DOHC ZC swap no start

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Old Jul 22, 2015 | 06:29 AM
  #1  
tanjulio's Avatar
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From: central valley, ca, usa
Default DOHC ZC swap no start

Hello I am trying to install an 90 JDM DOHC ZC engine into a "federal' 1990 civic standard 4 speed. I have the PM7 ecu.

I verified the engine turned on and had good compression before I bought engine.

I used the instructions from
http://www.zcspeed.com/DXZCwiring.pdf
and
CIVIC4G.COM - Honda Civic 4th Generation (1988-1991) Forum ? View topic - DPFI to MPFI Conversion

I have spark. I put correct wiring with distributor.
But no start.. it cranks good.

I changed the distributor, coil and igniter and still no start.
I verified that the engine 'grounds' were grounded.

NOTE:
The only variation I did was install all 4 injector wires (one per injector) to connect into ecu... and the other injector wiring goes to resistor box.
Could this variation cause the engine Not to turn on?

thanks.
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Old Jul 22, 2015 | 07:08 AM
  #2  
jonGSR's Avatar
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From: Southwest Texas
Default Re: DOHC ZC swap no start

Originally Posted by tanjulio
NOTE:
The only variation I did was install all 4 injector wires (one per injector) to connect into ecu... and the other injector wiring goes to resistor box.
Could this variation cause the engine Not to turn on?

thanks.
No, this will work perfectly fine. I've done about 6 mpfi swaps and have always wired them exactly as you did. I have never had an issue.
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Old Jul 22, 2015 | 07:12 AM
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arries289's Avatar
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Default Re: DOHC ZC swap no start

Do you have correct fuel pressure? Fuel at the injectors? Take a spark plug out and verify spark. Double check firing order.
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Old Jul 22, 2015 | 05:45 PM
  #4  
tanjulio's Avatar
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Default Re: DOHC ZC swap no start

Thanks for feed back guys.

I verified the impedance on all 4 injectors ; 3.4 ohms on ever injector..
I will verify that the injectors are spraying. I'll take off plugs and see inside cylinder. (I wont do it this way if it's DANGEROUS)
NOTE when I check for voltage on the injector wiring with key on I got 0.001 volts ; it changes when I put a ground...

Something interesting;
I noticed this link; attached picture.

DPFI to MPFI writeup | HondaSwap

The instructions ask me to run a wire from A 15 to the resistor box..
BUT
all other instructions ask me to take the yellow/ black wires from both injectors on DPFI system and solder them into one and connect to resister box yellow / black wire..
I believe this is correct as the current will pass through main relay... but I'm just assuming this step is important.

###
Which instructions are correct for the yellow/black wire to Resistor?

I assume that the injectors yellow/ black wire need to be taken from the previous 2 injectors because I believe the current passes through main relay...

Thanks.
Attached Images  
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Old Jul 22, 2015 | 06:29 PM
  #5  
jlicrx's Avatar
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From: colorado springs, co, usa
Default Re: DOHC ZC swap no start

Originally Posted by tanjulio
all other instructions ask me to take the yellow/ black wires from both injectors on DPFI system and solder them into one and connect to resister box yellow / black wire..
I believe this is correct as the current will pass through main relay
this is the correct way to do it - do you have the spark plug wires in the correct locations on the distributor? any codes on the ECU? ground at the thermostat housing connected, clean and secure?
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Old Jul 23, 2015 | 07:20 PM
  #6  
tanjulio's Avatar
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From: central valley, ca, usa
Default Re: DOHC ZC swap no start

I verified where TDC #1; it's the one @ 12 o clock I put plug #1 there.
No codes..

I found this video.. I will follow suggestions


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Old Jul 24, 2015 | 03:57 PM
  #7  
tanjulio's Avatar
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From: central valley, ca, usa
Default Re: DOHC ZC swap no start

Okay.
It turned on briefly when I sprayed in carb cleaner. I unplugged injector harness..
SO timing, ignitor and plugs are correct..

BUT
I don't have power going to injectors or to the plug on drivers side ;
Looks like it might be main relay"

I'll continue checking...

Any suggestions?

Thanks
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Old Jul 25, 2015 | 08:43 PM
  #8  
tanjulio's Avatar
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From: central valley, ca, usa
Default Re: DOHC ZC swap no start

UPDATE:
Main Rely was the problem.
Already resolved and engine turns on and No check engine light.
It runs perfect.

Thanks to everyone for the suggestions on problem.

Time to hit the race track.
Cheers.
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