Rough idle and lean AFR!
Account Disabled
Joined: Mar 2013
Posts: 714
Likes: 22
From: in a garage
What makes you think I don't work on Evos?
I work/ have worked on all sorts of things.
If you go fit a bigger fuel pump and ignore the fact that you're out flowing the FPR. Pressure is 5 or 6 PSI too high at idle / low load....as it normally IS.
Then you think that you're the worlds greatest tuner and you can tune around it.
Then your alternator fails and the voltage drops.
It's going to run lean.
Because you failed on the tuning.
Because the pump runs slower, no longer out flows the FPR, pressure drops to the correct value.
You can simulate that on any car just by removing the low curent plug in the alternator.
If it's all OEM and unmolested, the AFR won't change when you do this.
I work/ have worked on all sorts of things.
Then you think that you're the worlds greatest tuner and you can tune around it.
Then your alternator fails and the voltage drops.
It's going to run lean.
Because you failed on the tuning.
Because the pump runs slower, no longer out flows the FPR, pressure drops to the correct value.
You can simulate that on any car just by removing the low curent plug in the alternator.
If it's all OEM and unmolested, the AFR won't change when you do this.
They don't get dirty in the first place so there's no point in trying to clean something that doesn't need cleaning.
The only people who try to clean them are the people who don't know wtf they're doing.
As for what to do next.....check for stored fault codes and get a data log.
The only people who try to clean them are the people who don't know wtf they're doing.
As for what to do next.....check for stored fault codes and get a data log.
Account Disabled
Joined: Mar 2013
Posts: 714
Likes: 22
From: in a garage
90% of people here know that what I post makes 100% sense.
You're only going to make yourself look even more stupid.
Funny, was just talking to some workmates today
There's 2 sorts of people, listeners and talkers.
The listeners learn and get things done
The talkers are full of ****.
It's easy to tell on a forum, check the post count.
The talkers get it from google
The listeners do their own R and D and testing.
You're only going to make yourself look even more stupid.
Funny, was just talking to some workmates today
There's 2 sorts of people, listeners and talkers.
The listeners learn and get things done
The talkers are full of ****.
It's easy to tell on a forum, check the post count.
The talkers get it from google
The listeners do their own R and D and testing.
That guy pops into various threads with ideas nobody agrees with. It's odd.
Anyway, OP: This is a long shot, but those are usually the ones that fool us the longest: my problem was a bad alternator. It wouldn't supply enough power to charge the battery and/or run the car. I would run lean at idle. I didn't catch it until it started doing the same while cruising on the freeway (about two years later).
I bought a tester from Harbor Freight for $10 and found my problem. 'Thought I'd mention it, just in case.
Anyway, OP: This is a long shot, but those are usually the ones that fool us the longest: my problem was a bad alternator. It wouldn't supply enough power to charge the battery and/or run the car. I would run lean at idle. I didn't catch it until it started doing the same while cruising on the freeway (about two years later).
I bought a tester from Harbor Freight for $10 and found my problem. 'Thought I'd mention it, just in case.
huh that is weird... well it won't hurt to check I guess I mean it won't take a lot of effort to check my alternator so I might ad well but I'm starting to think it may be an actuator or something at this point that is bad or locked and hopefully not my cams being installed wrong
I know by practice and trial and error. I dont spew my mouth off and make no frigging sense to the people that know better on this forum, folks like you have continued to come and go over the years. when you keep an evo together for 150k hard miles then come and talk to us about what it takes to do so until then nobody wants your opinion and they have expressed that to you time and time again.
Take a hint.
Take a hint.
90% of people here know that what I post makes 100% sense.
You're only going to make yourself look even more stupid.
Funny, was just talking to some workmates today
There's 2 sorts of people, listeners and talkers.
The listeners learn and get things done
The talkers are full of ****.
It's easy to tell on a forum, check the post count.
The talkers get it from google
The listeners do their own R and D and testing.
You're only going to make yourself look even more stupid.
Funny, was just talking to some workmates today
There's 2 sorts of people, listeners and talkers.
The listeners learn and get things done
The talkers are full of ****.
It's easy to tell on a forum, check the post count.
The talkers get it from google
The listeners do their own R and D and testing.
What makes you think I don't work on Evos?
I work/ have worked on all sorts of things.
If you go fit a bigger fuel pump and ignore the fact that you're out flowing the FPR. Pressure is 5 or 6 PSI too high at idle / low load....as it normally IS.
Then you think that you're the worlds greatest tuner and you can tune around it.
Then your alternator fails and the voltage drops.
It's going to run lean.
Because you failed on the tuning.
Because the pump runs slower, no longer out flows the FPR, pressure drops to the correct value.
You can simulate that on any car just by removing the low curent plug in the alternator.
If it's all OEM and unmolested, the AFR won't change when you do this.
I work/ have worked on all sorts of things.
If you go fit a bigger fuel pump and ignore the fact that you're out flowing the FPR. Pressure is 5 or 6 PSI too high at idle / low load....as it normally IS.
Then you think that you're the worlds greatest tuner and you can tune around it.
Then your alternator fails and the voltage drops.
It's going to run lean.
Because you failed on the tuning.
Because the pump runs slower, no longer out flows the FPR, pressure drops to the correct value.
You can simulate that on any car just by removing the low curent plug in the alternator.
