Help getting B18C re-wired up, just bought a 92 Teg, and the extra ECU wires are out.

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1

I just bought a 92 Integra GS with a JDM B18C swap w/ a Blox Intake Manifold.
– It has a Blox Intake Manifold not a stock JDM B18C intake manifold…
Would this be a non-dual butterfly setup or not?

This is my 7th Integra, my last one was an LS/VTEC I built myself, so I have some experience with these things but can’t get this one working.
There are three add-on wires coming to the ECU, which got pulled out.

Currently, a rev limiter is kicking in a 6200, and VTEC is not working.
It came with an ‘OBD1 B18C ECU’

I traced the wires back to the VTEC Solenoid, VTEC Oil Pressure Unit (2 wires, only 1 to ECU), and unknown (assumingly knock sensor).

I wired the VTEC solenoid to A4
I wired the VTEC Oil Pressure sending signal (non ground wire) to D6
I wired the unknown/knock sensor to D3

I can’t figure out if I got the locations right or not, the ECU looks different than any diagram I could find, and I have yet to find a decent diagram showing which one is A, and which side is 1 and which side is 2.
I thought it had a P72 ECU in it, but pics I found online don’t match the ECU…

Can anyone verify I have the correct ECU?
1) Will the three missing wires / incorrectly wired sensors, cause the ECU to limit the rev to 6200?
2) I thought a B18C revved til 8200, obviously if the wires are wrong VTEC won’t work…
Can anyone tell if this is a P72 AND OBD1…
– I thought a JDM B18C was a OBD2 Engine.

Secondly, point me towards a GOOD diagram explaining VTEC solenoid, VTEC Oil pressure, and all VTEC B18C conversion wiring.

Is this a P72, or if not, what is it?

Like an LS/VTEC swap, shouldn’t a B18C swap be similar, with only three wires to the ECU, VTEC, VTEC OIL, and Knock?
– Or is it messed up further…

Diagrams I found…

from a g2ic thread attachment…

from http://www.honda-tech.com/showthread.php?p=41674308

2

You have an automatic OBD1 ecu, most likely it’s not the GSR p72 since I don’t think the GSR’s came in automatic (correct me if I’m wrong). You should open up the cover and look at the stamping on the board to make sure you know what ecu you have. It’s automatic because it has 4 female plugs. Automatic ecu’s must be converted to manual for it to work in a manual car properly, (else you will be getting codes).

The conversion is pretty simple, See here for guide on how to do it: you will need some soldering skills.
http://www.hondacivicforum.com/forum/drivetrain-diys-56/automatic-manual-obd1-ecu-conversion-82102/

3

The person I just bought it from, confirmed and says “it is a P72 OBD1 ECU”.

Question 1)
Would the three extra wires (VTEC Solenoid, VTEC Oil Pressure, unknown/Knock), cause the car to have a temporary 6200rpm rev limiter?

I tried connecting the wire, the car wouldn’t start after I did, I did get it started with just the VTEC wire connected, and it would rev to 7500, but as soon as I started driving the rev limiter dropped to 6200rpm.

Question 2
Are a valid VTEC signal, and VTEC Oil Pressure signal, and/or knock, required for the ECU to operate at full 8000rpms and VTEC? (Or a combination of the items, seller didn’t mention ever running a knock sensor wire)
– Is a knock sensor required to run above 6200rpms, 8000rpm?

Question 3
On the VTEC Oil Pressure sending unit, there are two wires, red w/ yellow stripe, blue w/ green stripe…
– Which one is the signal wire, and which one is ground?

Question 4
What color would the factory Knock sensor wire be?
– There is a third, red w/ blue stripe, wire run to the ECU,
that isn’t the same wire color run to the VTEC or VTEC Oil unit…
I’m thinking it is either the Knock sensor wire, or an extension random wire for the VTEC oil pressure ground.

Buying a car that “needs the solenoid pinned to the ecu”, and isn’t running properly probably wasn’t as good of an ideas as I thought it was… it makes me wonder why they are disconnected in the first place.

