Injector Flow Test

FWIW: 1990-240...most likely driven in-town in last five years by PO

Injectors were flow tested today, and one had more volume than three others before they were cleaned via ultrasound in cleaning solution. $60.00. I replaced defective thermostat in air-box, and exhaust manifold heat would have been used for intake air.

Translation - When driving highways, engine's head would have been running hotter in four cylinders, due to air box sucking exhaust manifold heat, and more hotter in 3 cylinders with those injectors not putting out enough fuel volume. It's quite possible an emission test would have been off also. Driving in-town would not have been an issue, but for road trips, lower fuel mileage, and a potential head gasket failure.

It's possible Techron Fuel System Cleaner could have cleaned up those injectors, but with this Volvo being about thirty years old, with road trips planed, $60.00 for a flow test, and some $15.00 for air-box thermostat is a cheap insurance policy. YMMV

Cheap insurance.

Injectors are easy to clean, often just the inlet screen is dirty.
Carb Spray Cleaner and a 9 volt battery and some compressed air will allow you to back flush them at home.

techron fuel cleaner won't do anything for these cars.

For backflushing, I use a 12V dewalt drill/driver battery.

Most of the time (three times in the last 10 years). I'll pull my injectors and have them ultrasonically cleaned like you did. Way more effective overall.

quillc said:

techron fuel cleaner won't do anything for these cars.

Click to expand...

In my K-Jet days, Techron fuel cleaner did make a difference...a big difference. This was before government mandated a detergent package to be added to gasoline fuels.

Today, I use gas stations that have TOP TIER

Developed by auto companies
Supplied by fuel retailers

All gasoline grades must be treated with an approved TOP TIER? Detergent Gasoline additive at the correct concentration.