Ok guys, sorry for posting a Sierra question on this Silvy board, but there isn't much content on the Sierra pages. OK, here we go. I have the infamous 5.3 liter engine with the even more infamous engine/piston slap. Like most all of yours, the slap goes away after 15-20 seconds, depending on how cold it is outside. ( I live in Minnesota, so it does vary more) I understand the piston slap and can deal with it, because otherwise, the engine is awesome (106,000 miles). My problem is as follows. I noticed when I really get into the throttle, either accelerating from a stop or while gassing it while cruising, once the engine gets to about 3,0000 rpms or higher, I notice a ticking sound, almost like a lifter tick, coming from the engine compartment. I don't hear the sound under normal acceleration, and like I said, this is even when the engine is warm and the piston slab is gone at idle. Also, if I pop the hood and rev the engine manually under the hood when the truck is parked, I don't hear it. It's like I only notice it when I am driving and the truck is in motion and I really get into it. It almost sounds liike a diesel, but more faint. Sorry for the wordy description, but it is the only way I can explain it. I need some opinions on if it is connected to the piston slap or if it is a bad lifter (would probably hear a bad lifter all the time though). It is also worth noting that I modified my air box by drilling a bunch of 3/4" holes in it. If you haven't done this, it adds a much more throaty tone to higher revs. With this mod done, I am guessing engine noises might be more audible????? Opinions?? Piston slap, lifter sticking, ????

PLEASE HELP

Might be an exaust leak? I would not sweat it though. You see when you own one of these wonders of modern engineering you shouldnt worry unless you just dont here anything then you sweat. If my 4.8 is not rattling ,clanking ,ticking or grinding I open the hood just to make sure sombody hasnt stollen the engine. But then who would want it?...jj

That sounds like gas pinging to me. You may want to try some gas treatment or a tank of mid-grade gas to see if it helps. If it does, then thats the problem. Long term fix, you may need to do a de-carbon procedure on your engine.

PGun67

Ok, so it sounds like it might be a carbon build-up problem.. What is the best way to "de-carbon" and engine? I run Sea-foam through my gas every other fill. I take it this won't do it. Do I need to run it through my Pcv?? Or just dump Seafoam in my oil before a change??

I understand the problem, but what is the best way to alleviate it?

Better yet, how do I troubleshoot to verify what the problem is?

Ok, so it sounds like it might be a carbon build-up problem.. What is the best way to "de-carbon" and engine? I run Sea-foam through my gas every other fill. I take it this won't do it. Do I need to run it through my Pcv?? Or just dump Seafoam in my oil before a change??

I understand the problem, but what is the best way to alleviate it?

Better yet, how do I troubleshoot to verify what the problem is?

I have same condition as you (without the bad slap noise). When gunning it to pass on highway, I get the diesling noise.
I was at the dealership last week with same question as you. The dealer has a 4 step kit form B&G (??) It requires special tools (pressurized can system) to hook into the fuel rails. It comes also with a fuel additive, an oil additive, and a throttle body cleaner. The kit costs $39.99 (about) and labor was $95. I told him I will be making an appointment. I had just bought this 2001 silverado with 38K on it. It looks like the person babied it (paint is excellent, very low miles) He said that it definitely will build up carbon from not using it much, something about the computer learning your driving habits etc etc. I will post back when I get around to having them do this.

Heres a pic of the 4 part system:
http://store1.yimg.com/I/tri-maxx2000_1868_2342134

heres where you can buy it (kind of pricey, but you can see what I am talking about. This kit comes with feeder tube ( i guess to hook into fuel rails) scroll down to see the 4 part
http://www.carfood.net/gran3stepdec.html

Good luck!!

I have same condition as you (without the bad slap noise). When gunning it to pass on highway, I get the diesling noise.
I was at the dealership last week with same question as you. The dealer has a 4 step kit form B&G (??) It requires special tools (pressurized can system) to hook into the fuel rails. It comes also with a fuel additive, an oil additive, and a throttle body cleaner. The kit costs $39.99 (about) and labor was $95. I told him I will be making an appointment. I had just bought this 2001 silverado with 38K on it. It looks like the person babied it (paint is excellent, very low miles) He said that it definitely will build up carbon from not using it much, something about the computer learning your driving habits etc etc. I will post back when I get around to having them do this.

