car is runing very lean, need help.
#1
car is runing very lean, need help.
I have catback exhaust, kinetix plenum and jwt intake. I had the car dynoed today and my AFR was 16.5. The guy said the normal rate is 13-13.5 and even lower at high end. at about 1500 rpm all the way to 5500 rpm the car is running 16.5.
My question is: Is there place that can tune the car with stock ECU so i won't have the problem? I asked Church Automotive, they said they dont have the software for the stock ECU to tune.
My question is: Is there place that can tune the car with stock ECU so i won't have the problem? I asked Church Automotive, they said they dont have the software for the stock ECU to tune.
#2
Originally Posted by Klubbheads
I have catback exhaust, kinetix plenum and jwt intake. I had the car dynoed today and my AFR was 16.5. The guy said the normal rate is 13-13.5 and even lower at high end. at about 1500 rpm all the way to 5500 rpm the car is running 16.5.
My question is: Is there place that can tune the car with stock ECU so i won't have the problem? I asked Church Automotive, they said they dont have the software for the stock ECU to tune.
My question is: Is there place that can tune the car with stock ECU so i won't have the problem? I asked Church Automotive, they said they dont have the software for the stock ECU to tune.
#4
#5
#6
Guest
Posts: n/a
You have cats still on the car? And you looked at the A/F at the tail pipe?
Aren't the cats going to make it LOOK lean, since they working to get rid of any left over fuel. Obviously you will be running just alittle leaner then stock... but I think if you were at 16.5 you'd notice the car running weird. My car had a glitch sometimes where at cruise it'd go to 17.0 until I tapped the gas and the car would feel rough when it got so lean. You should also be noticing a type of pinging with that AFR, and maybe increased engine temps?
Aren't the cats going to make it LOOK lean, since they working to get rid of any left over fuel. Obviously you will be running just alittle leaner then stock... but I think if you were at 16.5 you'd notice the car running weird. My car had a glitch sometimes where at cruise it'd go to 17.0 until I tapped the gas and the car would feel rough when it got so lean. You should also be noticing a type of pinging with that AFR, and maybe increased engine temps?
Last edited by AmateuRN; 02-11-2007 at 11:43 PM.
#7
Trending Topics
#8
Before you get too worked up, where did you have it dyno'd? Early last year I had my car dyno'd and saw crazy a/f's, some upwards of 16:1. I started wigging out, thinking about piggybacks and such. I even removed my crawford cats. I dyno'd again a few months later at a different location, and everything was fine. And I highly doubt the stock ecu is gonna let you run 16.5 all the way till 5500rpms.
I have attached a chart with three a/f's. The Blue line is from the first dyno location that just got goofy readings. Mods at the time were k&n filter, ztube, mrev+, crawford cats, and stillen exhaust. That particular day they had problems getting good reads from the sniffer. Temp: 72, Humidity: 25%.
The red line was two months later, at a different location. Much more competent. Probably the best local dynojet. Mods at the time were k&n filter, ztube, mrev+, and stillen exhaust. The only difference was I had removed the crawford cats. Notice the curve of the red line more closely resembles a typical g35 a/f curve. Temp: 72, Humidity: 33%
The green line was a dyno almost six months later, at the same location as the red line. I had added kinetix resonated test pipes and a stillen airbox. The curve is very similar to the red line, just shifted upward a bit(leaner). Below 5500 rpms, the airbox and test pipes made me run on average less than 5 tenths leaner. After 5500, I ran a bit richer. Temp: 77, Humidity: 23%
In summary, I think it's too early to flip out. Find another location and get another reading. Then you can make a decision.
I have attached a chart with three a/f's. The Blue line is from the first dyno location that just got goofy readings. Mods at the time were k&n filter, ztube, mrev+, crawford cats, and stillen exhaust. That particular day they had problems getting good reads from the sniffer. Temp: 72, Humidity: 25%.
The red line was two months later, at a different location. Much more competent. Probably the best local dynojet. Mods at the time were k&n filter, ztube, mrev+, and stillen exhaust. The only difference was I had removed the crawford cats. Notice the curve of the red line more closely resembles a typical g35 a/f curve. Temp: 72, Humidity: 33%
The green line was a dyno almost six months later, at the same location as the red line. I had added kinetix resonated test pipes and a stillen airbox. The curve is very similar to the red line, just shifted upward a bit(leaner). Below 5500 rpms, the airbox and test pipes made me run on average less than 5 tenths leaner. After 5500, I ran a bit richer. Temp: 77, Humidity: 23%
In summary, I think it's too early to flip out. Find another location and get another reading. Then you can make a decision.
