D15B7 in '96 EX, need to pass emissions

Ramses

New Member
Hello,

I recently picked up a 96 Civix EX which has had a D15B7 dropped into it at some point; so from vtec to non-vtec. I believe the ecu has been swapped out as well and don't think it matches the body or the motor; it's a p2p a31. Whoever dropped in the motor took the trouble to replace the sensors required for OBDII, except the crank fluctuation sensor. So the only code the ecu is throwing is for the missing vtec connections and that sensor. I think both would be solved with a non-vtec ecu. I need to get through WA emissions and I don't think I can do that with a code being thrown.

In short, is there an ecu I can use for the D15B7 with manual transmission that is OBDII?

Thanks for any help or advice.
 

MotorMo

Respected
The only D15b7's I know are in OBD1 Civics. The short answer to your question is no, I don't believe any OBD2 ECU will work without throwing a code for the crank sensor that would be missing in ur D15B7. OBD1=No crank sensor on the crank, OBD2= senor on the front of the crankshaft.
But I believe the Distributor sends a "crank signal" to the ECU in a OBD1 car---I wonder if you could REWIRE the OBD1 distributor to send that "crank" signal to the OBD2 ECU as if it was coming from the crank?? But that uncharted territory for me, and sounds doubtful. Sorry for your luck.
Looks like it may be time for a B series swap :thumbs up
 


Ramses

New Member
I've read about a way to tie in to that signal to beat the fluctuation sensor code, but that would still leave the code for the missing vtec. I can't pass emissions with an OBDI ecu without swapping the whole harness so I have an OBDI plug, right?
 

MotorMo

Respected
I not entirely sure of the exact smog laws in your area- In California the ECU needs to match the engine, and we cant go backwards ( OBD1 engine in an OBD2 chassis, boo on Cali ). If you replaced your ECU with a non-vtec OBD2 ECU ( maby out of a Civic Dx ) Then the vtec code wouldn't be an issue. But note that an automatic transmission ECU is different than a manual ECU. The non-vtec ECU also needs to be from a 96-98 Civic, as the connectors and wiring are different between the split years when Honda gave the Civic a "facelift". Also note the Idle Air Control Valve for your D15b7 is a two wire set up, and the 96-98 civics use a 3 wire control valve, so there would be some rewiring to do at the ECU in order for it to idle correctly. Here is the link for that-

http://www.hamotorsports.com/3-wire-iacv-2-wire-iacv-obd2a.html

Also note the EVAP Purge solenoid between OBD1-OBD2 have the same function, but the OBD1 solenoid is more of an on/ off switch, verses the OBD2 uses a pulse width modulated control. In other words the OBD2 pulses power to the solenoid to get the desired amount of action. This can cause the OBD1 solenoid to prematurely fail in my experience.

If your state allows it just get a "jumper harness" to convert the OBD2 wiring harness to fit the factory OBD1 D15b7 ECU. These are dime a dozen and makes swaps easy, but not all states allow them with smog.
 


Ramses

New Member
Appreciate the suggestions. I've picked up a p2e ecu for $25 (guy wanted $50) out of a '97 dx 5-speed, and will be double checking the IACV difference as MotorMo suggested. I'll update here how that goes over the next day or so. Thanks again!

I've never been lucky enough to have to go through Cali emissions, but I don't believe a vin matching ecu is required in my area. Even if they do, I'm 99% that 96-00 ecu's do not store the vin information.

If the p2e doesn't pan out and I source the correct ecu and use a jumper harness, will an OBDII scan tool still be able to read it? I'm guessing not, but haven't tried it before.
 
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Restotech

Respected
Ramses said:
Appreciate the suggestions. I've picked up a p2e ecu for $25 (guy wanted $50) out of a '97 dx 5-speed, and will be double checking the IACV difference as MotorMo suggested. I'll update here how that goes over the next day or so. Thanks again!

I've never been lucky enough to have to go through Cali emissions, but I don't believe a vin matching ecu is required in my area. Even if they do, I'm 99% that 96-00 ecu's do not store the vin information.

If the p2e doesn't pan out and I source the correct ecu and use a jumper harness, will an OBDII scan tool still be able to read it? I'm guessing not, but haven't tried it before.
Click to expand...
Honda ecu's do not store the vin number until they went to can (control area network) communication. This didnt start till the mid 2000's.
 

