbs.ft.) to 75-95 N-m. (55-70 lbs.ft.)(Figure 1).

2.Radiator support mount (P/N 15538569) from 40-55 N-m. (30-40 lbs.ft.) to 50-63 N-m. (37-46 lbs.ft.)(Figure 2).

The revised torque specifications started with the following VIN breakpoints:

Ft. Wayne ASM1GCDC14K0MZ168782

Oshawa ASM2GCHC39N1M1191836

Pontiac East ASM1GBGC24J4ME175532
Thank you
 

Originalthor

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I'm assuming your unit is a suburban 4x4? Just going by your name and profile picture here.

Is it a rotation rattle?

Have you checked u joints? They don't per say rattle but can make some bad noises when drying up and failing.

Also check your rear shock mounts on the frame. Those bolts like to hollow out the hole and rattle.
 

Ellie Niner

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the socket may **** at an angle and cause insulator cracking and/or breakage
Haha! I love how HappyWordz Profanity Filter™ spanked that GM TSB so we don't have to see suggestions of how spark plugs were violated.
Yeah, I wasn't thinking,we've been battling your esc. So long now everything is an 84 305. Even VW GTI it will get an esc controller a gm knock sensor and I have no idea how I'll get the hei to fit. Lol
*** is still engineering their Electronic Spark Control system... It needs to be molded into the underside of the dash pad, contain the glove box latch, be able to control the seat heaters, detect and scram whenever an emissions test might be underway, and take out the transmission if it fails.


Aw sh¡t... HappyWordz got me too. I guess we can't abbreviate Volkswagen Audi Group.
 

AuroraGirl

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Haha! I love how HappyWordz Profanity Filter™ spanked that GM TSB so we don't have to see suggestions of how spark plugs were violated.

*** is still engineering their Electronic Spark Control system... It needs to be molded into the underside of the dash pad, contain the glove box latch, be able to control the seat heaters, detect and scram whenever an emissions test might be underway, and take out the transmission if it fails.


Aw sh¡t... HappyWordz got me too. I guess we can't abbreviate Volkswagen Audi Group.
I said the c ends with k word . in the non saxophone way
 

Grit dog

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Only while in drive and my foot on the gas if I take my foot off it would stop
Look up pinging/pre detonation/ pre ignition and listen for that noise. Worse if you accelerate harder? If so likely pinging.
You could diagnose it start by making sure the timing is spot on.
Or first try a tank of good premium. If it goes away, the timing is a bit advanced.
 

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