Fuel cut!

[nuggets]

Okay


I have read tons of threads on fuel cut and have checked out EVERY possible problem people have had and how they have fixed fuel cut.

-My plugs are fine, my wires are fine
-I did a boost leak test and fixed all the pitting holes on my intercooler and any other leaking hoses
-My fuel pressure is fine
-I hold 10 lbs just fine





Still in the high rpm's around 5-6 i get nasty fuel cut. I'm running stock injectors, stock fuel pump, lower honeycomb removed (free mods), B&M command flow Fuel Pressure Regulator with fuel pressure sock.

On my other engine i ran 18psi just fine and never got fuel cuts. blew hg, long story, anyways, 2nd engine all of a sudden, same setup, getting fuel cut.. on stock boost.


I KNOW my turbo exhaust housing has a crack in it but could this be the culprit?? Thanks

 

[oldman]

Possible bad maf, wiring or ecu. I see free mods in your profile, does that include the maf? Assuming all conditions you listed are true.

 

[DSM90AWD]

I have read tons of threads on fuel cut and have checked out EVERY possible problem people have had and how they have fixed fuel cut.

Then you know the only way to eliminate fuel cut is thru an upgraded EPROM (dsmchips). Removing a honeycomb (or two) will delay the onset of FC but not eliminate it. Colder air = more airflow at same boost level.

On my other engine i ran 18psi just fine and never got fuel cuts. blew hg, long story, anyways, 2nd engine all of a sudden, same setup, getting fuel cut.. on stock boost.

18psi is not stock and with a similar setup on my 1G I got fuel cut until I got 550s and a S-AFC with which I could scale back the fuel (actually the air read by the MAS) further delaying fuel cut.

 

[TSIfreek]

I would bet on your mass air is at falt. Get a 2g mass set up and will cure the problem.
1g mass airs have a hard time with high boost.

 

[nuggets]

I guess my setup between the two motors isnt exactly same as before, but it's pretty close. Now I can't even run 10psi whereas before I was running 18psi no problem.


what i used to have:
stock 4g63
B&M fpr
stock exhaust system
K&N
free mods
^^^^^^^^^^This is what I had done when I was running 18lbs with no fuel cut

what i have now:
stock 4g63
B&M fpr
stock o2, 2.5 downpipe, 2.5 testpipe, 3 catback
2g exhaust manifold
K&N
free mods
removed balance shafts

^^^^^^^^^^This is what I currently have done and am only running 10lbs with fuel cuts


only difference is my exhaust system but much less boost.


In this thread, which I have read completely
http://www.dsmtuners.com/forums/showthread.php?t=929&page=3&highlight=fuel+cut

The LAST POST by crankbender (a dsm wiseman) completely explains fuel cut q's and answers saying it is not a good idea to run a 2g MAF unless it is balanced out by other mods. Could it be possible that my new exhaust setup could be flowing that much more where I cant even run 10psi? Therefore, getting a 2g MAF would do nothing for me?



The only other thing I can think of that might be a possibility would be the fact that I live in Wisconsin and it still is cold up here and it was summer when I was running 18psi on the older motor.

thanks

 

[DSM90AWD]

The LAST POST by crankbender (a dsm wiseman) completely explains fuel cut q's and answers saying it is not a good idea to run a 2g MAF unless it is balanced out by other mods. Could it be possible that my new exhaust setup could be flowing that much more where I cant even run 10psi? Therefore, getting a 2g MAF would do nothing for me?

The 2G MAS stock flows ~32% more air at the same Karman Hz so bolting one up (no add'l mods) would cause you to run 32% leaner and delay the onset of fuel cut. What people normally do (what I did) was to install 550s at the same time which flows ~ 22% more than the stock 450s so are now only running ~10% leaner so are pretty good complement. Can get these even closer to zero by way of a modified EPROM (which can also eliminate fuel cut ) or an AFC.

The only other thing I can think of that might be a possibility would be the fact that I live in Wisconsin and it still is cold up here and it was summer when I was running 18psi on the older motor.

The ECU calculates airfow based on actual Karman vorticicies read, barometric pressure and air temp. Colder than normal Air temps can cause fuel cut onset sooner as the air is denser = more overall air read fopr the same ATM, Karman count.

For sake of eliminating the obvious troubles, check to make sure that your intake/IC piping is leak free. Although your boost gauge is reading 10psi, you could be leaking out air read by the MAS, so actual boost at the compressor could be much higher.

 

[tsiboy83]

Doesn't fuel cut suck? I used to get fuel cut 17psi at about 3500-4000 and ever scince I put my safc in and had the car tuned right (by someone who knew what he was doing) I have never had a problem since. I run 20psi all day long with no problems!! I also am running a full stock fuel setup minus buschur fuel pump

 

[nuggets]

okay so. pretty much im going to have to get bigger injectors, 2g maf, chip/eprom my ecu and go from there. When I get the cash flow, I shall do it. Thanks for your knowledge guys