MitsuJoe

iTrader: (133)

Alright guys I need some help. I thought I fixed this problem with the MBC. I have boost set to 20-21lbs with my MBC. I have 3" full exhaust -no cat -, the UICP I just made, a catch can, Walbro 255, intake, with Dejontool intake pipe, and a TurboXS H34 BOV.

When I do a "hard" 3rd gear run to redline around 5500RPM the car backfires and I get a CEL. When I get the CEL checked they say it is Overboosting. Now the MBC is at a solid level and enough fuel should be there, my AF gauge does not lean out. What could it be? Have I finally reached the airflow limit of the stock ECU? It feels like fuel cut but it is just hard to believe. This has only happened since I put the test pipe on.

The car just stops going and then picks up where it left off until redline. It is really f*cking annoying. Any help!!!

Nez136

iTrader: (10)

when you hooked up your MBC, what of your stock boost controller??? did you take it out completely?

MitsuJoe

iTrader: (133)

I followed instructions on here by capping off the boost control solenoid and running a line from the wastegate to the MBC and then teeing in in between the BOV and intake manifold. I am more than positive I did this right.

Nez136

iTrader: (10)

im am running almost the same set up with out a cat but i have an e-01, my car backfires a lot but never sets of a cel or effects my porformance, what about your O2 sensor, what r u doing with that?

MitsuJoe

iTrader: (133)

I have two of the 18mm anti-foul adapters and an electrical cheater for the O2 sensor. Typically the only times I get a light for the O2 sensor would be when I am cruising, never at WOT.

I just came back from another run and it backfired or fuel cut again. Hopefully reseting the computer will fix it.

I am resting the computer right now. I will disconnect the battery for 15 minutes to try get things back to normal and then go for another run.

I am still on the stock clutch, although this feels nothing like a slipping clutch, further I doubt a slipping clutch will give you a CEL.

Evoisdream

iTrader: (27)

ummm when u set the MBC to 20-21 what gear do u set it in? shuold always be 3rd or 4th not 1st etc..... and second how are the plugs dont know if that could really cause it but i have herd of them getting blown out under a heavy load but if the CEL is reading overboost.... then its probly not them just an idea..

evoisdream

MitsuJoe

iTrader: (133)

I changed the plugs at 15k to BPR7ES

When I set the MBC I tested 3rd and 4th gear and the boost remains the same.

I reset the stock ECU as explained above and went and beat on it a little but and no fuel cut or Overboost CEL. I am sure this may change tommorow but resetting the ECU fixed the problem today.

matt55

iTrader: (12)

Overbosting , due to the MAF seeing "to much flow" and the ECU thinks the waste gate acutator failed so it cuts fuel . I think this happines at about 300-320whp , If your going to run the same boost level you should look into getting a "revflash" or "Mail in flash" or custom tune

EVO8 WHOA

iTrader: (10)

who put in your fuel pump? i had the same problem because i forgot to put this tiny rubber o ring fitting on the end of the pump and it wasnt getting power or fuel or somthing not sure what but when i fixed that it ran fine but mine did exact thing.

Cajun Power

iTrader: (3)

I couldn't have said it better.

That is EXACTLY what is happeing. You are hitting the fuel cut. Vishnu does an ECU Xflash and I beleive Dyno Flash does the same. If you want to run with big dogs you have to get your ECU flashed to allow for the increased fuel. You can hit the fuel cut as low as 280 AWHP. Per this weekend in a Vishnu tune.

One other note is that is your dealer has done the latest ECU update to your car the Flash will not take .

Hope this helps.

So, for now turn down your boost to get below the fuel cut.

Widebandphillip

iTrader: (1)

You shouldn't get fuel cut at all with at your level. Especially at 3rd gear or so. Pressure test your system for leaks.

MitsuJoe

iTrader: (133)

No I haven't had the PO300 flash done. So I am ok there.

I put in my fuel pump over 10k miles ago.

So far the car is fixed with the computer reset. Although all gremlins always come back sometime, it might just wait until after midnight.

WNLancer

which year and month bracket does need the flash from the dealer?

MitsuJoe

iTrader: (133)

Go look elsewhere...this is my thread!!!! j/k


Well I pulled the cable and it fixed the problem for a couple of runs...

My boost gauge is reading anywhere from 19-21 but does not appear to spike. I have a couple of excuses:
The cold Michigan air is bringing ambient temps down
Winter gas in Michigan contains additives that make it "winter ready" which makes the gas less pure
I have reached the limit of the stock ECU and I need to get a flash to compensate for all the extra airflow

PDXEvo

iTrader: (4)

Seems we are having identicle issues here.

I just had my car tuned with the UTEC and we are making 306WHP. I have had the boost set to 1.5 bar (21.73 psi) for a long time without issues but now in 4th gear pulls I am getting boost cut anywhere between 3800 and 6000 rpms. Very shocking to say the least.

I thought the stock boost cut was at 24psi but if what has been said here is true then the ECU must think the boost is higher based on MAF. Anyway to disable or raise this value without re-flashing? Or anyway to change the value in the UTEC?