Why am I hitting what seems to be fuel cut at 9-10psi?

SuperRallyRoo · Post by **SuperRallyRoo** » Tue Apr 22, 2008 3:53 am

I have a hybrid ej22T with a TDO5 16g slant mount intercooler and a professionally merged harness. I have a MBC installed and a MFCD installed as well. I can't seem to find a way to get the car to not die out at 10psi!? My touring wagon has the same setup and it doesn't do this at all? (I actually took the MFCD off the TW and installed it on the impreza) Everything was fine with the vf11 it never hit fuel cut. I put on the MBC and FCD to try and get rid of the problem but it has done nothing. It did hit fuel cut hooked up factory to the boost solenoid. Any ideas? This is my rally car project and I am definatly going to need more then 10psi. Or at least 10psi and not have it cut out all the time. Could it be my fuel injectors? I also have a walbro fuel pump btw.

douglas vincent · Post by **douglas vincent** » Tue Apr 22, 2008 4:03 am

Is your MAF maxing out? I bet it might be....

SuperRallyRoo · Post by **SuperRallyRoo** » Tue Apr 22, 2008 4:05 am

doesn't it do that at 15psi? And wouldn't it just make it run lean and not just hit fuel cut? My tw runs out at 15psi.

douglas vincent · Post by **douglas vincent** » Tue Apr 22, 2008 4:08 am

A bigger turbo will move more air @ less psi, or some such crap.....

Anyway, you need to somehow look at the voltage the MAF is kicking out @ 10 psi.....

SuperRallyRoo · Post by **SuperRallyRoo** » Tue Apr 22, 2008 4:10 am

hrm interesting... Piggyback here I come it looks like.

douglas vincent · Post by **douglas vincent** » Tue Apr 22, 2008 4:10 am

How are you tuning it?

Adam West has one of my Modified Big MAFs and will be tuning with it soon. That may be an option for you.

Is the maf you are using a metal or plastic JECs?

SuperRallyRoo · Post by **SuperRallyRoo** » Tue Apr 22, 2008 4:11 am

IDK you can see it top right of the pic I just put up. It looks plastic? I am going to give adam a call...

SuperRallyRoo · Post by **SuperRallyRoo** » Tue Apr 22, 2008 4:14 am

hrm well he didn't answer. What does your modified big maf do? Handle alot more boost? Is it plug and play? Can ya give me the run down? it might be just what I need? How much?

douglas vincent · Post by **douglas vincent** » Tue Apr 22, 2008 4:39 am

Thats the lowflow metal maf.

The plastic JECs will handle more airflow before it hits 5 volts. How much? Cannot give a number but it IS more than the metal maf. You need to ground the blue wire though (tap it and ground). Of course if you do this you need to have some sort of tuning.....

And the Doug Vincent Modified MAF? It lets you run 400 whp withou maxing out.

Do you need the BIG MAF? Well, first you need to find the current MAF signal and see if its maxing out. If yes, then you need a piggyback. Then you may/may not need injectors.

THEN you can install the plastic JECS and tune with that. And if you max that out, THEN you need my special MAF. Its $60 plus a core.

SuperRallyRoo · Post by **SuperRallyRoo** » Tue Apr 22, 2008 4:41 am

<confused. Come tune my car Doug. I would like piggyback anyway so I can run antilag

BXSS · Post by **BXSS** » Tue Apr 22, 2008 2:24 pm

Adding to what mxpunk wrote about the e-manage ultimate it lets you run the car MAP, eliminating the MAF.

It also does sequential fuel injection, A/F ratio target map option (Enter desired AFR @ load & this is supposed to write its own injector map), & MAP tracing data logging.

A 5bar map sensor is good for 58psi of boost, a 3bar is good for 29psi regardless of the size of turbo used....

All_talk · Post by **All_talk** » Tue Apr 22, 2008 8:51 pm

You may already know this but, the Turbo ECU's use the MAP signal for fuel cut. The N/A uses the MAF signal.

A friend of mine just found a problem similar to yours. He has a ’97 Legacy GT with an EJ20G, VF23, 550 injectors, stock ECU and a PP6. His last tune on the dyno found the limit of the stock MAF/ECU. I’m not sure he was truly maxing out the MAF, but he certainly was running the voltage up to the point the ECU wanted to cut the fuel. He’s running the e-manage now, and based on his experience tuning it, I say its worth the extra money over something like the PP6.

Gary

555BCTurbo · Post by **555BCTurbo** » Tue Apr 22, 2008 11:17 pm

SuperRallyRoo wrote:I would like piggyback anyway so I can run antilag

You don't have the pockets to run antilag

keirnna · Post by **keirnna** » Tue Apr 22, 2008 11:26 pm

I want to put a new age Impreza MAF on my EJ20K. Any ideas how to go about doing that?

Post by **Legacy777** » Wed Apr 23, 2008 6:44 pm

You should be able to just fit it in with an adapter pipe that holds the MAF. But then you'll need to address the ECU since the transfer function is different.

SuperRallyRoo · Post by **SuperRallyRoo** » Sun Apr 27, 2008 1:08 am

Ok fixed the problem it was stupid. The person who put my spark plugs in who will remain nameless... Didn't gap them correctly! The gap was too big and the boost was blowing the spark out. Kinda crazy!!! It now can be floored and its hitting 10psi no problem. Its stupid fast lol.

legacycentral bbs

A forum for 89-94 BC-BF(BJ) Legacy Owners and Fans

Why am I hitting what seems to be fuel cut at 9-10psi?

Why am I hitting what seems to be fuel cut at 9-10psi?