B16a2 wiring into EG5, IAT, Knock sensor - P30 ECU

[dorikin]

hey guys,

I have some wiring problems with my car so i'm thinking of pulling it all out and doing it over.

The ECU is a 37820-P30-G00 can someone confirm what car this ECU is from? It's currently powering a B16a2 from an EK4. I believe the wiring is the original EG5 VTi loom.

What wiring modifications would be needed to get all the above mated up? Is this the right ECU to be using and are there any benefits with using this ECU compared to others?

Thanks, still a newbie with hondas so will probably have heaps more questions

http://img295.imageshack.us/img295/4919/snc00941.th.jpg (http://img295.imageshack.us/i/snc00941.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

[fabezzz]

looks like a spoon ecu to me

[dorikin]

How can you tell?

[Samm928]

The P30 is a great ECU...if you can find it. They came from the uber-rare Del Sol VTEC models, the rev limiter I believe is 8400, but I'm not sure. I do know the redline is 8200.

What engine is this for??? B16?

The JDM P30 is a short box, the USA model is a long box.

JDM's are dime-a-dozen

USA's are very rare.

The P30 ecu has a knock sensor, and is made specifically for the B16A engine.

The P28 ecu does not have a knock sensor, but it can be converted to work for DOHC VTEC engines. (no knock sensor though)

[dorikin]

^^^Thanks mate

The engine is a B16a2 from an AUDM EK4. What exactly does a short box and long box mean? (sorry still a newbie with hondas) Does it refer to the shape of the ECU because mine is a rectangular shape?

From what i've gathered on google the P30-G00 means "General" and P30-J00 means "Japan", I think mine is a UK spec ECU. Someone correct me if i'm wrong please.

[Samm928]

short and long gear ratio's. aussie specs come with short.

EG5 VTi loom. i dont think it'll come with a vti loom if its got vtec. the harness is totally different.

the ecu is fine man. if it runs and its good. keep it if you think its sluggish then drop in a hondata s200/300.

go to the dyno day its $50 in the upcoming events at wetherill park sydney and test how your car performs. you'll get a rough idea if its good or not i guess.


:)

[dorikin]

nah, what I meant was the previous owner who did the conversion used the existing EG5 wiring loom (from what I was told).. which loom should I be using?

the car starts and runs but its not running properly, runs rich and pretty rough and doesn't rev out fully. thats why i'm planning to rip it all out and do it properly.

[ECU-MAN]

the ECU you have looks like its a P30 from Aus CRX,

it more than likely does not have knock sensor as mentioned above, but you will need to ensure your VTP and PO2H are wire int he VTi to be able to use that ECU without fault codes

your best starting point would be to check the ECU for codes

ensure your MIL is wires up corectly

fix any fault codes you have 1st, if it still runs like crap, do a continuity test of the loom to find the problem, takes time but will be the quickest solution

[dorikin]

^ Thanks ECU MAN very helpful

Just did the ECU check as you said (didn't think it would work because the engine light was always on before) but it did give me one flash. Almost mistook it for Code 1 but it was a long flash so realised its Code 10 - IAT sensor.

Then I read through your DIY diagnostics for IAT article, went to my engine bay and couldn't even find the IAT on the intake tube. That's when I realised there wasn't any sensor and the previous owner must have re-used the original EG5 VTI intake tube (no sensor on EG tube).. so the plug for for IAT was never even connected which is most likely causing the issues atm.

I'll have to hunt around for a proper intake tube with IAT sensor, which one should I be buying EK4, EG6?

[Samm928]

ek4's and eg6's anything with a b series vtec should have it.

[dorikin]

Yep picking up an EG6 one today :D now I need to get the sensor
does anyone know if you can buy aftermarket IAT sensors? does NGK, bosch or anyone make them for Hondas? Or should I just get an OEM one


One other question, what happens if there is more than 1 fault code in the ECU? Will it only show you the second code after you clear the first one?

