Nistune Forums

Hey all, my name is Stephen and I have two cars that I will be tuning with Nistune. The first is an S14 240SX with a cam'd VH45DE, auto, gutted, full drag car...

http://www.youtube.com/watch?v=4De3WVFV_X4

The second car is a Z32 300ZX, also with a VH45DE, stock.

http://www.youtube.com/watch?v=ksRhjw3uFqE

I have a spare 8-bit VH ECU that I have had socketed. I bought and installed a Ostrich 2.0 and a socket booster, per another Nistune user "qsiguy" who has successfully run Nistune on his Turbo G50 Q45. I have also purchased a LC-1 Wideband to monitor AFRs.

Yesterday, I made my first attempt to use the Ostrich/ECU combo. Keep in mind that I am having laptop issues that will be worked out this weekend, but as of right now I can't do a log in the car.

I hooked up the Ostrich to my desktop computer and installed the necessary software. I loaded Nistune and successfully connected to the Ostrich. I loaded the 8-bit VH45DE address file and the 1990 image. I successfully loaded this information to the Ostrich. I disconnected and brought the ECU out to my Z32. I unplugged the stock unmodded ECU and connected the Nistune ECU. I powered up the car and it started fine.

Thats where my successes end... When blipping the throttle the car essentially fuel cuts, and won't rev over 1500/2000 RPM. I don't know if I have the wrong address/image combination, or what is wrong. I'm going to try some other combinations later on this evening after work. I don't think I incorrectly installed any of the hardware, the car did run after all...

Here are where my real questions come in...

1 - Is there a way to adjust the VTC RPM Engagement points? This will be a fairly critical parameter to be optimized in my case, especially for my S14 with its new cams.

2 - What are ALL of the reasons why a Nissan ECU would hit Fuel Cut (TP Limit)?

My S14, prior to installing the cams, would hit fuel cut after going through the traps in the 1/4. It is not a top speed limiter, since the car uses a GM TH400 transmission and there is no speedo input to the ECU. I also checked the "TP Limit" table in Nistune, and it is all Zeros, which would lead me to believe there is no limit. Would the headers/exhaust/intake cause the motor to flow so much more air that it is exceeding the Max Pulsewidth by such a large margin that the motor fuel cuts? Is that even a condition for fuel cut?

My Z32 has done the exact same thing on the street as well as the dyno. This car does have a speedo input, but it has happened well below the limit.

3 - For all of the tuners out there, this is my first swag at tuning a NA cam'd engine, all of my prior experience comes from turbo motors. Any pointers? Advice?

FWIW, after I installed the cams on the S14, the motor experienced symptoms very similar to the Z32 with the Nistune ECU. It would refuse to rev over 1500~2000 RPM. I did not have Nistune setup at the time, but the car did have an SAFC on it. I added 5% fuel across the board and the motor would then rev higher, but then die. I added more fuel above those RPMs and the motor would rev higher still. Again, could the cams/headers/intake/exhaust cause me to jump past the Max Pulsewidth to a point of fuel cut? I would think not, since the AFC would trick the ECU into seeing more airflow to add more fuel, which would make the ECU hit that max faster. I'm at a bit of a loss at this point... HELP!

GSRSteve wrote: I also checked the "TP Limit" table in Nistune, and it is all Zeros, which would lead me to believe there is no limit.

Hi Stephen!

To fully disable the TP Limit you must set each entry to 255 not to 0!
Here is an example from my S14a with SR20DET:

MichaS14a wrote:

GSRSteve wrote: I also checked the "TP Limit" table in Nistune, and it is all Zeros, which would lead me to believe there is no limit.

Hi Stephen!

To fully disable the TP Limit you must set each entry to 255 not to 0!
Here is an example from my S14a with SR20DET:

I'll try changing that, but why would Nissan set it to all 0's from the get-go?

Hmm, in my original bin's there are nothing set at 0 in this particular map. With the 255 as values you disable the fuelcut for the SR20DET-engine. This is also written in the NIStune-documentation available here: http://www.nistune.com/documentation.html

Which adress-file and which base bin do you use for your cars?

MichaS14a wrote:Hmm, in my original bin's there are nothing set at 0 in this particular map. With the 255 as values you disable the fuelcut for the SR20DET-engine. This is also written in the NIStune-documentation available here: http://www.nistune.com/documentation.html

Which adress-file and which base bin do you use for your cars?

I've read all of the documentation, couldn't find my answer thats why I'm asking here.

I've opened every 256 image file with both of the 256 address files and they all have Zero across the board for the TP Limit.

