Thread: Grinding in reverse......

Car just started randomly grinding in reverse tonight. Does it when not moving if i hold brake aswell. I can feel it in the shifter and when i go over bumps. Ive yet to jack it up and check but only thing that comes to mind is somehow out of nowhere the downpipe is hitting the firewall. How after being fine for a month since the trans swap idk. I cant hear it from outside. All my mounts are poly so its not like they could of collapsed.

It is possible. And now that you say it.. after 3+ years of mine hitting....it hasn't been lately.

Well yup downpipe is sitting against the firewall. The trans mount is solid poly but the engine i used that windowweld poly stuff and when i put the spacers in for the struts it must of put to much pressure on it and collapsed one side. So ima bite the bullet and order a poly zzp one.

I find it really funny, like i said the downpipe is resting against the firewall and is vibrating/banging against it like crazy but not a blip of kr from it. How true is false kr really? Also the motor mount is completly blown out and nothing.

Ive heard people say befor that false kr is a myth, now im starting to believe it. There is no way a trans dipstick hitting a header could cause knock and my header slamming against my firewall constantly wouldnt.

False KR is a mechanical issue typically. It's completely possible for something rubbing/vibrating in the engine bay to cause the right frequency etc to be picked up by the knock sensor. You just aren't getting the right sound.

Til then the wife is probably enjoying the Honda Vtec vibrating seat option you caused...lol

Holy cow Ginseng, did you ever find the solution to this? I thought for sure it wasn't my downpipe hitting the firewall (the clearance is huge), but these are the EXACT symptoms I have to the T so far. Does it also make the noise if you take off from a standstill?

https://www.youtube.com/watch?v=Zjro...Vh-R-i-3RL6PCQ

Funny, I have the exact same problem. I don't think it's the downpipe, but the O2 sensor that is hitting even after the BFH mod. As long as I reverse in a safe manor it's non-existant, but if I give it any gas it feels like a jackhammer under my feet. First solution I'm gonna try is flipping the front squares and doing poly front rounds.