Decipher this log please!

[ReNaToMS3]

I'm basically on a quest to find what is causing my high LTFT. So i decided to take a look at the wastegate basically on this run and other things. I'm suspecting a bad TIP install but it's a pain to remove and install so im looking into the easier stuff first.

1- I just want to make sure but is the wastegate okay? Spiked to 73% when i began accelerating but way down after that.

I'm on a STOCK BPV for now. Switched to the stock one to see if my Forge was leaking/giving problems. Stock one seems to be holding boost well. When i had the Forge i would sometimes spike to 19PSI and come back down. With the stock one, it seems it just goes to 16 and tapers off.

2- AFR's looks okay? I was around 13's @ 3200RPM than finished at low 10's @6000RPM.

3- Is that ABS Throttle position right? I was flooring it but it only showed a max of 63%, which is weird. Is this the right setting to see if you're actually WOT?

Great if someone can help me a bit. I do a bunch of searches here but each case is a bit different so i'm putting mine. Thanks!

 

[bykeryder4life]

high LTFT is a vac leak post MAF pulling in unmetered air. Check your vac lines and inlet, then reset ecu and let it learn trims again. and I bet its gonna be lower, most likely your inlet man, dont go looking for easy stuff thats not how to be successful on a car like this. You put on an inlet and get high LTFT thats the problem plain and simple. As far as a datalogs, you should log boost, AFR, RPM, Knock retard, Boosted Air temp(to explain random knock events from heatsoak). Unless you have a full control flash from cpe/AP you wont have 100% throttle opening so dont worry its just how this car is, read up. With your mods dont worry about your WG duty cycle unless your boost starts acting up-spiking or falling FAR off target kinda stuff. Stock bpv leaks like a mother ******, so thats why your boost is different with the forge. With an intake and stock tune, it will spike, be ready, its tune time after more mods. Once again read up on whats normal. This car runs pig rich up top on stock tune so dont be surprised to see 9's at redline. It runs hot at spool for economy/emissions so 13's is common...zoom zoom boom at PT boost right there with all the timing it has, so thats why you drive either in vacuum or get fully on it when you wanna go. When you datalog run from 3k to redline in 4th gear. Thats what you wanna look at.

 

[AutoEuphoria]

I really don't see anything wrong with that. It spikes up high because it closes to build boost, then opens up to regulate that boost. The higher the WGDC percentage the more "closed" the wastegate is. Low AFRs are better than higher...so no issues there. You're probably losing a bit of power being so rich, but I'd take that over a blown engine anyday.

 

[ReNaToMS3]

Thx guys, appreciate the help.

And yes, i'm suspecting the inlet too, which i installed twice already to make sure everything was tight and i only suspect the coupler going into the turbo, which is kinda tricky. The clamp is tight but the angle might be off and i couldn't check it for sure.

Problem is i only got my DH after i installed the mods (big no-no i know). So i'm really not sure if there was a problem before that, maybe the purge valve solenoid leaking or a boost tube a little loose (which i tightened again).

I just read the WG could be a problem so i logged it to make sure it wasn't that. I don't have a problem working on the car, it's just 10 degrees out here now so that makes it a little tougher. (protest)

I will probably reinstall the stock inlet or just buy a COBB one and go silicone all the way down.

Thx again.

 

[Sport6]

Check all the tubes, IC hoses have been known to come loose or some forget to tighten them down all the way.

 

[bykeryder4life]

OP whats your vac at idle? and whats the elevation where u live to account for differences. mine is right around -21 to -22 at sea level

 

[ReNaToMS3]

Around the same as yours. Mine is around -20 to -21, elevation 450ft.

 

[Dano2010]

lose IC hoses would be very evident in the logs by a high WGDC and low boost. I think byke and others are right on target with a vac leak being the trouble. Esp since the OP just installed a TIP.

The TIP should sit flush with the compressor flange. If you have a silicone TIP it is hard to get flush due to the heater core hoses rubbing on the TIP. Work it until it is completely flush and put a t-bolt clamp on it if you are still worried. t-bolts don't back off, worm clamps do.

 

[matsuda]

I really don't see anything wrong with that. It spikes up high because it closes to build boost, then opens up to regulate that boost. The higher the WGDC percentage the more "closed" the wastegate is.

