Help ?? Weird Cut in 4th Gear

Ricardo_yen · Post by **Ricardo_yen** » May 25th, 2012, 4:05 pm

Please help

So the initial v 1.02 map, I upped the loads, and got what I believed is fuel cut, so I changed out the in tank fuel pump to the 260l kit and upgraded the cam driven pump (cp-e), and still the same thing.....

To describe it in, gears 4th as the rpm is climbing and my foot is flat out between 4500 and 5500 rpm I get a cut out and then its back on and climbing.... Quick vigorous jerk, and powers back on, I keep my foot flat out....... will change the relief valve tomorrow, and see....The load I'm commanding is 1.93 and the limit for the normal/overload and baro is set to 1.98.......So even More confusing,

I did a log with my dashdaq ( only thing I had... Laptop was at home) and the fuel pressure is not dropping, from what I can tell.....

I ran the car in 4th and got the cut off....

The wasgate duty cycle is up there, so is boost, I'm commanding 1.2 bars but its over, running to 1.28 or so.... Not sure what to look for now....

So part 2

If I'm in 3rd and I go WOT till 6K rpm nothing, change to 4th and rpm is high up, like 5 to 5.5K rpm, and I keep the pedal to the floor, NO cut out. Its only when I'm driving in 4th gear slowly, and I foot it, when I hit like 5 to 5.5K I get cut out,

skiptownmcat · Post by **skiptownmcat** » May 27th, 2012, 4:01 am

Without a log and going off the info given, I think it's the overboost fuel cut table that'll probably need raising a touch in those rpm's where the cut occurs. Raise the overboost throttle reduction table a touch as well.
If that doesn't work try the overload fuel cut table.

Kevin · Post by **Kevin** » May 27th, 2012, 11:22 am

Rix, like i mentioned in an earlier email. I had the exact same problem but it wasnt a fuel cut. It was my bpv that was leaking causing me to overboost and hit a cut. Try testing with another bpv / bov

Ricardo_yen · Post by **Ricardo_yen** » May 28th, 2012, 3:05 am

Hi Guys,

I have changedthe rail relief valve and my BOV to the Turbosmart Dual port, in doing so, i broke the radiator.............

,

so now i have to wait and see when i can replace that,

after that will test the BOV, and if that fails will give the tables a try...........

Ricardo_yen · Post by **Ricardo_yen** » May 29th, 2012, 1:29 am

Hi Andrew,

Attached is my log + Tune

mituc · Post by **mituc** » May 29th, 2012, 9:35 am

Not being able to open each others tunes not even in some kind of a read-only mode is highly frustrating and sucks a lot from the community point of view.

Long story short, you seem to have a 6MPS/Mazdaspeed6, the other guys with a 3MPS/Mazdaspeed3 or CX7 can't look at your tune. So I'm only going to guess what's going on.

When you cut you're at 1.23BAR of boost, this usually means (depending on what your elevation is) around 223-225kPa MAP (monitor MAP instead of boost with your Dashdaq, it will prevent it from making the MAP-BARO calculations all the time, you can eventually log BARO separately). Please check the Absolute Limits -> Overboost protection fuel cut table and make sure that the MAP-BARO values can go up to like 1.35BAR (that's 20PSI or so).
Also, make the Overboost protection throttle reduction values about 3-4kPa lower than the fuel cut table so that the ECU logic can close the throttle before cutting the fuel which is a pretty agressive safety measure (last resort).

In the same Absolute limits section check the overload fuel cut table and make sure the values there are with at least 0.2 higher than the per-gear load limits/targets in your tune at the same corresponding engine speeds.

Good luck and let us know what you find.

P.S. I'm glad to see other people using dashdaq, even though they f.cked up the maf voltage readings a long time ago and the BAT readings in their latest 2.0.96/97 releases. That's a pretty decent monitoring tool when you can't keep your laptop strapped with the passenger seat belt and also allows long trips monitoring.

Ricardo_yen · Post by **Ricardo_yen** » May 29th, 2012, 10:47 am

@ Mituc,

Im at sea level

Have a look at the attached file for whats on my current map,

my requested load limit overall is 2, and limit rpm is 2....... the rest is in the pictures attached

mituc · Post by **mituc** » May 29th, 2012, 4:40 pm

ok, so it's as I suspected. You will never meet your load targets with those overboost protection tables. Increase the overboost protection fuel cut values for the last 2-3 lines to 235-237kPa and make the throttle reduction overboost protection tables with 4-5kPa less (231-233).

The overload protection tables values are fine.

P.S.: you're targeting a bit too high load in the upper RPM's. make sure you make a few pulls in 4th and monitor BAT to make sure you're not overheating. I strongly recommend to lowering the load targets in 5th because the stoc turbo may not be able to push that much air up to red line to sustain that load without overheating or blowing the shaft.

skiptownmcat · Post by **skiptownmcat** » May 31st, 2012, 8:29 am

Any update? Mituc pretty much said exactly what changes I proposed in that email.