4

best thing to do, is remove all those wires and crap, altogether and redo it from scratch. One thing you could do, which would be easier, but costs more, is buy a VTEC conversion harness. I got one from Rywire. $60 well spent. They have a great diagram on their site. Since you have a non stock intake manifold, you won’t even have to worry about wiring up the IABs, so you can just clip those leads off and have a nice day.

As far as the actual colors go, I’m not sure which wires are what, all I did was reused my old LS harness and used the additional Rywire harness. Made the whole swap VERY easy.

For things that would cause you to have a rev limit of 6200 rpms on an OBD1 ECU…
First thing is first, you’ll need to check your CEL codes. Code 22 will kill ALL of your fun. Code 22 would be VTEC Oil Pressure Switch. If the switch is bad, or wired incorrectly, etc. you will have no VTEC, and worst of all, you’ll be throwing your ECU into “limp mode” meaning its running on parameters that are “just safe enough” to get you home. Wouldn’t recommend driving on these settings for more than a couple miles if you can help it.

So, in an attempt to answer your questions in order (which I guess I probably should have done in the first place, lol)
1- VTEC solenoid, no. VTEC Oil Pressure Switch YES, IAB or Knock, no.
2- Valid VTEC signal, no. Well, it won’t cause your car to go into limp mode, but will obviously not allow VTEC. Before I had my VTEC working right, I could rev to 8,000 all day. Though, when I encountered issues with the oil pressure switch, it put the ECU into limp mode. Knock sensor, no. I had an issue with the connector on my knock sensor that was throwing a code (23, if I recall correctly) But I still had VTEC and did NOT have limp ECU.
3- (as far as wiring colors go, I’m not sure on this, I didn’t have to mess with this. The VTEC subharness made my life easy. SORRY)
4- (same. I have the JDM B18C wire harness in my dad’s garage, but It might be a while before I can look at what color the wire is. Perhaps someone can post a wire diagram for you to help out)

This stuff can be remedied, fairly easily, with persistence and patience. If you wish to redo the wiring from scratch, you’re best bet would be to get hold of some kind of wire diagram for the plugs with more than one wire (mainly the VTEC Oil Pressure switch) so you can make sure you ground the right wire and get power to the other, obviously. VTEC and knock are both one wire plugs. IABs are also a two wire affair. BUT, since you no longer have the stock dual runner intake manifold, you don’t have to worry about them at all. You can ignore wiring them up altogether.

I hope that helps.

5

VTEC Oil pressure switch should be blue/black for VTM signal (wire nearest the plug release tab is the signal wire goes to D6) and black for the ground (goes to ground). You do not need to run this ground all the way back to the ECU if you don’t want to. Simply add a ground terminal and bolt it down to the thermostat housing ground point. VTEC spool solenoid valve should be green/yellow (goes to A4). Red/blue should be the knock sensor (goes to D3). Sounds like you have some wiring issues or possibly a bad ECU. Have you checked the codes? Do you have a multimeter (DMM or other)? The wiring is fairly simple. A few things about the swap.

You are running a non-dual butterfly setup with a Blox Manifold. You do not want VTEC kicking in at 4400rpm. Either chip that P72 or purchase a P28 or P61 ECU to chip.

If you are still having problems, shoot me an e-mail and I’ll send you my phone number. We can talk about it.

6

Advice from Dan, (G2guru) is rare these days. At least, it seems so, to me. Definitely take this advice. Filled in all the holes in my help post.

Best of luck to you.

7

I’ve done this before, which is why I’m confused as to it not working.

I’m going to completely rerun the wires

  1. Green w/ Yellom from VTEC Solenoid to ECU Pin A4
  2. ??? VTEC Oil perssure signal to ECU Pin D6
  3. ??? VTEC Oil pressure ground to engine ground
  4. Knock Sensor to D3

What is confusing me is the VTEC oil pressure sending unit… it has two wires…

  • Red w/ yellow stripe
  • blue w/ green stripe
    I cannot determine which is which, they aren’t logically colored.

Anyone know which, red /w yellow or blue w/ green is the signal wire, and which is ground? (This could be the main mixup)
– based on the previous diagram, blue/black = blue w/ green for signal, and red w/ yellow = other for ground?? I tried this way to no avail.

Secondly, I’m trying to figure out what the 3rd wire already run is,
Does anyone know the wire color for the knock sensor?

