knocking

i have a 95 silverado z71, 5.7 liter. a while ago i had a stalling problem, it was cured by changing a part under my air cleaner.(i didn't do the work so i don't know what it was.) when it was change the distributor had to be loosened. timing was reset. now my motor is knocking worse than ever. I thought the computer should adjust the timing itself, provided its not set too far off, and i thought these trucks have an anti-knock sensor. any help would be appreciated. thanks dave

Reply to
Dave
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Dave,

You need to verify that the timing was set correctly. There is a special proceudre to set timing on these vehicles. The computer can control for knockm but only up to a certain point.

If timing is ok, it's either:

1) failing fuel pump 2) plugged fuel filter 3) bad injector 4) 02 sensor

Doc

Reply to
"Doc"

where should the timing be set. dave

Reply to
Dave

At HOT idle, in park, with EST wire disconnected, spec is TDC (0* BTDC). Anywhere up to 4*BTDC is ok.

Doc

Reply to
"Doc"

doc it was set 4 degrees BTDC, now set back to 0. My egr valve was also bad. Dave

Reply to
Dave

So is it fixed now?

Doc

Reply to
"Doc"

sorry, yes the knocking is fixed. on a side note i have this ticking sound. my intake gasket was changed when it started. i was told that my number 1 lifter is sticking and it is not a result of the gasket being changed. if it really is the lifter is there a easy way to get unstuck?? it is very noticeable when the motor is first started then it quiets when the oil starts flowing, but its still there. dave

Reply to
Dave

You could try dumping a can of engine flush in there, run it for ten minutes or so, change the filter and refill with synthetic. If it's gunked up, the flush and synthetic should take care of it. If it doesn't, time for some new lifters.

Doc

Reply to
"Doc"

I've also heard that by replacing one quart of your motor oil with a quart of ATF will also clean varnished lifters. I've never tried it though. Motor flush scares me, had a bad experience with it. I left it in too long and the oil pump screen got clogged with all the crap from the motor that the motor flush released. But that was probably due to operator error! ;-)

Brian

Reply to
el Diablo

I think we've all had attacks of Polish!

Even after 35 or more years of experience. If a pint works, why not use two?

Don't feel bad, been there, done that. There's no shame in making a mistake. Not learning from them is the shame!

Refinish King

Reply to
Refinish_King1

what's the big difference between synthetic and regular oil ? will the atf just remove varnish deposits ? dave

Reply to
Dave

ATF belongs in your transmission, NOT your engine. Synthetic oils have a much higher level of detergents which will help break down the varnish that may have built up over time.

Doc

Reply to
"Doc"

doc i'm going to use sea foam. i already treated my fuel but the can does not say how to treat the oil, it does however say how much to use. should i leave it in for a whole oil cycle or is it like the flush where it should only be left in for 10 min? dave

Reply to
Dave

I dunno, never used Sea Foam in my oil before. Just buy a can of 10-minute oil flush and have at er'.

Doc

Reply to
"Doc"

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