Every set cleaned at Budget Injector comes back with a flow sheet. Here's how to read it and what to do with the results.
What a flow test measures
Each injector is fired under controlled conditions and the fuel it delivers is collected and measured. That gives you three things to look at:
- Flow volume — how much fuel each injector delivered during the test.
- Balance — how closely the injectors in the set match each other.
- Spray pattern and leakage — whether each injector atomizes properly and seals when it's closed.
1. Compare the injectors to each other
The most useful thing on the sheet is the spread across the set. Your engine computer adjusts fuelling for the whole bank, not each cylinder, so if one injector flows noticeably less than its neighbours, that cylinder runs lean. Look for the highest and lowest numbers and how far apart they are. A tight spread means a well-balanced set; one injector sitting well below the rest is your likely misfire or lean-code culprit.
2. Compare before and after
If you added before-cleaning numbers (+$5 per injector), you can see exactly how much each injector improved. A big jump means deposits were the problem. An injector that barely changes — or is still far from the others after cleaning — may be worn or damaged internally.
3. Check spray pattern and leaks
A healthy injector produces an even, cone-shaped mist. Streaming, dribbling or a lopsided pattern hurts atomization even if the flow number looks okay. Any injector that drips when closed should not go back in — it can cause hard starts, rich running and fuel smell.
When to replace instead of reinstall
- It still flows well below the rest of the set after cleaning and reverse flush.
- It leaks or drips when closed.
- The spray pattern stays poor after cleaning.
- It doesn't fire at all (dead coil or seized internals).
If one injector is done, you can replace just that one with a single injector, or upgrade to a matched set if you're building for more power. Diesel injectors are also available.
Keep your flow sheet
Hang on to the sheet. It's a useful baseline for the next time you're diagnosing a running issue, and it's great documentation when you sell a car or a used set of injectors.
Get your set tested
$15 per injector includes ultrasonic cleaning and a flow test after cleaning; before numbers, reverse flush, and GDI or diesel are each +$5. Drop off at 19320 65 Ave #214, Surrey — typical turnaround 1–2 hours. Book your cleaning.
Related: signs of dirty fuel injectors · ultrasonic cleaning vs. bottled cleaner