Fuel Cutoff

vqloven · 07-08-2012, 09:07 PM

Ok, so I had my first track day today, and honestly, I wasn't impressed with the power delivery at all... I knew I took a risk of going into limp mode a time or two without an oil cooler, but holy crap...

After about 4 laps into my 2nd session, the power cut off when I had the loud pedal floored. I figured it was because it was hitting limp mode, so I sat out for the rest of the session. On my 3rd session, power cut off again and I was starting to take it easy then on a simple acceleration at about 3k RPM, there was a really loud backfire and I'm pretty sure I shot out black smoke.

I took a couple seconds to think about it, and I thought about the fuel swishing side to side and the fuel pump not getting access to it, but I was still at 3/4 of a tank, so that wouldn't be the issue, I don't think.

The other thing, it was REALLY hot today, about 106F. Was this just limp mode from the scorching heat? Or was this something worse?

TYIA!

cossie1600 · 07-08-2012, 10:03 PM

Let me guess, it was after a long sweeping right hander? If you were hitting it at the same spot every time, it is fuel starve. Limp mode is overrated

vqloven · 07-08-2012, 10:13 PM

Actually, it was after a banked left turn the first time and after a series of s-bends the 2nd time.

I saw that fix-it thread too, but I think it would apply more if I had less than 3/4 of a tank, wouldn't it? Again, taking a shot in the dark here lol.

It was on Streets of Willow, going counter clockwise, if that helps anything.

Trips · 07-08-2012, 10:16 PM

Quote:

Originally Posted by cossie1600

Let me guess, it was after a long sweeping right hander? If you were hitting it at the same spot every time, it is fuel starve. Limp mode is overrated

Seriously 106f and no oil cooler is just begging for limp mode.

So how's that overrated in this case.

Fuel starve is a possibility I agree.

cossie1600 · 07-08-2012, 10:27 PM

Limp mode doesn't make the car hesitate, it just limits your RPM. You can easily lower your oil temp by just shifting 500RPM earlier.

vqloven · 07-08-2012, 10:47 PM

I thought as soon as it goes into limp mode, it doesn't let you accelerate fast anymore and it just feels like the engine's "holding back"?

After each incident, I didn't push the car anymore, just cruised back to the pits at much lower RPMs, so I don't think I can say if it let me accelerate hard anymore.

threeseventy · 07-09-2012, 12:28 AM

Limp mode

vqloven · 07-09-2012, 02:51 AM

So nothing really to worry about, right? Cooled it down, blah blah blah, and I'm good?

threeseventy · 07-09-2012, 03:10 AM

All good.. Shortshift like cossie said. Oil cooler!

ChrisSlicks · 07-09-2012, 08:11 AM

Limp mode initially kicks in at 280F and will limit you to 5000rpm, this is usually a good sign to back off a bit. If you drive hard on a stock car you get hit this is as little as 2 laps.

Full on retarded mode kicks in at 300F if you ignored the initial warning. The throttle bodies will not open fully and VVEL will be restricted. I believe you are also limited to somewhere around 3500rpm.

And yes you can get fuel starve at 3/4 of a tank, on street tires. But it is normally in right hand turns since the fuel pickup and pump is on the right.

cdoxp800 · 07-09-2012, 08:28 AM

Op, looking into to this

Fuel Starvation Control Product

vqloven · 07-09-2012, 11:45 AM

Oh yeah, I forgot to mention, I had the heater on blast and pointed out the window, and I never saw the coolant needle move. Just stayed in the center the whole time.

I'll think about the fuel starvation remedy. I really don't track that much so I have to think about if it's worth it or not at this point. I'm probably not going to go to anymore track days during this hot *** summer. In the winter time if I go and the same thing occurs, then I'll do some better thinking lol.

ChrisSlicks · 07-09-2012, 12:00 PM

Fuel starve isn't a big deal, just keep the car full. If you aren't trying to set track records the extra weight in the back is actually a useful balancing tool.

If you plan to keep tracking I would invest in an oil cooler though.

SwampFoxes · 04-23-2018, 10:17 PM

Quote:

Originally Posted by ChrisSlicks

Limp mode initially kicks in at 280F and will limit you to 5000rpm, this is usually a good sign to back off a bit. If you drive hard on a stock car you get hit this is as little as 2 laps.

Full on retarded mode kicks in at 300F if you ignored the initial warning. The throttle bodies will not open fully and VVEL will be restricted. I believe you are also limited to somewhere around 3500rpm.

And yes you can get fuel starve at 3/4 of a tank, on street tires. But it is normally in right hand turns since the fuel pickup and pump is on the right.

So I'm having this problem on any hard right I take with a lot of Acceleration from low rpm. What's the best way to fix the fuel starve, should I take the pump out and clean it?

Spooler · 04-24-2018, 12:40 AM

Quote:

Originally Posted by SwampFoxes

So I'm having this problem on any hard right I take with a lot of Acceleration from low rpm. What's the best way to fix the fuel starve, should I take the pump out and clean it?

CJ Motorsports road race pump setup. Let me see if I can find the thread.

