Bad Remap BMW 520 – Fixed
This remapBMW came in to us from Camborne with the customer reporting the engine failing to rev fully and a lack of power. Previously the car had been remapped by someone else. The incorrectly remapped BMW required a visit to Southwest Performance Cornwall, in order to be remapped to carry out a regeneration as well as reinstating the original DPF.
The Incorrect Remap BMW problem
Carrying out a diagnostic on the bad remap BMW, we could see it was not able to regenerate whilst driving, and that the pressure sensor readings were static and low for the Diesel Particulate Filter (DPF).
The first remap BMW had blanked the EGR and removed the DPF, however the DPF was still on the car. Due to the remap BMW still having the DPF without ‘knowing’ as it were, the DPF became blocked. The turbo would stall due to the blocked DPF, this then caused the air to not reach the engine when driving at 2700 RPM or higher.
Having removed the files for the DPF from the Electrical Control Unit (ECU), the car was unable to carry out a regeneration (clean itself). However, when the ECU was forced to have a static regeneration by being connected to a diagnostic scan tool, it was still able. The pressure sensor readings and active regeneration are the only files being deleted.
Correct Remapping
By re-flashing the original factory map and removing the incorrect map, we were able to bring back all of the readings.
We added a popcorn hard limiter during this remap, as an extra request of the customer. After carrying out an active regeneration which we observed carefully, the BHP had gone up to 231 and the NM is now 462.
By deleting the maps command structure, we were able to correct the Swirl Flaps problem as well as having the DPF reinstated. By correcting the Swirl Flaps issue, the ECU will not attempt to run Swirl or show a fault code, instead it will utilise an alternative mapping overlay, producing low end torque.
In the end we concluded the remap BMW was previously incorrect. The bad remapping consisted of a DPF delete, an EGR delete, Swirl Flap removal and we estimate it to have been modified to 420 NM and around 210 BHP. This particular incorrect remap caused a lack in power due to the Diesel Particulate Filter or DPF becoming blocked.
We have brought the car back to life by reinstating the correct specifications, fitted the DPF, removed the EGR as well as the Vmax and had the popcorn limiter added. The outcome being an increase in 9% in BHP and 9% in NM from the bad remap, plus, no faults to be caused by this remap now or in the future.
The Total Cost
Remapping costs can vary a little due to the condition of your vehicle and what you would like to achieve. Remapping starts at £100. This specific job cost £250 which includes running the initially diagnostic to discover the problem.
Who can remap properly?
Going to a reputable company for remapping your vehicle is always highly recommended. If you were to find yourself having issues with your car, you may not even begin to think it was the original faulty remap which is causing the issue. Just like this remap BMW owner, you don’t want to find yourself paying out for other peoples mistakes.
The very thesis used in training centres around the world on how to remap cars was written by the boss at Southwest Performance. This document is distinctly referred upon when mechanics are in training.
Click here to read the thesis >> https://www.scribd.com/document/317950309/So-You-Want-to-Get-Into-Mapping-Cars