#9
Originally Posted by DaveB
You're going to need to get some sort of ECU piggyback. In the meantime, yank that JWT intake off. The car will run richer and I guarentee you the car will be faster.
#10
Originally Posted by trey.hutcheson
IF his car is actually running that lean, and IF it's because of the intake, then I'd agree. But I have my doubts.
Anyways, I think it's a factor of all his mods causing the lean condition. Changing out the intake is the easiest way to gain back some fuel, especially since MAF and intake are in such close proximity of one another. IMO, it worth a shot since swapping the setup takes less than 30 minutes.
I also agree that the A/F ratios are most likely not as bad as he thinks. The tail pipe sniffers have a tendency to show leaner conditions than what is truely occuring just south of cats. The readings of the sniffers can sometimes get skewed because exhaust can sometimes get slightly mixed ambient air if the sniffer isn't stuffed into the pipe. Also, these cars run lean to begin with. At part throttle, they run really lean....as do most cars.
Klubb- I don't know about the idle on 6MTs, but my 5ATs idle has always been an indicated 500-600rpms (650rpms actual according to the logger). I'd think a 600rpm indicated idle would be right and 800-900rpms seems too high if the motor is full warmed. If the car doesn't shake at idle, I wouldn't worry about it. I also don't see how the mods could influence idle unless there was a vacuum leak and if you did have a leak, you'd know it by how crappy the car would run.
#11
Originally Posted by DaveB
Where the hell you been?
Originally Posted by DaveB
Anyways, I think it's a factor of all his mods causing the lean condition. Changing out the intake is the easiest way to gain back some fuel, especially since MAF and intake are in such close proximity of one another. IMO, it worth a shot since swapping the setup takes less than 30 minutes.
#13
Originally Posted by trey.hutcheson
I took a break from the whole car thing for a while. But I'm back now.
/off soap box
#15
Sorry Klubb for cluttering your thread.
I got a bit down because only partly because of the cost. The real reason I got down was because I couldn't make sense of my 1/4 times. First time ever at the strip I ran a best of 14.7@95, in huge heat. 6 months later, in temps in the mid 30's, I was running low 14's@101/101. Then I pulled some high 13's@101/102; I'm sure you remember that. And that was with a k&n and cats.
So in a period of 6 months, I dropped almost a full second in my ET's and picked up 6 to 7mph in traps; partly conditions, partly experience, partly mods. When the next summer came around, I was trapping in the 1/8th right at the same speeds I had the previous winter, so I was expecting a big jump when winter rolled around.
My one visit to the 1/4 in the summer saw traps of 101mph(~80 degrees). Then when I went later in October, in the mid 40's, I still only saw 101mph traps. I just couldn't make any sense of it. At no point had I lost power. And I had started to drive more and more poorly. That's the point that I started questioning the whole car thing.
Then, just after Christmas, I helped my buddy install a mopar stage2 kit on his srt4. That got me going again, a bit. Then I noticed oil consumption. The dealer has since given me a new long block, and I had headers put in for free. And I'm going in for a utec+tune in a couple of weeks at Sharif's.
After that, I'll be getting some 16" wheels+DR's, and I should be seeing some low 13's in cooler weather. And my performance mods will be done.
I got a bit down because only partly because of the cost. The real reason I got down was because I couldn't make sense of my 1/4 times. First time ever at the strip I ran a best of 14.7@95, in huge heat. 6 months later, in temps in the mid 30's, I was running low 14's@101/101. Then I pulled some high 13's@101/102; I'm sure you remember that. And that was with a k&n and cats.
So in a period of 6 months, I dropped almost a full second in my ET's and picked up 6 to 7mph in traps; partly conditions, partly experience, partly mods. When the next summer came around, I was trapping in the 1/8th right at the same speeds I had the previous winter, so I was expecting a big jump when winter rolled around.
My one visit to the 1/4 in the summer saw traps of 101mph(~80 degrees). Then when I went later in October, in the mid 40's, I still only saw 101mph traps. I just couldn't make any sense of it. At no point had I lost power. And I had started to drive more and more poorly. That's the point that I started questioning the whole car thing.
Then, just after Christmas, I helped my buddy install a mopar stage2 kit on his srt4. That got me going again, a bit. Then I noticed oil consumption. The dealer has since given me a new long block, and I had headers put in for free. And I'm going in for a utec+tune in a couple of weeks at Sharif's.
After that, I'll be getting some 16" wheels+DR's, and I should be seeing some low 13's in cooler weather. And my performance mods will be done.