In response to last post… Why pay $60+ for some conversion harness, when all I have to do is run there wires?

Last thought… rather than sticking loose wiring into the black plug spaces,
Does anyone know a good solution for getting new metal termination pieces for the three new wires,
that will properly slide into the ecu wiring harness plug?

8

Reread my post. It answers all of your questions. “VTEC Oil pressure switch should be blue/black for VTM signal (wire nearest the plug release tab is the signal wire that goes to D6) and black for the ground (goes to ground).”!!! Your plug not being logically wired means that someone spliced in a plug from a spare harness they had. Sounds like a IACV plug. Regardless, if you read my post above with the picture, it shows you which is which. Secondly, just jamming stripped wires into the holes is not going to work. If you need some ECU pins I can send them to you. I have many spare harnesses and can depin a few and send them your way. But when splicing the wires please use a soldering iron. At the very least use butt connectors. Do not just twist the wires together and wrap them with electrical tape. That is a recipe for failure.

What codes are you throwing? Your check engine light has to be on… correct? Your maintenance connector is behind the passenger side kick panel. Pull it down and short the two pins together. Turn the key in the ignition to the on position. Count the flashes. There is a write up on this in the teg tips section I believe.

Again, feel free to send me an e-mail. I could easily walk you through this. If my walkthrough doesn’t work either you are not following the instructions or you could have a bad ECU (which should also throw a constant CEL).

Best of luck.

9

Dan already said it, but simply depin an old harness or go to the junkyard and find any Honda car with a obd1 harness and take the pins from there. You should definitely solder all your connections, do not use butt connectors or the ghetto twist-&-tap method.

By the way, have you converted your ecu to manual? I did research and it looks like a p72 auto GSR did exist at some point in time, although it’s very rare. You will get code 19 if you don’t convert to manual either through chipping or through hardware mods. http://mycomputerninja.com/~jon/www.pgmfi.org/twiki/bin/view/Library/AutoToManual.html

If your car was not originally a GSR, then the wires for the three extra sensors where not from factory. As such you cannot simply go by the wire color codes. You must manually trace the wires from the engine into the cabin.
1> there is only one wire from ther VTEC solenoid, this wire should run to A4
2> For the VTEC pressure, please look at the connector and compare with the picture above. The connector only goes in one way, The wire closest to the clip on the connector goes to the ecu pin D6
3> The wire farthest from the clip at the pressure sending unit goes to ground
4> Again, you cannot judge which wire is the knock sensor in your cabin by using colors since your wires are likely not from factory… Do some work and manually trace the wire from the sensor itself to the cabin. Yes knock goes to D3.

From what I can see, G2guru, imcnblu, and I have already answered your questions many posts back…Either you are not reading our posts correctly or you are simply ignoring sound advice. We can’t help you if you don’t want to be helped…

10

I just myself rewired the VTEC Solenoid, and VTEC Oil pressure sending unit correctly to the ECU.

Found the Knock sensor is broken, with only the knock sensor not wired, would that prevent VTEC from operating and it revving past 6200rpm?

The guy I bought it from told me, it just needed the idle control valve cleaned, and the VTEC solenoid repinned to the ECU…
– The guy now tells me, he never even had the car running correctly, which is why he probably sold it.

Anyway know exactly what the Ohio law is for buying a car? If I remember correctly, if it is far different than described, the seller has to buy it back or pay for repair costs as long as it is within 3 days of purchase.

11

not sure on the laws in Ohio, but I’d be willing to bet that such a law would only apply to dealers, as they are licensed sellers. Private party sellers would be able to weasel their way out of such things due to technical loopholes as “The ad said it ‘needs work’ or that the car is sold ‘as is’,” etc. or it would even be a “your word against mine” affair in court. I could be mistaken, but I wouldn’t hold too much hope on that scenario.

Have you checked which codes your car is throwing? I know my car’s knock sensor (also running a JDM B18C SiR-G motor in my car) has been an off and on issue. Sometimes the CEL will come on, and its the code for the knock sensor. But even when it does come on, my VTEC still engages. Knock sensor issues only disable VTEC on OBD2 ECUs. OBD1 ECU and engines don’t have this problem.