*Edit EG6 intake pipe will not work because it doesn't have the extra hole for the IAT sensor

[ECU-MAN]

no it will show all codes one after the other

you need to use a honda IAT. If you have chosen to put it in the intake air tube then you have to extend your wiring as the VTi loom would of has the IAT setup on the Intake manifold.

[dorikin]

Damn now I'm questioning which loom is actually in the car because the PLUG for IAT is definitely there in the loom near the intake tube but its just hanging loose not plugged into anything so this would suggest that it is actually the EK4 engine loom in the car... soooo confused :confused:

I've purchased the EK4 intake pipe today, hopefully it fits up with everything and i'll go pick up a sensor on Friday


That's also good to know about the error code, I only get the 1 long flash being repeated so shouldn't have any other issues once this is fixed.

[dorikin]

What would be the easiest way to tell exactly what engine loom my car is running? Is there any distinguishable feature between EK4 and EG5 loom that can be easily spotted?

[ECU-MAN]

do you have the connectors at the LH shock tower for the engine harness ?

[dorikin]

I'll double check when I get home tonight and take some photos.

[dorikin]

do you have the connectors at the LH shock tower for the engine harness ?

Are these the connectors you're referring to? There are 3 main ones here

[ECU-MAN]

yeah

you have a Vti or VTiR loom from a B16 or B18

the original IAT sensor would of been on the manifold


howerver it could be a custom loom.

[dorikin]

^Yeh I though so

I got my hands on a used sensor from a D16y but I don't know whether its working or not because the ECU still throws an error code 10...

With the Key On Engine Off, the signal wire for IAT on the ECU side shows 4.99V whereas on the sensor plug side it only reads 3.07V.. this is with a semi-warm engine. Is this normal?

How would I go about testing the actual sensor?

*Edit - using the instructions from an EG Service Manual it says to test the resistance of the IAT sensor and it should be in the range of 0.4 - 4.0K OHM - tested mine and it was around 2.7K so it doesn't appear to be faulty. So based on the voltage readings above I think there is a short in the circuit between the ECU and the IAT sensor plug.... will do more tests tomorrow

[dorikin]

What a massive PITA :S

Turns out the plug that I thought was for the IAT sensor was actually for the VTEC pressure switch, dont ask me how.. I just assumed it was for IAT because it was unplugged near the intake pipe..... Now, because there is a loose plug for the VTEC pressure switch this rules out the loom being from an EK4 (no VTEC pressure switch in EK4 B16a2 engine) so this loom must be obd1.

After figuring this out, I decided to rip the whole engine loom out. Let me tell you it ain't a fun job when the engine is still in the car :(

After removal I discovered the loom also has the IAT wiring in the middle of the loom which means the loom is meant for an engine with IAT sensor at the manifold (gen1). And for some reason the IAT plug was connected into the Knock Sensor.. :S Retarded, I think the previous owner thought everything was plug n play lol

So this is where im at right now. Loom is out of the car, need to modify IAT wiring and extend it closer to intake piping, need to wire up the knock sensor, need to do something about the VTEC pressure switch and then pray everything works.

[dorikin]

Okay update.. modified loom to add in Knock sensor, extended IAT wiring, and added a relay for VTP. Car runs better and no more code 10 (IAT)

But now that its out of limp mode I am getting Code 21 (VTS) and Code 41 (P02H).

VTS - had to re-pin vts wire as I figured out the VTS wiring in the obd1 engine loom i have doesnt match up to the firewall wiring. Tested solenoid working, testing wiring for continuity to ecu working, but haven't tested ECU yet as I need to be driving the car and engaging vtec to test that.. so could be ecu problem, hope not.

