Archived Engine is making a pulsating reving sound

[dschmidt]

Can anyone give me some advice with a problem I'm having with a slight reving noise coming from the engine. While under power, I'm hearing this pulsating reving sound that is intermittent (2 - 3 seconds apart) and lasts about a second. It usually occurs when the engine is cold, and while accelerating, but has done it while cruising at a constant speed after the engine has warmed up. The RPM's do not fluctuate when this is happening, nor does the speed. It almost sounds like pump runs dry, and rev's up, then catches the fuel. I just had a new lift pump installed at 68K, thinking this might solve the problem, but it didn't. The original pump was weak but had not failed, so the dealer replaced it. Any comments would be appreciated.



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2002 QC 4X4 Auto, 68K, BD chip, all else is stock

 

[Alan Reagan]

Are you sure it's not the Torque Converter unlocking?

 

[Hillbilly Hotrodder]

My 2002 truck did that noise too. Under light acceleration or steady throttle, it would be a cyclic sound, louder then quieter, again and agin. Almost like the engine was surging but it wasn't.



It wound up being an injection pump timing failure, code 0216. Apparantly, the pump was cycling the timing forward and back over and over again.



A new VP44 pump cured it.

 

[dschmidt]

No it's not the converter because there's no change in the RPM's. Tach stays the same.

 

[dschmidt]

Can you have an error show up without a service Engine light? I haven't had any indicator lights come on.

 

[LKrueger]

my 02 HO has made that noise too,like the timing goes back and forth like you explained,but never noticed it unless driving with my comp on,never noticed it with it off. mines been acting up and started horribly latley. also heard it miss around a couple corners,finaly got a 216 code also,hope to have a new VP-44 this week!!

 

[TMWeber]

Mine does this too. New lift pump (the old one was weak but not dead so I replaced it anyway). Should I be going to the dealer for a new VP? I'm almost off warranty so if it's going to go now is the time.

 

[dschmidt]

After taking the truck in to see if the dealer could find the problem and you know that was the time it didn't act up, I decided to unplug my BD performance box. I've been running without it for around two weeks and it runs fine. All the problems I was having went away. Unfortunately the warrenty was up on that box six months ago and they wouldn't replace it. I'm going to switch to an Edge product in the near future.

If you're have similiar problems, try disconnecting the chip as I did.