i got a civic with a b16a2 engine and ECtune

my problem is that when i start my car it is at about 400RPM but after a few second the RPM starts to rise all the way to 1500-1600RPM... and it stays there...
if i hit the throttle, it goes up in RPM as usual but when i realease the throttle again it drops to 400RPM and once again rices to about 1500RPM..

my other problem is when i try to connect my computer to the ecu (datalogging) it just kills the engine, and then all the solenoid and valves and the main relay just starts clicking...

now i have been trying to measure some wires to see if they were right connected and i found a problem, i think...
the yellow/black wire which is connected to A24 on the ECU(ODB2a), where should that end up? i found the ecu pinout, but i don't know what IGP2 is...?

and sorry for my bad english, hope you understand what i have written...

hope some can help me?

 

are you plugging the USB directly to the laptop or are you using a hub?

do you have custom RPM scalars or are they the stock map coding scalars?


IGP2 is the power wire. It runs to the main relay and to the injectors. You should get battery voltage when testing.

 

it goes from TTL-serial-usb- computer no hub only a converter

it is not me that have tuned the engine i paid some to install ectune for me and as far as i know he has remapped it...

well now i see one problem then... the IPG2 measure 12,xx volt when engine is off but ignition on, so thats fine, but the wire doesnt go to the main relay

what is this plug for:

i tried to mesure at the yellow black wire that goes from the plug to a negative distribution plug but it it measure 12,xx volt with ignition on so it shouldn't be connected to the negative...

 

try and find someone locally with a laptop that has a serial input so you can bypass the converter and see if that fixes it.

all these converters and hubs can do some crazy things, trust me lol.

i would also make sure the drivers for the converter are up to date.

what datalogger are you using?

and that sensor looks to be the VSS.

 

i will try that..
i know the drivers are up-to-date cause i just reinstalled my laptop and downloaded new drivers

im using the ectune free datalogger version

the VSS? well what should that connect to? 1wire to speedo, 1 to + and 1 to - or what?

 

i meant what datalogging cable?

 

oh... ttl-serial is from http://www.gotspeedracing.com "RS232-TTL v2.0"
and the serial to usb is sandberg serial-usb converter

 

i would recommend using the hulog.

 

i will try to look it up

do you know what the wire in VSS sensor is used for? there must be something wrong since the yellow\black wire has a 12v output, but is connected to negative distribution plug...

 

i think i found the problem...



i have tried to illustrate it, hope you understand...

how should the wires be connected? should the wire form the main relay just go straight to the ecu?

 

that drawing looks fine.
the wire from the VSS to the ECU is a on/off signal. If you rotate one wheel the voltage on the line should drop to 0V then back to 12V multiple times per revolution.

make sure you're idle screw is adjusted correctly.
as far as conning to the ECU to datalog, it sounds to me like something is wired incorrectly, almost like the 5V line is being grounded somehow.


you have your drawing slightly wrong BTW,
pin1 - black = ground
pin2 - black/yellow = ignition 12V from main relay
pin3 - blue/white = VSS signal to ECU, speedo/odo, cruise control and TCM if applicable.


Modified by Relic1 at 11:42 AM 9/14/2008

 

oh my mistake i forgot to write that this is the wiring of the A24 from the ECU not the vss...
so the box in the middle is not the VSS, but some kind of distribution plug... its a brown plug...

i haven't been looking at the VSS yet...

 

A24 (ground) is connected to a lot of things. Directly... ECU-A23, G101(thermostat), main relay pin3, VSS, VTEC oil pressure switch.

and along the way there is several splitter connections that things branch out to go to these other places. As long as A24 and the main relay have a good solid ground reading on them there's no need to run a separate wire.

 

ohhh i have just been lokking at the pinout diagram... i couldn't understand why you say it is ground when i measure 12v on it, but it is because it's A25 instead of 24...

 

that makes a slight difference.

A25 - sourced from the main relay's output for ignition power.
ported to; ECU B1, injectors, O2 heater, EACV and EVAP purge control.
It's also directly connected to the plug on the driver's shock tower, the one that's a dead end plug with all the pins shorted together via a shorting plug. (yellow/black wires)

 

damn okay.. have to check that out.. :/

whaqt about the VSS sensor? right now i measure ground on both the black and the black/yellow...

as far as i can see the black goes to an grey "dead end plug" and the black/yellow goes to an blue "dead end plug"...

 

never mind, found out that the blue plug is the positive and the grey plug is the ground...


i got a yellow/black wire from the main relay , but i don't know where to connect it... it's at pin 3 on the main relay i think, there are 2 wires on that pin..
there is no output neither ground or + on the wire... is that right??


have been measuring at the TPS sensor and well i think it misses af ground..:
green/black goes to the +
red/black goes to "TPS sensor" on the ecu
yellow/blue goes to the "sensor voltage" on the ecu...




Modified by menthos at 1:20 PM 9/15/2008