White 87 13B

Okay, so I had my Rex running for two days...I cleaned the ground by the wiper motor, changed the battery and removed the wire that caused the EGI computer to blow the resistor...The Port Air Solenoid Valve circuit is now disconnected...

Well, I am driving along experiencing my mid RPM sputter, the car just all together stalls...I cannot get it to start again because I am getting no spark. I connected my Voltmeter to the coil wires and got a reading while cranking of 246.11 mV. When I am not cranking I am getting a reading of 6 volts...

I noticed a electrical burn type smell...I figured I blew the computer again...well, once I towed it home and the sun came up I was outside taking the EGI Unit apart...I found a 4 ohm 1 watt resistor that had almost blown. It was still getting continuity(sp?) and was reading 4.7 ohms. Well, I don't want to plug it in and have the same ish happen. So, what I am thinking is causing this crap is:

-Bad Coils, possibly just the ignitors.
-Improper engine ground (Under the Intake Manifold)
-Shorted wires...like I will be able to find that...
-Air Bypass Relay or something on that circuit.
-bad alternator/battery/coils

I really don't know and I am just completely confused. If anyone has a book on this car take a peak in the electrical wiring diagrams and confirm my trouble...The wire going to the EGI Unit from the Port Air Solenoid Valve is disconnected and the car was running.

The blue and white stripe wire connected to the computer from the Air Bypass Relay is still connected however that is the circuit that heated the resistor in the EGI Unit...Should I start with the Air Bypass relay and work down that circuit? Also, where the hell is that relay? I could not seem to find it...which could be the problem.......

Sorry, but I cannot do this on my own...

VroomVroomVroom

I dont recognize the"air bypass relay", but the schematic diagram on page 50-25 of the Workshop Manual shows the only blue/white (L/B in Mazda parlance) wire as going to the EGR solenoid. Are you sure you have the correct wires?
In any case, if you are cooking that resistor, then obviously there is a short to ground somewhere on that circuit which you must find.
Dave

White 87 13B

I am sure they are the correct wires...It's all stock...So, Um...it only seems to do that when the Battery voltage is below 12.1 v...I dunno...Ill have to check it out a little more in depth...

White 87 13B

Okay...I think it is either pin F or Pin S...I cannot seem to remember...When you are looking at the EGI Unit, it is the 3rd wire from the right on the bottom...the BIG connector... Also, the component locator in the manual should show an Air Bypass Relay somewhere near the front passenger headlight...

White 87 13B

LW (F) LW (EM) UPDATE: Okay, the car is in this condition, cranks but no start. No spark, at plug, between plug and wire, between coil and wire. Apparently the Coils are not getting power. The highest voltage I have seen at the coils is 8 volts. I am seeing about 6 volts normally. When I crank the motor the coils go to about 200 some odd amount milli volts.

The EGI Unit smelled burnt, I took it apart to find a heated resistor connected to a blue and white wire. The connector pin on the large yellow connector is what I believe to be pin "F" It is the third from the right on the bottom when you are looking at the three yellow connectors going into the EGI Unit. If I am not mistaken, the "F" pin is connected to the A/C main relay/fuse deal.
I disconnected the A/C Fuse/relay from the fuse box under the steering wheel.

On the wiring diagram the blue and white wire (LW) is labeled, "LW (F)" What is the F all about? The reason I ask is because the EGR has an LW (EM) wire going into the EGI Unit. It is not on connector F though. This is where I get seriously confused. So, if anyone knows about these diagrams please clue me in on what the LW (F) and LW (EM) are all about. I know that the LW is the wire color...but what is the other part. I need a better place to start...this car is going to give me a heart attack! :'(

WAYNE88N/A

"F" means front harness, "EM" (or whatever) is the emission harness (the main one that we're concerned with)...just a thought- make sure you totally ISOLATED all the wiring you disconnected from the solenoid valves, even if they're cut, some (all B/W wires come to mind) will still have juice on 'em...

White 87 13B

Thanks Wayne88N/A This really sucks. I cannot seem to figure out where the connection between me not getting spark and me blowing EGI resistors relates...I suppose with out one thing it may not shoot another thing. Damn, this sucks!!!!!!!!!! AAAAARGH!!!

***But seriously, thanks!

WAYNE88N/A

Know what? Just for $hits and grins, disconnect the black capacitor from ground (under the trailing coil), and keep it isolated from ground, then try to start the car again...If that cap is bad and intermittently shorting to ground, that might cause your probs...

White 87 13B

Okay...the black capacitor...Define??? I am lost...sorry...There is only so much car info in my brain right now...

Do you mean the main Relay...I am trying to remember what is under the trailing coil...this is the coil closer to the fire wall right?

WAYNE88N/A

There's a 1" square (or so) black "box" attached to ground with a bolt, probably 10mm, unless you're gumby you'll have to take the trailing coil pack off, or at least move it out of the way...It looks exactly like the cap mounted on the slave cylinder with a bolt...Pull the bolt, wrap some masking tape around the metal tab to prevent shorting, put the trailing coil back in place, and see how she does...

White 87 13B

So, if she starts...that black death box is grounding and that could blow my ish up?! Hmm...interesting...I will have to do that tomorrow when I have daylight. I will be sure to update on that. Someone else told me to check the ground on the engine block...so, I suppose if that black death box doesn't do it that I will continue my path of intolerance...Damn RX!!! GRR! Thanks again!

WAYNE88N/A

The ground on the rear rotor housing is also always a good thing to check- although if it was broken (or just dirty/corroded) it shouldn't short anything out. The capacitor is just a wild guess- shorts are always a bitch to track down, unless it's something visually obvious...Did ya check the solenoid wiring you removed/cut to make sure nothing's touching the block?

White 87 13B

Yeah...it is like a dread lock...both wires are pointing to the side of the engine compartment...I'll be sure to tape them up...as far as the wires coming from the EGI Unit...they are still in the little white connector!

So, let's just ignore the EGI Unit problem...could there be something MORE SPECIFIC that would cause the Coils to not work from time to time...?

WAYNE88N/A

hmmm, coils...well, you need:
1) power from the 40A EGI INJ fuse
2) main relay working (should hear it click when key is turned)
3) good igniter/ coil assemblies (coils can be read out)
4) good CAS inputs (CAS can be read out)
5) that capacitor we talked about being good
6) the ECU, and,
7) all the wiring connecting it all

White 87 13B

Okay... Here is what I have...

1)Power from 40a EGI INJ fuse...
2)Main Relay working like a charm!
3)ECU...

I will verify the rest of that stuff when I have time to do it! Coils can only display the Resistance right? They checked out. Unless there is a way to check power...I will have to consult the BOOK! Thanks I gotta head home!