Audi 8P A3 CFFB 2.0 TDI Crank no start. To misfire. To run

[Cat B Repaired]

Bit of a complicated one here guys with a few moving parts. Was hoping somebody could shed some light.

Recentley purchased a project a3 2.0 tdi. Previous owner advised that the car cut out one morning and since runs till warm and then cuts out again.

I found the car to have trouble starting with long cranking and then misfiring heavily. After a few attempts it starts and runs fine. Once warm it will start misfiring and die.

Vehicle has a dpf delete and egr off with remap.

Showing zero engine codes under the engine module. Even with components and sensors unplugged it has no engine dtc’s. Every other module has shown multiple low voltage errors etc from jump starts and low battery however nothing from the engine module. I have a suspicion that a previous owner has had the car remapped and had all engine dtc’s deleted.

Garage has replaced all injectors, fuel rail. Rail pressure sensor. Fuel filter and filter housing with no luck.

I have someone coming out to flash a stock map onto the ecu to hopefully get back some trouble codes. Just wondering if anyone has any thoughts here?

[stevieturbo]

And are you communicating with the ecu ok ? Can you see various sensor data etc ?

There are lots of butchers out there who will delete the ecu's ability to report codes. Best option is either get rid of it or start as you say, have a correct map loaded in so you can actually start to try and diagnose things properly

Has it ever run correctly, or did you buy it as a non runner like this ?

[LordLoveLength]

You haven’t got a hope in hell of sorting it until you get a proper map on it.
I think you’re right about someone mapping out the dtc info.

Problem is you have no idea if any of the real time data you are reading is correct or not, or even if the ecu is giving calculated readings as the ‘real’ data is missing or invalid.
Then you may find the original fault is something really basic like an air leak or Chinese mass airflow sensor

[Cat B Repaired]

Good to hear we’re on the same page lol. The sensors are generally feeding back so we have some communication with the engine ecu.

I guess ill be back with an update once we have a stock flash later today. Cheers gents

[Cat B Repaired]

Time for an update on this.

So the remap was successful and the car started and ran great for around two hours. It then started misfiring and refusing to switch on. But this time with a flashing glow plug and engine light.

P019300 - Fuel Rail Pressure Sensor 'A' Circuit High Input
P008800 - Fuel rail/system pressure - too high

Both of which point to a fuel pressure sensor as a first precaution which i replaced with a genuine part.

Ran the car for 2-3 hours and drove around 10 miles with no issues. Fingers crossed this holds but needs further testing

[E-bmw]

Cat B Repaired said:

Time for an update on this.

So the remap was successful and the car started and ran great for around two hours. It then started misfiring and refusing to switch on. But this time with a flashing glow plug and engine light.

P019300 - Fuel Rail Pressure Sensor 'A' Circuit High Input
P008800 - Fuel rail/system pressure - too high

Both of which point to a fuel pressure sensor as a first precaution which i replaced with a genuine part.

Ran the car for 2-3 hours and drove around 10 miles with no issues. Fingers crossed this holds but needs further testing

Well done, it was always going to be the only way.

Are you now reversing the egr/dpf mods as the standard map will be expecting them to be there?

[Belle427]

Sounds like very bad mapping work, i had the dpf/egr delete thing done due to problems (apologies) and done right there shouldnt be any issues at all.

[Cat B Repaired]

So i asked the mapper for a fresh base map file with the dpf and egr coded out to save having to map twice or remediate.

He wasnt able to check the original file as it was locked so overwrote the ecu.

Just fingers crossed now that the issue doesnt come back