Risk of ignoring lifter noise?

[VetteMed]

Originally Posted by Pete

I have a question did the noise start after you installed new injectors.
Another question did you buy the injectors from FIC?
You say it varies with temps?

I like to start from cheap to expensive.

I would check spark plugs new or not,i had a brand new spark plug drove me nuts trying to find the noise.
Check coils,wires.

Then move to lifters.
If you know which bank the lifter noise is on i would change all the lifters with new lifters on that bank price is not so bad $15-$20 each X 16 lifters,what i would do in your position is pin the cams like the FSM or post when you get that far and we'll help.
Not such a bad job just go slow and take your time,just make sure it's lifters.

Pete

Pete, thanks for the suggestions. Initially the problem seemed worse when cold; now I'm not so sure. Seems pretty consistent now.

I just put new NGK Iridiums in last week to see if there was any improvement. Plug wires are about 2 years old ACDelco.. Same for coils.


I'll pull the plenum later to check everything.

Injectors are FIC, about a year old now. Something that has bothered me, is how quickly the motor fires after sitting for several hours or days. Everyone says the LT5 needs to crank a bit before actually firing -- which mine does, when warm. Cold, however, it lights off on the first crank of the starter, so I've been wondering if an injector or two are leaking down.

Thanks
Andrew

[VetteMed]

Pulled the plenum;

All injectors ohm out to about 14.4-14.6.
Pulled fuel rails, set up rails and injectors over cardboard.

With Key on, engine off, fuel pressure is at about 44 psi, no drips from any injectors.

[VetteMed]

Plug wires all ohm out to about 4 to 6Kohms, depending on length (longer = proportionately higher resistance).

[VetteMed]

fuel pressure holding well at over 40psi 10-15 minutes after pumps disengage.

[VetteMed]

Ignition coils:

Primary: 0.5-0.6 ohms for all 4 coils
Secondary: 5.1-5.2K ohms for all 4 coils.

[VetteMed]

No smoking gun here, in the ignition or fuel systems, obviously... so I guess it's on to pulling the cam covers.

[Pete]

How is your oil pressure.

One more suggestion.
Is there any members close to you that you can swap out fuel rail/injectors.

Pete

[VetteMed]

Oil pressure, as indicated on the dash gauge, is 60+psi cold, and 30-40psi hot.

Nobody particularly close, unfortunately... there's Belsy about an hour and a half away but his motor is assembled and running; I'd hate to have someone take stuff apart for my troubleshooting.

Before I pull the cam covers, a thought... - I removed the serpentine belt, and jiggled the pulleys of the various components. the power steering pump has a little bit of a clackety-type looseness to it. I have a low mile used OEM pump on the shelf (I think I bought it from you, Pete), and it seems to not make the same sound when the shaft is jiggled.

Possibly the source of the noise??

[sammy]

could be , might be worth changing to see . what kinda bothers me is the shaking you said the motor had to it . just food for thought .i had 1 pole go out on one of my coils . the car would run but had a stumble to it low rpms and when i got up to around 3,000 would smooth out . might ask jerry of jerrys gaskets how to ck to see if you have 1 pole gone bad . he told me how but i cant remember what he said .

[VetteMed]

OK, so the noise is NOT the power steering pump. I got everything back together, left the serpentine belt off, and started the motor. The noise is still present. It almost sounds to me like the noise that the tensioner makes upon cold startup, but it's persistent in a roughly sinusoidal fashion. Few seconds quiet, then gradual increase, peak, then decrease to silence again. I guess I'll pull the cam cover on the driver's side and take a look around.