CRX LSVtec HELP
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CRX LSVtec HELP
Hey guys I've got a 1989 CRX HF with a B18A1 block and a 98 GSR head. now currently im working on getting it wired up correctly. I still have the stock LS ECU and wiring harness on it. I've been reading up on Vtec subharnesses and wanted to know if that would be a better choice than finding an OBD1 GSR harness itself. Also if going the Vtec subharness route what ECU should i go with? Any help at all would be greatly appreciated.
Re: CRX LSVtec HELP
Hey guys I've got a 1989 CRX HF with a B18A1 block and a 98 GSR head. now currently im working on getting it wired up correctly. I still have the stock LS ECU and wiring harness on it. I've been reading up on Vtec subharnesses and wanted to know if that would be a better choice than finding an OBD1 GSR harness itself. Also if going the Vtec subharness route what ECU should i go with? Any help at all would be greatly appreciated.
Alright, get the harness off the motor that was in the CRX. Those other two harnesses will not work with the main connections on the firewall/shock pillars! It will be a nightmare trying to get your dash/cabin harness to match a GSR or LS engine harness. Then you should really research the B-series swap and MPFI/VTEC wiring.
Originally Posted by me
7. Convert over to OBD1 if needed. All you need to convert your EF from OBD0 to OBD1 is a conversion wire harness, OBD1 ECU, and OBD1 Distributor. These can all be purchased online or second hand, or salvaged from the junk yard.
8. MPFI conversion. Now is a good time to think about doing the MPFI wiring if you must, I will included a detailed write up with pictures after the
engine installation.
8. MPFI conversion. Now is a good time to think about doing the MPFI wiring if you must, I will included a detailed write up with pictures after the
engine installation.
Originally Posted by Me again
Installing the engine should go smoother than the removal if this is your first time. That’s mostly due to the new found experience with the motor you have gained. It is essentially the same thing, but in reverse. Despite this, there are some tips along the way.
1. The first step of this swap is to move the old EF wiring harness over to the new B series motor. It is very straight forward. Nearly everything is in the same position and should not be a problem. There are a couple sensors that need to be lengthened, the Throttle Position sensor and the Idle Air Control Valve. Sometimes the Intake manifold temperature sensor will need to be lengthened.
1. The first step of this swap is to move the old EF wiring harness over to the new B series motor. It is very straight forward. Nearly everything is in the same position and should not be a problem. There are a couple sensors that need to be lengthened, the Throttle Position sensor and the Idle Air Control Valve. Sometimes the Intake manifold temperature sensor will need to be lengthened.
Originally Posted by YupItsMeAgain
DPFI to MPFI
The dual point fuel injection found on some of the EF D series motors is made for fuel efficiency. With that said, they are basically a glorified carburetor. Replacing the DPFI intake manifold with a MPFI intake manifold will increase performance even as a standalone modification. It is very easy to wire. Make sure to label wires. It is also a good idea to run them through a plug instead of direct wiring them to the ECU. That way you can disconnect the plug if you remove the motor again, instead of cutting wires.
Shopping List
1. Four injector Plugs
2. Injector Resister box (if applicable)
3. One ‘A’ Male ECU plug and one ‘B’ or ‘C’ Male ECU plug
4. Assorted colored Wire
5. Soldering equipment, crimping equipment, or anything applicable.
6. Heat shrink, electrical tape or liquid tape
7. Wire wrap (black plastic, about $1 per ft, OEM style wire covering)
Installation
1. If you have peak and hold injectors, you will need to install an injector resister box. I suggest the driver side shock tower mounting area.
2. The MPFI distributor should have a 7 pin plug instead of the 5 pin plug on the DPFI distributor. This means chopping off the existing plug on the engine harness and replacing it with a new plug.
3. There should be 2 wires that are not connected to the existing engine harness. These should be extended into the cabin through a small bushing near the, passenger side, rear transmission mount.
4. The injector plugs from the DPFI won’t fit the injectors on the new motor, so you will have to source 4 new plugs.
5. Remove the DPFI plug from the wires. You should be left with yellow and a yellow/black wire on one plug and a red and yellow/black wire on the other plug.
6. Connect both of the yellow/black wires together and run them to the yellow/black wire on the injector resister box. If you don’t have an injector resister box, I believe you run the wires to each injector’s red/black wire.
