New Engine - Weird feeling - OBD2 connector live data

[MustangNoob]

Hi Folks,

As some of you know I got my engine replaced with a new one. Currently in the break in process and the engine has about 400 miles. No check engine light. Runs and feels great by 99.999% of the time .

Few concerns

Concern #1
There were few instances (3-4 times) where while I was trying to accelerate from relatively low speed, it felt as if the engine cut power and I saw the RPMs to drop. The whole time-event was very instant. As a matter of fact, the first time it happened I thought I went over a small speed bump lol. This happened both in auto and manual modes (normal driving mode, rpms did not exceed 3-4k during acceleration).

Has anyone ever experienced this? Is this part of the re-learning process or part of the funky behavior that the manual describes for new engines/cars for the first few k miles?

Following the first event I bought a BlueDriver OBD2 module and I started logging data during my commutes and rides ( I also updated it before started using it) .
I was able to experience the same "power cut" while I had the BlueDriver connected but when I looked at the data for the specific timeframe it happened I could not see any signatures.

Concern #2
My second concern here is that I see some weird behavior in the live data, like spikes in the inlet and ambient temperatures , torque level, timing advance in cylinder #1 , fuel rate etc. Here are the plots from yesterday and today where I overlay the data with respect to when the ride happened. As you can see the only time I did not observe any of these spikes was last night (green data in the first plot and blue data in the second plot )... So my question is what are those spikes and are they "normal" or is there something wrong going on? It cannot suddenly measure -50C ambient temperature or 250F inlet temperature...

Concern #3

The BlueDriver app allows you to do Mode6 scan as well. In the report from yesterday and today I saw that almost all the cylinders are misfiring , but the number of misfires is ranging from 0 to max 7 across the cylinders. No check engine lights , no weird feeling of the car no weird idling or whatsoever. In all the reports thought all the cylinders are marked as pass. Here is a snapshot. Also, in one of the reports from today I saw " “Lean to rich sensor threshold voltage (constant) — Status: Complete and Fail” with a value shown as 0.0780871 inch vs max 0.0374574 (last time I checked the voltage is measured at volts not in inches lol). But at a later scan it was not there....

So what do all these mean ?

Any help much appreciated.

Thank you

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[fishinrich]

I think you're crazy.

Just drive the thing.

 

[Skye]

Swapping an engine in a modern vehicle involves countless electronic connections. With respect to concerns #1 and #2, my first thoughts were of the Throttle Position Sensor, Mass Airflow Sensor or Ambient Air Sensors. Not that there is a fault with these items, but that maybe one of the connectors is simply not seated well or locked into place.

With the engine cold, I'd do a simple check and review of the connectors, top to bottom (including the O2 sensors). I wouldn't tug on anything. Just a jiggle and a push. You're checking for anything obvious that might be an influence. Loose connectors, wiring that binding and being pulled funny, etc.

With respect to topic #3, I feel the occasional misfire is not an issue. The engine is constantly advancing and pulling timing. One way it checks itself is by measuring misfires. If you are consistently logging a misfire code (P0301-P0308), I'd consider that a problem. One cylinder mis-firing when the others are not is a problem. If any counter in your software is up-ticking once in a while, I'd not be concerned about that.

On the stumbles, something the Dealer or Technician is going to be looking for is repeatable behaviors. You're getting tells there might be an issue with throttle response. See how often and under what conditions you could repeat that. It's not something I'd spend an afternoon on. When it happens, make a brain dump in a notebook of what happened and when along with any measurable conditions. See if something trends out.

Something I'd not do: make changes of any kind. The parts and labor are under warranty. As things progress, if you see something that needs correcting or the data confirms a problem, I'd capture all that, return to the dealer and show them what you've found.

YMMV.

 

[Alan Applegate]

As a layman, if you measured your heart with a KardiaMobile® without knowing what you were looking at, you rush to the OR!

When an engine is in open loop, just about every measured electronic parameter continually changes. It is not uncommon to see spikes, dips, and blanks in the viewed data. And I'd bet, it would be a rare mechanic who could interpret the data just by looking!

You mentioned an apparent loss or reduction of power. If "I" were guessing, I'd suspect poor fuel quality. Especially so if you're using off brands like Walmart, Albertsons, and other non major brands.

 

[BimmerDriver]

... maybe one of the connectors is simply not seated well or locked into place.

... I feel the occasional misfire is not an issue. The engine is constantly advancing and pulling timing.

Excellent advice, I concur.

Also, because you recently got a new engine, you are probably understandably paranoid and hyper diligent for new issues.

Instead, chill, enjoy the car, and get past the break-in. Then you can start to worry if needed.

 

[robvas]

The spikes are likely due to your device

It shouldn't feel like it's cutting power though.

I'd log air fuel ratios and fuel trims. You could have a vacuum leak somewhere. You could have a loose or damaged electrical connection. Try to record and isolate the section when you feel the problem and analyze that.

 

[MustangNoob]

I think you're crazy.

Just drive the thing.

I actually started to become obsessive.....not worth it.
One more week until my oil change and then I will do some proper "therapy session"

 

[LouG]

Just to add to Skye's excellent advice, use electronic contact cleaner on the connectors as well.
I narrowly avoided having to buy very expensive BCM for one car by cleaning connectors, bulb contacts etc.

 

[MustangNoob]

I think once I'm able to do few hard pulls to the redline all the connectors might sit properly ...or get disconnected completely lol

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