If it's all OEM and unmolested, the AFR won't change when you do this.
Second update...
again just relaying some info to hopefully help.. when I first turn the car on after sitting for hours and it's cold it will start right up and idle perfect at 14.7 then seconds later something happens and it just almost stalls and goes to 16-17 AFR... any input I'm at a loss here again
Newbie
Joined: Nov 2011
Posts: 4
Likes: 0
From: NY, USA
I have the same exact problem with my evo rough idle at cold start. I want to know how you fixed it. I don't have a MAF. I have a speed density kit.
Hello all...
So I have been searching forums and doing some work to try and figure out an issue that just popped up and would love some help or ideas as to solutions,
As of recently my startup on my evo IX is incredibly rough like it almost stalls out before it finally warms up, while it's basically choking on startup the AFR will bounce all around to keep it alive, once it has warmed enough my AFR will sit anywhere between 15.5-17 while not moving and at warm idle, it was NEVER like this. While cruising it is perfectly fine easy throttle around 14-15 AFR and at WOT it's very low around 10.5-11 AFR. car drives fine and it does not fall on it's face but I am trying to get the AFR back to normal at idle..
mods include TBE, LICP, walbro 255, HKS 262 cams, manual boost controller
I have:
cleaned the MAF
did a boost leak down test to look for any leaks
checked for exhaust leaks
replaced timing belt (yesterday not for this reason but it eliminates timing issue)
fuel pump kicks on and I do not have a shortage when driving so it's not that
I'm just looking for suggestions on what it could be or what to check next, any help is highly appreciated!
So I have been searching forums and doing some work to try and figure out an issue that just popped up and would love some help or ideas as to solutions,
As of recently my startup on my evo IX is incredibly rough like it almost stalls out before it finally warms up, while it's basically choking on startup the AFR will bounce all around to keep it alive, once it has warmed enough my AFR will sit anywhere between 15.5-17 while not moving and at warm idle, it was NEVER like this. While cruising it is perfectly fine easy throttle around 14-15 AFR and at WOT it's very low around 10.5-11 AFR. car drives fine and it does not fall on it's face but I am trying to get the AFR back to normal at idle..
mods include TBE, LICP, walbro 255, HKS 262 cams, manual boost controller
I have:
cleaned the MAF
did a boost leak down test to look for any leaks
checked for exhaust leaks
replaced timing belt (yesterday not for this reason but it eliminates timing issue)
fuel pump kicks on and I do not have a shortage when driving so it's not that
I'm just looking for suggestions on what it could be or what to check next, any help is highly appreciated!
FWIW, countless evo owners have been using CRC MAF cleaner for years and years without issue, Just don't concentrate the spry directly on the thin wire of the resistor, have some common sense, We all know what the label says but when used correctly it works just fine and will not harm or break your MAF sensor in anyway.
I have never heard of one single person breaking or damaging a MAF using CRC's Product, Hell I remember a dude used break cleaner with no ill effects, I wouldn't suggest that But I personally used the MAF cleaner for well over 100k with no issue to speak of. Works great.
I have never heard of one single person breaking or damaging a MAF using CRC's Product, Hell I remember a dude used break cleaner with no ill effects, I wouldn't suggest that But I personally used the MAF cleaner for well over 100k with no issue to speak of. Works great.
i have also used the MAF cleaner countless times. Its still a hot air MAF with a honeycomb, so yes its fine to use it. Lol
Not sure if this will help but I had almost the same type of problem before I deleted my egr. I have an 03 evo and read somewhere long ago that they go bad the older the car gets so I just deleted it as it gave me something to do and funny part was it solved my problem. Im thinking it was slightly opening up at idle when it shouldn't be but i never checked the valve out as I just tossed it right after completing the job.
again just relaying some info to hopefully help.. when I first turn the car on after sitting for hours and it's cold it will start right up and idle perfect at 14.7 then seconds later something happens and it just almost stalls and goes to 16-17 AFR... any input I'm at a loss here again
not that anyone is still here but maybe for future refernce I am going to post my solution,
it was a combination of things...
1) terrible tune
2) a bad reading AFR this is very rare especially with AEM stuff but mine sadly is no longer reading correctly
Anyways I got my car Re tuned at RRT motorsports by Raif and he did a really good job of showing me the issues and making the car run perfect again, ended up being better than expected, hope this helps someone in the future!
it was a combination of things...
1) terrible tune
2) a bad reading AFR this is very rare especially with AEM stuff but mine sadly is no longer reading correctly
Anyways I got my car Re tuned at RRT motorsports by Raif and he did a really good job of showing me the issues and making the car run perfect again, ended up being better than expected, hope this helps someone in the future!
If you see above it was solved, I thought all these things too, Tuner said same thing but also said in a very rare case my 272 cams could set it off and only way to find out was to clear it and key cycle it a bunch of times, it never came back which means it was just tripped from the cams, its also potential to come back at some point but cams were installed correctly and Mivec cam gear and passage ways are good to go, best case scenario IMO
FWIW, countless evo owners have been using CRC MAF cleaner for years and years without issue, Just don't concentrate the spry directly on the thin wire of the resistor, have some common sense, We all know what the label says but when used correctly it works just fine and will not harm or break your MAF sensor in anyway.
For once I agree with this guy, your not supposed to use it, I read that directly quoted from Mike at RRE.