I plugged my Tactrix Cable into a frieds 04 STI last night because I noticed that his Defi Gauge wasn't reading even 14psi. His car (BLUE STI below in logs) had been utec dyno tuned by a local shop and they convinced him that there was something wrong with the defi gauge he has and that he is actually hitting his target boost of about 17psi.

So upon taking logs of the ecuExplorer program through SSM sure enough the stock ecu shows dead on to what the Defi boost gauge was showing. Not even hitting stock boost.

The owners brother also has a 04STI but without a utec and stock tune on the car, so we decided to take a log of his run (White STI below). We can see here that he indeed hits stock boost and runs well.

So I am very unfamiliar with Utec being mostly a RS turbo guy but the stock ecu and the Defi gauge which is tapped directly from the manifold at the same point as the stock boost sensor both read that he isn't hitting target boost.

Any Ideas?

BLUE STI
Perrin BigMAF
TBE
XXheaders
Utec dyno tuned

(RPM) (IGN) (MAF) (MRP)
3601 7.03 -7.81 44 1 14.6 2.64 0.98 44.46 -4.643
3685 7.03 -7.81 44 1 14.15 2.66 0.99 45.89 -4.788
3673 7.03 -7.03 44 1 14.89 2.66 0.99 45.45 -4.643
3757 7.03 -7.81 44 1 14.43 2.66 0.98 45.3 -4.788
3790 7.81 -8.59 43 1 15.36 2.7 0.98 49.28 -4.643
3848 7.81 -10.16 43 2 15.6 2.74 0.98 52.08 -4.208
3884 7.81 -8.59 42 2 17.4 2.82 1 56.4 -3.627
3937 7.81 -9.38 41 2 18.48 2.9 0.98 60.82 -3.192
3948 10.16 -11.72 41 2 19.37 2.9 0.98 62.21 -2.902
4021 10.16 -13.28 41 2 18.87 2.96 0.97 65.76 -2.757
4090 10.16 -11.72 40 3 21.81 3.08 1.02 75.65 -1.741
4263 10.16 -10.94 30 6 36.38 3.66 1.01 131.52 4.063
4388 10.16 -5.47 19 5 66.47 4.1 0.97 193.3 8.996
4579 10.16 0 17 4 107.45 4.44 0.87 254.11 12.333
4782 10.16 0 17 4 117.31 4.52 0.79 269.86 13.059
5057 10.16 0 17 4 114.36 4.54 0.75 274.27 13.204
5314 10.16 0 17 4 114.5 4.54 0.75 274.29 12.914
5540 10.16 0 17 4 114.64 4.54 0.75 274.31 12.478
5801 10.16 0 17 4 116.32 4.54 0.75 273.88 12.188
5983 10.16 0 18 5 112.33 4.54 0.75 274.41 11.898
6204 10.16 0 21 5 115.14 4.54 0.75 273.47 11.608
6353 10.16 0 22 5 115.2 4.54 0.75 274.5 11.318
6527 10.16 0 26 6 115.57 4.52 0.75 270.62 11.318
6750 10.16 0 29 6 115.2 4.54 0.75 273.65 11.318
6840 10.16 0 30 5 116.74 4.56 0.75 276.65 11.463
7106 10.16 0 24 0 4.55 2.08 0.75 15.86 -4.788
6848 8.59 0 24 0 4.38 1.56 0.82 7.75 -9.286
5716 7.81 0 46 0 28.05 3.4 0.91 109.18 -0.29
5341 7.81 0 30 5 74.06 4.06 0.96 191.19 6.529
5397 7.81 0 19 5 107.08 4.4 0.87 247.56 11.318
5399 7.81 0 17 4 118.64 4.52 0.78 272.96 12.478
5601 10.16 0 17 4 120.67 4.54 0.75 273.96 12.478
5690 10.16 0 17 4 117.75 4.54 0.75 274.46 12.333
5785 10.16 0 17 5 116.01 4.54 0.75 272.5 12.188
5971 10.16 0 18 5 117.19 4.54 0.75 273.98 12.043
6055 10.16 0 19 5 114.96 4.54 0.75 274.48 11.898
6170 10.16 0 20 5 114.51 4.54 0.75 274 11.753
6293 10.16 0 21 5 116.8 4.54 0.77 273.52 11.608
6336 10.16 0 22 5 113.53 4.54 0.82 274.02 11.608
6509 10.16 0 24 5 116.65 4.54 0.86 274.03 11.463
6599 10.16 0 25 6 116.84 4.54 0.91 274.04 11.463
6644 10.16 0 27 6 116.23 4.52 0.96 270.11 11.463
6706 10.16 0 28 6 115.88 4.54 0.99 274.04 11.463
6789 10.16 0 29 5 115.86 4.54 1.04 274.03 11.463
6790 10.16 0 29 5 4.35 4.54 1.11 274.03 5.224
6432 9.38 0 24 0 4.12 1.6 1.19 7.87 -7.69
6150 8.59 0 24 0 3.94 1.46 1.21 6.04 -10.157
5810 7.03 0 24 0 3.72 1.54 1.25 7.32 -10.592
5436 6.25 0 24 0 3.48 1.64 1.27 8.46 -11.027



