130% IDCs on 650s

[beat90tsi]

I'm running a MAFT 3.5" sensor (set correctly in the MAFT) blow-through setup with 650s and I am continually getting way high IDCs.

I am running slighly lower than base FP ~36.
The MAFT is basically set for 650s. My mid and hi trims are around 100. I'm running around 18psi, trying to resolve this problem. I get no knock in 1st and 2nd, sometimes 10 counts or so in the higher gears.

The car runs really well, no problems at all with driveability or power. My friend commented tonight that he thought it was similar in power to his modded STi. I have checked for boost leaks, and I have a small leak on the TB shaft seals, but nothing major, nothing that would let that much air escape. I am beginning to question my MAF.

Has anyone else run into a similar problem with the MAF reporting more air than it is actually seeing? Should I question my ECU? I know that fixing all of the boost leaks is important, but this is a wicked overshot in IDCs, and I can't believe I'm leaking that much air out.

Let me know if anyone else has had a similar problem.

 

[Sean485]

Do you have an SAFC that you can see what the max Hz reading is on a hard pull? Is the ecu reprogrammed in any way? If it isn't it seems odd that it would get that high, I would think it would find fuel cut at ~105%

Whats the reading on your air temp, coolant temp, tps and baromoter sensors?

 

[beat90tsi]

No SAFC, stock 90 ECU, coolant temp 192-201, TPS normal, air temp and baro NA since I'm running the MAFT. My air volume will get to 6, but the Hz never exceed 1605 or something around there since I'm reading it through the logger.

 

[Sean485]

I ask about the air temp and baro because the connector on the maft is shady and sometimes those wires dont make a good connection and can throw off the IDC's.

Do you have the "fuel cut" switch on the maft to disable fuel cut?

 

[beat90tsi]

yes i have the fuel cut disabled, i never monitor air temp or baro on the logger, but I will just to find out if they're in proper range.

 

[beat90tsi]

baro: 100-105
air temp: 74-78

actual outside temp during this run ~55 deg F
Does those numbers sound right for those conditions?

I ran to redline and got 122% DC, same problem as before.

I was at about 20psi, and I'm running an evo3, so I know it's going to be pushing a lot of air, but this seems ridiculous.

 

[beat90tsi]

are those good baro numbers for the MAFT?

 

[Sean485]

My baro reads 96 and my air temp reads 82 so I am guessing thats not the problem as the little bit of difference there shouldn't cause IDC's like that.

What kind of logger are you using? Try logging rpm and injector pulse width instead of IDC and then doing the math yourself with the rpm and IPW to see what the IDC is to make sure it isn't just a glitch in the way the logger is calculating the IDC.

 

[beat90tsi]

yeah i'll have to try that, or borrow someone's logger

 

[beat90tsi]

well i erased the memory on the palm, and reinstalled my pocketlogger software, still got IDCs ~120%

I mean, it's running well, there are no other indicators that things are not as they should be, but it's really pissing me off, I'm ready to sell this piece.

maf is getting swapped...

 

[beat90tsi]

I'm running the old version of the MAFT, I have read about some people have problems with it, is this one of them?

 

[Sean485]

How "old" of version? I'm running v1.3 and i'm only getting 68% IDC on 850's and thats with the fuel cut switch not limiting the Hz reading to 2249Hz like it does when you have the maft set to "prevent" fuel cut. Also i'm running pocketlogger software as well.

I would try switching back the maft to "allow" fuel cut and see if you hit it, and if you do what your IDC is at that time. I dont understand how the ecu would be allowing IDC's that high and not hitting fuel cut. The only way the maft can prevent fuel cut is by limiting the Hz reading to the ecu so it will think there is less air coming in than there actually is.

 

[beat90tsi]

Yeah, I'm 1.3 as well, it was the first version if I'm not mistaken. I wish I had more time to diagnose this, it's keeping me from getting that POS running better. I'll try the IPW tomorrow on my way to work and home.