WG duty is the duty cycle of the voltage that is applied to the valve (often referred to as the wastegate solenoid) that controls the mechanical wastegate pressure. The higher the duty, the more that the valve opens (0% = valve closed).

The ECU has no way of knowing about the actual wastegate being open or closed. There is no source of feedback.

BTW, the wastegate is normally closed. It is opened by boost pressure.

 

[matsuda]

Check your vac lines and inlet, then reset ecu and let it learn trims again.

There is no need to reset the ECU. It is always "learning" (adjusting) fuel trims.

 

[matsuda]

I'm basically on a quest to find what is causing my high LTFT. So i decided to take a look at the wastegate basically on this run and other things. I'm suspecting a bad TIP install but it's a pain to remove and install so im looking into the easier stuff first.

1- I just want to make sure but is the wastegate okay? Spiked to 73% when i began accelerating but way down after that.

The WGC duty looks normal. It is high when the actual boost pressure < target boost pressure. Also, keeping the solenoid valve wide open during spool-up helps the turbo to spool-up faster.

A normal WGC duty reading also indicates that the BPV is not leaking.

 

[bykeryder4life]

There is no need to reset the ECU. It is always "learning" (adjusting) fuel trims.

yes, true story. If you go over alot of things and install a new part like an inlet or re-install a part to be sure its on properly, its good to just reset and start fresh to see where the ecu ends up from scratch. This ecu learns so damn fast either way is good but I have crazy OCD so I just reset whenever something is done or changed. I dont want the ecu to remember anything from the past fresh start.

 

[bykeryder4life]

Around the same as yours. Mine is around -20 to -21, elevation 450ft.

if thats the case, its the inlet or boost tubes. Your vac system is good to go. Id say inlet because boost tubes would leak air under boost causing negative fuel trims, the inlet has a slight leak so air gets pulled in the turbo post maf

 

[Dano2010]

I don't know exactly how/why this thing works but what about a sticking purge sol valve. Doesn't it vent the gas tank? It might stay closed at idle = good vac, but when it opens while driving it sticks until you reach a high [Idle] vacuum when it gets closed again???? I to am having strange LTFT and STSF values and my vac is good at idle but during idle my trims will vary 5%. sometimes looks like a countdown timer STFT +5 4 3 2 1 -0 -1 then back up again?? LTFT stays the same at +7 for over 50 miles. yea I know i need to do a MAF Cal.

Thanks

 

[matsuda]

I don't know exactly how/why this thing works but what about a sticking purge sol valve. Doesn't it vent the gas tank? It might stay closed at idle = good vac, but when it opens while driving it sticks until you reach a high [Idle] vacuum when it gets closed again???? I to am having strange LTFT and STSF values and my vac is good at idle but during idle my trims will vary 5%. sometimes looks like a countdown timer STFT +5 4 3 2 1 -0 -1 then back up again?? LTFT stays the same at +7 for over 50 miles. yea I know i need to do a MAF Cal.

Thanks

To rule out the purge valve, you can disconnect its hose from the intake manifold fitting and put a cap on it (the manifold fitting). The hose from the purge valve can be left hanging for this test.

 

[Dano2010]

Thanks Matsuda, Do you have any thoughts about my STFT at idle changing so much?? It is very cold here, for AR round 20 could that be causing the variances?

 

[bykeryder4life]

stft is constantly changing, dont worry about that at all. You can blow hard on your intake and it will change. LTFT is what you wanna watch

 

[Dano2010]

ha! thanks!

I am just having big spikes +10 or so STFT at a couple of different voltages and thought it might be some sort of leak somewhere. I have a MSCAI2 and have already calibrated my MAF tables upward about 8% through the entire curve, matching the learned LTFT + STFT values of course, and there are still a couple of "rough" spots that go from -0.32 at 1.86 volts to +10.6 at 1.99 volts and 11.3 at 2.04, then back down to +5 at 2.11. I thought I was getting away from these spikes when I got rid of my Injen CAI and went to the MSCAI2.

Log attached if you care to take a look. This log is after I have already performed 1 run at a calibration. I am going to let this cal settle in for another 40 miles or so and look again before I make another correction. This one only has 5 miles on it.