Red Dragon

iTrader: (17)

This is a 2008 Evo X MR. My car is overboosting, at full and partial throttle. Every time boost hits +25PSI, it triggers fuel cut and DTC come up. I scanned the ECU and it shows P1235. The car drives fine, but every time, the boost builds up to 25 PSI, the car dies.

I have done no mods with in the previous 6 months. This problem just started 3 days ago. I have checked my intake piping and boost and vacuum hoses, and it appeares to be fine. I am currently running "Gonzo USDM SST 91 Oct map" I have been running the same map for a year. I have had over boost problems before which was caused by: dramatic temp changes; tightend wastegate (back to stock now). It has never been this bad before. The temperature out side is -3C; yesterday 15C; Tuesday 10C. I cannot hit peak boost (20-23PSI) at all, boost levels just keeps going and then cuts out.

Help me out, Give me some ideas on how to fix my problem.

Attached is a Log file. Log ID 28 shows the overboost.

goofygrin

iTrader: (5)

what are your mods?

you can disable the code, get a custom tune, or try and figure out the tables yourself. The log you posted is NOT a pull log (ie. 3rd gear from 2krpm until it pops, check the TPS column). You're getting this at partial throttle. You're going to need to adjust the airflow check tables as well.

weebles

I'd check for boost leak but if there isn't one present just re-adjust your airflow. You still using stock boost control solenoid?

Strange you would get a p1235 at 25 psi, I've overboosted to 30 psi without throwing that code before. You can also disable that DTC if you really want but it's better to tune it out

Red Dragon

iTrader: (17)

My mods
T1R Racing Test Pipe
Nisei UICP
Nisei intake Pipe
Perrin Drop-In Foam Filter

I just dont understand. I have been running this map for a while and never had a problem like this before.

I will do another log tommoral and then flash it back to stock to see whats up.

ddb

iTrader: (1)

Bump for an answer, if you found out what was your issue.

walukab14

i have a 08 gsr i know exactly whats the problem with car its the tune,not thw maf sensor, not throttle,specially not a vaccum leak its one of yoARARur mods in the car causing it, like what you said you have this problem before right and now it got worts..BEWARE TO ANYBODY WHO'S RUNNING A DROP IN FILTER WITH A CODE 1235 MAP this is cause by a cloged intercooler and piping due to the drop in filter foam that got suck for some reason and cloged the intercooler and pipings, if you guys look at your stock uicp it will swell up specially when giving it a gas if this happen disconnect your uicp and look into intercooler to see if it is cloged, SO EXPERIENCE WISE NEVER AGAIN USE A DROP IN FILTER,MY CAR STILL WAITING FOR MY NEW ETS INTERCOOLER KIT W/ 4"IC HOPEFULLY IT GETS HERE BEFORE 9/14/11 GUD LUCK GUYS

ddb

iTrader: (1)

I was simply wondering what was the issue. A friend of mine with a X had this overboost 1235 cel. Only mods were, AEM intake (rescaled), magnaflow cat-back, and HKS VTA bov.

He installed the recirculation kit and overboost went away. When i'm talking about overboost ,it was hitting load of 280 and 27 psi of boost when shifting. IDC were at 114%.

Hiboost

iTrader: (9)

A boost leak test is always a good idea before adjusting the tune if you have touched the intake parts. It's possible that the signal from the boost source to the Wastegate Actuator isn't strong enough. You can go to "safe mode" by hooking a vacuum line directly from the boost source to WGA which would verify that it can hold the ~12 psi base pressure. If it still goes crazy you have more issues for sure. It could be as simple as the numbers in the boost control portion of the tune are too aggressive and allowing the boost to go too high.

The overboost code is likely coming from exceeding the load values in the Boost Limits table which is typically set 20% above what you normally see. If the load exceeds these values for more than the default 1000ms (1 sec), it shuts down the party and your car hits a brick wall.

Best to get this sorted by a trusted shop or tuner before it causes engine damage if you can't figure out on your own.

Boost spikes between shifts on an MR are caused by the Lower Bound Ignition Timing table being too retarded where the problem occurs. To minimize this you need to set the timing to within few degrees below what the High Octane Timing map values and smooth out the transitions in the tables a bit.

ddb

iTrader: (1)

Thanks for your insight. But the problem is solved, it was really the HKS BOV VTA that caused overboost. Putting it in recirculation mode everything went back to normal. It is on a GSR 2008 also.

But what i'm not understanding is, how can a vta cause an overboost between shift. I mean pressure is still evacuated. I understand it can cause rich shifting and stalling issue but overboost?

fostytou

iTrader: (15)

I couldn't disagree more with this. If you can't properly install / use a drop in filter then I don't know if you should be doing any more serious mods.

Do you know why that pipe swells (stock)? ...because it is filling with boost.


The actual definition of this code in the FSM is:

(13A-618)

Your car was measuring more airflow than it consumed, so it did not know where the rest was going when you vented. In a car where it is designed for it or the airflow meter is before the BOV ALWAYS recirculate.

ddb

iTrader: (1)

Thanks, that's the answer i was looking for. So, if i understand well, the car overboosted only to try to regain the air vented to the atmosphere.

fostytou

iTrader: (15)

No, there was never an overboost (or at least that is not what this condition reported). There was a difference between the amount of air the car thought it should be using and what was flowing past the MAF.

ddb

iTrader: (1)

I really mean overboost, that log was on stock map.And simply putting the recirculation kit on the bov everything is ok.So, i wondered what happened.

ddb

iTrader: (1)

Ok, problem is back. i believe there is a leak near the blow off since switching the bov in recirculation temporarly corrected the issue.(maybe the rubber o-ring where the bov attach to the mount).

I'm gonna tried to switch to a stock bov to see what it does.