7. Take the yellow wire from the old DPFI plug and run it to cylinder #1
8. Take the red wire from the old DPFI plug and run it to cylinder #3
9. Run the wires from cylinder #2 and #4 into the cabin.
10. Wiring the ECU comes next, here are the pin outs for everything you have extended into the cabin
A3 - #2 Injector
A7 - #4 Injector
B10 – Move wire from C1 to here
B12 – Move wire from C2 to here
C1 – Blue/Green Distributor
C2 – Blue/Yellow Distributor
11. Test that the MPFI wiring is correct. Car should start, timing may be off if the distributor was changed.
12. Wrap all connections with appropriate tape and wrap in black plastic to give it a stock, OEM, look.
VTEC – Variable valve timing and electronic lift control
VTEC is a very cool feature available on a wide variety of Honda motors. VTEC is comprised of a solenoid and a pressure switch. When oil pressure reaches a certain pressure, caused by RPM, the switch activates the solenoid. The solenoid pushes oil through part of the head, activating a third lobe portion of the cam. This portion is larger than the normal lobe. The longer travel gives the motor more top end horse power. But it is not optimal at low RPM due to requiring more power to get the cam to spin. So in short, VTEC gives a motor more top end without sacrificing low end HP. Some consider it a gimmick. Many say, “There is no replacement for displacement.” But most people agree VTEC is a good feature that offers a compelling sound and boost to power.
Wiring VTEC
The VTEC wiring is very simple. On a motor with VTEC there is basically two wires to the ECU that need to be added, and a chassis ground.
1. Locate the VTEC Solenoid, near the distributor. There should be a single wire coming out of it. Run this to the cabin into A8 on the ECU.
2. Below the Solenoid is the pressure switch. One wire is the signal wire, one is the ground. The signal wire goes to B5 and the ground should be connected to a known good ground. One of the numerous bolts into the frame or even the transmission ground should work.
That is all that is required to wire VTEC. Make sure you have the knock sensor installed and wired also.
The dual point fuel injection found on some of the EF D series motors is made for fuel efficiency. With that said, they are basically a glorified carburetor. Replacing the DPFI intake manifold with a MPFI intake manifold will increase performance even as a standalone modification. It is very easy to wire. Make sure to label wires. It is also a good idea to run them through a plug instead of direct wiring them to the ECU. That way you can disconnect the plug if you remove the motor again, instead of cutting wires.
Shopping List
1. Four injector Plugs
2. Injector Resister box (if applicable)
3. One ‘A’ Male ECU plug and one ‘B’ or ‘C’ Male ECU plug
4. Assorted colored Wire
5. Soldering equipment, crimping equipment, or anything applicable.
6. Heat shrink, electrical tape or liquid tape
7. Wire wrap (black plastic, about $1 per ft, OEM style wire covering)
Installation
1. If you have peak and hold injectors, you will need to install an injector resister box. I suggest the driver side shock tower mounting area.
2. The MPFI distributor should have a 7 pin plug instead of the 5 pin plug on the DPFI distributor. This means chopping off the existing plug on the engine harness and replacing it with a new plug.
3. There should be 2 wires that are not connected to the existing engine harness. These should be extended into the cabin through a small bushing near the, passenger side, rear transmission mount.
4. The injector plugs from the DPFI won’t fit the injectors on the new motor, so you will have to source 4 new plugs.
5. Remove the DPFI plug from the wires. You should be left with yellow and a yellow/black wire on one plug and a red and yellow/black wire on the other plug.
6. Connect both of the yellow/black wires together and run them to the yellow/black wire on the injector resister box. If you don’t have an injector resister box, I believe you run the wires to each injector’s red/black wire.
7. Take the yellow wire from the old DPFI plug and run it to cylinder #1
8. Take the red wire from the old DPFI plug and run it to cylinder #3
9. Run the wires from cylinder #2 and #4 into the cabin.
10. Wiring the ECU comes next, here are the pin outs for everything you have extended into the cabin
A3 - #2 Injector
A7 - #4 Injector
B10 – Move wire from C1 to here
B12 – Move wire from C2 to here
C1 – Blue/Green Distributor
C2 – Blue/Yellow Distributor
11. Test that the MPFI wiring is correct. Car should start, timing may be off if the distributor was changed.
12. Wrap all connections with appropriate tape and wrap in black plastic to give it a stock, OEM, look.
VTEC – Variable valve timing and electronic lift control
VTEC is a very cool feature available on a wide variety of Honda motors. VTEC is comprised of a solenoid and a pressure switch. When oil pressure reaches a certain pressure, caused by RPM, the switch activates the solenoid. The solenoid pushes oil through part of the head, activating a third lobe portion of the cam. This portion is larger than the normal lobe. The longer travel gives the motor more top end horse power. But it is not optimal at low RPM due to requiring more power to get the cam to spin. So in short, VTEC gives a motor more top end without sacrificing low end HP. Some consider it a gimmick. Many say, “There is no replacement for displacement.” But most people agree VTEC is a good feature that offers a compelling sound and boost to power.
Wiring VTEC
The VTEC wiring is very simple. On a motor with VTEC there is basically two wires to the ECU that need to be added, and a chassis ground.
1. Locate the VTEC Solenoid, near the distributor. There should be a single wire coming out of it. Run this to the cabin into A8 on the ECU.
