Interesting problem. Tuned?
11-15-2008, 01:19 AM
#1
3rd Gear Member
Thread Starter
Join Date: Jun 2006
Location: California
Posts: 647
Interesting problem. Tuned?
So I noticed a weird problem with my car and maybe you guys can figure it out. When I bought my car it came with a JLT CAI, the one that extends down into the fenderwell. Car ran great. In order to get it smogged I had to put the stock intake back on. Put it back on and several times when decelerating the car stalled, basically when idling and coasting close to a stop. When I put the JLT intake back on I never had this problem. Then, because I like the idea of using the hood scoop, I bought the other JLT intake,the RAI, which keeps the shaker functional. Everything is fine with this intake as well, but I do notice a very slight drop in rpm when idling close to coming to a stop. So does anyone have any idea what this could be? I don't know anything really about tunes, but I thought one possibility could be that the car is tuned and putting the stock intake on does not go well with the tune. Forgive me if that's a stupid idea it's just the first thing I could think of. Either way it doesn't really matter because I don't plan on going back to the stock intake any time soon, but I just thought you guys could help me figure this out because it's been bugging me.
Sorry for the long post, cliffnotes- Car runs great with either type of JLT intake, stalls when idling with the stock intake. Could it be tuned?
Sorry for the long post, cliffnotes- Car runs great with either type of JLT intake, stalls when idling with the stock intake. Could it be tuned?
11-15-2008, 09:42 AM
#2
1st Gear Member
Join Date: Mar 2007
Location: New Jersey
Posts: 76
i HAVE the same problem. i did address it on here.... the CAI i have it very basic.. it has some shop name on it form michigan... its a metal shroud that covers half of the high flow filter and also does incorporate the shaker... when i got he car there was a piece of cloth over the filter and it had a name on it "pre-filter".. i had never saw one before so i thought it was maybe filter over kill so i took it off and threw it out... ever since then i have been having the same issue u just brought up
I think its because some CAIs cause a lot of turbulance in the incoming air and confuses the MAF..and i think that cloth shroud(pre-filter) calmed the air down.. maybe.. and maybe a tune could fix it
I think its because some CAIs cause a lot of turbulance in the incoming air and confuses the MAF..and i think that cloth shroud(pre-filter) calmed the air down.. maybe.. and maybe a tune could fix it
11-15-2008, 11:26 AM
#3
4th Gear Member
Join Date: Dec 2007
Location: Maryland
Posts: 1,503
You aren't alone in this boat. Most Machs show a variance of the rpm drop symptoms. Seems it happens more when moving above 10 mph or so but not in gear, or in gear with the clutch being pressed. It has to do with the MAF matching the air/fuel mixture per the requested throttle output from the driver, and that being a little trickier of a task with the Machs abundance of air to read and measure. Mine has done it before and after the JLT RAI. I'm sure the custom tune did throw yours off when going back to the stock intake. When gas was above $4 I would always ride in N downhills and this would always cause the problem so I was just tap the gas. Having the A/C or defrost decreased the likelihood the rpms would get low enough for the car to shut off. I guess the extra juice required helps the motor stay afloat or something, that's getting beyond my BASIC expertise. The problem also happens quicker and more often, to me atleast, when the air is cold (more dense) in the morning, lending more credence to the idea that the MAF reading being the culprit. Wouldn't worry too much about it, as we seem to all have it and noone's blowing up. Sorry for the long post, trying to help a brother out.
11-15-2008, 01:39 PM
#6
6th Gear Member
Join Date: Mar 2007
Location: Chicago, IL
Posts: 6,169
Did you put the stock screen back in? I had this same problem and I just put the stock screen back in and my car drove perfect. I bought the K&N intake for my mach when I had it and I called K&N with the same problem and that's what they told me to do. So put that small stock screen back in.
11-15-2008, 02:26 PM
#8
4th Gear Member
Join Date: Dec 2007
Location: Maryland
Posts: 1,503
Did you put the stock screen back in? I had this same problem and I just put the stock screen back in and my car drove perfect. I bought the K&N intake for my mach when I had it and I called K&N with the same problem and that's what they told me to do. So put that small stock screen back in.
11-15-2008, 02:37 PM
#9
6th Gear Member
Join Date: Mar 2007
Location: Chicago, IL
Posts: 6,169
They didn't have a reason why it worked that just said it does. They also said that they were going to start putting that in the directions to let people know from now on. Who knows if they really did or not. But I put it back in and the car ran fine for me.