02/10/2026
This Fiesta ST unpacks an eventful story, which started by taking his pride and joy to a claimed specialist for a STG2 package with their tuning.
After completing the package of hardware and software, the vehicle wasn’t data logged after their tuning was applied, the car was road tested and “felt alright”.
Unfortunately on his journey home from that specialist, his engine blew up. A replacement long block engine was supplied and fitted elsewhere, which lead to him coming here because something didn’t feel right..
Finding various fault codes, we also saw the STFT siting at +25% which highlights a fueling issue, AFR running into 17s and FRP dropping under WOT from 150000KPA to just 6000KPA…
This poor condition high pressure fuel pump has a binding issue which we’ve seen plenty of times, causes excess downwards pressure on the fuel tappet which in turns wears down the lobe on the exhaust camshaft. In this case it has actually flattened the lobe on the camshaft which now requires a replacement.
If the car had actually been data logged from the initial tuning session, this weak fuel pump would have saved the customer an engine, then not to mention almost kill the replacement. The car was being driven in a dangerously lean condition, which resulted in the failure of the engine.
A new HPFP, Fuel Tappet and exhaust camshaft and this will be back to full health.
Contact AJ Motorsport
☎️ 01375 470166
📧 [email protected]
🌎 www.aj-motorsport.com
📍 Unit 2, Enterprise Way, Wickford, SS11 8DH
Services:
Performance parts & fitting • Engine replacements & rebuilds • Servicing, diagnostics & repairs • Full vehicle health checks • Dyno runs & dyno hire • OEM ECU, TCU & standalone custom tuning • EGR, DPF & AdBlue solutions
Courtesy car available (terms and conditions apply).
Finance options available via Payment Assist and Klarna.
