[Ridgefield335]

So my car is at the dealer for long cranks, very rough idle (worse after longer cranks) and it likes to stall during idle. They have now had it for a day and couldn't pinpoint the cause of the issues.

Anyone else have these problems and resolved them?

[Sidewinderpb]

Ohhh have I!?!? Those are quite prominent problems with my car.

What mods do you have on your car? Mileage?

[Ridgefield335]

FBO minus meth. I ticked over 17k this weekend.

Car runs great besides these little annoyances.

[Sidewinderpb]

I'm jealous. My 2011 just hit 46k.

Do you have a JB4? If so, and you're running ISO 5.3, try swapping the MAF connector back to stock. The newest firmware doesn't utilize it, so if anything, you'll narrow down the issue. Also check to make sure all of your vacuum connections are firmly secured. If that doesn't work, you can grab the FlexFuel wires, and try raising the fuel mass at idle.

If all of that doesn't work, then you and I are in the same shoes. Possibly a fuel pump issue.

[Ridgefield335]

I bought my 11' 6mths ago with 11600 miles for one hell of a deal.

I brought my car back to the shop who did all my mods and I believe we did all the JB4 fixes we could dig up. Helped a little with the stalling. It's now down to 1-2 times a week vs 2-3 times a day.

When I get it back, hopefully fixed, I'll try the different flex fuel wires an messing with fuel mass like suggested. I'll keep you posted with what they find and maybe you can direct them in the same direction

[Sidewinderpb]

Yeah let me know how it goes man. Did you happen to notice whether or not the stalling is directly related to cold weather?

Mine is. If it's over ~34 degrees, the car will start without stalling. It may crank a lot, but she'll go.

[Ridgefield335]

Software update and the idle issue is gone according to the dealer. Hoping that sorts out the stalling. Checking the pump just incase

[JBird..]

Sometimes the N55 doesn't react well to DP's. Many people have had this issue and do not know where the problem comes from. It isn't the JB4 as Terry has shown this before. It is a scary thought though that our cars could stall out at any second.

[rr006rbc]

Originally Posted by jczepf96

Sometimes the N55 doesn't react well to DP's. Many people have had this issue and do not know where the problem comes from. It isn't the JB4 as Terry has shown this before. It is a scary thought though that our cars could stall out at any second.

It gets even worse with a JB4. Took mine off almost instantaneously. It made my brand new car run like shit.

[Sidewinderpb]

Originally Posted by jczepf96

Sometimes the N55 doesn't react well to DP's. Many people have had this issue and do not know where the problem comes from. It isn't the JB4 as Terry has shown this before. It is a scary thought though that our cars could stall out at any second.

Yup. That's the life of a tinkerer

[JBird..]

Originally Posted by Sidewinderpb

Yup. That's the life of a tinkerer

Not in the middle of a turn. That's happened to me.

[TZANIDO777]

I had the exact same problems as the OP, I was FBO except for meth with a JB4 however I have a 135. I was running like that for about 15,000 miles until I decided to switch to cobb...Its been 5000 miles and havent stalled or had nearly as bad rough idle as I did with the JB4.

Having said that the JB4 did make more power and had its perks with some nice features.

[Sidewinderpb]

Originally Posted by jczepf96

Not in the middle of a turn. That's happened to me.

Same. I've also had the throttle just stop working (fixed somehow).

[Ridgefield335]

So, after driving around all night after the software update from the dealer, the idle definitely seems to be much smoother and ive the feeling like its going to die has completely gone. Saying that, today was much warmer here in CT that its been in the past few weeks since the issue.

Ill report back if anything changes

[Sidnito]

mine does this. 86k miles 2011. when I turn off the AC it sometimes hiccups at idle but with the AC on and idling at 700 RPM-no jerks.
I put on a catless DP and it would stall out at every light so I took it off immediately. it sucked but idk what it could be, some say ratio of air and fuel but idkk.
I did have jb4 on it which worked pretty well but then my VANOS broke so I had to get rid of it.
I am trying to decide if I should put the DP back on or sell it

[Sidewinderpb]

Originally Posted by Sidnito

mine does this. 86k miles 2011. when I turn off the AC it sometimes hiccups at idle but with the AC on and idling at 700 RPM-no jerks.
I put on a catless DP and it would stall out at every light so I took it off immediately. it sucked but idk what it could be, some say ratio of air and fuel but idkk.
I did have jb4 on it which worked pretty well but then my VANOS broke so I had to get rid of it.
I am trying to decide if I should put the DP back on or sell it

Give it another shot

[Sidnito]

Originally Posted by Sidewinderpb

Give it another shot

why do you think so?

[Sidewinderpb]

Well if you'd like to be practical, and not have to worry about changing it out for emission testing and whatnot, then you probably shouldn't run the DP.
I, too, have had issues since installing mine. The N55 seems to be notorious for having a distaste for catless downpipes. That being said, I believe my issues stem from a failing fuel pump.
I admit to not doing any research regarding VANOS issues - so I cannot speak to that.

That being said, the stalling issues (I've also stalled at stoplights) seem to be dependant on the outside temperature - say, below 35 degrees. Is that applicable to your situation? If so, that may just be the typical moody N55.
Since it's getting warmer, why not give it another shot? The gains are rather compelling.
If you still have these issues in warm weather, then sell the DP. They've got pretty good resale value.
I mean, ultimately it's your call. I'm just biased towards downpipes

[Sidnito]

Originally Posted by Sidewinderpb

Well if you'd like to be practical, and not have to worry about changing it out for emission testing and whatnot, then you probably shouldn't run the DP.
I, too, have had issues since installing mine. The N55 seems to be notorious for having a distaste for catless downpipes. That being said, I believe my issues stem from a failing fuel pump.
I admit to not doing any research regarding VANOS issues - so I cannot speak to that.

That being said, the stalling issues (I've also stalled at stoplights) seem to be dependant on the outside temperature - say, below 35 degrees. Is that applicable to your situation? If so, that may just be the typical moody N55.
Since it's getting warmer, why not give it another shot? The gains are rather compelling.
If you still have these issues in warm weather, then sell the DP. They've got pretty good resale value.
I mean, ultimately it's your call. I'm just biased towards downpipes

Good point, I don't remember what the temperature was when it failed, I remember it was rainy haha
so you have your DP back on?
any tune?

[Sidewinderpb]

Originally Posted by Sidnito

Good point, I don't remember what the temperature was when it failed, I remember it was rainy haha
so you have your DP back on?
any tune?

Try to take note of that if (when) it gets cold again. Mine starts just fine when the weather is warmer. Of course, I now have the long cranks during warm startup. Just can't catch a brake haha.

Yes sir, I am rocking a downpipe to the fullest - and loving it! That, paired with my replacing the muffler internals with straight pipes, makes the car gurgle pop POP like none other. Driving through the parking garage at the office makes me chub-up

[Sidnito]

Originally Posted by Sidewinderpb

Try to take note of that if (when) it gets cold again. Mine starts just fine when the weather is warmer. Of course, I now have the long cranks during warm startup. Just can't catch a brake haha.

Yes sir, I am rocking a downpipe to the fullest - and loving it! That, paired with my replacing the muffler internals with straight pipes, makes the car gurgle pop POP like none other. Driving through the parking garage at the office makes me chub-up

hahaha nice, so do you think you could make a video of your car at idle, just to see if it's jerking or maybe stalling like mine did?

[Sidewinderpb]

Sure - if we get a cold morning to replicate the issue. I'll try to remember!
Can't do it when it's above ~35 degrees, because it'll just start right up.