MotorMo

Respected
Ramses- Your OBD2 DLC connector will read and work only if your running a OBD2 ECU.

Restotech- Cool to know about the vin # in the newer Honda's that run the can bus. Thanks for that fun fact, I did not know that. :thumbup:
 

Restotech

Respected
MotorMo said:
Ramses- Your OBD2 DLC connector will read and work only if your running a OBD2 ECU.
Restotech- Cool to know about the vin # in the newer Honda's that run the can bus. Thanks for that fun fact, I did not know that. :thumbup:
Click to expand...
No problem. I have forgotten a lot about Hondas but do remember certain things from my days working at a dealership.
 

Ramses

New Member
Got the ecu swapped out for the p2e and now the only codes I'm getting, as MotorMo expected, is for the IACV wiring and the crank fluctuation sensor. I've got the write-ups for both fixes on hand and will be getting those done soon. Engine is idling fine except on start-up, when it hovers at very low rpm for about a minute before rising and holding at 800-900.
 

98civex

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I thought if a car is 15 years old it doesn't require emissions testing?
 

Ramses

New Member
It depends on what state you're in. The cut-off in Washington is vehicles over 25 years old. My '93 F150 just got tested for it's last time, the slip will still be valid when I renew tags next year.
 

98civex

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Oh oh. In Mass it's 15 years and I just beat it since my car's been throwing an evap leak code that I can't pinpoint
 

Ramses

New Member
After looking online and at my local junkyard, I think I'll need to replace my intake for one that fits the 3-pin style IACV. My intake accepts the 2-bolt style with a figure 8 shaped gasket. I'm not really prepared to go buy an intake manifold just to get rid of the one code, so I guess I'm going to keep searching for an alternative solution in the meantime.
 
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MotorMo

Respected
Have you tried to re-wire the pins at the ECU? That would be the easiest. Other wise you could use an intake manifold with throttle body from a 96-98 Civic Ex Automatic- That way you get a good manifold, with the three wire IAC valve on the throttle body, but you still would need to change something in the engine harness to accept the new 3 wire connector, vs the old 2 wire connector for the IAC. Option 1 seems like a path of least resistance. Its only three wires :what:
 

Ramses

New Member
Re-pinning the ecu plug right now and running the third wire, without a 3-wire IACV, won't clear the code since it still won't be getting the 3rd wire's feedback with nothing to plug into. As it is, the engine is running with the IACV always closed and idles fairly smoothly, just low. Just in case I'm an idiot, I did swap the pin to see, and the IACV started to receive power and just bounced open and closed with a terrible idle jumping around 1500 rpm while still throwing the same code. I can't find another way around it so I'm working on sourcing an intake manifold now.
 

MotorMo

Respected
Oh, roger that, i see- I thought that there was a way to convert the wires at the ECU out put to handle a 2 wire IAC, but I now understand that if the ECU is designed to use a 3 wire IAC, then running a 2 wire wouldn't work. Sorry about that, I was wrong. You can find the manifolds on Ebay for about 150 complete. A couple things I learned the hard way is, not to use the EX injectors (use the existing ones), make sure its a 96-98 manifold, as the 99-00 manifolds have an air pulse injection system that isn't compatible, and also to make sure you get a manifold that has the throttle body attached, as that's where the IAC is located on the 96-98 Automatic manifolds. Thanks for the update.
 

Ramses

New Member
Alright. Finally got enough time to get it done.

Made a block of plate for the old IACV so I could just swap the throttle body instead of the entire intake manifold. Had to swap the end plate of the throttle that connects to the throttle cable, or just spin it 180 on the peg so it lines up right. Ran the third wire for the new IACV and swapped the pin at the ecu, so the IACV is working fine, that code is gone, and the engine idles just fine at about 1000 rpm. Tapped pin 1 into 4 and 11 into 14 on plug C at the ecu and the fluctuation code is gone now as well.

Haven't had it tested yet, I still need a muffler, but at least the codes are gone!

Thanks again for the help, fellas.

Bloodshot, it's coming for all of us. Just a matter of time.
 
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