Missed last week? No Turbo? No Problem! Part 3 Take the Fast Friday Poll.
They're Often Forgotten
Fuel injectors don’t typically generate a lot of interest unless it’s time to upgrade them. Since we’re wrapping up the non-turbo build, and since we have a brand new injection test machine here at ARD, I thought I’d cover injector servicing this week!
Fuel injectors typically either work or don’t and there’s not much in between. However they can become clogged or partially obstructed. Each fuel injector has its own small filter in the top entry port called the ‘filter basket’ and these can easily become blocked or obstructed with particulate such that injection flow is compromised. Balanced injectors are important to both good fuel economy and performance as an uneven fuel distribution to the motor can make for rough idle and inconsistent fueling to each cylinder.
These injector filters commonly collect up bits of dirt and debris from the fuel tank as well as fuel filter media. Fuel filter media is more typical for cars that have not had the fuel filter replaced in a timely fashion and in turn the filter media has started to come apart and head downstream along with the fuel. For some reason fuel filters seem to be commonly over looked as a maintenance item.
Servicing injectors includes replacing o’rings, filter baskets, and retainers. Additionally ultrasonic cleaning with a proper cleaning solution helps break up any carbon buildup that can exist inside the injector from combustion gasses that can form on the injector after engine shut down. This occurs over a period of time so if you’ve got 50K plus miles on your injectors some gains in both power and economy can be had. We use Alconox as our cleaner since it is intended for use in the ultrasonic range and provides excellent breakup of hyrdrocarbon solids.
Here’s a set of injectors from the non-turbo build with 145K miles on them and as you can see these 4 units flow quite differently from one another. Typically the allowable variance is 5-10ml apart when measured at their max flow. Max flow for these injectors at 3 bar is 310ml/min. At 20 seconds of testing, not even the full minute, you can already see how much variance there is. Ultrasonic cleaning is what ultimately got these injectors back into proper flow range as the filter baskets were pretty clean and not the cause of the variance.
This should help keep the engine running smoother and with more consistent fueling that will hopeful promote some faster times as we head back to the track and finish up the non-turbo build!
Robert Lucky Arnold
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