Nistune - Need Help

[300zxturboftw]

Hello - having a few issues my tune that I can't figure out.

Set-up:
VG30 bottom end with ported OWO heads
280/280 Isky cam grind
680cc rx7 fuel injectors
Equal length manifold to pt6266 gen 2 ball bearing turbo
HPX 1000+ hp MAF with ford connector pin
Ebay radiator fan with derale fan controller
No A/C
90 amp maxima alternator
No idle controls - using TB open slightly to stay running
Battery is Yellow Top Optima

I cannot get the car to idle at 14.7. If I bring the engine up to 1000rpm I can adjust k constant and get it there for a few seconds. Then it goes and does whatever the hell it wants ranging anywhere from 12:1 to 20:1. Once the car is warmed up the fan kicks on the engine RPM drops as if its under heavy load and the car AFR's drop to 20:1. I had it at one point where I could cruise around and it would go between 13.7 and 14.9 which I think is unfortunately just due to CAM size, but now I'm having issues where even driving the car is a hassle (this was before I changed to equal length manifolds, but was still having drivability issues). My biggest pet peeve is when the fan kicks on the car just can't handle it, and we are talking a 18" 12 amp fan. The car revs freely and the afr's are brought back but it still is all over the place. I tried enabling o2 and disabling and playing with latency and k constant, but still not having much luck. I will post the bin file once I am home, but please if you see anything I would appreciate it or have any ideas that you may have experienced the same.

[88sinZ]

It sounds like it's 'hunting'

I see you're using the AEM UEGO. A quick search doesn't say if it has a 'dummy' signal to the ECU. If it has this feature wire it in any report back.

I wouldn't worry about the TPS values if you're running the OEM TPS, wouldn't hurt to meter it just to be sure. I'm running a stanza TPS on a Q45 TB with a wiring mod, no idle controls at all, innovate LC-1 with 'dummy' signal and it idles fine. Cams shouldn't be considered with this issue.

Did you follow the most recent NisTune setup guide? is your software up to date?

[FlawleZ]

Have you flow tested your injectors? When the AFRS fluctuate dose the MAF voltage coincide? Where is your MAF placed?

[mtherkamp]

If you aren't running the simulated narrow-band back to the ecm, you will need to disable closed-loop and tune the whole fuel map, including the idle regions.

[300zxturboftw]

Running an innovate wideband, it's definitely accurate. Disabled closed loop and tuned fuel map with idle regions. I know it should work correctly as I already had the set-up working at one time, but now it's pretty wonky again.

Fuel injectors were flow tested. I'll have to check MAF voltage when I'm back with the car. MAF is currently placed about 24 inches away from TB right after a 30* bend down (has 4-7" on both ends of straight tubing. It's in a 3" tube reduced to 2.5. Going to weld it up so it's 3" tube to 3" all the way to Tb then reduced to 60mm.

I did forget to check TPS position as I put a new gutted plenum on, could be a major part of the issue. But I was still having trouble with fan pulling everything down via idle and AFR's, which I have no idea how it could stress the system that much.

[Pace]

Have you had the alternator and battery load-tested recently?

[FlawleZ]

Wait are you running the MAF blowthru?

[300zxturboftw]

Alternator and battery are new. Not the issue.

Yes, this is a blow thru set-up.

[mtherkamp]

Random question, but where is your intake located? I had trouble with mine when I went e-fan because the filter was right above the rad so when fans kicked on it sucked all that hot air in and messed with the idle to the point the engine would surge and run rough. No idea if this is your problem. Also, Innovate products have a bad reputation in the rotary community for being inaccurate and blowing sensors frequently. Also no idea if this is your problem, just thought you should be aware. Something about driving the sensor PWM instead of true analog voltage. Take it for what you want, but you should probably pick up a spare sensor just in case.

[300zxturboftw]

I have 3 sensors. They are the same sensor UEGO uses and your standard volkswaggen passat if you didn't know (just has different pigtails). I agree that innovate burns the sensors out faster than UEGO, but I was blowing tons of oil on the sensor as well before I had my old turbo rebuilt. Trust me, you can tell when your car is running wrong even without a wideband lol.

[FlawleZ]

How does the car run with a draw thru setup? The blowthru setup will not only be more difficult to tune but will also hit max voltage sooner. The MAF won't meter as much air on blow thru as it can on draw thru

[300zxturboftw]

I'm sure it will run OK on draw thru. Haven't tried it though. The HPX's are built for blow thru and a lot of people have great success. This thing won't max out because we can always just rescale the maps in nistune for MAF. Might have to contact HPX for someone who has a proper scale. Going to work on it this weekend will update you guys.

[88sinZ]

also on blow through, Q45 MAF with 3" pipe to 3.5" MAF lip couplers on each end. Blow through is just fine, it's worth mapping your Voltage values vs AFR.

I'd definitely clean your grounds for each critical sensor, battery, fans, and alternator. Dap them in some dielectric grease on install if you haven't been, just another step/maintenance item but it works..

[PegCityZ]

MAF is currently placed about 24 inches away from TB right after a 30* bend down (has 4-7" on both ends of straight tubing. It's in a 3" tube reduced to 2.5. Going to weld it up so it's 3" tube to 3" all the way to Tb then reduced to 60mm..

Not related to your current problem, but if you go with 2.75" tubing it matches the inlet of the 60mm throttle body. That's what I'm using as I don't expect to make over 700 whp.

[300zxturboftw]

So I chased back all the grounds and found the coil pack wasn't grounded well. That was an easy fix. Car runs much better, but again once fan turns on it draws the rpms down and afrs lean out a crazy amount.

I have a feeling my battery terminal cannot support that much flow thru it. I'll have to find a new solution.

Now I'm also thinking about what size piping to go with for intercooler. Should I go 2.5" from turbo to intercooler then 2.5" cold side over radiator to 3" blow thru tube then reduce to 2.75" to TB or run 3" all the way to TB from MAF. What I'm worried about is how air flow will be effected from MAF and what hp I will also max out on. The MAF blow thru tube is 7" long, and the maf is about 4.5" down the tube. This is why I think I might benefit from doing 3" to TB then reduce to 2.75" at the TB.

Should I just run 2.5 for hot side then 2.5 to 2.75 after radiator and to TB. Can always get a weld on flange for HPX, just need to make sure I can hit ~630 rwhp.

Thoughts?