A-Spec

I need help guys, I think the car is detonating...right now I hear a loud clanking sound when I give it gas...not all the time though. And today it happened and I lost power and now my idle is pretty weird, sounds like it's running on one rotor...

so please give me your best explaination of what detonation sounds like so I can determine if the engine is dead or to troubleshoot it more.

oh this is all in the low RPM range, I checked the plugs and they are black, running rich, no signs of lean conditions.

David

dra_gon_lee

does your car have power? did you hear a pop... i thought mine blew, but it was just the turbo to mani gasket blowing... check the gaskets, vacuum hoses... and if you can still take off in 1rst id say no.. you didn't blow it...

SilverRocket

It can sound different, depending on how bad it is, what it's doing, etc. On my FB when it happened, it sounded like a "rattling" noise coming from the engine bay. Also the rev's would pretty much stop, like it was hittin a wall. At this point, if you kept your foot on the gas the rattling would get really loud. It's worse under high load conditions, like climbing a steep hill, or WOT in 4th gear high revs, etc.

If this happens, don't keep doing it to try and "see what this sounds is". Just stop driving the car and figure out the problem. For me, I was runnin around with broken sparkplugs because my timing was set too aggressively (I took the advice of so-called experts, and didn't really know what I was doing, ****** rookie move).

If you think you're detonating, you should check the white ceramic part of the sparkplugs for cracks or all out breakage. If these break, the pieces can easily take out an apex seal.

What you said sounds kinda weird though, you'd expect it to happen at higher revs and high load... maybe you have an ignition misfire or something?

To know if your engine is good, get a compression test done. You can even do a rough test yourself, search the forum for how-to. Until you actually know, don't assume anything. Rotaries can run like **** for a million reasons, everyone always assumes they blew an apex seal.

Good luck!

A-Spec

Well it's dead....the rear rotor yielded a 100/100/100 psi while the front a 20/20/40.

Yeah I kept thinking it was something loose but I guess not, expensive lesson on how detonation sounds like...kinda weird though because I must've detonated like 7 or 8 times(I let off as soon as I hear it) and it still idled fine, till the last time it happened...

anyway I took out the sparkplug and the plug shows signs of running rich, no ceramics broke.

We'll pull it out and see what went wrong....

tks!
David

SilverRocket

Sorry to hear that man

I guess sometimes with cars, learning the hard way is how it goes... good luck getting her fixed up!

Nathan Kwok

FWIW, running too rich can cause detonation too. Sorry to hear about the motor .

SilverRocket

I was thinkin that too when he posted that his plugs were black, for some dumb reason I forgot to say it...

JONSKI

Running rich is smokey and can clog your cats, cake your turbos, etc. Running lean causes detonation.

A-Spec

heh no cats

yeah I wonder the same, how can running rich detonate?
also I noticed the spark from my sparkplugs wasn't really strong, isn't it suppose to be a really strong spark?

David

Nathan Kwok

There are two ways I can think of offhand (i'm not very knowledgeable about this so anyone who knows more please chime in):
1. Causes carbon buildup; this leads to possible hotspots because the carbon retains heat.
2. Causes ignition misfire, which, if bad enough, causes incomplete combustion, which in turn can cause detonation.