MX54PLA

iTrader: (2)

Well today was the day.......all systems check...fluid in.....Megasquirt connected....turn key It started first crank!!!! Thanks to Gil for helping me with Megasquirt. After we got it started took it for a tuning test drive. Cruising speed is very smooth...then boost kicks in...and about 7 p.s.i. it starts bucking.... I also noticed that my AEM wideband and Megatune A/F gauges were off by anywhere from 1.2 - 2.5... so we brought it back in and just before pulling in Megasquirt started to reset..over and over again.

Put it up on jacks and rechecked all connections.. Ran a dedicated ground from engine block to megasquirt..rechecked timing. This seems to have fixed reset problem...and cruising is alot smoother...but it still bucks. Any Ideas??

Also anyone running AEM UEGO....which setting did you use in setup??

Thanks

Arkmage

iTrader: (3)

bucking under boost generally indicates it's really lean.

Ben

iTrader: (33)

Well it was a bad idea to install both the turbo and MS at the same time, so it is going to complicate things. It was also a bad idea to just go out and start hammering on it untuned. While your issues are probably all tune related, you'll still need to rule out mechanical issues in your troubleshooting.

MX54PLA

iTrader: (2)

Megasquirt was installed when car was N/A..I know better than to go out and hammer it. We were doing tuning on the fly...I gradually eased into boost. Thanks for the concern. Will do more tuning later this weekand see how it goes..planning to dyno sometime next week...IF I get the little issues worked out

karter74

iTrader: (4)

Do you still have overboost protection on at 152kPa?

MX54PLA

iTrader: (2)

ummm probably

cardriverx

iTrader: (12)

+1, I made the same mistake haha

kotomile

iTrader: (24)

lol, I believe the stock overboost protection is set at 8 psi, sounds like that's what's happening.

ZX-Tex

iTrader: (15)

Same thing happened to me, overboost. Bucks like a **** when it kicks in.

RdSnake

Where the hell did this come from?

MX54PLA

iTrader: (2)

Overboost Protection
The MSPNP base map has a default Overboost Protection limit set of 152kpa which is about 8psi. This limit is there to prevent an overboost condition and to protect your motor. When the threshold it reached injector PW will be cut to 0 for a split second until MAP drops below the limit. Therefore with the default settings if you try to boost near or over 152kpa you will feel the engine cut out when Overboost Protection kicks in. This can feel like a single cut, or it can feel like the car is erratically cutting out if you stay on the throttle and continue to bounce off the limiter. To change the Overboost Protection limit from MegaTune, open the Advanced menu, select 'Over Boost Protection', and set the new limit in kpa.

Look what I found!!!