Heres a pic of the 4 part system:
http://store1.yimg.com/I/tri-maxx2000_1868_2342134

heres where you can buy it (kind of pricey, but you can see what I am talking about. This kit comes with feeder tube ( i guess to hook into fuel rails) scroll down to see the 4 part
http://www.carfood.net/gran3stepdec.html

Good luck!!

Tell your dealer that you do not want your injectors cleaned with the BG products, but you want your injectors cleaned per the procedure outlined in TSB ##03-06-04-030A
Also if you decarbonize your engine with GM Top Engine Cleaner pn #12345104
These 2 procedures will take care of your concern

Tell your dealer that you do not want your injectors cleaned with the BG products, but you want your injectors cleaned per the procedure outlined in TSB ##03-06-04-030A
Also if you decarbonize your engine with GM Top Engine Cleaner pn #12345104
These 2 procedures will take care of your concern

Will that cost me more? I actually got him to come down on his price. They made a mistake on quoting me for the 4 part kit. I am getting the 4part for the price of the 3part. which is a difference of $25 something. Do you think this BG would get the job done?

BTW I changed my fuel filter today (dealer noticed on his paperwork that it was not changed per GM certification when they put it on the lot.) and man that thing was clogged.

I have an appointment on friday after thanksgiving at 7AM. Please reply

Is a TSB something that is done for free, like a recall?? Please give me more detail as to the two steps you are talking about and do they have to be done by the dealer or can my mechanic do it too? Or, better yet, can I do it myself?? I just want to get rid of this damn ticking/dieseling!!!!!!!

Is a TSB something that is done for free, like a recall?? Please give me more detail as to the two steps you are talking about and do they have to be done by the dealer or can my mechanic do it too? Or, better yet, can I do it myself?? I just want to get rid of this damn ticking/dieseling!!!!!!!


No, A TSB (Technical Service Bulletin) is not free like a recall, it is merely something that may be a common problem to your particular Y/M/M, and GM simply publishes the fix for it so the tech can get it done quicker. You still have to pay for it though.

As for your "Ticking", noise, I doubt it's engine knock. The PCM would try to retard the timing to make it go away, and if it had to pull out too much timing, it would set the check engine light. I've seen spark plug wires that would arc under a load, but not revving it in park. If you could get a scanner hooked to it, it might tell you something in Datastream mode. Try it in Park, and then while driving, with someone in the truck with you to read it when it makes the noise. You may need to lay out some $$$ for some diag/scanner time, if you don't know somebody that can help you out.

A TSB (technical service bulletin) is a repair or set of instructions issued by the manufacturer on how to fix problems arising out of previous service or repair difficulties which have been plagueing a particular vehicle or or deficiencies with the original design which require modification. Generally a supplement to the original instructions in shop repair manuals. They are not done free but are more for reference to technicians to ensure a customer concern can get fixed right first time. If a TSB is issued for a particular truck problem and you choose to get it fixed without following the reccomendations and practices outlined in that TSB, then chances are pretty good that it won't get fixed right.

**UPDATE** I changed my fuel filter, the filter could hardly pass any air when I blew through it ( I mean barely). I dropped back down to 87 octane, drove normally for about 50 miles then checked driveability for knocking: NO MORE KNOCKING!! Even when I stomp it to the floor!! sounds much smoother too! I cancelled my appointment at the dealership. The PCM appears to be adjusting nicely to the improved fuel flow and the increased fuel pressure

**UPDATE** I changed my fuel filter, the filter could hardly pass any air when I blew through it ( I mean barely). I dropped back down to 87 octane, drove normally for about 50 miles then checked driveability for knocking: NO MORE KNOCKING!! Even when I stomp it to the floor!! sounds much smoother too! I cancelled my appointment at the dealership. The PCM appears to be adjusting nicely to the improved fuel flow and the increased fuel pressure


Good deal, quick and painless fix. :thumbsup:

Where is the fuel filter located? I have the exact same problem!

It is on the frame under the truck. Right before the driver side rear tire.

I had the same problem with my silverado, at virst i thought it could have been one of the valves tapping, but i put in octane boost and it went away so i dunno try a gas treatment or higher octane fuel.