Hey guys, I posted this to tech/general engine the other day but didn't get any hits, so I thought I'd try posting it here to see if my fellow V6 guys can shed any insight to this issue:

When I turn the key to ON, there's a strange noise coming from the engine bay. It happens when the fuel relay kicks in, it starts as a hissing noise, almost like something filling up, then when the relay kicks off it stops, then a second later there's a small vibrating noise. This happened after I pulled and reinstalled my fuel rail. Of course my first thought is I have a fuel leak somewhere, and I did have a small leak from an injector o-ring, so I bought new o-rings and replaced them. Now I can't find any leaks, no pooling fuel, but the noise is still there!

Whatever it is doesn't seem to be affecting the car much. She fires right up, drives and idles without a hitch, but I'm starting to hear a noticeable hiss/screech when the engine is running.

Probably not related, but now my SES light comes on with key ON and goes off while running, which it's never done before. I'm not pulling any trouble codes either.

What do you guys think? I could really use some ideas...

 

New development, car can't run long before white smoke begins rising from engine bay (Though when it is running it's running beautifully ). It's done this before on startup, but I assumed it was from sitting and the smoke cleared. Coolant level is alright, Oil is alright, temp gauge has barely even risen off of 100, what am I missing?. The smoke might not be related, as the PO has the fan wired to run directly off the battery (something i need to fix!!), but I thought I'd post anyways. There's no particular smell to it, unless you count warm engine...

It looked like it was rising from around the sides of the engine, could it just be too much oil? Car starts right back up and runs like a dream, even when the smoke show starts. I hope whatever this is reveals itself, this car is too fun to not drive! :P

 

Hi there,
Do you have any oil dripping on the sides of the engine? It might be oil dropping onto the exhaust manifolds and burning off. Look for leaks in the valve cover gaskets; a likely suspect.


Sorry, don't know what to say about the hissing.

 

No prob KT I appreciate the reply!
I looked today and noticed oil near my distributor, tightening it down fixed it for about half a mile, so I bought a new o-ring kit to install tomorrow

After driving I also noticed a small coolant leak (and heard it too! :P), one of my hoses running into the plenum must've came a bit undone. Car was running a bit hot, gauge was reading 3/4 240 degrees. the leak wasn't that catastrophic but hopefully that doesn't have anything to do with the PO's soon-to-be-fixed hack job on my fan! doesn't really explain why there's a hiss with key ON unless there's a coolant priming feature, but fingers crossed this is where the hiss is coming from

Thanks!

 

The hissing while the fuel pump is running is the sound of the fuel snaking its way through the fuel lines and rails.

As for the coolant leak near the TB, the fitting that goes into the intake just below the TB is an issue. GM actually used pot metal ones at some place in time. Guaranteed to fail.

GM has/had a fix kit for it that supplied a machined metal fitting.

RBob.

 

Thanks RBob, it was just unusual as the car only started making that noise after I pulled the injectors. Oh well haha

As for the coolant leak, there's just a section of hose there with those screw-down clamps, so should just be a matter of readjusting the hose back on it's port

 

The check engine light will be on when you have the key on, engine off. That is normal, every car will do that. The noise is probably something you just never noticed before until you repaired the car and now are paying attention to what's going on to make sure there is no issue.

 

I second drdave. The amount of times ive fixed something, driven it for a shake down all nervous hearing noises feeling things . get back and check it over, its fine, its just me , heightened senses and paranoier !

 

Hahaha thanks guys, Glad to be learning as I go along