MonkeyMagic

I swapped a jdm 13b s4 engine into my 88 fc, and cannot get it started. First off, it was not getting fuel. I fixed that, but now, I have a spark problem. It used to fire every now and then, but I unhooked my ecu to check it out, and when I plugged it back in, I got nothing. I purchased another ecu and tried that, and still no spark. The coils have 1-2 ohms of resistance and have power going to them, but it seems that they are not getting a signal from the ecu. Any ideas? Could two ecu's be junk?

1SxyRXy

check main relay

MonkeyMagic

will do

MonkeyMagic

any more ideas?

Sideways7

iTrader: (7)

Check the fuses for continuity. Just because they look good desn't mean they are. Also, check the harness for brocken wires. You might have had an almost broken one before that cause it to spark sometimes, and you totally pulled it loose when you pulled it out.

rotarygod

iTrader: (1)

The cas really has no way to break so don't worry about it. The ecu almost never goes out either although it is easy to blame it for things. If the ignition isn't firing, it can only be the coils, a fuse, ecu, cas, or the air flow meter. If the air flow meter doesn't work, it will not let the ecu send the correct signal to the coils. I had mine fail several years ago and I checked everything before realizing the afm could do that. Check all of those things.

rogrx7

iTrader: (11)

Check your ground!

iceblue

Shhhhh.

The coils fire by grounding the coil, the coils and injectors are hot all the time they get a ground from the ECU to triger them on.

I went through 5 ECUs when I had this doing the swap yes 4 of them were bad. Clean the contacts and check the wires for contenuity. I had a bad wire to my L coil and it intermitantly went out. I ohmd it out and bent it around with my hand and found it. Solderd in new wire all is good since then. As well I would not trust the JDM ECU if you are using one. FC's in Japan had no order to the CAS plug in the harness some were in the body harness some were in the emissions harness. If they are oposit from the ECU that car came in you can see that no spark would be found. In USA all zenki FC's had the CAS plug in the emissions harness while all Kouki FC's had then in the body harness.

If you searched you would have found several posts from me regaurding this exsact issue when swapping a 13bT.

MonkeyMagic

cool, thanks a lot guys. I'll check all that out and let you know how it goes.

MonkeyMagic

Well, just for an update, it was the ecu. I bought a third one and plugged it in and got spark. Unfortunatly, as some of you might have already read, I need a rebuild. After all the work I did doing the swap, the engine has no compression on the front rotor.

snddoc1

iTrader: (11)

Where is the main relay? I'm having the same problem with my 87 T2.

Aaron Cake

iTrader: (1)

As it is clearly stated in the Factory Service and Haynes manuals, the main relay is on the inner fender wall near the trailing coils. It's a silver box held on with one screw with a large harness and connector coming out the bottom.

HAILERS

Check your Engine fuse in the interior first. It powers the main relay. The engine fuse in turn gets fed by the EGI INJECTOR fuse in the engine compartment. NOTE: IF you fuel pump works when the fuel pump check connector is jumpered, then the engine fuse is good an most probably the main relay since both the circuit opening relay and the main relay are powered from the same fuse.

Download the fuel section of the fsm and see the page called Contro Unit. It lists the output/input of each pin on the ECU. Take special interest in the output of pin 2a, 3I, 3J and compare them to the fsm values.

2a is the ref voltage signal in the ECU. If this voltage isn't darn close to 4-5vdc, then the ECU is junk or one of the sensors that is fed by the pin 2a is dragging it down. The ECU will not trigger the coils if this voltage is corrut/bad/sucks.

'And we know you have the cas plug on or you would not have written your question.

Get a digital meter if you don't have one.