D15B ecu question

[jamie langdo]

I have a d15b 3 stage vtec motor, but i dont have the right ecu. im running the ecu for a d16y8 vtec. i beleive i need the P2J to run properly right? my cars runs good. its been a year that ive been using this ecu, but its got some issues, and i thinks its because i dont have the right ecu. i found a ecu for it, but its for an automatic..will that work? may have to get it chipped??

 

[psychotic_civic]

an automatic ECU will not work and a D16y8 is for a single stage Vtec. You need the correct ECU to run properly. I think the OBD-2 D15B was the only 3 stage Vtec. DO NOT get the P08 for a OBD1 D15B cause that is only single stage. Change the head to a y8 and keep your ECU

 

[psychotic_civic]

p2j-003 i think is the correct ECU for a 5speed but that is an obd 2 ecu. its much easier to change your head

 

[SGGilmo]

i know you can convert a p28 auto ecu to a manual by removing jumpers RP17 and RP18 then jump RP18 with a 0ohm resistor.

not sure if it would be the same with that one though.


EDIT: nope its not

 

[SGGilmo]

i found this. dont know if it will do anything for you

I personally know one guy in Malaysia who had his gearbox changed to manual and still using the auto ecu. His car is a JDM EK3 with D15B 3 stage VTEC and CVT tranny converted to manual. As his car was OBD2A, the ECM (Engine Control Module) and TCM (Transmission Control Module) was a seperate unit.

The principle problems when retaining the auto ECM is that (assuming gearbox swapped and auto ECM used):
1. Car will start in P or N but will not rev pass 5KRPM and no VTEC
2. Car will not start in D but with full rev and VTEC functions
3. Other things i.e. ignition key mod, reverse switch bla bla bla etc I'll skip here.

Another guy from Thailand cranked the motor up without the TCM. The transmission technical manual stated the TCM receives information from transmission sensors and ECM input. That also means the engine will start with or without the TCM.

Basically the ECM has to be tricked to work in manual environment.

Getting manual ECU is ideal but ultra rare. Manual ECU have slightly different requirements than auto ECM. Auto ECM calls for 3 wire IACV and narrowband O2 whilst Manual ECU calls for 2 wire IACV and wideband O2.

OBD2B is different from 2A in a sense that the TCM and ECM are combined unit called PCM (Powertrain Control Module). I believe that the tricking process is the same but no solid proof yet.

This is my understanding for JDM D15B 3 stage only. Your vehicle may be different case than mine.

I wouldn't know about Accords but for Civic finding a manual tranny ECU for D15B 3 stage VTEC in specific is very hard to come by.

There have been some examples of swaps where they retained the obd2 auto ECU and still manage to operate both VTEC-E & VTEC on the D15B 3 stage. Some wiring needed to be done to trick the ECU that everything is OK whilst using manual tranny.

Last night I tested this again on my 2b ECU by unplugging the 8 pin solenoid harness connector to simulate limp mode for the CVT.

The engine didn't throw a CEL but D indicator blinks constantly whilst still in P. The car will start. The manual states the CVT can still operate on full manual mode i.e. without TCM control / limp mode. I believe the same can be done on the Accord's auto ECU.

Changing to manual ECU is still the best option though auto ECU will suffice to some degree. Manual ECU will need 5 wire wideband O2 and 2 wire IACV as opposed to 4 wire narrowband O2 and 3 wire IACV.

I personally own a 37820-P2J-003 obd2a Manual ECU for my motor but I reckon maintaining the 2b auto ECU would be a quicker/cheaper route. I'm keeping the 003 just in case I really need it.

 

[psychotic_civic]

again we get to the prob of him being OBD-1 cause he is posting in the 5th gen section and the ECU being OBD 2 so now he has to convert which sucks balls

 

[nightmarebd]

D15b got p06 ECU for manual transmission, i have got eg8 jdm d15b with a p06 ecu.
if u cant find that one then why not you go for the after market ecu?

 

[SGGilmo]

D15b got p06 ECU for manual transmission, i have got eg8 jdm d15b with a p06 ecu.
if u cant find that one then why not you go for the after market ecu?

wrong d15b. there are three different d15b engines. a non-tec, a single stage vtec, and a 3-stage vtec, all of which just say d15b on them. he has the three stage you have the single stage. the P2J-003 is the correct ecu for the manual stage-3 vtec d15b engine

 

[nightmarebd]

how to find how many stage vtec is there?

 

[jamie langdo]

thansk for all the info guys. I do have the 3 stage, and i think i will just keep looking for the proper P2J ecu. i dont want to f**k with the ecu too much in case i fry it and cant find another one. thanks

 

[Big[V]]

thansk for all the info guys. I do have the 3 stage, and i think i will just keep looking for the proper P2J ecu. i dont want to f**k with the ecu too much in case i fry it and cant find another one. thanks

You could still use the auto ecu. By far still the fastest route and P2J auto is dime a dozen though might need to live with the annoying CEL codes due to the absence of the CVT tranny.

You will also need to check what is the year on the block stamp. If it is 97 and below it is obd2a, 98 and above is obd2b.

Primary difference is that obd2a have seperate CVT control unit (TCM) whilst obd2b is integrated in the ECU. also wiring pin locations on the ECU plugs are different.

Once you got the conversion issues sorted with auto ECU you can run it for the while whilst looking for your P2J manual.

P2J manual will be ideal but need to convert to 2 wire IACV plug, manual IACV and wideband primary O2.

Good luck.