SOHC TO DOHC Wireharness

[Nismo1182]

Well ive searched and didnt find the answer I was looking for.

My friend blew his sohc ka in his 89 240. I had a spare 93 dohc ka sitting in my garage so i decided to swap it into his car. I have everything from the 93 donor car:

enginetrannyecuwireharnesscoil packign chip

Motor and transmission went in with no problem at all. I took out the sohc wire harness and put in the dohc wireharness. Everything is connected on the motor side and the ecu is plugged in but theres a connector on the dohc wireharnes (ecu connector end) that does not match up to a plug on the sohc underdash harness. What is this plug for?

*Edit* With a bit more searching, ive found posts saying this plug is for the gauges and that its not really required to make the car run. And to change plugs, just switch the wires over color by color (perfect match?)

[Nismo1182]

Ok, got the dash wiring done. But the car has no spark or fuel. everything is connected, no fuses are blown. Im out of ideas.

[mattback]

battery box plugs plugged in ?

[Nismo1182]

yup, car cranks but wont turn on. No spark, fuel pump is getting some weird low voltage but wont pump fuel into the line.

[slw240sx]

that lil plug that plugs into the dash is very important it wont start with out that wired up right... did you match color for color or just postion to position on the DOHC AND SOHC plugs?? this will affect starting !!!!!!

[Nismo1182]

i did color to color. The dohc plug has 7 fewer wires than the sohc plug. I had 2 wires left over on the dohc side also.

[mattback]

check fuses and power to the distributor and stuffs.

[Nismo1182]

other stuff gets power, fuel pump reads 8 volts going thru. I havent checked power to the distributor. none of the fuses are blown.

[Nismo1182]

just want to make sure the little plug under the dash is for the gauges. Like i said before, i got most of the wires matched up except for 2 on the dohc harness. This swap is making me angry. 1. its taking up my garage space 2. kid needs his car back 3. his sister is hot so i dont want to look stupid by letting her little brother down

Any help is much appreciated.

[slw240sx]

haha... let me check my car and see what those extra wires are for... i think if my memory serves me coorrect one maybe a mix match and it does cause no spark ...

[Nismo1182]

cool thanks. since your car was sohc before, i just need a diagram of the dash plug. Then ill have to find a diagram of the dohc harness elsewhere.

[mattback]

I never hooked up the dash wires and i had a sohc --> dohc run absolutely perfect.

that's not your pboelm, you have problems elsewhere.

check to see that both your mafs and your distributor are getting power.

was this a known running good swap ?

[Nismo1182]

I never hooked up the dash wires and i had a sohc --> dohc run absolutely perfect.

that's not your pboelm, you have problems elsewhere.

check to see that both your mafs and your distributor are getting power.

was this a known running good swap ?

yeah motor ran fine. It was pulled for a SR swap, it only has 100k miles on it.

Ill check the power to those.

Would a faulty ecu cause those problems? No power to fuel pump or ignition?

[mattback]

well it could be a bad relay on the sohc itself.

did the sohc run great befre you starte??

[Nismo1182]

It ran fine until a rod bearing went out.

[mattback]

make sure youre getting powe to the battery

make sure lights are coming on inside of the car.

make sure ignjition relay is working. see if the grey and borwn plugs are getrting power.

[Nismo1182]

yup, lights work, car cranks but wont turn over. I'll check a few more electrical things tomorrow and ill let you know what i come up with.

[Nismo1182]

nevermind, i got it to start and run. thanks for everyones help.

[mattback]

what was it ?

[Nismo1182]

something stupid on my part, it was so simple im suprised i missed it. I forgot to ground a wire, i grounded it, fuel pump primed and i guess it got the ignition working too. Car starts with no problems at all.