The pieces you need to in order to plug the wires into the ECU correctly are ECU pins. You can buy them from Xenocron (as well as other places that sell wiring accessories). Xenocron sells them for $5 for a pair.

Honestly, man. It sounds to me like you’re having the same issues I had when I first did my swap. First and foremost, you’ll definitely need to check your codes. G2guru described how to perform this test in his post. If you need further help, get with me or him and we’ll help out, gladly. After you’ve figured out what codes you’re throwing, then you can get to work on remedying the problem(s).

Here are the codes that you’re more than likely throwing:
Code 20 - Electronic Load Detector (this is a code you have no need to worry about. Reason being, if you ONLY had this code, it won’t even trip a CEL on it’s own) This is extremely common, and basically guaranteed on any swap that originated from a DC or EG, as their cars utilize an ELD, and DAs don’t.
Code 21 - VTEC solenoid (if it’s malfunctioning, you obviously won’t have VTEC. But, it wouldn’t cause “limp mode” *6200rpm rev limit, etc. that you’re experiencing)
Code 22 - VTEC Oil Pressure Switch (this will prevent VTEC, and if you throw this code, then code 21 WILL come with it at the same time, regardless if the solenoid is wired up and functioning correctly, or not. This code WILL cause the ECU to go into limp mode and is a very serious issue that will need immediate attention if you want your engine to last.)
Code 23 - Knock Sensor (This will throw a code, but will NOT disable VTEC in an OBD1 car, and will NOT cause limp mode in an OBD1 car.)

If you’re throwing a code 22 (the most likely cause for your ECU going into limp mode, unless the ECU itself is bad.) you have several options.

First, the switch itself could be bad and needs to be replaced. Or, the ground isn’t good and will cause it not to function as it’s supposed to. There is a small trick that can bypass it altogether. I don’t recommend it, but it does work. You can bypass the VTEC oil pressure switch altogether by bridging the wires at A4 (VTEC Solenoid wire) and D6 (VTEC oil pressure switch). IF you do opt for this option, make sure you unplug the plug on the switch and disconnect the ground or you WILL short it out and be in more trouble than you’re already in. Simply expose some wire on each one (A4 and D6), solder them together, and cover the exposed wire. Now, the ECU thinks that the pressure switch is functioning normal and will allow VTEC (so long as the solenoid itself is working normally).

Hope that helps. Honestly, I’d test for continuity first, and see if power is getting to the switch. If it IS getting power and it’s grounded correctly, that means the switch is bad, and needs to be replaced.

Best of luck. if you need further help, email me your phone number, and I’ll text you my number. You’re welcome to call and I’ll happily help out as best I can.

email: jake870621345@hotmail.com

12

Turns out the Knock sensor on the car is faulty/broken, I traced the wires to it, and the knock sensor was literally in two pieces, with the knock sensor wire going to a broken off piece of the sensor.

I believe the Knock sensor functioning properly is required for high revving and VTEC, as an invalid signal forces the ECU into a “safety” mode, correct me if I’m wrong.

I ordered a new knock sensor for $30 and if I can get it installed without pulling the motor, hopefully this will fix the problems I’ve been having.

Thanks for the Diagram in post #5, the wire harness used on the oil sensor had different color wires, but thanks to that diagram, it was clear which wire was which. (top wire on plug is signal, other is ground).

That ensured I have the oil pressure signal properly wired up.

13

[QUOTE=G2guru;2217242]
You are running a non-dual butterfly setup with a Blox Manifold. You do not want VTEC kicking in at 4400rpm. Either chip that P72 or purchase a P28 or P61 ECU to chip.

If you are still having problems, shoot me an e-mail and I’ll send you my phone number. We can talk about it.[/QUOTE]

thanks for confirming what I believed to be the situation, non-dual butterfly.

The person I bought the car from said VTEC engages at 5500rpm, only time will tell how it actually operates.

If I do get everything working on the P72 Auto ECU, and VTEC engages at 4400rpm, wouldn’t it be easier just to install a VTEC controller?
If VTEC engages too low, would a VTEC controller fix this?

When should VTEC engage on a JDM B18C w/ Blox Intake Manifold? verses when should it engaged on a P72 ECU?

