HELP! Severe acceleration lag

Ren425

Thanks guys. Getting more insight. To break it down a bit further, the car feels as if it slips/hesitates between 0.8-3.2K RPM. I suppose an analogy is like your dog is on a leash and the you've got a grasp of your dog who wants to run free.

The catch is, I've already installed a oil cooler from 2 years back. Usually keeps my temps between 180-220 depending on how hot it is outside and how lead-footed I am. LA traffic definitely contributes to higher oil temps.

Do you guys still think it could be related to IAT, oil cooler or oil temp related? Heat soak is definitely a factor, but the problem only comes around when the Z reaches the 220-230F mark.

If it were the brake switch would it occur at any oil temp?
Could also be throttle response at that specific oil temp?

I'll have to see if the problem returns after like a quick stop on the side of the road or re-cranking. Further comments are appreciated, cheers guys.

SouthArk370Z

Get an OBD monitor and watch IAT. I'm betting it goes high when you stop moving and the nannies kick in. Your oil temp is not high, just elevated enough to indicate warm ambient temps.

__________________
Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub
Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

Datsun Z

Hi all. I have exactly the same issue as as juld0zer has. My car is a completely stock 2009 model with a manual transmission. This issue only surfaces if my oil temperature gauge shows above 90 Celsius or 194 Fahrenheit. Does anyone have a solution for this issue?

tjlazer

I think it's IAT as I had been monitoring my air intake temps. It would spike when sitting at a red light, heat soak has to be it. I seem to have issues when I get to 190-200. Very bad lag on low rpm take offs.


Sent from my iPad using Tapatalk

__________________
2009 370Z Monterey Blue,Nismo Conversion,RE-11's, K&N Typhoon intakes,Blue Kickplates,Homelink,FI 18" CBE,ERZ HFCs,Hotchkis sways, Swift Spec-R, EVO-R Highwing, UPREV

Datsun Z

[QUOTE=tjlazer;3607284]I think it's IAT as I had been monitoring my air intake temps. It would spike when sitting at a red light, heat soak has to be it. I seem to have issues when I get to 190-200. Very bad lag on low rpm fake offs




Please excuse my ignorance. I'm guessing IAT is Intake Air Temperature. From my experience even if it's very hot outside with temperatures past 40 Celcius / 104 Fahrenheit as long as my oil temperature shows under 90 Celsius / 194 Fahrenheit it won't lag at all.

Could this mean that under heavy heat soak/ high under hood temperatures our engines are getting pre ignition/pinging and the knock sensors are retarding the ignition therefore we are losing low end power?

Did you find a solution for this issue?

JARblue

Yes, IAT = Intake Air Temp. Heat soak is a bitch in this car, especially without a proper oil cooler. There are a number of things you can do to help combat it, but there is no true solution except for driving fast to get some airflow.

The stock intake box and silicone post-MAF tubes are a lot better at insulating intake air from the engine bay heat compared to metal tubes on most aftermarket intakes. The are some DIY mods for older model years with the "fangs" in the front bumper to help get more airflow to the intakes, but ambient temperature only does so much against the heat of the VQ.

A proper oil cooler helps with engine bay temps. As can upgraded radiator and/or fans. A tune can adjust the fans to come on sooner (lower temp) to help stave off heat soak as much as possible.

But the end result is if you drive the car hard its going to get hot. And if you stop while its hot, it is going to heat soak. And high IATs are going to pull timing.

__________________

KrnAndy

Would love to see if anyone has a solution yet. Same problem as op. Don't think it's heat soak, the problem will go away mid drive occasionally (even sitting at a stop to induce heat soak)

JARblue

You're saying you drove it hard to get the temps up high and then sat stopped to induce heat soak and could not replicate the acceleration lag? Sounds like you just didn't heat it up enough for the ECU to pull timing, but if it was doing it earlier on the drive when the car was cooler and then didn't do it when you stopped to induce heat soak, you might be right that it's not temperature related. Are you monitoring IATs at all?

__________________

Datsun Z

My issue was fixed with a throttle body clean. After that my car ran great. So far so good.

VKNismo

I had a similar problem. My car also died on me a few times, while idling and coming to a stop. I thought it was my fuel pump but it turned out to be my throttle body. Problem resolved after I clean the throttle body.

Sent from my SAMSUNG-SM-G935A using Tapatalk

KrnAndy

I never drive the car too hard at all anymore, but the problem usually arises during normal driving conditions when oil temps are at normal operating temps around 180-200

Not saying it was the most accurate research, but the problem could come up after a hard pull, waiting just a second at the stop, then going, and then the problem could not even happen after a few hard pulls, and sitting at the stop for a bit with a toasty engine. I read a few other threads about a brake switch problem, thought maybe it could be the problem but it happens when i come to a very hard stop, or my engine temps are warmed up. feels like the car is starting from 3rd gear, my friends 370 feels way different, he was confused too!

conclusion is from reading over a hundred pages from different threads in this forums is

brake switch, brake booster sensor, MAP (manifold pressure sensor), timing being pulled? (inconsistent so idk)

already cleaned mafs, im on stock intake boxes, throttle bodies were taken off to look at the back side and in to see if there was any build up, but looked pretty clean to me, didn't want to have to do a relearn by manually opening the valves.

i just don't know any tbh, the 350z and g35 i had before pulled really nicely regardless.

im at a loss, the 370z is a great car but i can't figure this one out.

jchammond

Un-sure if this would help; but i deleted my coolant hoses that flow through the throttle bodies....they are there to prevent icing up in very cold condition's.
There is a thread on this....unsure of performance gain's/losses....but definitely run's fine in cold weather.
I had a recent glitch in mine (2 week's ago) where it wouldn't rev past 6500k or so (wot) & felt like is was stumbling....manually shifted to next gear & same thing.
check'd all hoses,connection's & even purged a fuel sample from rail....all looked good;put back together & run's fine....???
Hope that doesn't come back,,,but wasin a bit of traffic that day & oil temp was around 200*,,,ambient temp was 70'ish

__________________
MazWorx built long block | FI-TT-100 Stage 2.75 | IPT built 7A/T

http://www.the370z.com/members-370z-...s-musings.html

jchammond

My next step was to install fuel block & fuel pressure gauge/as I thought maybe pump was getting weak...but this is where the rpm's peaked in 2nd & manually up shifted to 3rd...same thing. And was stuttering & weak.
3/17/17'
About 600 miles ago.
poor picture quality is from the vibration from the stuttering....as this happened on a Friday & had me sick all weekend running test's on it.


Sent from my iPhone using Tapatalk

__________________
MazWorx built long block | FI-TT-100 Stage 2.75 | IPT built 7A/T

http://www.the370z.com/members-370z-...s-musings.html