White STI
TBE
Stock Tune

(RPM) (IGN) (MAF) (MRP)
3535 -4.69 19.53 25.43 20 0 9.8 2.28 -9.286 0.95
3532 -4.69 11.72 28.79 46 0 10.55 2.32 -9.286 0.88
3549 -3.91 17.19 36.21 46 0 13.63 2.54 -9.286 0.97
3528 -3.91 18.75 61.15 42 2 21.07 2.92 -2.612 0.96
3526 -3.13 24.22 71.51 39 3 25.58 3.06 -0.58 0.95
3611 -2.34 20.31 88.92 35 5 30.82 3.3 1.451 0.85
3699 -2.34 19.53 112.27 28 7 40.24 3.54 4.063 0.84
3785 -1.56 16.41 141.2 23 8 54.1 3.76 7.69 0.77
3899 -1.56 0 173.25 21 10 64.04 4 12.043 0.75
4020 -1.56 0 190.56 23 11 72.04 4.1 14.945 0.75
4191 -0.78 0 197.76 22 10 75.09 4.16 15.525 0.75
4359 -0.78 0 209.91 22 9 79.97 4.22 15.525 0.75
4472 -0.78 0 220.15 22 9 83 4.28 15.525 0.75
4619 0 0 225.95 23 9 84.75 4.3 15.671 0.75
4801 0 0 235.15 23 9 88.08 4.38 15.525 0.75
4924 0 0 240.18 24 9 90.33 4.4 15.525 0.75
5073 0 0 246.11 24 9 91.98 4.44 15.38 0.75
5250 0.78 0 248.68 24 10 94.08 4.44 15.235 0.75
5348 2.34 0 253.83 24 10 96.97 4.48 14.945 0.75
5506 2.34 0 252.96 24 10 98.67 4.46 14.655 0.75
5601 2.34 0 254.68 24 10 97.97 4.48 14.22 0.75
5753 2.34 0 252.52 24 10 98.18 4.46 13.929 0.75
5862 2.34 0 255.1 25 10 98.8 4.46 13.639 0.75
5962 2.34 0 251.23 25 10 97.94 4.48 13.349 0.75
6082 2.34 0 251.66 26 9 98.61 4.48 13.059 0.75
6185 2.34 0 253.82 27 9 100.28 4.46 12.914 0.75
6305 2.34 0 254.69 27 9 100.88 4.48 12.769 0.75
6382 2.34 0 259.19 28 9 100.74 4.48 12.769 0.75
6503 2.34 0 253.86 29 8 99.88 4.46 12.624 0.75
6614 2.34 0 253.43 30 7 100.18 4.48 12.624 0.75
6658 2.34 0 250.44 31 6 98.01 4.46 12.769 0.75
6793 2.34 0 253.46 32 5 99.99 4.48 12.624 0.75
6825 2.34 0 252.19 32 5 97.54 4.44 12.624 0.75
7322 2.34 0 80.17 24 0 4.69 2.96 -3.337 0.75
7143 2.34 0 10.12 40 0 4.57 1.82 -10.012 0.83
6786 2.34 0 123.64 45 0 40.54 3.66 0.871 0.91
5520 2.34 0 200.96 31 5 77.71 4.2 7.4 1.03
5388 2.34 0 236.52 26 10 96.55 4.38 13.349 0.91
5418 2.34 0 243.28 23 8 99.39 4.42 15.235 0.82
5442 2.34 0 244.57 23 8 97.51 4.42 15.235 0.75
5495 2.34 0 243.31 23 8 96.13 4.42 15.09 0.75
5593 2.34 0 239.54 23 8 94.26 4.42 14.945 0.75
5631 2.34 0 242.52 23 8 94.91 4.42 14.8 0.75
5686 2.34 0 245.53 23 8 94.62 4.42 14.51 0.75
5788 2.34 0 240.46 23 7 93.84 4.42 14.51 0.75
5810 2.34 0 243.88 23 7 95.43 4.4 14.365 0.75
5866 2.34 0 242.23 24 7 95.1 4.42 14.22 0.75
5948 2.34 0 245.24 24 7 96.44 4.42 13.929 0.75
5978 2.34 0 246.57 24 7 95.64 4.42 13.784 0.75
6039 2.34 0 241.05 24 7 94.04 4.4 13.784 0.75
6140 2.34 0 244.47 25 7 95.62 4.42 13.639 0.75
6184 2.34 0 244.1 26 8 96.31 4.44 13.494 0.75
6212 2.34 0 242.85 27 8 95.41 4.4 13.349 0.75
6302 2.34 0 241.62 27 7 94.11 4.4 13.204 0.75
6350 2.34 0 245.93 28 7 93.46 4.4 13.204 0.75
6353 2.34 0 245.13 27 7 94.86 4.42 13.204 0.75
6403 2.34 0 246.89 28 7 95.61 4.42 13.204 0.75
6488 2.34 0 246.05 29 6 96.88 4.42 13.059 0.75
6536 2.34 0 244.35 29 6 96.21 4.42 13.059 0.75
6574 2.34 0 242.26 29 5 95.37 4.4 13.059 0.75
6620 2.34 0 244.01 30 5 96.03 4.4 13.059 0.75
6631 2.34 0 246.61 30 4 96.19 4.42 13.059 0.75
6700 2.34 0 242.78 30 4 95.77 4.4 12.914 0.75
6707 2.34 0 242.8 31 3 94.43 4.4 12.914 0.75
7475 2.34 0 52.62 24 0 4.78 2.38 -9.141 0.75
7105 2.34 0 6.19 24 0 4.55 1.42 -10.012 0.83

