Mr. Gadget

Originally Posted by WAYNE88N/A
Whip out a meter & start troubleshooting:
1) main relay (does it click?)
2) 40A EGI fuse (easy enough)
3) 12v at the black/yellow wire at the leading ignitor/coil connector
4) .8v timing signal at the green/yellow wire, same connector
5) good metal-to-metal ground between the coil pack & the chassis
6) CAS input signals to the ECU
7) good plug grounds on the engine (clean threads)




Using the chart above (thanks to Wayne for his great posts!)

I am at point 4. is this with the car cranking or just key on? With key on I am at .07v

Also, grounds are better than factory. I also jumpered the test lead to check codes and the CEL did not even come on - at all. Any guidance boys?

Car facts: 89 vert using a 90 coupe wiring harness ecu = 353 (vert) PS pressure switch un plugged at this point (see another thread) A/C not hooked up. Engine is one of mine - fresh rebuild that has 10 hours running out of the car so I know it works. Its getting fuel (I had to fix a fuel leak when I first went to start.

WAYNE88N/A

You're not going to get the timing signal unless she's running & the ECU is getting good CAS inputs, Mr Gadget....For now, do all of your troubleshooting at the ECU itself, and then when everything is verified there, you can worry about the wiring. Can't help ya much on the pinouts, since you've got S5 stuff going on here... Edit- you should get 'em while cranking, also, I should think...

HAILERS

If you really have 12v at the lead coil plug, and have no spark, and the cas is connected up.....I vote that you have a whacked ECU. Prove it by putting a ,meter on any brown/white wire, such as on the tps. If there is no five volts ref voltage....you ain't a gonna get any sparking action either.

Mr. Gadget

checked the brown and whites at the tps volts = 0.15 some voltage however nowhere near the 5.0 you suggest. I hate this electrical stuff- give me a rebuild any day of the week. Glad I have a good paying day job!

WAYNE88N/A

Considering all the "mixing & matching" you're trying to do on this car, is it any wonder you've run into some problems? You checked the 5v ref output at the ECU?

Mr. Gadget

not yet, electrical is not my forte, which pin out?

Mr. Gadget

the only mixing really is a coupe harness on the engine and the problem i have to overcome for the PS system. All else is either universal or came off the vert.

WAYNE88N/A

Man, I can give you S4 pinouts all day...Don't tell me you don't have the FSM wiring manual for your babies? It's pin 2A on the S4's, or, just look for the brown/white wire at the ECU (if it's the same color as the S4's)...Sorry I can't help ya more...

Mr. Gadget

have the fsm for the 89's 2a is the mop. am I looking for the wire connected to the coils?

SonicRaT

iTrader: (6)

The harness is no different between the coupe/vert.

Mr. Gadget

yes, thanks. I learned that from rted the weekend the board was upgraded so i went ahead and used it, now I have to figure out why this thing wont fire

DerangedHermit

(except on that job part)

WAYNE88N/A

No, you're not looking for any coil wiring yet, Mr Gadget, you're looking for the 5v output reference pin. Because if you don't have it there at the ECU, then what Hailers said about your ECU gone "whacked" is true. If you do have it at the ECU, then it's time to dig into the wiring. BTW, it'll be around 5v with key on, or while running, the ECU must have its own voltage regulator inside, because that ref voltage doesn't go up any with the 14+ volt alternator juice flowing, like it would if it was just using a resistor bridge.

AND, who calls themselves "Mr Gadget", yet doesn't like playing with electrical stuff?

Mr. Gadget

LOL, wife gave me that name becasue if its new, I buy it. HAve 7 or 8 PDA's i dont use, get a new cell phone every 6 months or so, 2 plasma's (both HD of course), and the list goes on. I like electronics - cant fix it well.

HErmet, why is that wierd? I started out my career as a recall rebuilder for MAzda before most of the board members were born. do it now just to help others out and my love for rotaries. Hell I even dread wiring stereo's. Always hated the electrical diagnoses part of the industry - thats why I dont do it for a living (and I make 3-4 times as much doing something else).

Mr. Gadget

by the way I hope this gets fixed before the thread ends up as long as the "searching for freeze plugs" saga.

WAYNE88N/A

Lol, especially considering the difference in "real world" rotary experience between you and Gnome...

Well, which direction are you going now?

HAILERS

There's the problem. Your gonna have to get the pinouts for the series five and make sure the ECU is getting the battery voltage so it can make the output voltage to drive the coils. Sorry, I don't think I have the pinouts for a series five anymore. Also sorry, but I do not know what parts are series four/five on this car. Just what do you have? I didn't read the whole thread. Just for clarification.

Mr. Gadget

HAilers, thanks, printed the pinouts off the fsm and will attack it tonight. Got fed up last night and had a beer or 6. Its a biache working a dvom on the floor of a rx7 when you weigh 145+ kg's and have a few in you.


Wayne, I thought you would like that one. LOL.

WAYNE88N/A

All right, you're on your way...With a "different" harness, it'd be a good idea to check all of the ECU inputs & outputs anyways, just to be sure everything's working as it should...

I gave up drinking while working on my cars a long time ago...Last time was when I changed the wife's heater core in her Grand Am, took all day, and was so ****-faced by the time I was done I had a hangover for two days, lol...Never did get all the interior pieces back together right

HAILERS

Not to beat this thread to death, but........make life easier on yourself. Unbolt the ECU from it's mount but leave the plugs connected. That way you can invert the thing to get at the lower wires easier.

I'd turn the key to ON and look first at the one that says V REF. Back probe it and you should see b/t 4-5 volts. It's pin 2A on a series four. Series five?????

If it ain't there....I'd look at the pinouts for MAIN RELAY for 12volts. That's gotta be there for voltage at 2A to exist. Those are the two most important followed by the four for the injectors which should show 12v ea.

The one marked BATTERY is useless, on a series four anyway. I can disconnect or pull its
fuse and the car will keep on truckin.

OH! An IDEA *scary*. IF the grounds for the ECU are not bolted on the rear rotor housing....that car ain't a gonna start no way, no how. So check for the pins that should show a ground. TAke the plugs off and read back into the harness for those gounds to see if they are there.

Mr. Gadget

thanks buds, no beer tonight for me! going to nail this thing down ( I hope)

Mr. Gadget

Many thanks to Wayne and Hailers for their help. Ended up replacing the ECU and fixing a ground. those two issues were the problem. The car now has 50 miles on the new engine and runs great.

Thanks again guys!

Mr. Gadget

And for S5 guys the pinout is 2i for vref.