07-08-2012, 09:07 PM	#1 (permalink)
vqloven Base Member Join Date: Jun 2012 Location: LA/UCSD Posts: 119 Drives: 11 G37S 6MT Rep Power: 13	Fuel Cutoff Ok, so I had my first track day today, and honestly, I wasn't impressed with the power delivery at all... I knew I took a risk of going into limp mode a time or two without an oil cooler, but holy crap... After about 4 laps into my 2nd session, the power cut off when I had the loud pedal floored. I figured it was because it was hitting limp mode, so I sat out for the rest of the session. On my 3rd session, power cut off again and I was starting to take it easy then on a simple acceleration at about 3k RPM, there was a really loud backfire and I'm pretty sure I shot out black smoke. I took a couple seconds to think about it, and I thought about the fuel swishing side to side and the fuel pump not getting access to it, but I was still at 3/4 of a tank, so that wouldn't be the issue, I don't think. The other thing, it was REALLY hot today, about 106F. Was this just limp mode from the scorching heat? Or was this something worse? TYIA!

07-09-2012, 08:11 AM	#10 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	Limp mode initially kicks in at 280F and will limit you to 5000rpm, this is usually a good sign to back off a bit. If you drive hard on a stock car you get hit this is as little as 2 laps. Full on retarded mode kicks in at 300F if you ignored the initial warning. The throttle bodies will not open fully and VVEL will be restricted. I believe you are also limited to somewhere around 3500rpm. And yes you can get fuel starve at 3/4 of a tank, on street tires. But it is normally in right hand turns since the fuel pickup and pump is on the right. __________________ Hotchkis ARB \| Stillen CAI \| Art Pipes \| Berk CBE \| Stillen AP Racing Brakes \| AE Performance Oil Cooler \| BC Racing ER Coilovers \| Doran Control Arms

07-09-2012, 08:28 AM	#11 (permalink)
cdoxp800 A True Z Fanatic Join Date: May 2009 Location: FL Posts: 1,337 Drives: 2011 Nismo Rep Power: 19	Op, looking into to this Fuel Starvation Control Product __________________ 2011 Brilliant Silver NISMO 370z. #: 0046. PPE LTH \| MillSpec Cats \| F.I Exhaust \| Akuma Intakes \| Rotora 6/4 Brakes

07-09-2012, 12:00 PM	#13 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	Fuel starve isn't a big deal, just keep the car full. If you aren't trying to set track records the extra weight in the back is actually a useful balancing tool. If you plan to keep tracking I would invest in an oil cooler though. __________________ Hotchkis ARB \| Stillen CAI \| Art Pipes \| Berk CBE \| Stillen AP Racing Brakes \| AE Performance Oil Cooler \| BC Racing ER Coilovers \| Doran Control Arms

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07-08-2012, 10:03 PM	#2 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 30	Let me guess, it was after a long sweeping right hander? If you were hitting it at the same spot every time, it is fuel starve. Limp mode is overrated

07-08-2012, 10:13 PM	#3 (permalink)
vqloven Base Member Join Date: Jun 2012 Location: LA/UCSD Posts: 119 Drives: 11 G37S 6MT Rep Power: 13	Actually, it was after a banked left turn the first time and after a series of s-bends the 2nd time. I saw that fix-it thread too, but I think it would apply more if I had less than 3/4 of a tank, wouldn't it? Again, taking a shot in the dark here lol. It was on Streets of Willow, going counter clockwise, if that helps anything.

07-08-2012, 10:27 PM	#5 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 30	Limp mode doesn't make the car hesitate, it just limits your RPM. You can easily lower your oil temp by just shifting 500RPM earlier.

07-08-2012, 10:47 PM	#6 (permalink)
vqloven Base Member Join Date: Jun 2012 Location: LA/UCSD Posts: 119 Drives: 11 G37S 6MT Rep Power: 13	I thought as soon as it goes into limp mode, it doesn't let you accelerate fast anymore and it just feels like the engine's "holding back"? After each incident, I didn't push the car anymore, just cruised back to the pits at much lower RPMs, so I don't think I can say if it let me accelerate hard anymore.

07-09-2012, 12:28 AM	#7 (permalink)
threeseventy Track Member Join Date: Mar 2011 Location: Huntington Beach, CA Posts: 600 Drives: Opinion Rep Power: 15	Limp mode

07-09-2012, 02:51 AM	#8 (permalink)
vqloven Base Member Join Date: Jun 2012 Location: LA/UCSD Posts: 119 Drives: 11 G37S 6MT Rep Power: 13	So nothing really to worry about, right? Cooled it down, blah blah blah, and I'm good?

07-09-2012, 03:10 AM	#9 (permalink)
threeseventy Track Member Join Date: Mar 2011 Location: Huntington Beach, CA Posts: 600 Drives: Opinion Rep Power: 15	All good.. Shortshift like cossie said. Oil cooler!

07-09-2012, 11:45 AM	#12 (permalink)
vqloven Base Member Join Date: Jun 2012 Location: LA/UCSD Posts: 119 Drives: 11 G37S 6MT Rep Power: 13	Oh yeah, I forgot to mention, I had the heater on blast and pointed out the window, and I never saw the coolant needle move. Just stayed in the center the whole time. I'll think about the fuel starvation remedy. I really don't track that much so I have to think about if it's worth it or not at this point. I'm probably not going to go to anymore track days during this hot *** summer. In the winter time if I go and the same thing occurs, then I'll do some better thinking lol.