P02H - this one has got me confused, I can only see one metal wire coming out of my o2 sensor (looking directly below the intake manifold) and the loom has a plug for only 1 wire. I think the previous owner re-used the original EG5 o2 sensor. Can someone confirm for me that EG5 have a 1 wire O2 sensor? If so, do I need to buy a 4 wire O2 sensor and add in new wires to the ecu????
The other weird part is that I'm not getting a Code 1 error (o2 sensor)

[tiksie]

looks like a spoon ecu to me

wtf @ this ? lol.

Def not a JDM P30 or else you would have had the TCS #36 error.

[ECU-MAN]

you dont have a JDM ECU anyway

not all JDM ECU have TCS

your P30 requires a 4 wire O2, since your engine only have a 1 wire O2 it will give you code 41

I can modify your ECU to work with a 1 wire O2 if you need it, or simply wire up the 4 wire O2

[dorikin]

Thanks ECU-MAN. I figure I might aswell take this opportunity to buy a new O2 sensor and wire it up properly as the old one probably has never been replaced before..

If the VTS problem turns out to be an ECU fault, are you able to repair that?

[ECU-MAN]

yeah I can fix that


are you 100% sure its the ECU, have you checked continuity from the VTEC Solenoid to A4 of the ECU ? also have you checked the resistance of the VTEC Solenoid

[dorikin]

Not 100% sure yet, the ECU voltage test is the only test I haven't done yet as I need to be driving the car to engage vtec.

Did resistance test 20 W,
also did the jumper wire test to battery and the solenoid does click

Continuity tested ok between vts plug and ecu pin A4 (after re-pinning canon connector)

I'll be doing the ecu test later this week and get back to you with results

[dorikin]

One more question, I've been doing some reading on honda-tech and came across some info regarding the type of relay that should be used when doing the VTP ECU trick.

http://www.honda-tech.com/showpost.php?p=11907905&postcount=24
Now we realize that the ECU is looking for a normally closed (connected) path to ground on pin D6. When the vtec engages, the pressure switch opens the ground connection. To fake out the ECU you need to install a $3 SPDT low current relay switch. We used a NTE R70-5D1-12. This is a 1 amp, 12VDC, SPDT relay. Radio Shack also sells a low current relay that will probably work. It is important to use a low current (5A or less) relay. This will have high coil resistance (150 ohms or more), which will keep the ECU load on pin A4 low. You cannot use a generic black 20 Amp (4 pins) automotive relay! It does not have normally closed contacts and the coil resistance is too low.

Connect one of the (relay) coil pins to ground (I used the screw on the ECU). Connect the other (relay) coil lead to A4 (vtec pressure solenoid). Connect the (relay) common pin to ground, and the (relay) normally closed pin to D6. This will cause the D6 to be normally grounded, and open with vtec activation.

When I hooked up my relay I followed ECU-MAN's wiring diagram which is the same as above, the only concern I have is with the type of relay I should have used. From memory I used a generic 30amp SPDT relay I had lying around. Is it critical that I change the relay to a low current type (5 amp or less)?

[ECU-MAN]

well it is possible the relay coil is increacing the resistance on the VTS line and the ECU sees this as a faulty VTEC solenoid.

try a smaller type of relay ( jaycar )

if all else fails, I can disable O2 heater and VTP in the ECU for you

[cvc247]

the ECU you have looks like its a P30 from Aus CRX,

it more than likely does not have knock sensor as mentioned above, but you will need to ensure your VTP and PO2H are wire int he VTi to be able to use that ECU without fault codes

your best starting point would be to check the ECU for codes

ensure your MIL is wires up corectly

fix any fault codes you have 1st, if it still runs like crap, do a continuity test of the loom to find the problem, takes time but will be the quickest solution

ECU man, how do i check for fault codes with my hondata s200 on a b18/20?

Ever since changing from stock to hondata the engine light just stays on but everything works fine.

Ive had a look through threads but cant find anythin? Can you please direct me?

[ECU-MAN]

you need the Hondata serial cable, a standard serial cable wont do. then you use the software


just use the SCS to find codes.