My 2001.5 Audi S4 will not start, it has the mods in m sig. This is a complicated and long story so please bear with me. I will explain how it built up to a no start in chronological order. FYI, I was an ASE certified master tech for years but only worked on American and Japanese cars, so when in doubt I covered the basics. Also I have NO catalytic converters.

1. It started to lack power but idled perfectly. It made full boost but low power and NO misfiring.
2. It then set the check engine light, I got a code for bank one cam sensor out of sync.
3. I then data logged the heck out of it and found that everything was ok except for the lack of timing advance. At the most it hit was only 6 degrees advance most of the time it was at zero. I have many logs upon request. NO misfires showed up either.
4. The code for the bank one cam sensor kept coming back so I changed the cam sensor and verified a proper power and ground with the help of my bently.
5. Code remained after changing the sensor, then I got an intermittent crank sensor out of sync.
6. It sat for a week while I moved.
7. I finally started it again and it hardly idled and ran. Pulled codes and got codes for both cams.
8. It sat again for another week. Then it started idled like crap then died.
9. Now if I clear codes and then crank it only these 2 codes come up. 16730 - Camshaft Position Sensor (G163): Implausible Signal &16725 - Camshaft Position Sensor (G40): Implausible Signal
10. I verified this again and again, I could smell fuel out the exhaust when I was trying to start it, so it is not a fuel pump.
11. I went ahead and changed the crank sensor and the other cam sensor, still the same codes and no start.
12. Next I disassembled the cam covers and removed the valve covers to confirm the t-belt was still lined up and that the chain joining the 2 cams was ok too. All checked out ok.
13. Now I am thinking I have a computer problem. What do you think?
14. However for the heck of it I thought I would do a leak down test even though the engine should be warm when performing it and the fact I ad excess fuel in the cylinders doesn’t help either. Here are my leak down results.
Cyl # 1 = 17% leakage, Cyl # 2 = 18% leakage, Cyl # 3 = 33% leakage, Cyl # 4 = 21% leakage, Cyl # 5 = 68% leakage, Cyl # 6 = 8% leakage. I know these numbers are bad but when the engine still ran it had no blowby and no smoke out the exhaust, it also had no misfires while logging or misfire codes. I am thinking it is this bad because of cylinder wash down from the no start. IT SHOULD START WITH THES NUMBERS.

15. So everyone please give me some ideas of what to check next. Also where can I take or send my ECM to get tested? Does anyone live in the California Bay Area that can let me plug my ECM into their car to see if it starts?
The bottom line to me is why the heck would I get cam out of sync codes if everything is lined up. It makes me lean towards an ecm.

PLEASE HELP!!!!!!!!!!!!!!!!!!!!!

 

I sent this post to APR and this is what they said.

Those two error codes can really only be one of 4 things...

1) Bad camshaft position sensors
2) Out of phase/improperly installed camshaft position sensors
3) Bad wiring from the sensors to the ECU
4) Bad ECU

If the Bentley troubleshooting procedures are followed for those DTC's (16725 and 16730), and the sensors and wiring are ok, then it probably is a bad ECU. We would not be able to test the ECU for something like that here... I would think the next step would be to replace the ECU

SO WHO HAS AN ECU THEY CAN SELL ME FOR A 2001.5 B5 S4.

Please!

 

Just a few questions:

1. How many miles you have on this car?
2. Is it timing chain or timing belt driven?
3. Did you check all the fuses and relays (no exeptions)?


I had a very similar problem and it was just a fuse, number 10. But then again, we have different cars, I own a 2001 audi tt quattro. It sounds like a blown fuse prior to your timing belt skiping a tooth or something like that. Let us know please.

 

1. It has 90k miles
2. It is t-belt driven to the primary cam then the secondary cam is driven from that with a chain. 2k miles on t-belt. Tore down motor to verify t-belt is still lined up and that the chains were ok. Everything lines up.
3. All fuses and Relays ok. That doesn't make sense to be the cause for the codes I got nor the lack of power for extended periods of time.

UPDATE: I tried a stock ecm, still no start

I am thinking the reluctor ring on the flywheel may have somehow slipped?

Anyone have that happen?

 

fly wheel yes .i had a custumer with a6 2,7t no start condition the guy had tryd every thing at the end he broth the car to my shop. i replace the fly whell and that was it.

 

flywhell

 

Update: I fixed it a couple weeks ago. It was the flywheel. AWE warrantied the flywheel after 2 plus years and 50k miles.

Great guys at AWE.

Thanks