Strange sound while accelerating...

dp · Post by dp » Fri Aug 18, 2006 7:35 am

When I accelerate softly, I barely hear it unless I get in front of the car while it's stopped and I pop the hood. It definitely sounds like fuel injectors. It's a soft hissing firing sound. Anyway, when I accelerate heavily (aka almost floor it) I can hear the fuel injectors louder than ever before. I didn't use to hear them before. Not this loud. And every day they sound louder. Is something loose in there? Why couldn't I hear that before? It's worrying me... I'm so fucking paranoid.

MoxHair · Post by **MoxHair** » Fri Aug 18, 2006 8:12 am

Sounds like Piston Slap.

a Normal thing with Neons. Some people get it fixed by the dealer, Usually New Pistons or a Whole new Short Block fix it. People say it doesnt do any damage to the internal workings. I have no idea as I do not have the issue.

Try changing over to Mobil 1 and see if the Synthetic Oil Fixes it.

BlackRoseRacing · Post by **BlackRoseRacing** » Fri Aug 18, 2006 9:12 pm

Piston slap....my NEW shortblock did it from day one, if you are a car guy, do you start your car and just go?
Not reallly, most car guys run there motor or car for atleast 1 min before doing anything...
My car warms up before I go anywhere, if it does not I GRANNY shift it at 2500rpm MAX until it warms up...
The car runs great....

dp · Post by dp » Sun Aug 20, 2006 9:45 am

It's nothing to really worry about then? When my car is idle I get the same sound (much lower) and a slight vibration that makes a soft but very fast (just like the first sound) sort of "clack-clack-clack" sound. It comes from right in front of me, but I try to hold everything, steering wheel, dash, knobs, and nothing seems to be making that sound so I don't know if its coming from inside the dash or the engine or what. Ughs... I hate weird sounds...

dangerdavex2 · Post by **dangerdavex2** » Sun Aug 20, 2006 11:06 am

dp wrote: Ughs... I hate weird sounds...

Haha, welcome to the Neon world.

OB · Post by OB » Sun Aug 20, 2006 7:57 pm

Piston slap aint a good thing. If thats what it is, it will surely lead to problems later on down the road. People act like its no big deal, but the more that happens, the worse its gonna get. usually that happens when the bore is too big for the piston or if the rings are shot. I cant imagine a NEW block with fresh internals causing this, unless of course the bore/piston is the wrong size from the factory (possible).

On the other hand, ive heard many times that the valvetrain and injectors are very noisy in neons, especially with high mileage ones (and with all of them when the engine is cold). using a different weight oil may help, or a better (syn) oil as brr suggested. also, to agree with brr again, it is very important to allow the car time to warm up when cold. anytime I get in my car I allow at least 15-30 seconds, if not a solid minute when i have time. every part of the motor will benefit from this, no matter how new the car is. warm=good.

other than that, its anyones guess, cuz afterall, it IS a neon! noisy mofo cars.

fixitmattman · Post by **fixitmattman** » Sun Aug 20, 2006 9:32 pm

Every SOHC 2nd gen I've seen has had piston slap. You can even hear it in other cars in mall parking lots. It's a nusiance more than anything. There is a lot more to piston slap than just the fit in the bore. As it is, it's a normal thing for a Neon.

It would have been nice if they refined this when they went from gen1 to gen2, but no. This is the only annoying noise I haven't worked out of my car because it's not worth building a shortblock to get rid of it. Short of that, the engine would really purr if it wasn't for this.

Piston Slap = Matt not happy to buy another Crysler 4cyl anytime soon

Matt

OB · Post by OB » Sun Aug 20, 2006 9:44 pm

I dont understand how you can be 100% sure of something just because you think u can hear it. Thats not a very good way to diagnose something IMO. If all the noise coming from all these motors is slap, how are they running well over 100k miles without every one of them suffering from severe cases of blowby, smashed rings, and all kinds of other problems? Im not saying that I know what the sound is or that its not slap for sure, but it just doesnt make a lot of sense to me. My car is noisy when cold (valvetrain seems to be the culprit IMO), and when warm, the ticking coming from under the hood sounds like injector pulse, to me. Plus, I thought slap was much louder, similar to misfire.

fixitmattman · Post by **fixitmattman** » Sun Aug 20, 2006 10:02 pm

Everybody seems to blame injectors. The funny thing is, injectors really arrent that noisy. They're about as loud as snapping your fingers with a metallic tone to them.

Just because you have piston slap doesn't mean your engine is going to blow up. My car has had it pretty well since I bought it, I'm sure it did it before and I've put over 37 000k on it since then with more to come. Short of this sound the engine is in perfect health and there's no issue with getting another 100 000 mi.

Matt

OB · Post by OB » Sun Aug 20, 2006 10:17 pm

I just dont understand how u know its slap just by hearing it. sure, process of elimination would help to locate the source of the sound, but what makes u so sure? perhaps its such a small amount that it doesnt hurt anything, but many people who claim their neon's pistons slap say its very loud and even sounds like misfiring.

btw the sounds my car makes arent much louder than snapping fingers, thats actually quite a good way of explaining it. if your car is doing something a lot louder than that, id be a bit worried.

fixitmattman · Post by **fixitmattman** » Sun Aug 20, 2006 10:29 pm

orangeblastsxt wrote:I just dont understand how u know its slap just by hearing it.

It's mostly experience. Kind of like how a musician can hear a note and tell you what note it was.

It also helps if you've heard slap in other engines before and someone told you "hey you hear that sound, that's piston slap."

Matt