Interestingly enough, the Z32 256 bit VG30DE NA engine has 255 across the board just as you would expect.

Is it possible that the Q45 address files are wrong and referencing bad data?

Hi Steve

Can you email me your BIN and address files which you are using?

Doesn't sound like a TP cut at that low and shouldn't really happen on a NA engine since you're not going to get that much load

Sounds like something else wrong. What is the part number on the ECU you are using also? Maybe the BIN/ECU isnt matching up and its having a dummy spit?

I havent looked at VCT on that one yet but if its there might be able to find it for you

Matt wrote:Hi Steve

Can you email me your BIN and address files which you are using?

Doesn't sound like a TP cut at that low and shouldn't really happen on a NA engine since you're not going to get that much load

Sounds like something else wrong. What is the part number on the ECU you are using also? Maybe the BIN/ECU isnt matching up and its having a dummy spit?

I havent looked at VCT on that one yet but if its there might be able to find it for you

Hey Matt,

I have tried every 256k bin and address file in the rom pack available in your downloads section. Some work and give me the condition mentioned above, some won't even let the car start. Another characteristic of the problem, if I stab the throttle the car dies and then recovers when I get off the throttle, but if I open the throttle very slowly the motor will rev all the way to redline. The key is no quick throttle changes. FYI, with a spare stock ECU this motor runs fine.

I didn't think it was a TP cut issue, and after discovering the slow throttle change property described above, I really don't think it is now.

The part number for the ECU I am using is "A18-A21 P66". There is no Nissan part number on it. This ECU came out of a MY91 or 92 Q45, I can't remember since I bought two parts cars. I should have labeled them, I know... The car ran fine before the ECU was pulled.

If you get a chance to look up the VTC data that would be great, but just getting the car running right now is my priority!

Thanks!

Well, I'm starting to believe this is a hardware problem. I found the correct bin for my ECU using an online ECU database from JWT. I then attempted using Tunerpro RT with the Ostrich and the correct bin file. Same result, the car will run, but any abrupt throttle input causes a misfire. Slowly ramp the throttle and the engine revs fine.

I'm going to try to give Moates a call tomorrow. Maybe I have a bad socket booster?

yeah i forgot about that bit with the VH45 ECUs

viewtopic.php?t=694

i used a shorter cable and the ECU worked. it was in limp prior

are you able to talk to consult at all? if not then you need the booster / shorter cable so the ECU works

i dare say the ECU is in limp mode. Is the ECU light continously on or flashing on/off repeatedly?

explains why it dies regardless fo ROM image

Matt wrote:yeah i forgot about that bit with the VH45 ECUs

viewtopic.php?t=694

i used a shorter cable and the ECU worked. it was in limp prior

are you able to talk to consult at all? if not then you need the booster / shorter cable so the ECU works

i dare say the ECU is in limp mode. Is the ECU light continously on or flashing on/off repeatedly?

explains why it dies regardless fo ROM image

I am using the socket booster already.

I never tried connecting with consult, I can give it a try.

Yes, the light is on continuously, even if I turn the pot to check for DTCs, the light stays on.

I'm going to need to look for a shorter cable I guess. Not sure where to find one.

Moates has the shorter cable. Whats the current length you are using?

Matt wrote:Moates has the shorter cable. Whats the current length you are using?

Well, I just modified my cable to be shorter. Apparently the ends are reuseable. I was using an 18" cable, I'm now using a 2.5" cable, just enough to get the emulator outside of the ECU.

Same problem, and for what its worth, the ECU does the same thing with or without the booster installed. Possibly a bad socket booster? Or could the ECU have been damaged when it was socketed? What about a bad Ostrich? I just don't know where to look next...

the ecu could be damaged from socketing.

we have had problems with Z32 ECUs which are similar to those

look like perfect install and still doesnt work (even through verified working fine prior and all the tracks buzz out from the pins to the processor chip)

your only way of really knowing now is putting the original chip in. if you cant get the LED to flash diagnostic codes then i think its stuffed and you should try another ECU or recheck the socket installation (no lifted or cut tracks)

Unfortunately I don't have the original chip. I do, however, have a couple spare ECUs. I'll take one to a local electronics shop and have it socketed and keep the original prom, that way I can check both ECUs afterwards...

This is frustrating, I know it's not Nistune's fault, I just want to get tuning!

i know where you're coming from...

at least you have the socket booster. it had me stumped for a few days why the Q45 would run with my chip, emulate with my romulator but not with the ostrich. I've got boosters and shorter cables for my units now