[Leane90]

Hey guys I got a 07 e90 with a jb4 tune on it . Been running perfectly fine until yesterday . When I try to floor it it puts me in limp mode aka the yellow half engine light starts to appear and I have no real power . But soon as I shut off the car and turn it back on the light goes away ? Anyone know why that could be ? Please help !!!

[Muwiee]

Sounds like a coil pack. Next time it does it read codes. Actually you could read codes now and see if any stored. If not then next time it comes on pull over and read the codes. Most likely it's cool packs or possible spark plugs. Once you get the codes people can provide more help.

[fazman]

Originally Posted by Leane90

Hey guys I got a 07 e90 with a jb4 tune on it . Been running perfectly fine until yesterday . When I try to floor it it puts me in limp mode aka the yellow half engine light starts to appear and I have no real power . But soon as I shut off the car and turn it back on the light goes away ? Anyone know why that could be ? Please help !!!

i'm short cutting steps, but my guess is you have a high mileage e9x n54 that has never been carbon blasted or is of unknown status of when (if ever) has been carbon blasted. With that said i would rule out all the cheaper and items that usually need wear/tear service.

1) free - check to make sure you have the latest and greatest jb4 firmware updates. Also make sure you have the correct settings from the user adjusements tab screen shot: http://www.n54tech.com/forums/showthread.php?t=10605

2) try map 5 on jb4 and retest WOT to see if you get the issue again? try again in map 0 and retest WOT to see if you get the issue again?

3) Use the jb4 guage hijack to clear codes and the once you reproduce the 1/2 engine light, tell us what that code(s) is and we can guide you better.

4) Toss parts at the issue:
a) new spark plugs, you need them every 25k miles on a tuned car.
b)swap around coils if you get cyl misfire codes, see if the problem follows the coil
c) if one coil is bad, the other 5 are close behind in failing soon... replace all 6 coils at about $30/coil from AAP using coupon codes.
d) clean and swap the VANOS solinoids.

5) carbon blast for about $250 plus a new manifold gasket $40 (do not reuse the old gasket).
a) install a bms OCC while you are carbon blasting
b) install a RB PCV

6) possible boost leak, replace vacuum lines (rear ones are a PITA)

-Faz

[SHEEDI]

Originally Posted by fazman

i'm short cutting steps, but my guess is you have a high mileage e9x n54 that has never been carbon blasted or is of unknown status of when (if ever) has been carbon blasted. With that said i would rule out all the cheaper and items that usually need wear/tear service.

1) free - check to make sure you have the latest and greatest jb4 firmware updates. Also make sure you have the correct settings from the user adjusements tab screen shot: http://www.n54tech.com/forums/showthread.php?t=10605

2) try map 5 on jb4 and retest WOT to see if you get the issue again? try again in map 0 and retest WOT to see if you get the issue again?

3) Use the jb4 guage hijack to clear codes and the once you reproduce the 1/2 engine light, tell us what that code(s) is and we can guide you better.

4) Toss parts at the issue:
a) new spark plugs, you need them every 25k miles on a tuned car.
b)swap around coils if you get cyl misfire codes, see if the problem follows the coil
c) if one coil is bad, the other 5 are close behind in failing soon... replace all 6 coils at about $30/coil from AAP using coupon codes.
d) clean and swap the VANOS solinoids.

5) carbon blast for about $250 plus a new manifold gasket $40 (do not reuse the old gasket).
a) install a bms OCC while you are carbon blasting
b) install a RB PCV

6) possible boost leak, replace vacuum lines (rear ones are a PITA)

-Faz

Hey Bro,
Welcome back on e90post , few questions......so how often N54 engines need walnut blast? before installing jb4, what parts need to be addressed/replaced?

[SHEEDI]

Originally Posted by Leane90

Hey guys I got a 07 e90 with a jb4 tune on it . Been running perfectly fine until yesterday . When I try to floor it it puts me in limp mode aka the yellow half engine light starts to appear and I have no real power . But soon as I shut off the car and turn it back on the light goes away ? Anyone know why that could be ? Please help !!!

OP, get OBD reader or go to indy shop to scan your car's computer for codes and take it from there.

[fazman]

Originally Posted by SHEEDI

Hey Bro,
Welcome back on e90post , few questions......so how often N54 engines need walnut blast? before installing jb4, what parts need to be addressed/replaced?

It really depends, I did mine at 45k miles and again at 95k miles. I started getting the 1/2 engine light at about 90k miles and tracked down the issue using the process I listed above. My issue was solved when I did the carbon blasting but mine wasn't that bad from what ZNM Auto said when they did my blasting.

Nothing needs to be done before installing the JB4, the only thing that might happen is it will show you your cars weaknesses which would probably have shown up later (a little sooner). But it won't cause any problems. It's usually better to replace things as needed or on a schedule (or in my case, anytime your already digging into a car... change stuff to save on labor).

Also if you want a JB4 G5, my friend just sold his 335 and has one available.

- Faz