sup fellas. I just want an update on the evo's idle. I have over 1000 miles on it right now. is it normal for the evo to idle rough? I mean not really rough but my goes like rmmmmmmmmmbroprmmmmmmmroprmmmmm. I this car suppose to idle smooth? Also is it because the evo runs alittle rich right from the factory? Well since I brought up the mixture of the evo, I was wondering since it runs a little rich, won't that shorten the life of the cat?

thanks for any reply

 

I also have a little miss problem at idle and it idels kinda high, around 1400rpm. It drops down to 900ish afetr it warms up. Still seems kinda high.

 

The installation of an engine grounding kit significantly smoothed out my rough idle.

 

https://www.evolutionm.net/forums/sh...hlight=sticker

Posted here that the Evo's idle should be within 850 RPM +/- 50 RPM's. Not surprisingly high for this type of car. The high idle at warm up is typical of pretty much all new cars to speed up the warming up process.

 

Oh how I'm familiar with this. I've heard some guesses like "it's the cams" or "grounding wires". Sounds like the grounding wires might work. I'll probably give it a shot. couldn't hurt.
But when idling I can see my steering wheel shake.

 

Wow! your steering wheel shakes. It seems your idle is worst than mine. I put on a grounding kit(homemade) hell, how hard is it to make several 4 gauge wires and grounding them all over the engine bay. anyway, hope by changing to cooler plugs might help. I try it out and when I do, I will post an update.

peace!

 

Yep. Mostly when the A/C is on, but every now and then you'll catch the steering wheel vibrating.

 

I can definitely feel some rough idle.

But last week...I dumped a couple bottles of octane booster and it actually went away. The motor purred at the dunkin donuts drive through in the morning

 

I have found that the idle stumble/miss that you described is usually cause by fouled spark plugs. Try cleaning or replacing them.

 

Would you just take some gas and a wire brush to it like any old plugs from the "old days"?

 

Spark Plugs? I really doubt that. I noticed that my Evo did the same thing at 8 miles on the odometer and even now at 5k. And its more noticable when you first warm up the car.

 

I call no way on the plugs too I have 3400 miles and have colder plugs as well as stock and have tried multiple gaps with no results. I will try the grounding mod

 

What he is describing is a miss, there are several things that can cause this, but in my experience with the EVO (19K), fouled plugs caused this very problem on my car.

High vibration or eratic idle is somthing all together different, these cars do vibrate more than most at idle, that's just the way they are. I guess you need to determine if yours is vibrating more than a typical EVO.

Do NOT do this with the iridium plugs! The center electrode can be easily damaged, you need to use a real plug cleaner.

BTW I only had limited success cleaning the stock plugs, I cleaned them 3-4 times. Each time they would work great for a couple of days but then would foul out again. Eventually I put a new set in, problem solved.

Sometimes the deposits seem to get so engrained into the insulator that it is almost impossible to get it all out.


Your situation may not be the same problem, obviously we cannot tell over the internet. It is possible that you had a defective plug from the factory or some contaminated fuel left a nasty deposit on the ceramic insulator?
Or it's somthing completely different, I am simply suggesting a possibility that has actually occured with my car.

What sort of plugs are you using? Keep in mind that cooler plugs will become fouled much easier than the hotter stock plugs so.....
Once you develop carbon tracks on the ceramic insulator, you can gap them any way you want, your still going to have problems.
If you are using a standard type of plug with a much larger electrode, they do not fire over as easily as the iridium plugs to begin with, so...

Adding additional grounding wire is not a bad idea, I put them on my car within the first week, it did not help anything but it certainly doesn't hurt.

 

The EVO only runs extremely rich at high RPM (>4/5K), under boost, idle, and every other situation it actually runs a bit lean IMO.