wiring schematic

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byebyebaby

Byaaah!
whats up all, im in desperate need of a wiring diagram/schematic for a 1991 honda civic dx. i need to know what wires are what for the ecu but i dont need a pinout or anything, if that makes sense. im in the process of doing my own obd0-obd1 wiring conversion and i wanna make sure im not using the wrong wires and start a big fire lol.
 
these are from the 90 Factory Electrical Manual (91 is the same) for the DX - please note that HONDA numbered the ECU pins in this manual different from the other manuals - in these schematics at the ECU, the pins are numbered consecutively across each row, not alternating like other manuals - for instance, the top row on the 'A' connector is numbered A1, A2, A3, A4, blank at key, A5, A6, A7, A8 - the bottom row is numbered A9, A10, A11, A12, A13, A14, A15, A16, A17 - the 'B' connector is numbered 1 thru 10 on top row and 11 thru 20 on bottom row - the 'C' connector is numbered 1 thru 8 on top row and 9 thru 16 on bottom row
 

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since that schematic doesn't identify which ECU plug is which, use this to find what wire goes to what plug - the DX is in the column on the left
 

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  • DXpinouts.pdf
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well i appreciate it guys but heres my problem, there are wires that are wired the same(red/white and red/white) for example and i need to find out which ones go to what if possible in a way other than hooking up a test light and doing that all day.
 
still need a wire diagram check this out
 

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RPM Pulse.

Hey, is there no RPM referance at the ecu on a 91?? My friend has a 91 EF and he bought a Gauge Cluster w/Tacho for an 88-91ef. Anyone have an idea of it's location at the ecu? Or should I just wire straight off the Ignitor in the Dizzy??
 
Hey, is there no RPM referance at the ecu on a 91?? My friend has a 91 EF and he bought a Gauge Cluster w/Tacho for an 88-91ef. Anyone have an idea of it's location at the ecu? Or should I just wire straight off the Ignitor in the Dizzy??
no rpm signal at the ECU - just connect tach to the blue wire in the 2-wire distributor connector
 
Hey guys what's up I'm Eric I'm fairly new to this and have a few questions first off I have a pr4 chipped for VTEC and the sensors disabled Cuz I'm running a d16y8 in it my main question is what wires do I have to run from ecu cabin are to engine bay
 
Thanks jlicrx for the tach wire ID on the 91 DX. I am trying to install a Rostra cruise control on my 91 DX 5 speed manual. Now I know where the tach wire is.

Any idea if I have a VSS and if so, where it is located? Do not want to install the magnetic speed signal generator. Did that on a 70 Fiat 128 back in the day and it kept losing the signal when I went over dips in the road. That was one of the first Front Wheel Drives about the same time as the Subaru came out and the axles just bounced too much. Maybe the DX will not have that problem?
 
Any idea if I have a VSS and if so, where it is located?
on the 91 DX with stock transmission, the VSS is on the back of the gauge cluster where the speedometer cable attaches - has yellow with red stripe signal wire that runs to ECU pin B16 - also has black ground wire
 
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Thanks jlicrx. Would have still been struggling without your direction. Found the correct VSS wire which turned out to be a different PIN, but color was at least the same. Evidently Honda wired each DX that year differently. Could not believe the various different diagrams I found. Once I got the VSS and tach wires located the rest of the install was a breeze. Used the loop throttle connection so I did not have to fabricate any brackets. Worked perfectly on my recent 2400 mile round trip.
 
on the 91 DX with stock transmission, the VSS is on the back of the gauge cluster where the speedometer cable attaches - has yellow with red stripe signal wire that runs to ECU pin B16 - also has black ground wire
Need your help again jlicrx. Still having wiring issues with my 91 DX. You solved the cruise control installation for me last October, so maybe you will be able to help with this problem. My radiator fan motors are not coming on. Verified they are good. The temp switch is not on the bottom of the radiator as the Haynes manual says. Have a pipe plug in that hole. I think I found it under the distributor in the block. Verified 12 volts to one of its wires. Put a jumper on it and fans still do not run. Must be a relay somewhere, but can not find any on any of the diagrams I have located. Any ideas?
 
Need your help again jlicrx. Still having wiring issues with my 91 DX. You solved the cruise control installation for me last October, so maybe you will be able to help with this problem. My radiator fan motors are not coming on. Verified they are good. The temp switch is not on the bottom of the radiator as the Haynes manual says. Have a pipe plug in that hole. I think I found it under the distributor in the block. Verified 12 volts to one of its wires. Put a jumper on it and fans still do not run. Must be a relay somewhere, but can not find any on any of the diagrams I have located. Any ideas?
on your stock DX engine the cooling fan switch is located on the back of the block next to the oil filter - has a big round black rubber boot on it - should be 2 wires, one black and one yellow with green stripe - the sensors on the end of the head are also coolant temp sensors - the sensor with the one wire connection (yellow with green stripe) is for the temp gauge - the sensor with the 2-wire connection (red with white stripe and green with white stripe) is the TW sensor for the ECU
 
I a wiring issue in my 91 Honda civic dx hatchback. It idles fine but when the lights go on it dies then when brakes are pushed the blinkers flash? Then when I try to put it in gear it bogs down an dies? Any help, me an the people I know have no ideas?
 
I a wiring issue in my 91 Honda civic dx hatchback. It idles fine but when the lights go on it dies then when brakes are pushed the blinkers flash? Then when I try to put it in gear it bogs down an dies? Any help, me an the people I know have no ideas?
 
I'm in same boat. I had fire now trying to tum all the correct components for fuse circuts. Mainly fusebox to cluster ignition and to tails fuel pump ect.
 
O to 1 not exactly what u needed but color codes pins
 

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Thanks jlicrx for the tach wire ID on the 91 DX. I am trying to install a Rostra cruise control on my 91 DX 5 speed manual. Now I know where the tach wire is.

Any idea if I have a VSS and if so, where it is located? Do not want to install the magnetic speed signal generator. Did that on a 70 Fiat 128 back in the day and it kept losing the signal when I went over dips in the road. That was one of the first Front Wheel Drives about the same time as the Subaru came out and the axles just bounced too much. Maybe the DX will not have that problem?
Depends on if your running cable trans with a cable speed sensor still. There's only one sensor on a cable trans And It's For Reverse Lights. Besides that there's a cable sensor to the hole in back side of tranny and it reads revolutions off of distributor Via Blue Wire On 2 Plug connector With Blk Yellow Ignition Wire
 
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