Turning over but wont start/blowing engine management fuses

[jaustin]

I have a 2003 a4 1.8t avant that I can get to turn over but will not start. The fuel pump seems to be working fine and I am getting coolant into the fuel rail. The coils and spark plugs have been replaced within the past year.

I am getting a code 17072

and I checked my fan relay (I read that it could be in water in a thread)

here is a picture of the relay looked okay a little brownish in a spot but nothing that looks horrible.



any thoughts? I have it out in the garage with the dehumidifier running in case its just some water on something electrical in the engine bay.

[ddillenger]

Open the ecu box, check for water. Even if it looks ok, remove the ecu, remove the 4 torx bolts, and check for water damage. Then, with the ecu out of the car, turn the key on/crank the car and see if the fuse blows.

[jaustin]

Okay, I will remove the ecu in the morning and see what happens.

[diagnosticator]

Exactly what fuses are blowing? Could be a bad ECU power supply relay or one of the coilpacks might be shorted internally.

[32_d3gr33s]

Coolant into the fuel rail? Sounds like a problem...

[A4 TSCHUSS]

Coolant into the fuel rail? Sounds like a problem...

That has to be worded incorrectly because that isn't even possible.

Might be the coilpack harness is super brittle and worn out and the wires are grounding against each other somewhere in the harness. You can tear the harness apart starting at back of engine and work toward the connectors for the coils and look for the wire insulation missing or wires sticking out and touching each other possibly. Just another thing to look at if you don't find the problem with other suggestions from above.

You can also replace the harness by cutting it and splicing in a new section http://www.034motorsport.com/ignitio...l-p-19338.html

[jaustin]

I am blowing fuse number 29. I have unplugged the larger plug to the ecu and the fuse will not blow with it out.

In my first post it was supposed to be fuel and not coolant.

I'm thinking my harness might need some attention.

Anymore more thoughts? Any other options besides that 034 one? Seems expensive.

[diagnosticator]

Yeah, the coilpack harness is likely where the short is located. the VW OE harness should work, IIRC, others have used that harness, it's the same except cheaper. The DTC you mentioned before, is setting After the fuse blows. It is "Load circuit open". If you clear the code, then disconnect all the coil packs, (also disconnect the injectors for testing, ) the DTC should not reoccur, unless the short is a hard short to ground, or the signal side wire to the ECU from a coilpack is shorted. With the ECU connector disconnected, the ECU power supply relay does not actuate, so the fuse does not have any load current when you crank the starter.

[jaustin]

Well I went back into the garage and tore the coil pack harness apart and started at the one closest to me. (looked to be worn the most) upon slicing and removing plastic I could start to smell burnt wire and melted plastic. I have temp fixed it and it started up.

I guess now I am at the point of how I want to go about permanent fix.

[monpaps]

I am blowing fuse number 29. I have unplugged the larger plug to the ecu and the fuse will not blow with it out.

In my first post it was supposed to be fuel and not coolant.

I'm thinking my harness might need some attention.

Anymore more thoughts? Any other options besides that 034 one? Seems expensive.

OHHHHH WELL DONT KNOW HOW LONG UR POST IS, BUT HAVE TO SAY AM HAVING THE SAME PROBLEM, FUSE 29 KEEPS BLOWING, WITH THE BLOODY ECU ON, BOUGHT THE SECOND ECU, SAME THING, WAS TOLD TO CHANGE THE 1/HARNESS 2/COIL PACK...
So pissed off with this thing, y make a car with so much mistakes?

[monpaps]

Okay, I will remove the ecu in the morning and see what happens.

Hi guys, can anyone show me the location of ''''ECU POWER SUPPLY RELAY AND THE ECU SENSOR'''''

[old guy]

Hi guys, can anyone show me the location of ''''ECU POWER SUPPLY RELAY AND THE ECU SENSOR'''''

Relay 219 in the ECM box is the ECM master control relay. Therre is no ECM sensor. You have to fix the short in your ignition wiring harness or the problem isn't going to go away.

[sepanskB6]

I am that guy who resurrects an terribly old thread, but at least I used the search...

I am having the same issues. It is currently at the stealership. They initially said it was the plugs and coils...Well I pull the plugs and disconnect all coils Fuse 29 Engine Management blows out when putting the fuse in without a key even in the ignition.

Looking for some advice so I can get the car running to at least drive 287 miles back to Michigan to trade it in.

Ninja Edit: Forgot to ask if anyone had the part number for the coil harness?

[blitz2190]

did you try the same fix as the op?

[AudiA4_20T]

ditto, did you look for water in the ECU box?

[sepanskB6]

I have not looked for water in the ECU box yet. The car is currently at the stealer...i am flat trailering it back to Michigan today and gonna do some deeper dive there.