Weird boost/fuel cut at 0.7 BAR - EVO 4

[Pullout1979]

am getting a weird boost cut (I think) when I hit around .7 bar. I lose acceleration and start to back fire if I hold the gas pedal down.

I went to a local mechanic and we checked for boost/vacuum leaks and couldn't find anything. Also took a look at the plugs and he saw signs that my car is probably running lean (in his opinion)He recommended a new tps and boost sensor.
Troubleshooting done so far:
-Changed plugs gapped to .026
-Checked battery and alternator
-Set tps to .07V at idle/ played around with different tps settings
-Ordered a new tps that will arrive soon
Next we did some logging on evo scan.

These are 3rd gear pulls at WOT. Boost builds cleanly then cuts out at .7 BAR

I am at a complete loss here, any help would be appreciated

AFR

Link to download logs here: https://drive.google.com/folderview?id=0B1okhUkO4dhuN0pqOVY1cldNRE0&usp=sharing

 

[And@fcm]

What are you using to log the afr? Has this just started our did you change something? Has the car been mapped? The logs show the tps working so would have said its not that. What does it read at full throttle?

 

[Pullout1979]

I am using evoscan to log the air I'm not sure where it's getting the info from?
I put on 3 inch cat back exhaust plus a 3 inch test pipe to remove the cat this was about a month ago.


I'm not sure what you mean by mapped? I have not since it's an Evo 4 and the ecu cannot be replaced flashed or mapped

This was foot to the floor full throttle. Sorry if I don't understand your question correctly.

 

[Simon@NTS]

Need to log 1 byte load as well as to see what loads your hitting on wot, also a wideband is required AFR MAP is no good here, use tps percent rather than volts

 

[And@fcm]

where are you based?

When logging you only need to select the following items,
RPM,TPS,TimingAdv,Load1Byte,WideBandAF,Load2Byte,InjPulseWidth,InjDutyCycle,KnockSum,WGDC.

it will mean that you'll get a better resolution in your data. You'll need something like an innovate lc-1 to log the afr, as Simon said the AFR is not what the actual fuel is but what the ecu will try and do.
I'm not sure why your knocksum always reads 1 it should read 0.
What ecu do you have in the car? Sorry noticed that its a standard ecu you will need to replace this with a 5 or 6 ecu.

We'd really need to be able to see the load and actual afr before going any further. Depending on the rom he 1byte might not be enabled so you'll have to modify it to record the 2 byte load or select LoadCalculated (and the other items this needs).

The change of exhaust and decat will allow the engine to breathe easier so will mean that you will be getting more load which is why its fuel cutting. You really need to get the car mapped before you cause any damage.

Andy

 

[Pullout1979]

I live in Vancouver, Canada

The car has the stock ECU and I have no idea where to source a 5 or 6 ECU

We did not enable the load log so I will enable it tomorrow and re try.

I have been running this exhaust for quite awhile just not sure why this is happening now.

 

[And@fcm]

its more than likely that a change in the weather (getting colder) will cause it due to the air becoming denser

You could source an ecu from the UK and get it shipped, you can also use an ecu from a 7 or 8 but would have to swap a few wires over

 

[Pullout1979]

Could you point me in the right direction? IE: a specific site etc?

 

[And@fcm]

theres one on ebay here
Evo 6 ecu. Lancer evolution vi gsr virgin ecu | eBay

 

[Simon@NTS]

My concern here is that its happening at .7 which is not really fuel cut territory, logging the load could show up a boost leak, have you changed the coil packs? fuel pump?

 

[Pullout1979]

Coil packs are farely new ~1 year old. Never changed fuel pump. I really need to get a boost leak test done

 

[Simon@NTS]

Coil packs are farely new ~1 year old. Never changed fuel pump. I really need to get a boost leak test done

Id be changing the fuel pump as part of course if you've never changed it mate

 

[Pullout1979]

Id be changing the fuel pump as part of course if you've never changed it mate

Which is a good drop in and forget fuel pump?

 

[Pullout1979]

I made som enew logs with the requested data

 

[And@fcm]

Drop a walbro 255 pump in, you'll have to drop the tank to do it properly.

The load looks very wrong the 2 byte isn't setup on a standard rom so you'll have to usethe calculated one.

 

[And@fcm]

Also it looks like your throttle isn't openning fully what does the tps read with out the engine running when you put your foot to the floor?

 

[Pullout1979]

Also it looks like your throttle isn't openning fully what does the tps read with out the engine running when you put your foot to the floor?

It reads about 80%

What do you mean by using the calculated one?

 

[Pullout1979]

Would this fuel pump work in my 4?

Walbro 255lph Fuel Pump W/Install Kit :: EVO 8 / 9 Fuel :: Fuel Supply :: EVO Performance Parts | EvoMoto.com

 

[Simon@NTS]

Your logging load 2 byte which is not logging correctly give me Rom Id and should be able to give you mut table addresses also wot is max 87, do a static log check wot is 95percent plus

 

[Simon@NTS]

Sorry 2 byte load I refer to