View Full Version : 2001 A4 1.8t cranks but won't start.

08-17-2016, 07:01 PM
Hello all, I picked up a clean b5 last week from my uncle who had this car since new. I bought it knowing that it did not run but was up to the challenge, so now I am here for help. As the title states, the car will crank but it will not start. I have already replaced the ECU, ECU relay, Fuel pump relay, all fuses that had any corrosion, CPS, Coils have a constant 12v supply with key on, getting fuel to the cylinders, great compression, Check engine light is on as well as the EPC light on the instrument panel. No immobilizer icon. I have 12 volts in/out of fuse #29, 6 volts when cranking at fuses #32 and 34. Everything works (radio, windows, heater, sunroof) but I am getting no spark at any cylinder.

My uncle had the timing belt and all associated parts replaced about 15,000 miles ago.

Any thoughts?

Vag Com on the way, should be here Monday but I have all weekend to mess around with the car while drinking some damn tasty refreshments.

Any help will be greatly appreciated.

08-17-2016, 07:36 PM
I put a new crank position sensor in mine and it worked. I had the same issue you had

08-18-2016, 08:23 AM
I wouldn't keep throwing parts at it. If you've got Vagcom coming, that should help figure it out.

08-18-2016, 04:26 PM
I have a electric short and draining battery, prior was crank no start also. Check all fuse n under hood and knee panel plus the fuse box nothjng was wrong?

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08-19-2016, 04:41 PM
You can get a cheap ebay kkl adapter and use VCDS Lite to get all the information you need to determine if it's a bad sensor. In the mean time it's worth it to do a compression test just in case.

Make sure the adapter you get is the FT232 or PL2303 type

08-27-2016, 01:25 PM
Ok, VCDS showed G28 "engine speed sensor implausible signal" with the occasional G28 "engine speed sensor no signal." Swapped it out again, same messages. I can watch it on VCDS read 160-200 rpm when cranking then it goes to 0 rpm after a few revolutions. Battery is holding a charge, all fuses are brand new as are the ECU and Fuel Pump Relays. Still getting no spark, battery is at 12.1 volts. The only thing that is really standing out to me is there is a hole in the bell housing right where it connects to the block that looks like a sensor should go there, I can see the ring gear, is this supposed to be blank?

08-28-2016, 03:53 PM
Turns out, the hole is for the crank sensor on the 2.8 engine. Went through the wiring today, everything looks good, all relays are good, fuses are good, changed the plugs again to rule that out. The only thing I can think of is bad coils. But what are the chances of all 4 going out at the same time?

08-29-2016, 02:26 PM
Small to nothing that all four have gone bad at the same time. If you could record a video of it cranking, maybe i could help. If I were you, this is what i would check:

- Fuel pressure (you can get a gauge cheap which you can connect between the rail and the rubber hose attached to it)

-Is there a spark (check by unplugging one coil, remove a spark plug and connect it to the coil, touch a metal part of the car with the top of the spark plug and have someone crank the car. You should see the spark. Try not to hold the coil cable as it may shock you :D

I can't think of anything else... Maybe the new ecu isn't the right model for your car...
Also, there i'm pretty sure the car won't start if the speed sensor isn't working correctly, so check that.

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08-29-2016, 02:58 PM
Ended up putting everything back to stock other than the ECU, charged the battery out of the car over night, swapped the coil harness plugs and it fired up, ran it up and down the street a few times and noticed that once I hit boost and depress the clutch the engine revs up around 5000 rpm. Would this be a diverter valve or boost control issue?

08-30-2016, 12:01 AM
First thing that comes to mind is that the wastegate actuator is not working. Be easy with the throttle until you solve it because you could blow up your turbo and/or engine from the overboost.

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