Cars interesting problems- need ideas

phunk

They do read different but you can still make sure they are both comparing properly. There will be a relationship between the 2 that will be visually apparent in the log if it is correct or incorrect.

It could be a problem with the pedal or in the wiring. my 350z had the same symptoms intermittently but it disappeared forever when we changed the engine harness for a new one that had to be constructed for the new engine setup.

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DOOMMONKEY777

Anyone tried turning off the throttle map?? I actually did that on my Z and love it. No cruise control, but i dont use it anyways.

I found that the car responds better, sharper. Try.

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Kids don't do Drugs, Drugs are bad, so let the professional druggies do Drugs for you. 537whp/496lb/tq@8-9PSI 93 octane

ChipsWithDips

All the 370s seem to limit the throttle below 2k rpm. Running the engine at high load and low rpm is probably not good for your engine anyways, that might be why Nissan put that limiter in there.

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PPE Headers SS/Coated/Wrapped | Ebay y-pipe | Custom 3" single exhaust w/ Magnaflows | UpRev | Racingbrake 2pc Rotors | 40th calipers | Eibach sways | SPL endlinks, diff mounts | RJM pedal | Stillen Intakes, UDP, Flywheel | M370 Manifold | Z1 engine mounts, CSC-EK, Clutch | Forgestar F14 18x10 | Conti DWs | Quaife diff/4.08 gears | Nismo diff cover

juld0zer

i have changed the gas pedal already so it cant be two dud pedals in a row. harness issue is interesting though.

how about issues relating to the VVEL system? is there any common faults since you guys have more VQ37 motors there compared to here?

phunk

I have never heard of any. But if the logs are showing that the throttles are not open when they are supposed to be, I would focus my investigation on the throttle system. I would log everything and see whats happening.

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ChipsWithDips

If you are having problems accelerating in 6th gear, might I suggest downshifting?

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PPE Headers SS/Coated/Wrapped | Ebay y-pipe | Custom 3" single exhaust w/ Magnaflows | UpRev | Racingbrake 2pc Rotors | 40th calipers | Eibach sways | SPL endlinks, diff mounts | RJM pedal | Stillen Intakes, UDP, Flywheel | M370 Manifold | Z1 engine mounts, CSC-EK, Clutch | Forgestar F14 18x10 | Conti DWs | Quaife diff/4.08 gears | Nismo diff cover

phunk

^ that is why I would like to see a better log... without RPM and speed showing, I cant tell if they are flooring it at 1500rpm in 6th, or if this is something that is happening in low speeds low gears

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juld0zer

if you dont mind, can i direct you to my thread regarding this problem? i uploaded some logs there: HELP! Severe acceleration lag

you can tell what i was trying to do in the logs by the vehicle speed, accelerator position etc. Please feel free to ask questions for more info as i want to sort out this issue not just for myself but for the community here as a reference point.

Just as a brief preface to viewing the logs, i limped the car home and tried extremely hard to not stall the motor because stalling and restarting would mean the fault vanishes. I dont stall often but when this lag hits, it's very easy to stall if you aren't aware of it. After limping home to get my laptop and cable, i went around the block to some slightly hilly sections where i attempted to accelerate from a standstill. I then tried to see if i could still access the upper rev ranges because folks stated they experienced a 3500rpm fuel cut. It did reach redline but it took forever compared to how it would normally behave. I literally ran out of road before i reached redline.

juld0zer

either way, poking the pedal while cruising at 60mph/100kmh in 6th gear usually gives a small kick. So it's not completely gutless on my car.

When the lag is happening, poking the pedal at the same speed/gear results in no perceptible gain in speed or shove. I have to downshift an extra gear to get satisfactory acceleration. While this is happening, the TPS on my scangauge shows a limit of 20ish degrees. I just dont get what is commanding this choking.

Thanks again for your inputs

DOOMMONKEY777

^^^A/F ratio table thats sits @14.7:1 till 3200rpm, i think that this is ur problem.

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Kids don't do Drugs, Drugs are bad, so let the professional druggies do Drugs for you. 537whp/496lb/tq@8-9PSI 93 octane

mike12002us

I took my car to a shop and everyone seems to believe the tps sensor is faulty. The problem being that I have to get all new throttle bodies to find out if this is correct. Might just go ahead and see what happens. very expensive though. We tested them but the problem would not recreate itself.

juld0zer

as Phunk stated earlier, id expect critical components like electronic throttle bodies and their inbuilt TPS modules would be pretty perfect these days and if something wasnt right, a DTC with limp mode should result.

cost and availability are the two reasons ive held off replacing them. There are some Hitachi generics on amazon and ebay for less than half the cost of the genuine Nissan ones. I wonder what the differences are because i have a Hitachi PDF that states the same part numbers. Surely casting Nissan and Renault into the exterior doesnt cost $600

ChipsWithDips

I guarantee you new throttle bodies won't help because every 370z has this same behavior from the factory. Its mostly not noticeable unless you insist on accelerating in 6th gear everywhere you go.

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PPE Headers SS/Coated/Wrapped | Ebay y-pipe | Custom 3" single exhaust w/ Magnaflows | UpRev | Racingbrake 2pc Rotors | 40th calipers | Eibach sways | SPL endlinks, diff mounts | RJM pedal | Stillen Intakes, UDP, Flywheel | M370 Manifold | Z1 engine mounts, CSC-EK, Clutch | Forgestar F14 18x10 | Conti DWs | Quaife diff/4.08 gears | Nismo diff cover

mike12002us

It is a very noticeable change when the car acts up. Ive had the car for 2 years and up until a few months ago I never had any issues so it doesnt come like that.. I was using 6th gear as a reference. When in 6th gear on the highway i can hit the gas and feel the jolt backward into the seat and pull pretty hard. When the car acts up the car does not pull and will not accelerate very fast due to power loss.

DIGItonium

Yea, it's not a good feeling. Using my aftermarket oil temp gauge as a reference, the car loves to build boost and vent at partial throttle when the oil temps are hovering around 160-180F. Once it approaches 180F it takes more throttle effort to build up boost.

The torque feeling is amazing, too, from a start. The further you press down on the pedal, the more power you feel. Once it starts acting up, there's not much more power felt. It's more difficult to build up more than 5 PSI of boost. My car get unusually quiet since the throttle isn't opening quickly or as wide. Plus, econo-cars get off the line quicker.

When my car was stock I made some videos where the car would spin the tires in 1st and 2nd from a roll, and after while it couldn't spin the tires anymore. I also recorded 2nd gear pulls. When the car acted up, it would take longer to finish the 2nd gear pull. Revs were slower to build up, and the motor didn't scream.

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