Hey HT,

Trying to work on the car and get it ready for the roads so it can be certified, etested and to have a good running car without any issues.

The car is a 1990 Honda Civic SI with a B16A, previous owner told me its using a JDM OBD0 ECU.

The car will not go over 4K, he told me that he hasn't put in the codes for VTEC to engage.

So should I find some body to input the codes or would it be better to get an OBD0 to OBD1 harness and pick up a OBD1 ECU that already has the codes for VTEC to engage?

I was thinking about just grabbing a PW0 ECU locally.

Sorry for the newbie questions, just trying to learn so I can fix future problems and such.

Thanks in advance!

 

first i would check to see what ecu u have in there... easy, pull up the carpet under the glovebox and look on the side of the ecu ( might have to unbolt it. 4- 10 mm bolts) it will have numbers on it like this 0000-xx0-x00 the middle #'s are the ECU. the last 2 # will tell u if its an auto or manual. above 50 auto, below 50 manual.

 

if its not a pw0 or pr3, then the easiest route would be to get one. vs going obd1

 

Ok, the car is being stored in my buddys garage so I'll have to check tonight. I've stripped the interior so I've found the ECU just haven't checked the numbers. Thanks for the input I'll check back sometime tonight.

How will I know if it either or?

 

It will look something like this: In this example it's a OBD-0 b16 Manual ECU



See where it says PW0? This will tell you what kind of ECU you actually have. PR3 and PW0 are both OBD-0 b16 ECU's

 

Yeah I see it, thanks for the input & the reference pic !

 

So I went to check the ECU last night, its a PR3. What would be my options now? I see the wiring but looks like a hack job, I want to basically hook up everything myself. Does anybody have a DIY hooking everything up?

 

ok, u are running the right ecu. pr3 have vtec, so previous owner lied (whats new). know down to the problem. to me it sounds like it could be running in limp mode. is there and codes on the ecu? turn ign on and watch the led light flash on the ecu. short flash = 1... so "." "." "." whould = 3 check for codes

write up on a diy b16 in a ef
http://crxresource.org/modules.php?n...rticle&sid=134

 

Thanks for the help and source man, will be going back tonight to check things out!

 

Alright so I'm here checking it out. After reading on some of those Diy wiring on vtec the pins where all the vtec solenoid, oil pressure etc are suppose to go are already filled with other wires. Am i suppose to splice those wires and connect them to it or replace it with the ones for the vtec solenoid and so on?

 

I checked the red LED on the ecu, short flash then a long flash and then followed by long flashes. So im assuming i got a code 11?

 

If they have pinned wires in them already then there is a wire out in your engine bay that can be used rather than splicing.
However, you will have to find out where it is.
If you have a Helm's manual then this is fairly easy as it has a complete wiring diagram with wire colors and what senor the wire connects to. (The color often changes at the main harness connector in the engine compartment.)

If it's too much hassle to find the sensor the wire originally went to, you can use a multimeter to check for continuity at the pin on the ECU connector and probe the harness connector in the engine bay until you find it. Then at least you can cut into the corresponding wire on the engine harness rather than splicing into your under-dash harness.

 

Sounds more like code "1" and then maybe "10" or "20"
How many long flashes?

Code 1 Oxygen Content
Code 10 Intake Air Temperature (IAT)
Code 20 Electronic load detector (ELD)

Code "11" does not exist.

 

Thanks, I'll go grab my MM tomorrow and figure it all out, but if I were to just splice into the wire would there any issues? or the wires are no longer connected into anything so they would be free too use.

Well when I first turned on the car. I just get one short flash then long flashes and it doesn't really stop, it just keeps giving me long flashes after that 1 short one.

 

Before splicing and stuff, I think at this point you should check things out for yourself and see if the vtec solenoid is hooked up or not.
So far you are just going by what this previous owner has told you.
If you can trace the wire from the ECU you may find that it goes to an unused plug really close to where it needs to be.
Typically that's how it goes and looks cleaner than splicing a new wire into it all.

Your code sounds like "10".
If it were "20" the long flashes would be grouped and then a sizable blank between them so you would know they were together.

IAT is that white sensor on the top of the intake manifold.

 

I checked everything out and its all hooked up but by the looks of it, previous owner did a really poor job. The wires that run to the ECU weren't connected properly, he inserted the wires in the female holes of the harness then plugged it into the ECU and I think I'm very sure thats not the proper way you connect the wires.

I could be getting that code 10 because atm I don't have the throttle body and intake manifold attached to the engine due to I'm having them both cleaned out of dirt/carbon grime, would that have anything to do with why I'm getting that code?

BTW the oil pressure ground wire was really short I don't think it was grounded properly as well. It was grounded somewhere on top of the VTEC solenoid. Where would be a appropriate place to have it grounded?

 

yes u will not get a proper reading, get everything hooked up reset ecu ( pull hazzard fuse "enginebay") run up and down the street recheck codes

thats where mine is grounded to

 

^ Okay cool, I'll do that once everything it hooked up back together.

From reading this link:

http://www.angelfire.com/d20/hcivic88/4gtech_vtec.html

Its telling me to run the wires to a 4pin connector then to the ECU, would it be alright to just run the wires straight to the ECU or is it mandatory for the 4 pin connector to be used?

So far I disconnected all the wiring from all the vtec components. I also removed the vtec solenoid to clean it out and to replace the top and lower gasket. So now in the process of wiring it all back.

 

they are saying 4 pin conector because those are 4 new wires to run to the ecu, u can run all 4 direct to the ecu. it just makes it easier to pull the motor if u can unclip a conector vs cutting a wire.

 

^ Oh okay makes alot of sense now, Thanks.

Btw where would I be able to grab those tiny connectors that you have to crimp around the wires to plug them into the ecu harness? I have no idea what to ask for if I were to head to a parts store.

 

Btw my header only has one o2 plug, when I first looked at it before I started to re-wire it was pluged into the ecu. I was doing my research and said you need to have 2 wires, my header only has one plug and one wire. What should I do? Splice into that wire?

 

dont crimp the wires. the best way to go about it is get a solder gun and solder. and some shrink wrap.. <~ this is the strongest why

 

dont splice i tried that along time ago. sounds good but the 2 diff. o2 measure diff. so not work. i too only have one bung in my header, i ordered a 30 dollar cat off ebay with the other bung. with the obd0 ecu u should use both o2 too run perfect.

 

read the thread I wrote dpfi to mpfi without issue. code 4 is the one that wont let the car rev out. the reason your car wont rev is because the ecu pins are installed incorrectly. Follow my instructions in the thread to fix your problem.

 

Alright, I've found a guy selling a o2 sensor with 4 wires, would I be able to just replace the current o2 sensor that has one wire with that and wire everything up that way instead?

Thanks for your input man but its hard to read that picture cause the text is too small.