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Thread: Chevy Cruze 1.8 Turbo Tune Guidance & Reduced Engine Power

  1. #1
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    Chevy Cruze 1.8 Turbo Tune Guidance & Reduced Engine Power

    SD Tuning Step 34 - TURBO 1.4 MAP - Chevy Cruze 1.8.hptreduced.hplAs Found Chevy Cruze 1.8 6-3-20.hpt2012 Chevy Cruze E78 - 12646746.hptHey Gang... Matt here...

    I'm working on tuning my 2012 Chevy Cruze manual with a 1.8 and a T04E turbo (internal wastegate set at 7-8 psi). I made a custom log style manifold, increased the stock exhaust from 2.25" to 2.5" with a high flow cat, and straight through muffler. Upgraded to 60# injectors and have scaled the map. There really wasn't much information on them, but the car seems to like the MPW around 1.05. I have switched the stock MAP sensor with a 3bar sensor from a 1.4t. The intake pipe is now 3" vs the 2.5". The MAF sensor is in line, but the intake pipe is really short. I currently have the downstream 02 sensor unplugged and my AEM Wideband in place.

    I have attempted to tune the car with a the MAF sensor initially, without much success due to the larger diameter of the pipe. I'm not sure if I need to recalibrate it, or get a different one? I'm new to all this...

    I started tuning the speed density route. Got the car fired up with some test drives around the parking lot. Got it cruising around town okay.

    Some of the issues I have ran into is the car going into Reduced Engine Power mode. I have attached my latest tune, a log when it went into reduced powered. I have also attached the as found tune, and a Cruze 1.4 tune in which I have copied some of the fuel scaling info, and I have used some of the MAP information as well in hopes to get this thing Dailed in a more.

    The other issue I'm having is when I'm logging my user math to get the fueling closer to lambda 1, is some spots go really high, I imagine because it's a stick trans and it's what is being recorded between shifts. I initially would paste special > multiple by half %, and the hit calculate, and the map would go to hell. So I've learned to smooth out some of the areas that just look like way too much of an adjustment. Some days the tune seems like it's getting closer, then I'll have days where my tuning overshot the adjustment.

    Here are the engine codes pulling up when the car goes into limp mode.

    0x7E8: P0036 - HO2S Heater Control Circuit (Bank 1, Sensor 2) (Permanent)
    0x7E8: P0068 - MAP / MAF - Throttle Position Correlation (Pending, Current, Old)
    0x7E8: P0138 - O2 Circuit High Voltage (Bank 1, Sensor 2) (Permanent)
    0x7E8: P0140 - O2 Circuit No Activity Detected (Bank 1, Sensor 2) (Permanent)
    0x7E8: P0420 - Catalyst System Efficiency Below Threshold (Bank 1) (Permanent)
    0x7E8: P1101 - Mass Airflow Sensor Out Of Self Test Range (Pending)

  2. #2
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    Have you scaled the MAF curve? Moving to a larger dia pipe will decrease the flow registered by the MAF, but this allows you to use the blade-style MAF (factory) with higher power levels easily. I'd rescale the curve (downward) by -17% (start with -10% and see if it works) as a rough change in flow from 2.5 -> 3" pipe. This should help with the P1101 code as the ECM is seeing large differences in MAF flow. E.g. ECM expects 10, actually sees 8.5ish as intake tube is larger and throws correlation code.

    For the P0068, Engine Diagnostics -> Airflow Correlaction -> P0068 then look at the Max airflow, airflow delta, and MAP delta tables. I'd start with the Cruze 1.4T values here and update accordingly. This will definitely cause limp mode and no throttle, the ECM expects 10 and sees 20, throws rationality code and kills power/throttle.

    Engine Diag -> Exhaust -> Post O2 Test and Catalyst Test, update this as you have the B1S2 O2 unplugged right now for tuning (will need to put O2 back in and re-enable this for the cat test to pass). Also kill the DTCs for the codes you're seeing.

    Did you add the TIAP sensor from the factory Cruze/Sonic's to the charge pipe? If you just swapped the MAP sensor, I'd suggest changing the MAP Sensor config back to NA-MAP as you only have the 1 MAP sensor (no Baro, no secondary TIAP). IDK if the E83 can actually use the TIAP either.

    I think you may still have LTFTs enabled, not sure if updating just the O2 Readiness Voltage is enough to disable LTFTs. Look at the LTFT Min/Max ECT values.

