Tuning question - shouldn't the motor have popped?

[Murray_Calavera]

Hi all, 

I've just started learning a bit about tuning, I'm half way through reading Engine Management: Advanced Tuning by Greg Banish which I'm enjoying so far. 

I've got an R33gtst with very basic performance mods. Haltech pro plug in, 3" turbo back exhaust and a turn flow front mount. Engine-wise everything else is stock (engine, turbo, injectors etc).

I've just installed a wideband, air temp sensor and oil temp sensor which are happily chatting with the Haltech. I did my first data logging run today and I found the results both terrifying and confusing. 

Is anyone able to help me interpret my data log? The thing that has me confused is, why at 6000rpm and 11psi is the car at 100% injector duty cycle and 15 AFR? 

My first thought is there is issues with the fuel pump, possibly it's old and struggling and when the car was previously tuned, they tuned around the issue by having the injectors stay open for longer to compensate for dropping fuel pressure. But this is me guessing, I really have no idea lol. 

The other thing that has me worried is, shouldn't I have encountered some form of engine failure by this stage? I've been driving this thing for years, done multiple track days, drift events and 15 AFR with pegged injectors on WOT seems very dangerous to me. 

I've attached a screen shot of the data log. If anyone wants to look at the full log of 200 or so channels feel free to PM me and I can send it to you. 

Cheers

[GTSBoy]

First things first, don't be trusting the wideband unless you have cross checked it with another.  There are various things that can be wrong and make it read wrong.  So check it before trusting it!

Second....assuming the AFR is real, it might be recent.  All the past thrashing might have been done with enough fuel and the pump is only just dying now, or the filter only just dirty enough to cost flow now, etc etc.

Third.  11 psi is they max that you should consider running on an R33 for a number of reasons.  But assuming that everything is actually working, I would expect that the injector duty cycle would be 100% or thereabouts for 6000rpm and 11 psi.  That's because the mixtures are already rich under boost and going to 11psi only pushes you further up the map into a region that Nissan flooded with fuel to prevent people hurting the engine.  If you could look at the standard R33 map in Nistune (which you can't, but you can look at an R34 one) the commanded duty cycles are flat out up there.

But, yes, assuming the mixture is real, running it under full load for more than a couple of second should lead to detonation and engine damage pretty quickly.

[Murray_Calavera]

Moving forwards, would it make the most sense to replace the fuel filer and install an upgrade pump with the appropriate relay first?

If that doesn't improve the mixtures, then throw the car on the dyno and check my wideband against the sniffer they put up the cars butt?

I'm going to do the injectors/pump & relay/turbo anyway, so I don't mind doing the pump now if that might solve my AFR problem. 

[Dose Pipe Sutututu]

I suspect the FPCM causing the issue, just earth off the pump OR delete the resistor complete, i.e. join both wires together and throw out the resistor. It's located next to the jack in the boot and opposite the electric antenna.

See if that helps, if there is some improvement - go straight to hard wiring the fuel pump with a proper relay, decent 4mm wires with a new plug going to the fuel cap. Kudos MS sells them brand new, so great for DIY work.

Lastly, another thing to check would be the stock FPR vacuum hose, they tend to crack/pop off over time and because there's a hard plastic shield over it, sometimes the leaks aren't evident.

[iruvyouskyrine]

Is this really SAU? Someone doing research and checking over the health of their car before going straight to ebay and buying a bigger turbo for it? 

Not only that but doing easy and vital mods first such as fuel pump and relay?

What a time to be alive.

[Murray_Calavera]

I'm not having any luck finding the kit on Kudos Motorsports, other sites I'm checking the kits seem inconsistent with what they supply and prices are $30-$100. Also I'm not sure what the plug going to the fuel cap is exactly?

Is this as simple as going to Jaycar, picking up a 30A horn relay for $6, grabbing some 4mm wire and crimps/heat shrink? I understand that all I'm really doing is using the relay like a light switch that sends direct power from the battery to the pump, do I need to use any fuses at all? It seems like people are getting this job done a few different ways. 

Would it change anything say running a 60A relay and larger gauge wiring? Am I right that using too small wiring/relay could burn them out but is there any advantage or disadvantage for going too big?

I'll check the FPR vacuum hoses as well.

[Dose Pipe Sutututu]

Sorry I should have clarified, they sell new power connectors to the top of the fuel tank for your fuel pump power.

And yes, you essentially you're connecting the fuel pump directly to the battery via a relay, and fuse.

I suggest at the very least 30AMP Narva or Bosch (or anything decent, no eBay shit) relay, 4mm wiring, good fuse holder and run a 20AMP fuse.

No harm going balls out big lol

[Murray_Calavera]

Ah yep, that makes sense now

[Murray_Calavera]

Thanks heaps for the advice  problem fixed! 

As advised, I threw in a 30AMP relay with a 20AMP fuse and hardwired the fuel pump. I can't believe the difference it made. 

I've got another log to upload, look at that beautiful sweeping AFR as the boost and RPM rise. A nice and safe 11.1 AFR with 6500 RMP and 10 psi of boost. 

I also switched over to wideband O2 control, so satisfying cruising around at 14.7 AFR now. Previously it would run super rich on light load and super lean on high load getting me around 15 liters per 100km. I'm looking forward to seeing how much my fuel economy improves. 

Very excited, it's like I have a new car