S13 SR No Rev. Please Help. Using Nistune.

[persain48820]

Just as the title says, the car will not rev at all. Car is basically stock aside from bolt-ons, CP Pistons, Z32 MAF, Walbro 255, and a T3/T4 turbo. Also has a new Wiring Specialties harness, new CAS, and stock 370s. I finally got it to start and idle perfect with AFR between 14.4 and 15 but as soon as I remotely try and feed it some throttle, nothing happens, simply will not rev past 1000 RPMs. It's like it hits a fuel cut at 1000 RPMs. I tried bring the Theoretical Pulsewidth (Load) Limit up to 255 from 136 and there was no change. What am I missing? Do I need to add timing? Play with Warm Enrich Throttle? If someone has any type of input, it is much appreciated! Thanks!

[mhubble91]

Hm... could be so many things man...

First off - check all wiring and connectors for loose, frayed, or corroded parts.

After that it's really just guess and check.

In my mind, the first thing that pops up is the MAF...
have the vehicle running and disconnect the MAF harness. The vehicle will most likely sputter and die. Start it again. Notice any difference?
If there is no difference in haveinf the MAF plugged in or unplugged at all there maybe be a problem with the MAF / MAF circuit.

Post reply and let me know how it goes, Good luck.

[airman]

Stupid question - your rev limiter in Nistune isn't set to 1000rpm, is it? Lol...

[badbob2121]

do you have your tps plugged in? lol

[persain48820]

Stupid question - your rev limiter in Nistune isn't set to 1000rpm, is it? Lol...

No...
do you have your tps plugged in? lol

Yes! Lol
Hm... could be so many things man...

First off - check all wiring and connectors for loose, frayed, or corroded parts.

After that it's really just guess and check.

In my mind, the first thing that pops up is the MAF...
have the vehicle running and disconnect the MAF harness. The vehicle will most likely sputter and die. Start it again. Notice any difference?
If there is no difference in haveinf the MAF plugged in or unplugged at all there maybe be a problem with the MAF / MAF circuit.

Post reply and let me know how it goes, Good luck.

I will be trying this tonight. I guess it's good that I have three Z32 MAFs sitting around should this be the problem. And heaven forbid I have another wiring issue! That's the reason I bought a new WS harness!!!

[mhubble91]

Hope it went well...

Post your findings! Ill try to help you.

[steve shadows]

not a big fan of nistune...

[Darren]

not a big fan of nistune...

Why's that? if you don't mind me asking

[persain48820]

Hope it went well...

Post your findings! Ill try to help you.

Well, I changed MAFs and nothing really happened, but I have narrowed down the problem. The K Constant was 21000, at idle which equated to 14.4-15 AFRs. That's all fine and good, but it wasn't enough fuel to get the car started, even after adjusting the Crank Enrich tables. Why that doesn't work is beyond me but that's a story for another time. So, when I raised the K Constant to 60000, the car fired right up with no hesitation but being that the K Constant sets the fuel for the entire RPM range, it was pig rich at idle, 8-8.5 AFRs.

So, with all that being said, I had read that adjusting the Injection Latency to a lower number, say 400 compared to the stock setting of 580, this should lower my AFRs with that high of a K Constant. Well, that did not happen. As I lowered the K Constant and raised the Injection Latency, the AFRs balanced out, but the car will not start with these settings. WTF, now I'm at a loss. The only thing that I can think is that the injectors are clogged. I say this because it's taking way more fuel to start the car over stock, 50% more where the stock setting is around 30000 and I set mine to 60000 or so. So, more fuel is being forcefully dumped into the cylinders letting it start. Again, anyone with some input, please feel free to suggest something, anything at all and thanks!!!

[4x4le]

Why's that? if you don't mind me asking

Because he has been banned once for spamming and carrying on in every thread related to nistune........


Anyways yes it is very hard to tell whats going on from the info given.

There is a screen that will display gauges from all of your sensors. watch them and see what goofy stuff is going on. What is the maf doing? What is your wideband telling you?
Are any sensors such as coolant temp doing anything stupid?

[4x4le]

As a side note, Id love to help you out as much as possible over the forum for free or even by phone, but I am just a couple hours away if you feel inclined to get it on a trailer for a full tune.

[r33nota240]

had this problem before it was clogged injectors 2 of them and i found out thet running 2 times the fuel pressure helped the problem thats what led me to check the injectors but mine had a small misfire that was hardly notacable well sent them off to get tested and 2 were half clogged. but good luck with urs it sux when they dont run right. just gives u that empty unhappy feeling. my r33 is down now due to the bad injectors

[persain48820]

had this problem before it was clogged injectors 2 of them and i found out thet running 2 times the fuel pressure helped the problem thats what led me to check the injectors but mine had a small misfire that was hardly notacable well sent them off to get tested and 2 were half clogged. but good luck with urs it sux when they dont run right. just gives u that empty unhappy feeling. my r33 is down now due to the bad injectors

Holy hell, it's funny you mention that. Moment of clarity? The stock K Constant for SR on Nistune is around 30000. If I want it to start, I must crank the K to around 60000! Then, it gets way rich at idle after its warms up, so I lower the constant back around 30000 and it runs too lean! Time for some injectors!?!?