S13 CA18DE - Pulsing RPM at low speeds with no throttle

knightrous · Post by **knightrous** » Tue Sep 11, 2007 9:34 pm

I'm not sure where to put this question, so apologies for if I've stuck it in the wrong section...

First off, I've no prior experience with tuning motors besides the odd muck around with the CAS and a timing like, and lots of carby work on wiper snippers. So please be kind, I bought Nistune to learn more about my car

I recently installed the Type 1 board into my CA18DE Automatic S13 Silvia. I've been enjoying the ability to log my movements in the car and try to see what happens while I'm driving. But when I installed the Nistune, I found I had a problem that hadn't shown before. If I cruise along to and lift my foot off the accelerator, if the RPM drops under the ~1400RPM, the motor starts pulsing between 1000RPM and 1400RPM. If I let it go for a bit till the RPM drops a little further, it goes back to normal and the revs maintain themselves and slowly decrease until I come to a stop. If I put my foot back on the accelerator, it picks up like normal and shows now hassle. The O2 and Injectors go pretty crazy when this happens, but the timing seems to stay fine. This happens in all 4 gears... I've changed spark plugs just to make sure they weren't a possible cause.

I've attached a log file, it's a bit long, but the problem starts at the 3:50 mark and ends at the 4:20 mark. If anyone could have a look and post up some advice or suggestions to look at, it would be most appreciated.

Thanks in advance,

Aaron

knightrous · Post by **knightrous** » Tue Sep 11, 2007 9:36 pm

Also attached the current rom loaded onto my ECU. This is a stock rom that Matt sent me, and has worked great, bar this little problem...

RB30-POWER · Post by **RB30-POWER** » Tue Sep 11, 2007 10:50 pm

if you attach the address file as well, i can open it and have a look for you.

knightrous · Post by **knightrous** » Wed Sep 12, 2007 9:38 am

Sorry, forgot not everyone has an S13 CA ADR file

Matt · Post by **Matt** » Thu Sep 13, 2007 1:54 am

Log only goes to 2:17???

Anyway somethings not right with the recording from that log file. What version of NIStune were you using when you recorded this? The reason why I ask is that the playback is in big chunks of data, the resolution is really poor compared to other CA18 playbacks vetal and mircea have posted ...

Also what is the ECU ID and the Patch Rev shown when you connect to NIStune?

Just some things to check
- If you put the factory EPROM chip that was orignally installled... it returns to normal?
- What is the original part number of your ECU? Does this match the part number above with what you were sent with the NIStune board?

Something definately doesnt sound like its working properly with the firmware loaded on the board. From what you report appears to affect logging playback resolution and operation of the engine...

Let me know the above and can progress from there

knightrous · Post by **knightrous** » Thu Sep 13, 2007 3:02 pm

Version as above

Above shows the log at the problem area where the RPM pulses up and down with no throttle.

Also uploaded the log file to my server in case there was something funky with using the forums upload thing.

I'll provide the rest of the information when I get home.

Thanks again

Matt · Post by **Matt** » Fri Sep 14, 2007 12:42 am

try 0.9109 for the logging stuff since 0.9110 is a bit screwed up with that at the moment. thanks for the screenshot, see what you mean

i put that version out for Innovate Wideband and Emulator update testing. that installation package has been moved to another folder in the download area called 'test'

yeah if you can let me know the ECU ID on the lid of your ECU and what is loaded into your board (ie display on connection) and see if those two match first

23710-xxxx

knightrous · Post by **knightrous** » Fri Sep 14, 2007 4:14 pm

ECU: 23710-36F00 REV: 12

I'll check the cover of ECU this evening.

ByReaL · Post by **ByReaL** » Thu Sep 20, 2007 5:04 am

ecu mec d07 i belive with mec d09 image on nistune board (the firmare before adding the register for the ingnition map change) anyway both non lambda used all nistune versions even the latest one and no problem.

Matt · Post by **Matt** » Thu Sep 20, 2007 10:26 am

My thoughts were the base ROM image on his ECU specified in post above didn't match ECU hardware close enough to run properly

I have seen some ROM/Hardware incompatbilities with SR20/KA24DE cause problems in the past which is why I try and line the two up. So his ECU has MECD07...?

Needed the ECU part number on the casing since didn't have that in my database when the order was placed unfortunately

knightrous · Post by **knightrous** » Thu Sep 20, 2007 8:08 pm

Okay...... Long confusing story time

My ECU is a CA18DET ECU. My car is a CA18DE (Non Turbo). I have the CA18DET ECU with CA18DE rom uploaded...

Both ECU details are as follows:

CA18DE ECU (Originally in the car)
65
23710-35F11
MEC-D014-A1-9310

CA18DET ECU (Modified into Nistune Type 1)
99
23710-36F11
MEC-DO15-**-8427

** No revision number shown...

Does this help clear things up?

ByReaL · Post by **ByReaL** » Fri Sep 21, 2007 4:29 am

Matt wrote:Needed the ECU part number on the casing since didn't have that in my database when the order was placed unfortunately

if you are referring to me do not worry i have no problem mec d07 with mec d09 image works grate (i'll update the firmware and maybe request a mec d07 firmware after the knock issue is resolved)

GZ@hybridka · Post by **GZ@hybridka** » Fri Sep 21, 2007 6:09 am

knightrous wrote:I have the CA18DET ECU with CA18DE rom uploaded...

More than likely there are a few hardware differences between the DE/DET ecu. Even if 99% of what you can see of the ecu board seems to be the same, the code could be trying to configure and use some hardware that is not there or some hardware is not being configured, responding inproperly etc...

Maybe knock hardware?

Even though you are tuning the DE you should start with the appropriate DET base code for that ecu and retune it for whatever you need.

Ka24e ecus have a similar issue, there are two board revisions, one for S13 (G40) and one for U12 (G41) and you have to do a relatively thorough inspection to find the hardware differences. The ecus will run for a short time with the incorrect code before causing all sort of weird problems.

EDIT: On second thought, if the ecu is running fairly decently overall, the code may be running ok (without error) but the ecu hardware might have a closed TPS or idle controller incompatibility with the CA18de engine(the symptoms would indicate). Or, you may also have some auto/manual conflicts.

Matt · Post by **Matt** » Fri Sep 21, 2007 12:02 pm

Sounds like in compatibility problem with the ROM images

You have two options...

Install a socket/cable into the CA18DE ECU and install the board in that ECU or...

I can send an exchange replacement board to be sent out with the correct ROM image for the CA18DET ECU you have and then you upload the DE maps over the top

This is most likely causing your problem, since the NIStune firmware code itself would not affect idling operation

Let me know what you want to do, I can supply another cable if you wish