92 5.7 Weird Noise

stepsidejay · 04-05-2009, 10:02 PM

Ya I just got this 92 single cab, swb, 2wd, with the 350. Runs GREAT, only has 128K on the truck, the guy I bought it from said he had chevy replace the motor at 46k cause of burning oil(who knows??) Ne ways the problem i am having is a noise, sounds like its coming from right under the pass. floor board. Its a weird rattle, only does it when the truck is warmed up, only does it when u acc too quickly or try to take off fast(pretty much only if u put ur foot in it),and only will do it once, then the SERVICE ENG SOON light comes on, as long as the lights on it will never do it again. But if u turn the truck off and crank it right back...no light and the noise will happen again if u mash the gas too much! Cannot figure out what this is. Have had people tell me lots of things like the CAT, LIFTER, KNOCK SEN, but I dunno!! Figure if it was the CAT or LIFTER it would do it every time u mash on it!!HELP HELP HELP!!!

Case 7230 · 04-06-2009, 03:48 AM

Sounds like a bad engine or transmission mount to me. No, I don`t know why it would not do it all the time.
Also with the CEL on there is an error code stored so I would pull the codes. You only need a paperclip to jump two terminals on the diagnostic connector and count the light flashes. That may give a guide to what is happening.

leolkfrm · 04-06-2009, 04:49 AM

welcome to the forum
scanner is the first step, then post the results and go from there.

stepsidejay · 04-06-2009, 02:21 PM

Well like i said i just got the truck, and right after i got it i replaced the tranny mount. motor mounts look fine to me. guess ill just have to go put it on a dyno or something to get the codes off. but i always thought to check why your SEL or CEL are on that they have to accually be ON while checking?? does the computer store and save the codes so u can pull them at any time???

leolkfrm · 04-06-2009, 03:45 PM

yep pull them, and when it's fixed clear them for the next problem

hotrodpc · 04-06-2009, 08:28 PM

I like that term,

"if you mash the gas to much"

You shouldn't need a dyno to get your stored codes. Get your stored codes, address and fix them, then clear the codes. Hopefully they won't come back. Also keep in mind, noises can play tricks on you and not be coming from where you think they are.

stepsidejay · 04-07-2009, 01:05 PM

well i had a guy pull the codes... just a local guy!! he jus called me and told me its throwing a code to the knock sen. (never heard of this thing) but he told me to check the wires and then if that don't fix it then change the SEN it self!! but i forgot to ask him what the code was....dum me!! let me call him back...

bradrhale · 04-07-2009, 02:38 PM

maybe code 43?? Knock sensor signal was not received by ECM for 4 seconds when engine was running.

stepsidejay · 04-07-2009, 02:49 PM

ya thats it code 43, he just called me back!! SOOO....What the heck does that mean? And why is that coming up?

bradrhale · 04-07-2009, 02:53 PM

something could be unplugged or the sensor could be out. i would check connections first before you start replacing stuff that you dont know about. waste of money to me. if all the connections are right and tight, then have it scanned to determine what the problem is. too many times has a code popped up saying that a knock sensor failed, or an EGR failed and that part not be the culprit.

04-05-2009, 10:02 PM	#1
stepsidejay Full Member Join Date: Apr 2009 Location: TEXAS Posts: 37	92 5.7 Weird Noise Ya I just got this 92 single cab, swb, 2wd, with the 350. Runs GREAT, only has 128K on the truck, the guy I bought it from said he had chevy replace the motor at 46k cause of burning oil(who knows??) Ne ways the problem i am having is a noise, sounds like its coming from right under the pass. floor board. Its a weird rattle, only does it when the truck is warmed up, only does it when u acc too quickly or try to take off fast(pretty much only if u put ur foot in it),and only will do it once, then the SERVICE ENG SOON light comes on, as long as the lights on it will never do it again. But if u turn the truck off and crank it right back...no light and the noise will happen again if u mash the gas too much! Cannot figure out what this is. Have had people tell me lots of things like the CAT, LIFTER, KNOCK SEN, but I dunno!! Figure if it was the CAT or LIFTER it would do it every time u mash on it!!HELP HELP HELP!!!

04-06-2009, 04:49 AM	#3
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	welcome to the forum scanner is the first step, then post the results and go from there. __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

04-06-2009, 03:45 PM	#5
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	yep pull them, and when it's fixed clear them for the next problem __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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04-06-2009, 03:48 AM	#2
Case 7230 Senior Member Join Date: Dec 2007 Posts: 547	Sounds like a bad engine or transmission mount to me. No, I don`t know why it would not do it all the time. Also with the CEL on there is an error code stored so I would pull the codes. You only need a paperclip to jump two terminals on the diagnostic connector and count the light flashes. That may give a guide to what is happening.

04-06-2009, 02:21 PM	#4
stepsidejay Full Member Join Date: Apr 2009 Location: TEXAS Posts: 37	Well like i said i just got the truck, and right after i got it i replaced the tranny mount. motor mounts look fine to me. guess ill just have to go put it on a dyno or something to get the codes off. but i always thought to check why your SEL or CEL are on that they have to accually be ON while checking?? does the computer store and save the codes so u can pull them at any time???

04-06-2009, 08:28 PM	#6
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,175	I like that term, "if you mash the gas to much" You shouldn't need a dyno to get your stored codes. Get your stored codes, address and fix them, then clear the codes. Hopefully they won't come back. Also keep in mind, noises can play tricks on you and not be coming from where you think they are.

04-07-2009, 01:05 PM	#7
stepsidejay Full Member Join Date: Apr 2009 Location: TEXAS Posts: 37	well i had a guy pull the codes... just a local guy!! he jus called me and told me its throwing a code to the knock sen. (never heard of this thing) but he told me to check the wires and then if that don't fix it then change the SEN it self!! but i forgot to ask him what the code was....dum me!! let me call him back...

04-07-2009, 02:38 PM	#8
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	maybe code 43?? Knock sensor signal was not received by ECM for 4 seconds when engine was running.

04-07-2009, 02:49 PM	#9
stepsidejay Full Member Join Date: Apr 2009 Location: TEXAS Posts: 37	ya thats it code 43, he just called me back!! SOOO....What the heck does that mean? And why is that coming up?

04-07-2009, 02:53 PM	#10
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	something could be unplugged or the sensor could be out. i would check connections first before you start replacing stuff that you dont know about. waste of money to me. if all the connections are right and tight, then have it scanned to determine what the problem is. too many times has a code popped up saying that a knock sensor failed, or an EGR failed and that part not be the culprit.