C00k13

Ok, not getting spark... The car is an '87 NA with an '88 NA engine and tranny swap. When i first dropped the engine and transmission in I hooked all of the basics up and was successful in getting it running. After I pushed it into an enclosed area, I proceeded to hook everything else up. All that is left to do is put in the radiator and mufflers. Tried starting it to ensure it would still fire up only to be disappointed. I figured out that the spark plugs were not firing. So I replaced spark plugs and wires, Tested all three coils with an ohm reading of .3-.4, Tested main relay for continuity with success, Every fuse I could find is ok, Tested crankcase sensor with readings of 162 and 162.3 ohms, All grounds cleaned, and neutral safety switch is fine. The only thing that I can possibly think of is the ignitors but have no way for checking that. Could anyone please help me?

HAILERS

Go to either of the coils and see if there is batt voltage on either of the two wires on the COILS. Not the ignitors but the COILS.

Does the fuel pump run if the yellow two wire fuel pump check connector is jumpered and key is put to ON. Should if the ENGINE fuse is any good.

Does the MAIN RELAY pull in? Should click when the key is put to ON. Not sure? Disconnect the two wire plug on that relay. Now key to ON. Now put that two wire plug back on the Main Relay. You should feel the relay pull in and click.

Got a meter? Yes you have a meter. Pull the small plug off the ECU. Key to ON. The two wires on the far left of that plug should have batt voltagel. Pins 3I and 3J. Also all of the four light green wires on THAT plug should have power. They are the fuel injector wires.

Huh. Hard to say. It ran once you say, so at that time all was well. Maybe you disconnected something and forgot to reconnect it?

All I know is.........you turn the key ON...........that puts power on the ENGINE fuse......engine fuse powers the Main Relay up............EGI fuses pass power thru that Main Relay now to the ECU, fuel injectors and coils. ENGINE fuse also powers the fuel pump thru the Circuit Opening Relay.

AFM disconnected electrically????? Who knows. The Shadow Knows.

ifryrice

Edit: Damn, beat by HAILERS...

It's rare that the coils go bad. Have you verified continuity between the ECU pins or checked them as per the FSM? Have you also checked the wires @ the coils?

Check the B/Y wire at the coils and make sure it has +12V switched from the ignition. The trailing has two if I recall, both are in the same 2 pin connector. They're powered by the main relay through the EGI INJ. fuse if I recall.

ECU Side:
1M (IGf-T) should be <2V
1U (IGs-T) should be ~4.4V
1V (IGT-L) should be 0v
1X (IGT-T) should be 0v

yudaya

i spent 3days on trying to start my rebuild it did the same thing, when i realized the ecu ground was poor and the ground from my tranny to fire wall was missing as well, i fixed the two and she started right up

HAILERS

IF the fuel pump check connector when jumpered and key is to ON, does not produce a working fuel pump, the it's possible the ECU ground on top of the rear rotor housing is undone/missing.

The reason behind this statement, is that the ground wire in the yellow two socket fuel pump connector, is spliced into the ECU ground #24. See FSM wiring diagrams.

What you do when you jumper the yellow two socket connector, is to make a circuit b/t ground point #24 and the Circuit Opening Relays coil to pull the relay in. Make sense? Yes.

C00k13

So I've checked the b/y wires and have no volts to my coils. My fuses are good and the AFM is connected. Relay is good. Pins 3I and 3J are both reading about 6.4 volts and all four green wires are getting power. The ground from the firewall to the rear housing is good but I cannot find the other ECU ground. Where is it? And also, where can I find the FSM wiring diagram? I should also state that I'm not getting power to my crank angle sensor. Figured that out after you guys started running ideas by me.

HAILERS

The ECU ground is not from the firewall to the rotor housing.

It's located on the top of the rear ROTOR housing and biased to the left a bit. Upper intake has to be removed to see it. But you can tell if its grounded by pulling the small plug off the ECU and seeing if the two BLACK wires are going to gnd or not (pins 3A and 3G). If they show less than .5ohms, then I'd say the ECU gnd on top of the rear ROTOR housing is good.

ALL cas wires are INPUTS to the ECU. ECU does not output to the CAS.

HAILERS

There are two EGI fuses.

The EGI COMP feeds the ECU and the solenoids on the vacuum rack (pin 3I)

BTN fuse via the ROOM fuse feeds 3J (car will run without 3J though).

The EGI INJ fuse feeds the coils and the fuel injectors. Got one, should have the other.

6vdc is waaay too little for the light green/black, light green/white/light green/red and light green fuel injector wires on the small ECU plug. UNless the battery is 6vdc also.

CAS make voltage by spinning and pass it along to the ECU. The CONTROL UNIT of the FUEL AND EMISSIONS SECTIONS shows what each CAS wire should read at idle and just key ON.

misterstyx69

iTrader: (142)

Check to see IF a Thick black wire is running from the Fuse Block To the harness.(that it is Hooked up).If that wire is Not connected,you get Nothing.(it suppies voltage to the Engine,headlights,ETC.).
I missed this wire on my Swap,and I couldn't figure why I could not get the car to roll over.

C00k13

Hey, I wanna thank you all for your help. Apparently there was something wrong with the ECU. A friend of mine gave me an ECU he had lying around and told me that it couldn't hurt to try it. Same model and year. Sure enough, fired right up... but it won't stay running. Screwed if I do, screwed if I don't.

rshn117

https://www.rx7club.com/showthread.p...67#post9053867

start a build thread, ill take pics and post em up