I've heard a whining or screeching noise coming from literally right at the far right fuel injector (when looking from front of car to cockpit). At first I believed it was an intake manifold leak because during my motor drop 5 years ago by an unreputable shop they failed to install the intake manifold properly as they only serviced domestic cars (not an excuse!) I believe. I also believe that none of the bolts anywhere in the car got re-torqued after the initial start up/warm up, because as all of us good mechanics should know that the bolts may loosen after the car gets hot, and should get torqued to spec again in my opinion (intake manifold, exhaust manifold, and all other exhaust bolts at minimum). I had a leak on the other side aswell which I was able to correct. I had idle issues which were corrected by un torquing all manifold bolts, and re-torquing them to spec in the proper order (criss cross working out and in even sequential turns), therefor I assumed this was the case now. I figured when my car got hot (and this is only when the sound effect occurs) the metals separated creating a gap between block and manifold. The noise is only really apparent at idle. I can still hear it when I get to around 1000 RPM's but the motor/exhaust is louder and drowns the noise out. At idle thought its very loud. On cool days though, it doesn't seem to be an issue.

I recently attempted to re-torque everything again, no luck. I used a tool to isolate where the general location of the sound was from. Than I used wd-40 to attempt to locate the spot and it seemed like it was right above the injector. I would spray, sound would go away. I wiped the area clean and used an high temp silicon seal to seal the manifold leak but it seems to always come back. Its not coming from the timing belt/water pump area, nore the head. I've isolated the sound to right around the fuel injector. Could it be the actual injector "whining"? It seems to have occasional misfires on hot days typically and it seems to be worse when the injector is whining. On the other hand though, an intake leak would cause an idle issue as well.

Also, something else interesting. When I spray the wd-40 around the injector, could the fluid be causing the injector to cool down where it would stop whining if it was even possible for it to be making that sound in the first place?

Thanks in advance for any of your opinions. I searched for issues with injectors, but no other posts involved any strange sounds as a product of an issue.


Modified by mattsnooz at 2:44 PM 7/21/2008

 

bump, Come on H-T, any thoughts no matter how far out I'd appreciate.
thanks!

 

i noticed a similar sound only at around 800rpm. you rev it up or make the revs drop and the sound disappears. i never looked into it though.

 

yeah, thats very similar to mine...
I even add load by turning AC on and the sound diminishes.
I can't figure it out. I've been probing for a couple more hours tonight but I havn't figured anything benificial out.

Would a pin hole leak between the intake manifold/gasket and the block cause a similar noise at all? I would think it would sound like a high pitched "EEEEEEEEEEE"

Anybody else have any suggestions?

I'm tempted to pull off the entire intake manifold just to make sure its not a leak at the gasket, but its such a shiet job. Atleast the bolts aren't siezed on, but Its still a 4 hour job for me to uninstall intake manifold properly labeling everything etc. I