14

It really depends on the cams. GSR to ITR cams really should be crossed over at 5500-5800rpms depending on compression. V-AFCs cost anywhere from $100-$200. I would ditch the auto ECU before buying a V-AFC.

15

Update, it has been a while since original post but I gave up for a while thinking I wouldn’t be able to change the knock sensor easily.

As of today, I have now run the three (four including ground) myself.

  • VTEC Pressure Switch - to D6
    • VTEC Pressure Switch - to ground
  • VTEC Solenoid - to A4
  • Knock Sensor - to D3

I discovered one can actually change the knock sensor without removing the intake manifold.
I installed a new knock sensor and wired it up.

Still having the same issue with not revving past 6k.

Would it not rev high if the car is not moving?

  • I know this would cause a difference in pressure.

What I’m going to do next, open to any suggestions!!

  • double check I didn’t cross any of the wires
  • reset the ECU
  • check for codes
16

I reset the ECU (following Teg Tip [pulling ‘Back-Up’ fuse for 10 sec).

I jumped the green/brown harness with a paperclip and got what I believe are the following codes…

Code 10
Code 20
Code 21
Code 41

I guess now I have a place to start looking.

17

doubled checked the A4-VTEC Solenoid wire again, still code 21.

I also have had a coolant leak very slow since I bought the car.

I just noticed that the coolant appears to be coming from somewhere near/under the VTEC solenoid.
It is right there on the corner of the transmission/head/block, I really hope there is something around there and it not be a head gasket.

I bought this car two years ago, with the receipt for the JDM B18C less than 2 years old, so it can’t have more than 60,000 miles, (40k at import + 2 years of driving).
You don’t think it would be a head gasket at such low mileage?
– I’m starting to think the car was for sale for a reason.

I’m about to give up myself.

At this point I need what, a new VTEC solenoid, oxygen sensor, figure out what causing the intake air temperature sensor.

Could any of these issues be caused by a dirty FITV or IACV? Those were next on my list to clean, because it does not idle smoothly.

My last thought is still puzzlement at the ECU, could I have an OBD2 ECU with OBD1 style plugs?
I seem to find no information on any OBD1 GSR P72 ECU that has 4 plugs.

18

Here is my only real question that makes NO sense to me…

Why do I get a code 21, after resetting the ECU (clearing the codes), when I check the codes without ever even running the engine?
maybe this will help pinpoint the problem

19

I’ve always been a fan of resetting the ECU by pulling the battery cables and then honking the horn/flashing headlights etc, just to be sure of all remaining electricity to be discharged from the circuits. Wait a minute or two, then reinstall the battery…

You should be able to rev to redline while not moving… MPH has absolutely zero to do with being able to rev. Besides for ECUs with two-step launch control… But that is another matter completely.

The main coolant inlet (from the heater core) is on the distributor/solenoid side of the head. Make sure the hose and/or coolant inlet are properly tightened. My motor had a leak that looked very similar to a headgasket leak on that front-passenger corner. Turned out to be a loose coolant inlet on the head.

Yes, the car can have a blown gasket with that low of mileage… A blown gasket can happen at virtually any mileage.

A CEL can come on, without the car being started, if the wiring is faulty… If the ecu notices a sensor unplugged, as far as I know, it can throw a CEL before actually cranking the car.

No, you can not run an OBD2 ecu in your car. But you CAN try any b-series obd1 vtec ecu to at least fire the car up and see if that particular code goes away.

I’m pretty sure that Code 20 is an indication of your problem… either wiring or ecu. Our cars don’t have an ELD, as far as I’m aware, so that code typically means there is a wiring fault.

20

I just realized, everytime I hookup the battery, with no key in the ignition and the car being off, the ‘parking lights’ (front corners and rear brake lights come on’.

When I turn on the lights I think the brake lights come completely on so they’re no brake lights.
Also, when the car is turned on the reverse lights come on too.

I have to disconnect the battery when it is parked otherwise the lights will kill the battery (the switch is off).

Any ideas on this crazy situation? I still haven’t fixed the car. I’m finally actually looking at it today for real. Cleaning all the parts and replacing all sensors throwing codes, but that electrical problem I just noticed is gonna be a problem.