RB30 help

[atomic_stone]

Hey guys,

Just have a couple of things to pick your brains on.

First off I have a VLT which is completely stock, except for some larger siemens 60lb injectors and the nistune ECU which, after a short while I found out was from an R31 Skyline. After having a bit of a fiddle getting the new injectors re sized and getting the car to idle as close to stoich as possible, I noticed that every 10 seconds or so my AFR gauge would spike lean, and then it would even out. After reviewing a log of the car idling, it became apparent that my injection time would spike up to 329ms and the injector duty cycle would also spike up to 219%. A quick look across the log graph shows that this annomalie seems to be only from the injectors, no other sensor is giving a bad reading and nothing else seems to spike before or at the time of the spike. I did notice that sometimes after the injector spike had happened the AFM would also spike up but not as much, and this did not happen all the time. I'll attach a couple of short logs where you can see the injection time and duty cycle spike.

I thought this may be sensor related and started to go through and see if any sensor was causing this massive spike. Nothing i unplugged or disabled in the flags would stop the spike in injection time. Another issue popped up which was whenever the AFM was unplugged, the Nistune software refused to consult the ECU, even though the PC recognised the nistune board as being plugged in. So I redid all my grounds, ran a new body strap, new battery and terminals and ran into the same issue. I realise that i will have to install a larger AFM to match up with the larger injectors but this seemed like a very strange thing.

And then another issue popped up randomly. I realised that the car wasn't turning the accessories off whenever the ingnition was turned off and key was out. I could still view my AFR gauge, turn on wipers and indicators. I put this down to the ECU being out of an R31 skyline and not a VL and i know of a couple of slight differences between the VLT ecu and R31 ecu such as the fuel pump control but nothing with the ignition or ECCS.

Any help would be be greatly appreciated!

[Matt]

Second hand ECU from memory? Just looking and I did the update from CR31 ROM image to VLT FP1 base image

1. Spikes in the log file are not good. Not sure what is causing those, but you said the MAF voltage also spikes? To what voltage? Same time? Those logs don't show the MAF spike though. Strange. Not seen that before. Have you reloaded the factory file and tried the injector resize again. What about doing CTRL-ALT-Q to 'repair' the ECU maps with the one from the VL_RB30ET_B490F_MT_FP_maps.bin file?

2. When you disconnect MAF, there is a MAF DTC fault. The Nistune firmware only operates when the MAF voltage is good (it was the only good place I could inject the routine call for high speed updates without affecting other ECU operation). That is why you cannot connect. That is normal

3. Turning off the ignition but ECU stays on (watch LEDs) is a fault with the second hand ECU you have. It has had the igntition signal input line damaged, likely the diode is holding up voltage. Should not be related to Problem 1. At this stage either repair the ECU (change diode and try reflash board again on the bench and I monitor spikes) or replace ECU

[atomic_stone]

Hey Matt thanks for the reply!

Yeah I sent my ecu off to you about a fortnight ago to change the base image on it. I knew I should've sent my working ecu through to you, instead of going secondhand.

The AFM voltage spikes only happens occasionally. It spikes up to about 3.5 volts about .5 second after the injection spike. Tomorrow when I have a bit of time I'll re load the factory tune and resize the injectors again. If the ignition signal input line has been damaged who knows if the injector driver is bad as well?

Also good to know about the AFM fault, i thought it'd be something simple like that.

If all that fails I might have to send you through my other ECU!

[Matt]

How often do the 'injection time' spikes happen? I would like to see if that would happen on my bench and how long to leave it for

Likely you will need to post both ECUs here and move the board across. However to doing the 'repair' method firstly and let me know via email