Duncan Sterling
07-12-2005, 10:16
Howdy,
I've been doing alot of work on my '91 burb to get it ready for a long trip.
Recently I replaced the dying stock exhaust with a Banks stinger. It made a racket at first because of mounting issues (one of the pipes was vibrating against the frame), but those are resolved.
Now I have a weird new noise only at idle--kind of a pulsating/rythmic/surging rattle, sounds like it's coming off the exhaust system.
The exhaust system (attached/hung per Banks instructions--and all mount points and clamps tight as far as I can tell) seems to vibrate alot too--if you hold a wrench or screwdriver against it when the motor is runing it sounds like you're ringing a bell. If you look at the motor while it's running, it doesn't appear to be shaking abnormally.
Turning on the A/C or putting the truck in drive or reverse mostly kills the rattling noise, as does stepping on the throttle slightly.
The motor doesn't smoke except for a small puff of blue at startup (all my diesels do that at cold start), I have 35-40 PSI oil pressure at idle with 50-60 PSI (depending on whether it's cold or hot) when you open the throttle. Motor has 117k on it (and a fresh GM balancer). Idle is steady. Starts easily and seems to have as much power as you would expect from a 6.2 N/A.
Could this vibrating be caused by a bad injector(s), or is something else going on?
TIA,
--Duncan
[ 07-13-2005, 03:28 AM: Message edited by: Duncan Sterling ]
I've been doing alot of work on my '91 burb to get it ready for a long trip.
Recently I replaced the dying stock exhaust with a Banks stinger. It made a racket at first because of mounting issues (one of the pipes was vibrating against the frame), but those are resolved.
Now I have a weird new noise only at idle--kind of a pulsating/rythmic/surging rattle, sounds like it's coming off the exhaust system.
The exhaust system (attached/hung per Banks instructions--and all mount points and clamps tight as far as I can tell) seems to vibrate alot too--if you hold a wrench or screwdriver against it when the motor is runing it sounds like you're ringing a bell. If you look at the motor while it's running, it doesn't appear to be shaking abnormally.
Turning on the A/C or putting the truck in drive or reverse mostly kills the rattling noise, as does stepping on the throttle slightly.
The motor doesn't smoke except for a small puff of blue at startup (all my diesels do that at cold start), I have 35-40 PSI oil pressure at idle with 50-60 PSI (depending on whether it's cold or hot) when you open the throttle. Motor has 117k on it (and a fresh GM balancer). Idle is steady. Starts easily and seems to have as much power as you would expect from a 6.2 N/A.
Could this vibrating be caused by a bad injector(s), or is something else going on?
TIA,
--Duncan
[ 07-13-2005, 03:28 AM: Message edited by: Duncan Sterling ]