Can't find solution for lack of performance when car at OPERATING TEMP.

Eris

I've searched far and wide within this community and elsewhere online regarding this somewhat common issue where the car has delayed/inadequate throttle response/engine power when the engine oil goes up to 200, and haven't found any way to fixing it.

The car is stock... is otherwise fine... and the oil temp hardly ever goes over 210, if at all. When I drive around and there's the sun shining in all its glory, with normal traffic, if the commute is an hour or so long, it gets sufficiently hot that I notice a steep decrease in power... perhaps not abysmal... but it feels as if I were losing around 25 hp or a bit more perhaps.

I've had throttle bodies checked and clean... fuel pump checked and had its filter cleaned... checked engine oil... checked temperature sensors... checked MAFs... have had the ECU reset through the OBDII... have changed transmission and differential oil for an unrelated issue - though this last but did improve things slightly... it used to suffer much more when heated - checked air filters... and yet the problem still remains.
As per faults with sensors and whatnot, never has there been an error code either...

The car pulls hard when it's cold (the car...not the air temperature outside), and when it's hot, it sometiems pulls well... it sometimes doesn't. I don't live in a terribly-hot weather place... all of this happens when weather here is at most around 85.

At night when its cooler the car fares much better of course

I've read a few other solutions like ECU programming...but im still under warranty and can't touch the ECU.

Any thoughts?

Thanks, friends.

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sportsman2003

It is normal to have some power loss when the environment temps are higher.
This has to do with high IAT (Intake air temps) when the ECU see's higher temps it pulls timing to prevent ping ( detonation ) The only way to help prevent this I guess would be higher octane fuel or possibly a true cold air intake set up.

Basically heat = power loss.

Eris

Thanks for replying, friend.

I understand that, however, I'm not referring to different environments. Within the same environment temp, say, 80 Fahrenheit, the car will pull hard the first 30 minutes... after it gets to operating temperature, the car will have a noticeable power loss.

I don't find it too normal that one can only enjoy one's car for 30 minutes only, before it gets too hot and loses 15% power perhaps...and also the problem with throttle response... the first fifth of it has almost no response after driving the car for 30-40 minutes.

They told me it was indeed IAT and the ECU pulling timing... but I don't live in high temp places. Highest I see here is 85... and that only in direct sunlight

But whether it be 85 or 50, after driving the car for 45 minutes, it starts losing power... even if engine oil is 180-200, so far from overheating.

I figured this isn't too normal.

Worth pointing out that I don't push the car... im a calm driver... so even if im driving calmly with cool weather, after 45 minutes or so... throttle stops responding properly and car won't take off as usual... this is very evident when merging where I have to get up to speed.

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SouthArk370Z

I'm with sportsman2003 - sounds like high temp(s) are causing the ECM to reduce power output to prevent pinging. Verify that both radiator fans are operating properly (FSM will help; link in sig). Check radiator for bent fins, pinched tubes, and anything else that might reduce air or water flow. Verify that temperature sensors are reading correctly.

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JARblue

It's called heatsoak and is pretty typical for the Z, which has poor cooling in general. One thing a tune can do is turn the fans on earlier. That will help a little. Tune can also help with throttle response (separate issue from the heat problem you are experiencing).

I got my tune long before my warranty expired. Never had warranty service denied due to it either.

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BettyZ

Tune def helps in turning the fans on earlier. As for heat soak.. the first mod anyone should do to the 370Z is an oil cooler. That changes the whole ball game. After that you have bigger radiator, vented hood, oil pan spacer, yanking all the unnecessary crap in the bay to allow for better airflow...

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Eris

I appreciate your inputs... I'll try what here has been recommended.

One last question

Would heatsoak be a thing even when driving in 50-60 f weather? Cuz it happens even with cool to cold weather conditions... and it happens noticeably. I can't imagine how hard heatsoak must be in 110 weather! Car must he undriveable, yet I see many people driving these cars in texas and such without too much of an issue.

In my case I do lose a lot of power and throttle response even when it's 55 f, like this morning.

Thank you.

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cv129

I do lots of short trips in the family hauler G37, so the effect OP described feel very pronounced to me when I do longer trips, especially in warmer days.

Regarding throttle response...on stock tune, it almost feels like the throttle body is opening up even slower when fully warmed up and heat soaked, it’s a much more sluggish feeling vs that of a cooled engine. I think this greatly compounds the feeling of losing power.

Not saying there’s nothing wrong, just the stock delayed throttle response doesn’t help at all.

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JARblue

My Z was a daily driver in Texas summer heat for 6 years. In stock form, I routinely hit 240F+ temps and the occasional 250+ temp literally while just using cruise control at 70-80 mph driving across the state. If I came to a light, it would heatsoak and pull timing like a mofo. Never found it to be a problem on the street tho - still had plenty of power for a reasonable acceleration pace to get back up to speed.

On the track it was even worse. In stock form, the car was basically done after 1 warm up lap and 1 full speed lap at Circuit of the Americas. The following lap on the back straight I was up in the 280F range and it was limiting RPMs to 5000K at which point I slowed down to pit.

Now that it's no longer my DD, I have installed the necessary mods to address all of those cooling issues.

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BettyZ

You mean you have the mods sitting in your garage

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JARblue

The only cooling mod not installed is the brake ducting (and your intake duct ). Mods sitting around to be installed are pretty much all suspension and drivetrain

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SonicVQ

Well, since you asked

If that was my car, I would use a good/fast wireless OBD scanner (OBDLink MX+, VeePeak BLE) and a good OBD app, like OBDFusion (or OBDLInk) and datalog:

• Cylinder #1 ignition timing
• Engine RPM
• Vehicle speed
• Short term and long term fuel trims for each bank
• Engine coolant temp
• Intake air temp
• Absolute engine load
•*O2 sensor lambda bank 1/2
• Mass air flow A/B (Bank 1/2)

(Note: OBDLink MX+ can read about 40 PIDs/second, which results in about 4 samples per second per PID)

Log the data on different days and make of note of when you think the issue is happening.

Then, post your log file here and I will have a look. As a VQ specialist, I have been reviewing data logs for the last 5 years and have a good idea of what the "expected" values should be, for different driving conditions.

If the above is not too much effort or cost, it might shed some light on what is going on.

Eris

SonicVQ... that is amazing from you. Id certainly appreciate it.

I'll give it another go at the stealership... which isn't paying off, but given that I'm under warranty - warranty that they haven't so far neither honoured nor respected -... if not, I'll do what you suggested and I'll send you the data logs for the info above. Sounds very thorough.

I appreciate your time.

Sorry for the delay.

Hadn't logged in until now.

Cheers!

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SonicVQ

No rush... this is a lifetime offer

geeteezee

I believe there's a TSB for heat soak on '19s, not sure about '18s. It's an updated ECU flash afaik. Maybe your dealer checked for this, maybe they didn't.

Edit: Misremembered this apparently. It's lack of power during a cold soak after sitting >6 hours.

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