87 FC n/a no spark, fuel or tach
 

Hey guys! Long long long time reader 1st time poster!

So I've been reading on here for a few months now on this subject I can't find anything yet so I'm hoping some of the s4/s5 guys can help me out.

Car ran when I got it after plugging in coils, removing the old gas for new, adding a new fuel filter, plugs and wires.

It has the dreaded 4800 "rev limit" like the secondary injectors don't fire or something. And the fuel gauge was buried below zero. As far as I know that's all that was wrong with it so I went and took out the fuel pump harness and moved the float arm back and forth to see if it was stuck put it back in and cleaned the little ground on top of the fuel pump harness.

It started right up and the gas gauge worked so yay success. So I turn it off to go back to work for 3 hours come back to start it and it starts then dies after 2 seconds.

Now it will crank but no tach movement, no spark, no fuel and no sounds of relays clicking on when keyed to the "on" position. All the gauges don't work except the voltage. (12.62v)

I've cleaned all the grounds at there locations, replaced the main circuit relay, the circuit opening relay and all fuses.


I'm stumped I can't find loose connections, broken wires or anything obvious so any insight or advice would be greatly appreciated!

Pop the spark plugs out and see if they are WET..if they are then you are getting fuel and it is most likely flooded.

Not that nubie sir lol be there done that, that's how I know it's not getting fuel. I probably should've mentioned this isn't my 1st rotary, and all basic non starting problems have been looked over like flooding and loose connections. Definitely not getting fuel or spark. (Why I changed the main circuit relay and opening relay)

If I figure it out I'll be sure to post what it was for sure!

Check the 15 amp engine fuse (interior). There is a plug w/2 wires to focus on at the main relay for with key to on the B/W wire in this two wire plug should have power (12 volts). Does it?

Alright I'll check that asap.

With the key on, it has 11.80v

In the 4 wire plug of the relay the B/Y and B/W wires should both have 12 volts w/key to on all plugs plugged in.

The B/W wire gets 11.70v but nothing off the B/Y. I rechecked the 2 wire plug again for shits and giggles and no voltage off either wire. (Knew I should've checked that myself lol) so the only wire getting voltage for the main relay is the B/W wire on the 4 wire connection

The B/Y is powered by the White/Blue wire of the relay plug w/key to on. If B/Y is powerless w/key to on then check the White/Blue wire for 12 volts (no key needed). If this wire is w/o voltage then it's likely the EGI INJ fuse is blown (fuse powers the coils and injectors).

And the B/W wire in the 4 wire plug can only have voltage w/key to on because w/key to on the relay is activated by voltage on the B/W wire in the 2 wire plug thus if you have power on the 4 wire plug's B/W wire then the other B/W wire (2 wire plug) must have voltage. And it's good to use the negative battery terminal to use as a ground source for testing voltage.

likely a blown EGI fuse and likely a shorted ACV solenoid wire pair.

So I found it keeps blowing the 15a engine fuse in the driver kick panel. So imma check some wires and see what's up.

the ECU and fuel pump are powered off that fuse, so i would probably suggest disconnecting one or the other and check their nearby wiring to be sure something wasn't smashed to metal and grounding out.

The wire from that fuse directly powers the alternator, main relay, and circuit opening relay on 5 speeds via the B/W wire.

well those things too, could be a short in the plug behind the alternator.

That's what I thought too, so I disconnected the alternator (2 plug at back of alternator) with a new 15a fuse and cranked it over a few times still popped the fuse. So next is the fuel circuit. I was told the green 2 plug connection at the passenger side engine compartment is to the fuel circuit and to jump that connection and turn the key to "On" (not start) and see if the fuses pops. Sure enough it did.

The circuit opening relay clicks regardless of good fuse, bad fuse and no fuse so I assume the short is on the fuel pump side of the circuit?

theres a relay under the steering column with a blue connector, try disconnecting that one as it disconnects the fuel pump from the engine fuse.

OK I'll do that asap. That should tell me if it's on the fuel pump side of the circuit or not, if I'm not mistaken.

We are getting closer! I can feel it! Lol

The power wire for the fuel pump was frayed on the inside of the tank where it bolts to the top of the fuel pump holder and causing the fuse to pop. Everything works great now! Thanks for all the help guys! :blue:

cool