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Misfire and low compression on Cylinder #4....Info..?

Posted: Sun Oct 25, 2015 11:03 pm
by tdi-red di
Misfire and low compression on Cylinder #4....Info..?

How are things lads...?

One of the lads bought an altezza recently and tbh she wasn't running right at all, well I didn't think she was...there was always a slight misfire...

Anyways he said he brought it out to some Toyota mechanic the last day and that Cylinder #4 is down on compression (70, I think...I'll double check this)...

All other cylinders are 100% and are in very good condition and great compression so he says...?

Anyways he's been quoted at 1500+ to get it sorted out and he's not sure what to do, and if the mechanics trying to pull a quick one...?

I think its funny because its easily the fastest tezza iv ever been in :p lol

Its clean as well so I'd hope he keep it, if not I'd almost purchase it...:)

Anyways his question is how does he go about checking what's causing the low compression... I was thing a wet compression test...?

I'm not a mechanic so I said I'd ask on this..

Cheers lads :)

Re: Misfire and low compression on Cylinder #4....Info..?

Posted: Sun Oct 25, 2015 11:04 pm
by tdi-red di
He's also just mentioned that the injector was not seated correctly on chamber #4 and mechanic reckons this could have scored the cylinder if that's a possibility..? Mechanic reckons a new engine or full rebuild to sort it out as well...does this sound right..?

Re: Misfire and low compression on Cylinder #4....Info..?

Posted: Mon Oct 26, 2015 7:29 pm
by Tosh21
I dont see how an injector could cause scoring to the bore, unless it was running too rich and giving you borewash but i dont think a poorly seated injector would do that. A wet compression test is definitely the next step, a normal compression test doesn't really tell you much it's just good for spotting which cylinder is faulty, not why it's faulty.

Unfortunately, being number 4, if you need new rings or anything piston related it's quite hard to do and is usually and engine out job as you can't get to it from underneath. Get a wet compression test done and let us know what he reckons it is and exactly what he wants 1500+ for