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-   -   Fuel Cutoff (http://www.the370z.com/track-autocross-drifting-dragstrip/57460-fuel-cutoff.html)

vqloven 07-08-2012 08:07 PM

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!

cossie1600 07-08-2012 09:03 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 09:13 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 09:16 PM

Quote:

Originally Posted by cossie1600 (Post 1812128)
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 09:27 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 09:47 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 07-08-2012 11:28 PM

Limp mode

vqloven 07-09-2012 01:51 AM

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

threeseventy 07-09-2012 02:10 AM

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

ChrisSlicks 07-09-2012 07:11 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 07:28 AM

Op, looking into to this

http://www.the370z.com/track-autocro...l-product.html

vqloven 07-09-2012 10:45 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 11:00 AM

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 09:17 PM

Quote:

Originally Posted by ChrisSlicks (Post 1812414)
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 04-23-2018 11:40 PM

Quote:

Originally Posted by SwampFoxes (Post 3749829)
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.


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