Duty Cycle on Stage 1 Fuel pump needed?


Registered User
Logged my mates TT its a stage 1 enlarged tip K&N with 3 bar fpr by the looks of the logs running 260bhp he had his injectors cleaned so we fitted them and i had my laptop so we logged 2 quick runs in 3rd gear.

for people that know. how is the AFR and is the duty cycle getting a bit too close to 100% and would this be the fuel pump getting tired


cant seem to upload

any help is appreciated


  • LOG-01-002-031-xxx.zip
    5.1 KB · Views: 97

Stuart B

Registered User
I asked wak a similar question and (I think) he suggested the injector cycles are upped to meet the lamfa so if the fuel flow is too low they will just stay open for longer, until the AFR is met - all this at the blink of an eye - cars are crazy.



Site Sponsor
logging will help.. but maf output will also influence what % the lambda's adjusting.. An under reading MAF by 20% is not unheard of, and will result in a lambda adjust of also 20% +

On the dyno its easier to correlate measured power with the divide by 0.8 estimator to get a "feel" on maf reading..
Once maf's confirmed as "ok" then a resultant large +ve adder of lambda is fuel pressure related.. Tired pumps. Old cars.