2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

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SHIMHEAD
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2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by SHIMHEAD »

Hello,
Working on a 2019 Maserati Ghibli with 3.0 liter biturbo. Setting code P0299-00 (Underboost), and P0301-303. Have attached a couple of screenshots of and MDEVO bank 1 and bank 2 actual Lambda values ahead of catalysts, and a Pico Scope of one injector positive and negative from each bank while the issue is occurring. It seems the bank 1 Lambda values go very lean (much more lean on decel) on bank 1, but not bank 2. It also appears the #1 injector is not being grounded (I suspect the whole bank 1 is experiencing the same issue). My theory is that bank 1 is not firing any cylinder when this happens, and therefore the bank 1 turbo does not have sufficient exhaust pressure to develop boot accordingly. Looking for thoughts from others here. FYI, 20:1 attenuators were in place on all channels as a precaution, Pico 4423.
Attachments
2019 Ghibli Lambda both banks P0299-00.jpg
Pico Screenshot in Paint.png

Iver
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by Iver »

Hi Shimhead

Just some basics to get going with please.
Is this petrol or diesel ? Single or Twin turbo?

I'm sure I could guess but it is always best practice to have the facts written down.

If you are using 20:1 Attenuators then please adjust the software settings. Rather than just a screenshot perhaps upload the .psdata file using a timebase that shows several events - 20 or more.

thank you

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Grant_Baker
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by Grant_Baker »

The Cyl1 direct injector waveforms showing zero voltage drop could be normal. The research I have done on GDI indicates system design usually includes sister cylinder power feed within a computer ...even though a wiring diagram may not show it. So in your case there is likely a sister cylinder that did fire that will be time-aligned with the Cyl1 direct injector voltage waveforms. If you measure direct injector current not voltage, you will see if any work was done. If you take a capture with an ignition trigger for one cylinder, this will give you a 720 degree reference. Then add current for one of the direct injectors (current probe on its negative wire only). You should then see that injector fire once per 720 cycle. Look at each injector; add channels as you have current probes available or just do the 2 traces and keep it simple.

I learned about sister cylinder power feed from John Thornton, in his GDI class. I heard this same class should be available online last this summer. It may be available through aeswave at that time. Or, you can sign up to be alerted at automotiveseminars.com

I was not able to find any theory of operation information on Maserati lambda sensors. Since there are no other PID's on the graph, it is difficult to put the photo in context with your comments. What number indicates stoich? lean? rich? Does the scan tool graph auto-range; or, is this range the maximum low and high values?

As for the P0299-00, I don't have much to say yet. It might be a good idea to take a scan data capture with MAF, IAT, MAP, BOOST pressure, wastegate control PID's, RPM, TPS. Any bidirectional tests for wastegate/boost pressure controls?

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Grant_Baker
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by Grant_Baker »

https://automotiveseminars.com/online-training-events/

August 2020 GDI Online Class with John Thornton

SHIMHEAD
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by SHIMHEAD »

Petrol engine, twin turbo, merged boost ducting to single throttle body, boost sensors before throttle and in intake manifold. Turbo wastegates common vacuum controlled by single solenoid, vacuum applied to CLOSE wastegates. Each turbo has an electrically operated dump valve. Two knock sensors, one per bank (buried under oil cooler in the valley), interchangeable connectors with sub-harness to main harness (could be swapped bank for bank). To clarify, injector patterns were from Power and ground sides individually for each injector. Training manual states that injectors are "Current control via boost voltage and PWM controlled maintaining, one injector driver for two injectors". It does not state WHICH injectors are paired.
I am also considering the possibility of a bank 1 knock sensor issue, and associated response from the ECM in order to protect the engine from damage, possibly even stopping injection entirely on bank 1. I have tried connecting the Pico to the knock sensor leads, but did not get an appropriate signal when backprobing at the ECM. Signal seemed OK with Breakout Box, but it is too big to use when driving. Was using the presets for Knock sensor.
Hoping to get current probe patterns of injectors soon, will post when I do.

Iver
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by Iver »

To clarify, injector patterns were from Power and ground sides individually for each injector. Training manual states that injectors are "Current control via boost voltage and PWM controlled maintaining, one injector driver for two injectors". It does not state WHICH injectors are paired.
Quite likely they use a Capacitor to get the Firing Voltage up.
I am also considering the possibility of a bank 1 knock sensor issue, and associated response from the ECM in order to protect the engine from damage, possibly even stopping injection entirely on bank 1.
Then I would expect to see it throw a knock sensor code ?? Especially if it using that to protect the engine and shutting down injectors. In this scenario with the Knock sensor fault flagged it should not flag 301 or 302 - Not in the ideal world anyway.

I have tried connecting the Pico to the knock sensor leads, but did not get an appropriate signal when backprobing at the ECM. Signal seemed OK with Breakout Box, but it is too big to use when driving. Was using the presets for Knock sensor.
Knock Sensors will give a great response on the scope at cranking, disable something to get a longer crank.
Hoping to get current probe patterns of injectors soon, will post when I do.
I would want to know if the misfire is caused by lack of fuel or spark, Raw data from the O2s would be a great place to look.

If it is fuel then Injector current, Fuel Pressure Sensor, Primaries would be worth a look as it faulters.

2019 car ! How many miles ? and is it not under warranty ?

Dejan
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by Dejan »

Hy,
I'm curious how that engine detects misfire,by CKP sensor only or by "eldor ignition module" if that engine have it like a 2.9 twin turbo in Alfa Romeo Giulia QV.Maybe it's same or similar engine.I think/suspect that both engines are derived from Ferrari.

Best regards Dejan

SHIMHEAD
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by SHIMHEAD »

Just an update with a solution. In the end it appears the bank 1 injectors were not delivering enough fuel at high load and rpm. The NCM (ECM) would eventually shut down all cylinders on bank 1 if allowed to misfire long enough. I had suspected this for some time, but there is no way to flow test the injectors on the vehicle that I am aware of. The underboost code was a result of the reduced exhaust flow from the misfiring. Being an in stock vehicle under warranty, I was bound to following instructions from Maserati Technical Support. MANY parts were replaced in the hunt, but the injectors fixed it, they come pre-assembled in complete bank rails. If anyone has suggestions for verifying injector function/flow rates of direct injection injectors while still in the engine, please advise.......

Dejan
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by Dejan »

If the mixture is so much lean that cause cylinder to misfire that should be seen clearly in secondary ignition waveform! Sparkline voltage goes up rapidly! Trick is to look at it at the moments when misfire is present.I used this method many times.

If there is no easy access to secondary then primary waveform could be used also.

If there is no easy access to both then scoping lambda upstream signal MAYBE could be used in some cases to determine if the cause is fuel or ignition.

In my cases fuel trims was useless because misfire was very occasional and intermittent..

This is how I handle that situation... :)

picowight
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Re: 2019 Maserati Ghibli, low power under high load, sets P0299-00 and P0301-303.

Post by picowight »

Interesting case!
I assume the fuel trims would have been pegged high for B1?
But I don't understand -
It seems the bank 1 Lambda values go very lean (much more lean on decel) on bank 1

Then -
In the end it appears the bank 1 injectors were not delivering enough fuel at high load and rpm.
As for measuring flow rates, I would think a bank to bank comparison of injector on time vs relative fuel pressure drop (from the HP sensor) - you would need the on time as the fuel trims would be altering it - else you could have two very similar pressure drops hiding a poor flow rate. You should also be able to see the HP pump chamber performance in the pressure trace - depending on pump speed and number of chambers they may or may not be fixed per cylinder/bank of cylinders.

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