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Help!!! motor making strange noise!

dominic

dominic

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Drummond N.-B. CANADA
I went for a ride with my 1982 gmc jimmy and it started to make weird noises when i press harder on the gas pedal.when it's idle it runs perfect,no noise at all.even when I am in park and I rev it up I cant ear any noise at all. but as soon as put it in drive and start driving and the motor starts to torque a little it starts.just like a pingging noise.I put some 91 octane gas insted of 87 octane and it did not make a difference.I hope it's not the crank bearings starting to let go. weird,I am puzzled at the moment.any ideas people.it's a 400 sbc.
 
I don't know about the '82s but if it has a knock sensor perhaps it has gone bad? Or maybe the wire came off? I would assume that would mean a check engine light, but ... like I said, I don't know the 82s. :)
 
I dont know if it as a knock sensor,check engine light is not on.I know fuel injection have knock sensors,good idea will have to check.
 
I only ear it will driving but it sounds like its coming from the motor,I cant see what else would make a noise like that only when the motor starts to torque up.
 
Timing too advanced. You'll only hear it when it's under load...back the timing off a few degrees.

Rene
 
87 k5 engine bog

So I Have a new to me 87 K5 totally stock except for 33" bfg's it came with. Previous owner had it for ten years and has not really driven it for about 5 years. Problem is every time you hit the gas it tries to stall. Once you nurse it up to speed it works well and once in 10-20 trys you can gas it off the line.
Has efi system cleaned it with carb cleaner without removal. Did tune up and fuel filter, now it runs smoother with the same loping idle and and trys to stall when i hit the gas.
throttle position sensor is next to be changed what else?
Oh yea has 305 engine (i'll take care of that in a year or two I need to go through the rest first). Has a great body and interior (black outside deep red interior) and only couple of small rust spots except for front bumber that is pretty rusty.
thanks for any help
 
My Burb started to make a noise one day, same symptoms. It was a torque converter bolt that was backing out and rubbing, only did it when in gear not in park. Just a thought and something to check.
 
87Freckleton said:
So I Have a new to me 87 K5 totally stock except for 33" bfg's it came with. Previous owner had it for ten years and has not really driven it for about 5 years. Problem is every time you hit the gas it tries to stall. Once you nurse it up to speed it works well and once in 10-20 trys you can gas it off the line.
Has efi system cleaned it with carb cleaner without removal. Did tune up and fuel filter, now it runs smoother with the same loping idle and and trys to stall when i hit the gas.
throttle position sensor is next to be changed what else?
Oh yea has 305 engine (i'll take care of that in a year or two I need to go through the rest first). Has a great body and interior (black outside deep red interior) and only couple of small rust spots except for front bumber that is pretty rusty.
thanks for any help
Click to expand...
I doubt it's the TPS. I would check for vacuum leaks first (free!), then check the EGR (unbolt, clean), then the PCV valve, then the IAC. Of course, if it's been sitting that long, you may have bad gas.

Mine had a similar problem and I gave it a tune up - new cap/rotor/plugs/wires/egr/pcv/iac. I also replaced the injectors (pay attention to those o-rings, put ATF on them to lubricate it when you reassemble) and FPR and now I have zero problems. Starts right up!
 
I think I will change the spark plugs and wires,+cap and rotor.check the timming and check for vacuum leaks. thanks guys
 
I retarded the timing a little and it slow down my rpm's,so I adjusted carb idle screw to bring it back to normal rpm.went for a ride and it still did that knocking or pinging sound as soon as I press on the gas pedal. So I decided to check my sparks,there all grey tan colour like there suppose to be. It's sounds just like a spark knock. could this be detonation? ...I have a fireball crane cams hi-6 ignition box on my 400 sbc,cast iron heads,performer aluminum intake,normal gm quadra jet carb,k/n filters,accel spark plug wires+cap+rotor,ac delco plugs. does anyone see a problem here? thanks
 
Finaly found my pinging noise in my motor,I took the motor out of the truck and took it apart.Found a busted head gasket, between #4 and #6 pistons,right in the middle about 3/8 wide.But was not burning preston,just ****ing up compression and fire between them 2 pistons just like pre-ignition.
 
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