What is Roughness Monitor Cylinder # ... ?

i tried to do research on "roughness monitor", but can not seem to find a lot of info on this parameter... what does it exactly mean?

 

during WOT my roughness monitor for all cylinders is "0", but during idle cylinder # 3 sometimes jumps to "1"... this does not occur consistently, but when it does it always seem to be cylinder #3...

 

everything else is normal, the car does idle rough for few seconds when cold... otherwise idle seems to be normal for a subie engine...

 

should i be concerned or look further into this?

 

thanks for help !

if the number gets too high it throws a misfire CEL for that cylinder

This is part of our "rough idle" and is considered somewhat normal, not a good thing, but normal. I used to get a "1" on cyl. #3 also. I changed the plugs and it got better. I changed to different/bigger injectors and it went away completely.

If you constantly get it on the same cylinder, there could be a bad coil, plug or injector on that cylinder. If you want to track it down try swapping coils then plugs(if needed) then injectors (if needed) with cylinder 1 and see if the roughness changes cyliners. But I would not worry about 1 count.

yeah, CEL doesn't trip till about 30-40 count

my cylinder 2 is getting upwards of 30 at idle, under wot its 0 however. Also threw a p0302 misfire code from cylinder 2. Im doing a compression and leakdown test next week yipee

my cylinder 2 is getting upwards of 30 at idle, under wot its 0 however. Also threw a p0302 misfire code from cylinder 2. Im doing a compression and leakdown test next week yipee

 

let's hope it's only a bad spark plug or injector...

not the plugs i just changed them. I'm prepared for the worst. This car this summer is a money machine. I'm about ready to throw in the towel and let it sit for a while until i can just tear down the entire thing.

not the plugs i just changed them. I'm prepared for the worst. This car this summer is a money machine. I'm about ready to throw in the towel and let it sit for a while until i can just tear down the entire thing.

 

You don't love it, it knows it and is pouting.:lol:

ya tomorrow ill swap coil packs and fuel injector. If not those ill pull plug #2 and put it in # 4.. after that im done, its going to a shop.

my cylinder 2 is getting upwards of 30 at idle, under wot its 0 however. Also threw a p0302 misfire code from cylinder 2. Im doing a compression and leakdown test next week yipee

 

A misfire count of 30 is not a good sign. Unless you have a bad plug or injector in that cylinder you might very well have a broken ring land. Heck I've seen cars with lower misfire counts on a cylinder have a broken ring land.

^sweet

Suck, I need to log mine

^you're probably fine, i noticed my idle has gotten REALLY rough recently and car feels down on power.

Already placed this in a thread on the O2 sensor. After pulling off my UP and down pipe due to a leak, I now have a mis at idle.

I am thinking it could be the front O2 sensor but I am not sure if this could cause the problem.

It doesnt seem to do it all the time though. There are days/times that it seems OK.

I guess Il get a cable and log it.

Any opinions if the O2 sensors could cause a mis at idle?

leakdown/compression test #'s

 

#1 25psi/65%

#2 05psi/55%

#3 125psi/4%

#4 130psi/6%

 

new short block time

 

is your car even running with these numbers?

yes, stalling a lot and running in 10's in closed loop though. With the leakdown they said it was hard to pinpoint the leaks it was coming from a lot of places. Im going to call them tomorrow and discuss in more details. Also seems strange if 2 cylinders are dead im surprised it would run?

leakdown/compression test #'s

 

#1 25psi/65%

#2 05psi/55%

#3 125psi/4%

#4 130psi/6%

 

Ouch #2 is the typical cylinder to fail on the LGT but #1 is a new one to me.

the numbers are suspect. Obviously something is wrong and the engine needs replacement, but i feel as if 2 cylinder were dead the car A would not run and B would not have made 350wtq on the dyno a week ago unless it had catastrophic failure afterwards. The car still runs, has power, stalls time to time, etc. I think they meant either 125 in cyl 1 or 105 in cyl 2.

the numbers are suspect. Obviously something is wrong and the engine needs replacement, but i feel as if 2 cylinder were dead the car A would not run and B would not have made 350wtq on the dyno a week ago unless it had catastrophic failure afterwards. The car still runs, has power, stalls time to time, etc. I think they meant either 125 in cyl 1 or 105 in cyl 2.

True but look at the leakdown numbers as well. 1 and 2 both don't look so hot there either.