Noise under load??

**michael redmon** · 10-10-2016

Here is a video of my car knocking under load. I have heard flex plate, lifters, rod knock, bearing, etc. Any suggestions as to what you think it is would be appreciated. I would like to fix it but I can't even diagnosis it.

https://youtu.be/QScDntr2QaE

**Explicit_Spade** · 10-10-2016

What were you doing before/when the noise started?

**michael redmon** · 10-10-2016

It's.been like this for years. I have piston slap in the morning so it kinda masked it. Thought I had stuck lifter and after engine flush, numerous oil changes with varying oil weights this noise is what's left after car warms up.

**GoldGTP** · 10-10-2016

I'm leaning towards a lifter/cam noise...

After many years with mine making the same sounds, i popped the lim off to find a toasted lifter...

After replacing the lifters/rods, mine still makes noise under load/hard acceleration...

I am now assuming the cam is shot and needs replaced.

New lifters will only work for a while.

To do it right, replace the cam/lifters at the same time.

**michael redmon** · 10-10-2016

How did yours sound in park when you reved the engine?

**michael redmon** · 10-11-2016

Local mechanic says it's in the valve train. I'm thinking of ripping apart the engine as a winter project. Problem is I don't a rod from a lifter or from anything. I suppose that's what the internet is for! Thanks guys

**michael redmon** · 10-23-2016

Is it possible I just have a noisy fuel injector? See the picture. Using my stethoscope the ticking is very loud on the fuel rail. No noise anywhere else on the engine area but the cover that says "3100 SFI" on it. The rear fuel rail is much louder than the front fuel rail. Does it matter if my fuel injector is noisy? Should I throw some seafoam or other crap in the fuel tank to clean it out? Thanks as always!

**michael redmon** · 10-24-2016

Threw some MMO in the gas. Just shooting in the breeze

**CHI2000GTP** · 10-24-2016

I've read on here plenty of times that the injectors in the 3800's are loud. Not sure about the 3100's. But loud ticking can be coming from the injectors. You're likely diagnosing this correctly. I've also heard of exhaust leak, lifters, or a broken valve spring causing a ticking problem. Some posts on here recommend nothing more then an oil change to try and fix it.

Here's a link to a post that mentions the 3100 engine, and this happening when cold outside. Post #2 in this thread below. Good luck.

http://www.grandprixforums.net/threa...oise-when-cold

**michael redmon** · 10-25-2016

Im going to run this MMO and then some bk44 fuel injector cleaner and see if it gets quieter. If I figure it out I'll report back. I think the default answer to ticking is "lifters" but I've heard of guys changing them out and the ticking is still there. Thanks

**michael redmon** · 10-30-2016

Question for you smart guys. Ran a tank of gas with MMO and half a tank of bk44....so far there has been no change (still have have a half a tank of bk44 to go). Based on the symptoms I am pretty sure I don't have rod knock. If my valve train and lifters were the problem....wouldn't I hear noise under the valve covers??? I got out the stethoscope again and the noise is exactly on top of the silver cover (intake) and the fuel rail. I'm just trying to figure it out so I don't rip into and change parts to just change parts. Thanks in advance

**stealthee** · 10-31-2016

I don't think any kind of injector cleaner is going to fix injector tick. It's just the nature of the beast as they get old and worn.

**michael redmon** · 12-11-2016

I started a new job December 1st. The training location is about 75 miles away and I have been putting 150 miles on the car every day. I have decided it almost has to be a fuel injector. The damn car runs strong as hell. Same gas mileage now (24mpg) that I got when I bought the thing in 2002. I got some private messages from a couple of guys saying they went into the top end and changed a lot of parts out (valve train items) and nothing changed. Still ticked. So basically I have decided to keep trucking, not fix anything and then report back here in a few months to let you know if that was a mistake or not. The tick is LOUD, especially when cold. If it is the injector then it isn't worth the hassle to fix just to get rid of the noise.