370z Ignition cut at Full Throttle
I need some help here folks. I have a tuner working on the car, but for whatever reason, we cannot get it sorted. Everything works fine, except when you plant your foot after 2-3 laps (once everything is warm), the ignition completely cuts out. If you leave your foot planted, the engine pops and doesn't regain ignition until you ease off the throttle slightly. If you don't plant your foot and let the car rev, it WILL hit redline on its own, but for obvious reasons, while racing, we kinda need max throttle.
Here is the lineage of the vehicle: -Full race trim, not street legal -Stock VQ37VHR motor -Stillen cold air intakes w/air sensors -UpRev software -Stock fuel tank removed (Custom Fuel Cell) -Return line fuel system set at 70psi -High pressure fuel pump in surge box -Fuel temp sensor delete (switched off in UpRev) -Flat foot shifting switched off in UpRev -All unused wiring harnesses removed, cut back and made safe (Capped) -Completely rewired signal lighting and headlights (not part of factory bus) -A/C Delete -TCS Delete -ABS Delete -Dyno tuned to 354RWHP stock I think that's the most pertinent information. We noticed on the Dyno there were some unusual oscillations in the horsepower curve, not sure if that is pertinent to the situation at hand or not. The VVEL was damaged in a racing incident, but was replaced (not sure if this is pertinent either). We have one of the best tuners around (Vinny Ten Racing), and we have been working with UpRev on zeroing in on the problem, but as yet, we have not nailed it down. I figured I would throw it out in the open forum to see if anybody else has seen any issues similar to this. I have a video of the cutout happening, but it is particularly large, not sure how I can cut it up and upload it. Maybe I can put it on youtube and link it to here? |
What revs does it happen at (or any RPM)
Sounds like the ECU thinks you have hit rev-limit for some reason If you have hacked the canbus and are still using the OEM ECU, you are into test-pilot territory |
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It’s a shame, this car is so capable on track. It routinely eats E-46’s, many mustangs and some vettes, but right now, we are on a ledge ready to jump off. |
Have you disconnected & ohm’d the tps?
Being a race car & hard on the throttle pedal may have got something loosened up in there, Wouldn’t hurt if you had a spare to try. |
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Sure sounds like a bad TPS....
Ive had a couple that would not work at certain specific throttle angles. Worked fine every where else. |
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Though other sensors do different things during wot, the tps was the first thing that popped in my head & then thought about a possible short to ground in the disconnected A/C circuit or a failing o2,A/F sensor.....I know they don't like leaded fuels.
After engine is warmed up, seems like a good Lab-Scope would pick this up. |
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If you can data log the engine parameters, that might help. |
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Don't Jump...it's not worth it....i'm sure you'll find it soon. |
Check your brake switches at the brake pedal. If the ECU see's that it is mashed, it will kill the throttle. Ecutek can cut that off with Throttle Highjack feature. Not sure about UpRev.
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I have an M150 Motec running my OEM VQ37VHR engine using the VitViper package. I can provide a patch harness to connect the M150 into the OEM harness for an M150 running Vitaly's package if you require. |
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We took the trouble to have Vitaly hooked up whilst we were setting the car up ... and then spent an hour on the dyno making sure that we had the tune "correct".
Biggest issue to debug was that the Australian spec MY2009 car has elements of the USDM "sport" setup and we had problems with the ECU losing power when the car was cranked. Vitaly sorted that for us overnight. The package price is NOT cheap, but I am tipping AUD30K+ into a full race engine and already have a Quaife QBE69G sequential gearbox so a proper competition ECU (enabled for paddle shift sequential in good time) makes sense to me. If you seriously want the budget numbers, please PM me. |
We changed the TPS and started the car. What was strange was that the engine was surging in RPM, then it would make a "Whoosh" sound and go back to idle. It did this over and over again. I shut the car off and restarted a moment later and it was fine. I re-did the learning procedure as indicated and it warmed up and idled properly.
Now I have to break some local laws and take the car out on the road to test it. It sucks that the nearest track is 3 hours away. Just a thought in case anybody would have input. Could this issue possibly come from the VVEL controller? |
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