    Some of your VVEs are spiky and have large dips, make sure to smooth these out. I typically mirror all VVE tables as well on non-DOD vehicles.
    ~Erik~
    2013 Sonic RS - manual, CGM, 6M, sunroof, mods in process
    2008 TrailBlazer 3SS AWD LS2, loaded, dropped, modded, SE22 Performance tuned. And then some...
    2002 TrailBlazer LT 4WD 4.2L I6, lifted, tires, exhaust, SE22 Performance tuned

  3. #3
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    Quote Originally Posted by ScarabEpic22 View Post
    Have you scaled the MAF curve? Moving to a larger dia pipe will decrease the flow registered by the MAF, but this allows you to use the blade-style MAF (factory) with higher power levels easily. I'd rescale the curve (downward) by -17% (start with -10% and see if it works) as a rough change in flow from 2.5 -> 3" pipe. This should help with the P1101 code as the ECM is seeing large differences in MAF flow. E.g. ECM expects 10, actually sees 8.5ish as intake tube is larger and throws correlation code.

    For the P0068, Engine Diagnostics -> Airflow Correlaction -> P0068 then look at the Max airflow, airflow delta, and MAP delta tables. I'd start with the Cruze 1.4T values here and update accordingly. This will definitely cause limp mode and no throttle, the ECM expects 10 and sees 20, throws rationality code and kills power/throttle.

    Engine Diag -> Exhaust -> Post O2 Test and Catalyst Test, update this as you have the B1S2 O2 unplugged right now for tuning (will need to put O2 back in and re-enable this for the cat test to pass). Also kill the DTCs for the codes you're seeing.

    Did you add the TIAP sensor from the factory Cruze/Sonic's to the charge pipe? If you just swapped the MAP sensor, I'd suggest changing the MAP Sensor config back to NA-MAP as you only have the 1 MAP sensor (no Baro, no secondary TIAP). IDK if the E83 can actually use the TIAP either.

    I think you may still have LTFTs enabled, not sure if updating just the O2 Readiness Voltage is enough to disable LTFTs. Look at the LTFT Min/Max ECT values.

    Some of your VVEs are spiky and have large dips, make sure to smooth these out. I typically mirror all VVE tables as well on non-DOD vehicles.
    Thank you!!! I really appreciate the help and advice. I haven't scaled the MAF curve yet. I'll be sure to do that. I'm learning as I go and as issues come up. I've disabled a couple of the code it has been throwing while tuning.

    I didn't add a TIAP sensor. It has the factory sensor, so I'll be sure to change that back. This weekend I'll weld in another bung for the 02 sensor. I'll have to extend the sensors wiring to get it past the cat. Couldn't find an extension for the type of plug, or maybe I don't know what I'm looking for, but I've already extended the MAF sensor harness, so this will be a piece of cake.

    You're right about the VVE's. I've learned to smooth some of the areas out, and what has been giving me issues is the fact my car is a manual. So the spikes / dips are the shift points, which I started to recognize the pattern and learned to smooth those spikes out, which has been making tuning a challenge for a newb like myself.

    The lingo is starting to sink in as well, which has been a little bit of a learning curve.

    One of the other issues I'm trying to sort out is scaling my spark table, and setting up a histogram to log KR. Seems when I scale it the histogram will only log 3 row axis. Any clue as to why this is?

    Here's the Cruze how it's currently setup. I'm working on finding the room to get the intake routed to a cooler part of the bay. Perhaps in the wheel well, but just trying to get some drivability dialed in. I've managed to get the car running pretty well, and have worked my way up to it running 9 lbs of boost thus far. IMG_9226 2 copy.jpg

  4. #4
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    If you're trying to scale the Spark tables, are you updating the row axes values? Not sure on the logging, would have to see the log and histo setup to look at it.

    Make sure to filter out the transient values for VVE/MAF, throttle opening/closing shouldn't be directly applied to the tables or things will get weird quickly and you'll end up chasing your tail.
    ~Erik~
    2013 Sonic RS - manual, CGM, 6M, sunroof, mods in process
    2008 TrailBlazer 3SS AWD LS2, loaded, dropped, modded, SE22 Performance tuned. And then some...
    2002 TrailBlazer LT 4WD 4.2L I6, lifted, tires, exhaust, SE22 Performance tuned

  5. #5
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    Ive seen this build on Youtube, good work man! I would start by disabling SD, and tuning MAF only. As mentioned P0068 settings will need to be modified and I'd have a look at torque MGMT > SC/TC Boost control settings such as knock airmass. I think my NA 1.8 reaches around .5g spark airmass, and the axis on my spark table is editable and has 33 data points. For the pressure you're running you shouldnt exceed 1g airmass and you can divide the points from 0-0.9 by .3 and however you want for the last .1g for simplicity. Tuning VVE/SD will require a dyno most likely, as VVT really complicated things.

    EDIT: Because this is now a forced induction application and the cruze has a returnelss fuel system you may need to go to fuel > general and mess with flow rate vs MAP
    Last edited by ColdShad0w; 06-24-2020 at 10:09 PM. Reason: afterthought