always faster

So after a 3 months of trouble shooting because of :bad start,bad msd pro billet,bad timing,huge miss,huge lag....I finally start it.

I put new:
-Flush the motor oil(still in break in)
-Flush the 12 bolts
-Delco opti
-Msd blaster coil
-Taylor spiro pro cut to lenght plug wire
-Otvc side loom kit

And the car start perfectly.It idle great,no miss,the throttle response is also good.The car temp stay around 170degree and oil pressure is at 60psi cold and 40psi hot.

But it got a last annoying problem it whistle like hell
So far after some suggestion from member of the board i ve tried:
-Taking of the strap but it was still whistling so the alternator/power steering pump/ac delete pulley are not the problem...
-I ve put back my stock tb that wasnt producing any noise on my last motor but it also didnt change anything so the tb is not the problem...

Im almost(95%)sure that the noise(whistle) is coming directly from the front of the engine.Its also louder has the rpm goes up.

So any suggestion would be test before taking the front of the car apart to take off the timing cover

Thanks

Edit:I just came back from a road test with some 3-4-5 gear wot and the car seems to pull stronght but when i cam back home it begin to have some kind of miss/lag when im starting from a stop,just like if it wanted to die when i give it some throttle than it run fine

always faster

Well dont be shy

Dave1980

IAC whistle?

stereomandan

Did you change your intake, from filter to intake manifold, at all?

Dan

96z28t56

You dont have a 1LE intake elbow do you? that possibly could be the whistle, as for your miss / lag does it do it after i warms up, or anytime?

always faster

I ve put a oem Lt4 intake because the engine is a LT4 crate motor.The rest is the same(trickflow elbow/moroso cai)

The whistle is still there even with all the intake plumbing off(elbow/maf/cai) so its not the problem.

It lag/miss when its hot(normal operating temperature range).

Sweetred95ta

Vacuum leak? Have you tried removing all the vacuum accessories from the intake and capping them? If it goes away, re-install each one until you find the whistle.

Also, open the tb blades and make sure that none of the gasket isn't in the way, which could cause a whistle.

always faster

I dont have enough plastic nipple to block all the ports but here is what i will do.I ve bought some liquid start(ether) and i will shoot it around all the vaccum port hose and around the intake gasket with the car at idle speed.If the rpm rise in some spot i will know if there is a leak and were is it.

If no sign of rpm rise this would mean that i dont have a leak and i ll probably try a new IAC and look to be sure that there is nothing blocking the opening of the tb.

Are those good idea???

Sweetred95ta

The ether will definitely work. I think I used duct tape to block my ports off when I was checking for a leak.

always faster

Ive done the "liquid start"(ether) test and the rpm didnt move at all and i ve used 1/2 of the can all the way around the intake gasket/tb gasket/tb plate/underneath tb/and all the vaccum plug.

So he whistle is not coming from a intake or vaccum leak.

The whistle seems to be coming from just under the tb could a bad iac whistle?

Sweetred95ta

You could check the IAC port for debris/dirt. When you swapped out tb's, did you use different IAC's? If so, you could probably rule out anything having to do with the IAC and port. I guess the tb gasket isn't ripped where the IAC passage is, is it? I've never heard of a bad IAC whistling.

'94 Bad A Z28

My buddy had a whistle on his firehawk it was his cat.

always faster

I reuse the same IAC but clean the port.The only thing that i ve notice will switching tb is that the tb gasket cover 1/3 of the round intake hole between the 2 ports...


I got no cat.

always faster

Ok i ve change the IAC and of course the whistle is still there

I ve bought a mechanic stethoscope and did all my engine and everything seems fine(tb,iac housing,intake,etc) but i manage to find it.

When i touch the stethoscope to the timing cover i clearly hear the whistle.

If its coming from under the timing cover...so it must be the timing chain.

My motor is a crate engine from gm(the last lt4) and right now i only got 140miles on it.

So what should i do?

Sweetred95ta

What timing set are you running?