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csanderlin
01-04-2015, 03:57 PM
Well I got a 00 a4 1.8t that sat for 8 month got home hooked up battery and new gas started right now drove fine for couple days changed plugs and changed coil pack pigtails after it started up ran fine. Well next day went to go out and car cranks over fine but no start getting fuel you can smell it but no spark. Changed #29 fuse and the ecu relay any other ideas?

walky_talky20
01-04-2015, 08:34 PM
You've changed the fuse and the relay that drive power to the coil packs. Replacement of those items would suggest that you are aware that coil packs are not getting 12v+.

So item #1: Do you (now) have 12v+ to the coil packs with the key on (in RUN position)? This will be pin #1, the Red/Green wire. Check cylinder #1, as that one has the longest length of wire.

If that checks out, then continue interrogating the cylinder #1 coil connector: Should have 2 grounds. Check resistance to negative battery post is less than 1 ohm for each.

Final check is the trigger wire from the ECU. Checked during cranking with an LED test light. Not a regular test light, must be LED. Or with an o-scope. Will be positive square wave signal (LED should flash).

That finishes all 4 pins. If everything checks out, then you will have spark - unless the coil pack or spark plug is faulty.

csanderlin
01-05-2015, 12:12 AM
All coil packs not getting spark not just one

B5A4coastie
01-05-2015, 03:13 AM
Sounds like a bad ICM. My factory location was on top of my air box.

csanderlin
01-05-2015, 03:16 AM
Didnt think 00 had them

B5A4coastie
01-05-2015, 07:16 AM
I apologize, I don't do any research. If you have an issue with all of them then the only common thing between them is the ground. I would test them like Walky described in his post.

B5A4coastie
01-05-2015, 07:19 AM
Also verify you have 12v on the coil side of the fuse and relay.

csanderlin
01-05-2015, 08:56 AM
so replaced the ecu relay with a other one it started for one sec then stoped any ideas ?

csanderlin
01-05-2015, 10:13 AM
so just checked getting 12v to coil pack any ideas

B5A4coastie
01-05-2015, 12:07 PM
OK, you replaced the relay and it started then died, now you have 12V to all 4 coils, but it won't start? You never mentioned if your grounds measured out. Grounds are required for 12v systems to properly work, if you have a loose or corroded connection, you will have intermittent issues.

csanderlin
01-05-2015, 12:48 PM
Will check next

walky_talky20
01-05-2015, 09:16 PM
All coil packs not getting spark not just one

I realize this.

I also realize that if you figure out why you don't have spark on #1, you will have it fixed for all 4. I suggest testing with #1 because (A) it is near the front and easiest to work with and (2) it is the longest wire length. Any break in the power or ground wires will show there (but may not if you test at #4).

Just continue with the steps I laid out.
- Check power
- Check grounds (both)
- Check trigger wire

I guarantee you are missing one of those. You just need to find out which one. (unless you have 4 bad coil packs, which I have actually seen before)

If the problem is intermittent, you may need to check all of these during cranking.