2. Below the Solenoid is the pressure switch. One wire is the signal wire, one is the ground. The signal wire goes to B5 and the ground should be connected to a known good ground. One of the numerous bolts into the frame or even the transmission ground should work.
That is all that is required to wire VTEC. Make sure you have the knock sensor installed and wired also.
Re: CRX LSVtec HELP
Definitely go to the junkyard and find an engine harness for your model of car. You need to match the big white plugs that go through the firewall, that's the most important part. The engine sensor plugs can all be extended or added to the harness for the LS/VTEC. So keep your LS harness and just borrow the plugs from it.
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From: colorado springs, co, usa
Re: CRX LSVtec HELP
if your CRX HF has the original chassis harness, you need the CRX HF engine harness - The DX engine harness will not work and the Si engine harness will not work
Re: CRX LSVtec HELP
This is very important, it's why I said match the big plugs.
Last edited by Freemananana; Oct 29, 2013 at 08:38 AM.
Honda-Tech Member
Joined: Sep 2002
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From: colorado springs, co, usa
Re: CRX LSVtec HELP
Re: CRX LSVtec HELP
Wooops! I don't really know which is which, guess that's why there's this!
Should be very easy to get the correct harness and wire it up since you will only have to extend a couple sensors and add the wiring for VTEC. Which is very simple on an OBD1 motor since all you need is the VTEC solenoid, VTEC pressure switch and ground the other side of the pressure switch.
Originally Posted by 4drEF
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Re: CRX LSVtec HELP
Well wait. Maybe i don't have an ls harness on it. It runs and i drive it. Doesnt stall out after sitting idle or overheat or anything like that. It sputters/bogs around 3000 rpm after being on. But I think thats my fuel pump which im ordering very soon. But it starts and runs and drives. But it has a P75 ECU. So how can i check what wiring harness i have..?
Re: CRX LSVtec HELP
Well wait. Maybe i don't have an ls harness on it. It runs and i drive it. Doesnt stall out after sitting idle or overheat or anything like that. It sputters/bogs around 3000 rpm after being on. But I think thats my fuel pump which im ordering very soon. But it starts and runs and drives. But it has a P75 ECU. So how can i check what wiring harness i have..?
You're on your own now. You're doing wizard stuff at this point. I'm lost.
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Re: CRX LSVtec HELP
Okay so i figured it out. I have the HF wiring harness with a P75-A31 ecu jumper harness to have it connected. I know if have a non vtec ecu. So do i just need a p72 and rywire vtec sunharness and ill have vtec?
Re: CRX LSVtec HELP
Whoa, let me save you some mega money. Get the p72 or convert the P75 to VTEC. Converting is easy if you know how to solder. Next, the VTEC subharness is a joke. There is one wire that goes from the VTEC solenoid and one wire that goes from the VTEC pressure switch into the cabin area and connect to the ECU. Just do that. Since you have a jumper harness, there should be a couple loose wires for these to connect to already.
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Re: CRX LSVtec HELP
I havent hooked it in yet. This car was a garade find. And it doesnt have vtec hooked up yet. I need to get a golden eagle vtec for the oil lines in order for it to work. So i figured id wait for the ecu cause wouldnt it mess up without vtec?
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Re: CRX LSVtec HELP
You will probably throw a vtec oil pressure code on the P72 since you don't have oil hooked up. Vtec won't work and obviously revving the motor over 5k isn't going to be much good.
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Re: CRX LSVtec HELP
Yeah i figured that. Im getting the golden eagle or blackworks racing lsv kit. Any other suggestions or advice would be greatly appreciated. Also i have a starting problem that i cannot figure out. Sometimes it starts and sometimes it doesnt. The fuel pump primes and relay clicks. But it doesnt turn over. The starter does nothing. It has been getting worse with the cold weather. But i roll start it and for the rest of the day it starts no problem. Any ideas?
Re: CRX LSVtec HELP
Yeah i figured that. Im getting the golden eagle or blackworks racing lsv kit. Any other suggestions or advice would be greatly appreciated. Also i have a starting problem that i cannot figure out. Sometimes it starts and sometimes it doesnt. The fuel pump primes and relay clicks. But it doesnt turn over. The starter does nothing. It has been getting worse with the cold weather. But i roll start it and for the rest of the day it starts no problem. Any ideas?
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Re: CRX LSVtec HELP
Alright thanks a lot. Ill do that. Also got the codes its been throwing occasionally. Codes are 20 and 8. Ones the EDL im pretty sure. And the others TDC sensor i looked it up. How should i address these problems, new distributor to fix the TDC sensor? Or do i need to just fix the timing on my motor?
Re: CRX LSVtec HELP
Alright thanks a lot. Ill do that. Also got the codes its been throwing occasionally. Codes are 20 and 8. Ones the EDL im pretty sure. And the others TDC sensor i looked it up. How should i address these problems, new distributor to fix the TDC sensor? Or do i need to just fix the timing on my motor?