Weird valve rattle?

[jamesclbrn]

Ok so I put a header, cai, aftermarket muffler and msd coil on 2005 stock sxt. Now i get a rattle at above 3000 rpms. It doesnt rattle like that at any other rpms. I can drive all day under 3000 and no rattle at all. Any help will be appreciated.

[occasional demons]

Unless the stock coil was bad, the MSD was/is of no benefit. In most cases, the oem coil puts out more spark. If the original is still good, I would put it back on as a first step in diagnosing it.

[JeremyJ]

Make sure the CAI isn't touching the hole that it goes through in the frame. Also double check all of your header bolts. Make sure they're tight.

[jonnymopar]

OEM ignition coil = 40kV
MSD coil = 36kV

If you just like the look of the red, spray paint the stocker. And as Bill already suggested, try that as your first step in diagnosing the rattle.

[occasional demons]

Jeremy's suggestions are also good. But maybe a better description might help. Is it a rattle, or a spark knock sound?

Normally a header and muffler will have about zero impact engine performance on an otherwise stock 2.0.

In addition to the header seal, check the flex joint on the catalytic converter for any cracks.

If this is a cheap ebay CAI, the biggest thing you will gain is a more aggressive sound, and optimistically 1 or 2 hp out of the header, CAI and muffler.

Also, how many miles are on the o2 sensors? If 70,000 plus, they can become slow to react, and the added pieces might be showing that weakness.

Your 2005 has an NGC engine management, and is the most aggressive in keeping air fuel ratios as close to stoich as possible. If the o2 sensor is getting tired, it can possibly create issues from the added efficiency of the header.

NGC has long been a known pain for most bolt on's making added power. To make any real gains, you need to $pend for a reprogrammed PCM.

It seems that that option isn't currently available though. Modern Performance did carry Syked PCM's, and their Electronics section has a picture of said PCM, but when you click on it, there is nothing there as far as reprogrammed PCM's.



http://www.modernperformance.com/category/00-05-neon

[jamesclbrn]

I will change them back when i get home

[occasional demons]

I will change them back when i get home

Change what?

If all is tight and sealed, the only thing that I would change is the coil. The rest of it would be too much effort, and may not fix the issue, unless it is the CAI.

You could pull the CAI tube from the inner fender, and take it for a short drive without it, if you are not on a gravel/dirt road, just to see if the noise goes away.

If it does, reinstall the tube/filter, and know that the sound is just the tube rattling on the body, and get some foam door seal/similar from Home Depot to wrap around the hole to insulate the tube from the hole.

[jamesclbrn]

Yeah sorry, I meant the coil. But i have checked the cai to make sure it wasnt that.

[JeremyJ]

When I think of "rattle" I don't think of valve noises. Maybe it's just semantics on my part, but I'd be looking for loose parts and worn motor mounts. Noisy lifters are also a common issue with these cars.

[occasional demons]

If it was the lifters making noise only above 3000 rpm, I would suspect an oiling issue, or weak springs. Otherwise it would be a constant.

When people say "valve rattle", back in the day, it was actually detonation, as valves really don't rattle. If they got that loose, there would be other obvious things happening.

[BlackRoseRacing]

Did you ever figure out what the issue was?

[occasional demons]

Last active:Tue Sep 11, 2018 2:03 am....

We may never know.