I have an 88 firebird with a TBI 305. around 1300-1500 rpm i have a loud ticking noise from the engine, never heard the sound revving the engine in park or neutral, only in gear. Im thinking its ignition related because it got a little better with correcting ignition timing, but i dont know a huge amount so any advide would be helpful. A few different times while driving ive had a check engine light come on for code 42, an open circuit or short in the knock sensor or ignition system, but it hardly ever comes on and only has lasted for 5 minutes at the most. ticking also gets much quieter as the engine warms up and is signifigantly louder on cold start ups

 

I'd have to hear it, but lifter/valve train noise and connecting rod bearing knocks, generally are worse cold.

I would replace or further diagnose the knock sensor, first.

 

might be a little bit before i have time to test it, but ill get back when i do

 

In the meantime, add a bottle of Rislone Engine Treatment, preferable to fresh oil and filter. IF its dirty lifters, this will begin cleaning them. Sometimes takes 2 oil and filter changes, and 3000 miles driving after each, substituting Rislone for a qt. of oil, to stop the noise/


https://rislone.com/product/engine-treatment-100qr/

 

with the last oil change i used the liqui moly oil additave specifically for sticking lifters, do you think the rislone stuff would work better?

 

Description sounds to me like an exhaust leak. Probably very close to the head.

A mechanical "tick" noise wouldn't care about in vs out of gear. A KNOCK, maybe; a "tick", ... not so much

Same for "timing". only reason that would affect such a sound is likely to be that with the spark occurring early enough that combustion is more nearly complete before the exh valve opens, there's less of that going on in the manifolds.

I wouldn't waste money on Rislone or any other "rebuild in a bottle" regardless.

 

Also a waste of time looking at the knock sensor. That's not related in any way to your noise. Nothing the knock sensor can do about a mechanical noise at 1300 RPM.

GD

 

I have cured noisy lifters on 2 of my cars and several customers cars, using Rislone Engine Treatment, combined w/ fresh oil and filter. It may take a few hundred or couple thousand miles, Sometimes couple of oil and filter, and Rislone services.

It will not cure mechanical problems. It is a slow acting detergent additive, that has been around 50 years, or more.

I am NOT a fan of additives, there are only a few I recommend. I said OP could TRY it it "in the meantime" IE before his teardown. Nothing to lose, but a few bucks.

 

could it be an Exhaust manifold leak?

 

I can full rev the engine without any sound if im in park, i would assume that you would hear an exhaust leak if you were in park or gear, not just in gear

 

Then you would most likely be wrong.

Exhaust leaks are most audible at low to moderate RPMs and high load.

 

The ticking is a bit quieter at high rpm when im driving, would that be another thing pointing towards an exhaust leak?

 

Cut the filter.

Adjust the valves.

Look for exhaust leaks.

Not really that complicated.

GD

 

checked for exhaust leaks and the manifolds both have very bad leaks so i found my problem. Does anybody know a low budget seat of headers and a Y pipe?

 

" Low budget" headers to fix an ex manifold leak? Good luck! New OE quality gaskets, check manifold for straightness by running a "Flat Bastard" file over it to resurface. Make sure head surface is clean. Re tighten ex bolts, after one heat cycle. Done