The UTEC caps the MAP signal being sent to the ECU. With a UTEC installed, MAP sensor readings from the ECU are not accurate while in boost.

What are the MAP sensor parameters on the UTEC? (intercept, gradient)
Can you hook up another boost gauge?

well. I realize that the MAP to the stock ecu could be capped, but why would the Defi gauge in the car read the exact same?

The blue STI w/ utec is hitting significantly higher MAF voltage, but it has a BIGmaf. I would think MAF voltage would tend to be lower with the BIGmaf, so that leans to the Blue STI actually making more power, but what about the Defi gauge?

Also: The boost signal that the stock ecu is seeing doesn't look clamped at all if you look at it.

The blue STI w/ utec is hitting significantly higher MAF voltage, but it has a BIGmaf. I would think MAF voltage would tend to be lower with the BIGmaf, so that leans to the Blue STI actually making more power, but what about the Defi gauge?
The Defi gauge may be defective, but you can only verify this by hooking up another boost gauge and/or datalogging with the UTEC (after verifying proper MAP sensor parameters).

Also: The boost signal that the stock ecu is seeing doesn't look clamped at all if you look at it.It may not look clamped, but you can be sure that it is. It's not a "hard" clamp, if you know what I mean. Do some searching on the UTEC's hardware FCD.

ok I guess i'll have to bring down a boost gaige I know works, and look at it on the utec

we are going to try another boost gauge this week. ill let you know what that reads.

hito, take logs from the utec to get accurate readings.

it also may be spoofing mav voltages. in fact it probably is.

also, the only thing that is worrying us is the owner of the blue STi, Josh, is sure that he has seen 18psi on the defi gauge while using his high-boost map and 16psi on his low boost map. this all starting getting crazy when he blew a vaccum line off his fuel pressure regulator. his CEL was flashing indicating knock because his ecu wasnt reading the boost, therefore not adding the fuel for the boost. ever since then it has not been the same. while on a road tune after the line falling off, the shop tuning the car noticed that the laptop they were using to tune the utec, was reading 18psi and his defi was only hitting 13psi.

this all starting getting crazy when he blew a vaccum line off his fuel pressure regulator. his CEL was flashing indicating knock because his ecu wasnt reading the boost, therefore not adding the fuel for the boost.If the line comes off of the FPR, it's not the ECU you need to worry about.

The FPR needs that vacuum line to raise fuel pressure with boost (keeping static fuel pressure ~3.0-3.5 bar). Without that vacuum line, the fuel pressure would drop dangerously low for WOT/boost conditions and it is very likely that the UTEC would detect knock caused by the lean AFR.

is this josh and justin's cars?

yeah thats what i was explaining.