Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - MPGuino install: '90 CRX HF without splicing into Harness

mbolton1990 · 07-20-2014, 11:41 AM

hi!

When I bought my HF,I wanted two things:
A fully working MPGuino
and a still "intact-uncut" harness.

And long story short,after a little pulling my hair out,etc I got it figured out!

This is here to help other people that want what I wanted,I know I can't be the only one..

So here it is,vehicle in question..

Behold,1990 CRX HF totally stock minus JDM D15B shortblock.
290k(and counting,

)

Now let's get to the good stuff,this is your ECU.Hidden under a panel underneath the passenger's feet closest to the firewall.Held in with 4 10mm nuts,carefully pull back the carpet,and you'll see it.This is also useful for OBD purposes but we'll get to that later...Voila,here she is in all her OBD-0 glory

Notice mine has those wires coming out,that corner of the panel is lifted up and has one screw left out?There's a reason for that.I decided to solder directly to my ECU pin's VS cutting into my harness.The reason?IMO it's wayy easier to replace a ECU VS replacing a entire harness in the absolute worst case scenario things went 'haywire,and I've seen them for sale as little as $25 online..

Let's get to the basics,a MPGuino,needs 4 things:
Injector feed
VSS (aka Speed Sensor)
Positive wire
Ground

I decided to go right here for my Injector feed.

And for the VSS,I went to pin B18 is it?

Here's a PM8 pin-out for reference
http://cx4fwq.bay.livefilestore.com/...u3/pinout2.jpg

And for my positive wire,I went through the fuse panel and found a 'empty' fuse that wasn't used for anything and just used a spade connector,it's nice and solid it fits just like a fuse would.

For my Ground I did this,it's by the upper-right side of the fuse-box, nice solid mounting point as well.

Hopefully at this point,you've got a Guino that will now turn-on and register your speed-pulses but needs the correct "settings",and this also show's how I mounted mine.I tried the 4x2x1 box from the 'Shack' and honestly it was such a pain to adapt over I threw it away,haha.Double-sided tape works just fine,as long as you have the good quality stuff.

Press the three buttons all at once to enter the settings menu.

VSS Pulses:

Microsec/Gallon:

Now I know I left some things out,but this covers the 'jist' of it.

07-20-2014, 11:41 AM	#1 (permalink)
mbolton1990 EcoModding Apprentice Join Date: Jan 2014 Location: perry fl Posts: 103 eco-crx - '90 honda crx hf Team Honda 90 day: 56.89 mpg (US) Thanks: 23 Thanked 11 Times in 11 Posts	MPGuino install: '90 CRX HF without splicing into Harness hi! When I bought my HF,I wanted two things: A fully working MPGuino and a still "intact-uncut" harness. And long story short,after a little pulling my hair out,etc I got it figured out! This is here to help other people that want what I wanted,I know I can't be the only one.. So here it is,vehicle in question.. Behold,1990 CRX HF totally stock minus JDM D15B shortblock. 290k(and counting,) Now let's get to the good stuff,this is your ECU.Hidden under a panel underneath the passenger's feet closest to the firewall.Held in with 4 10mm nuts,carefully pull back the carpet,and you'll see it.This is also useful for OBD purposes but we'll get to that later...Voila,here she is in all her OBD-0 glory Notice mine has those wires coming out,that corner of the panel is lifted up and has one screw left out?There's a reason for that.I decided to solder directly to my ECU pin's VS cutting into my harness.The reason?IMO it's wayy easier to replace a ECU VS replacing a entire harness in the absolute worst case scenario things went 'haywire,and I've seen them for sale as little as $25 online.. Let's get to the basics,a MPGuino,needs 4 things: Injector feed VSS (aka Speed Sensor) Positive wire Ground I decided to go right here for my Injector feed. And for the VSS,I went to pin B18 is it? Here's a PM8 pin-out for reference http://cx4fwq.bay.livefilestore.com/...u3/pinout2.jpg And for my positive wire,I went through the fuse panel and found a 'empty' fuse that wasn't used for anything and just used a spade connector,it's nice and solid it fits just like a fuse would. For my Ground I did this,it's by the upper-right side of the fuse-box, nice solid mounting point as well. Hopefully at this point,you've got a Guino that will now turn-on and register your speed-pulses but needs the correct "settings",and this also show's how I mounted mine.I tried the 4x2x1 box from the 'Shack' and honestly it was such a pain to adapt over I threw it away,haha.Double-sided tape works just fine,as long as you have the good quality stuff. Press the three buttons all at once to enter the settings menu. VSS Pulses: Microsec/Gallon: Now I know I left some things out,but this covers the 'jist' of it.