Anyone know of any vendors that sells engine wiring harness for an s4 turbo?

 

mazda trix or mazda direct. but it will cost you.


Whats wrong or what do you need fixin?

 

It wont start. Seems like an electrical issue. Was getting no spark to the leading coil, replaced and now getting weak spark. Still no start.

 

the engine harness, the one that actually goes on the engine, doesn't have anything to do with the coils, the coils are on the body harness

 

See, now THAT's why I always run things by you guys before I jump.

 

Was the car running fine before or did you buy this car and it already had the problem?

Any work done on the car recently?

 

Make sure the Brown/White wire of the TPS, boost sensor has 5 volts w/key to on. If it has a ground then the engine will not start.

 

Was running fine until I installed an air horn.
It overloaded something. Since then, hasn't started.

Figured out that it wsn't getting spark. Replaced the coil, now it's getting spark, but from what i've heard, the spark should be almost a bluish bright color. It's like a small dull orange spark. Assuming that's why it won't start as it has compression, fuel and timing.

 

The coils ground through their body past their brackets past their mounting to the body. Make sure all is clean, secure and no corrosion where parts touch.

 

Blue would be the weakest color and Orange the strongest.

 

The Brown/White on both the TPS and the Boost Sensor have 2.2 to 2.4 volts with the key to on.

 

If the Brown/White wire has less than 5v, could that be a cause of the non-starting issue?

 

Yes. Your AFM or another engine sensor could be shorting out this wire. Remove the plug connecting to the engine sensors one by one and test the voltage of the Br/W wire w/key to on after each sensor has been unplugged to locate the sensor shorting the wire. The sensors are the AFM, TPS, boost sensor, variable resistor and the atmospheric pressure sensor.

 

I am a little late in posting this but, which grommet did you go through and how did you do it? I am also assuming you went through a grommet in the firewall to get a negative switched horn wire.

Depending on how you did it you may have chaffed some wires in the process.

 

It's been awhile, but if I remember correctly, I used the signal lead from the stock horn. I didn't go thru the firewall.

 

I've tried uplugging each of those sensors one by one, but it continues to read 2+ volts. Are there any other sensors i should be unplugging to test?

 

There are different possibilities at play here. So, in retrospect you unplugged each of the five sensors listed above or just some of them?

One thing you could do is check the voltage to the ECU. Pin 3I (B/W wire) should read 12 volts w/key to on. For that pin to have 12 volts then the B/W wire in a 4 wire Green check connector near the lead coil should also have 12 volts w/key to on. Check this wire first. If it has 12 volts w/key to on then check pin 3I of the ECU. If the B/W wire at the check connector fails the 12 volt test but shows a rather low reading then you would need to look elsewhere for the cause. So, see what you get at the check connector first and report back w/your findings.

 

[QUOTE=satch;11845917]There are different possibilities at play here. So, in retrospect you unplugged each of the five sensors listed above or just some of them?

I used the boost pressure br/w wire to check voltage(w/the boost pressure sensor still plugged in) while I unplugged each of the other sensors, checking voltage every time i unplugged each sensor.
Then I checked voltage at the tps while unplugging the boost pressure sensor.

 

I'm getting 12.0/12.1 volts at that black/white wire.

 

The stock horn relay is negative trigger all the way up until the relay itself.

I'd have to see what you did.

 

Then you need to check pin 3I at the ECU. It is possible that one of the main connectors near the ECU has a poor connection and preventing the ECU from being powered properly. This is one possibility.

Another possibility is the Vref wire at the ECU is pulled back and not making good contact w/the ECU.

Other possibilties are the Br/W wire is grounded out w/the grounding not caused by the sensor(s). You could set the meter to ohms and read the resistance off of the Br/W wire. Easiest way to do that would be to unplug the Atmospheric pressure sensor and unplug the ECU housing the Br/W wire and w/no key place one meter on the ECU plug wire and the other lead on the wire at the APS and see what you get. It should read a rather low number.

You also might want to unplug all of the sensors you unplugged one at a time and recheck the wire once again.

 

After spending a number of months and $$$'s to an rx7 mechanic trying to figure this out, I decided to purchase a parts car that had a Microtech. I transferred all of the ignition related components from that car to mine, bypassing the ecu and much if not all of the ecu wiring harness and that solved most of the issues. It's not running/idling yet, but it does get ignition.

Thanks for all your help. Rtek 2.1 anyone?

 

wtf? i mean, you have fuel you have spark. check to make sure your plugs arent fouled.