Car keeps hitting fuel cut

[Supraflymk3]

When I get on it in 1st through 3rd at higher rpms my boost goes up to like 11 lbs and then I hit fuel cut. I can't figure out why its doing it. I'm running wastegate pressure and I have Apexi intake, 3" turboback exhaust, and driftmotion intercooler kit. Oh and its a 7M-GET.

 

[88t]

Mine was doing that and i discovered my wastegate hose had a hole burned into it. The cold weather could also do this. Did your car start doing this all of a sudden?

 

[Devin LeBlanc]

Yep, Mine did the same, Until I got tuned.. Don't hit fuel cut anymore

 

[Supraflymk3]

Its not because of the cold because it started doing it right when I got it all together. And I replaced the wastegate vac line with a new one already thinnking that was the problem.

 

[boostcraver]

You didn't say what size turbo you have. What is your WG psi? If it's bigger than stock or a ct hybrid of some kind, it could bring on the FC before the car "sees" 14.5 psi. The intercooler's denser charge is also probably contributing somewhat. Get a tune, and maybe some bigger injectors with a walbro and see if the problem persists GL!

 

[Supraflymk3]

Its still a stock CT-26. Over the winter I'll be doing suspension and brakes. Then in the spring I'll be doing LEX MAFS, bigger injectors, twin turbo fuel pump, afpr, safc and I'll be tuning for E85.

 

[boostcraver]

For now you could just get an electronic boost controller and keep the boost regulated to say, 8-9 psi, and see if you still get FC. If so, back it off half a pound at a time till you no longer get it and leave it set there for now. Don't let anybody talk you into using any kind of FCD device, as I know of several people who have blown their motors by using these "little black boxes".

 

[Supraflymk3]

Getting a boost controller won't be any help. If the wastegate won't open until higher than 11 psi then it won't open lower than that.

 

[Devin LeBlanc]

I hope your planning on going full stand alone because you cant run E85 on the stock computer even with a SAFC.. The ignition timing will be all jacked

 

[boostcraver]

Getting a boost controller won't be any help. If the wastegate won't open until higher than 11 psi then it won't open lower than that.

Ok, true enough. Guess I kinda forgot you had already said that it was on wg pressure.

 

[whitemike]

I'm not that familiar with the stock setup, but perhaps I can help by stimulating your search in the correct direction!

-Do some people not boost their stock MKIIIs to 11psi? I don't feel like you should be hitting fuel cut. <- If this is true, you should be checking for intake leaks post AFM.
-Has this problem always occurred? Or was there a point in time where this setup worked perfectly? (was it before it got cold outside? air density..)
-If it used to work fine, and now doesn't.. ask yourself.. what have you messed with since then?
-Do you not have an adjustable 1:1 fuel pressure regulator? You may be able to band-aid the issue with that..

 

[supradjza80]

My car would fuel cut between 10 and 15 psi (this was with a full 3-3.5" straight turbo back exhaust) depending on temperature when it was on the stock turbo, so 11 psi without leaks could definitely be causing FC.

 

[bountykilla0118]

If you are running a stock turbo and a stock afm housing then your are on par with what normally happens ......11-12psi is where people normally hit fuel cut on the stock afm ......... thats the reason why people go 550's and lex afm because with the right setup and tune you can get into the 20+psi range but that depends on the size of the turbo.

 

[Devin LeBlanc]

Also remember this is a GE so the higher compression spools the turbo faster than normal bringing it into the fuel cut range sooner.. My brother ran 18 PSI on a big t4 with never hitting fuel cut.. That was on a stock AFM and stock 440cc injectors.. It just didn't spool till 4000

 

[pete]

hey guys i have the same problem an i dont know what to do iv been told with my mods i9 need a new ecu or piggy back?? i have 3"zorst aftermarket cooler and hiflowed ct26??

 

[bountykilla0118]

Do you have a widebad?? If you dont have one, please save yourself the headache and wait until you do have one ...... or you will be pulling the motor to rebuild it faster than you think.

 

[Supraflymk3]

yes i have a wideband.

 

[Nick M]

When I get on it in 1st through 3rd at higher rpms my boost goes up to like 11 lbs and then I hit fuel cut. I can't figure out why its doing it. I'm running wastegate pressure and I have Apexi intake, 3" turboback exhaust, and driftmotion intercooler kit. Oh and its a 7M-GET.

It is supposed to do that by design. Fuel cut can happen between 11-13 psi, depending on other factors calculated by the ECU. The main input being the airflow meter frequency.

Also remember this is a GE so the higher compression spools the turbo faster than normal bringing it into the fuel cut range sooner

How soon the turbo spools has no bearing on fuel cut. The volume of air being pushed out by the turbo does.

.. My brother ran 18 PSI on a big t4 with never hitting fuel cut.. That was on a stock AFM and stock 440cc injectors.. It just didn't spool till 4000

Your post is full of misinformation and misleading information. Try not to do this.

 

[bountykilla0118]

Adjustable fuel pressure regulator and a SAFC would be next...... then tune only the high setting which should be set around 70% throttle. A data logger saves a lot of time and you can get one for $300bucks brand new from driftmotions.

 

[Scot]

From just the ECU standpoint, what can trigger fuel cut and from which sensors?