How to find a bad HOWO truck injector?

Posted by bruce zhu on January 5th, 2022

If your HOWO truck injector is running rough like it has a miss on 1 cylinder, the issue might be a bad truck injector. Fuel injection is good when all is working rightly but sometimes troubleshooting the unit can be like soothing in the dark. You cannot just remove your air filter and seem inside like you can with a carburetor.

Once I got it running, it had some distinct miss of the dead cylinder. I first checked to ensure it was getting spark to the plugs. I did this first by using a might in-line spark tester. This tool flashes when the coil sends some fire to the plug.

All 6 were flashing. I then pulled the plugs out one at a time and visually inspected them. They all seemed fine and all seemed the same giving me no clue which one was the trouble cylinder. On older truck engines – you’d simply remove the plug wires one at a time to see which one didn’t make any difference, in the way the truck engine runs.

Though, I’ve found that you cannot do that on advanced ignition units as the power in the spark plug wire will provide you a very uncomfortable zap if you try to remove it while the engine is running.

To check the HOWO truck injector, I used a stethoscope. I placed the tip on every injector body and listened at idle. One of the HOWO truck injectors that worked rightly, there was a very distinct ticking sound.

On the HOWO truck injector that was giving issue, there was no ticking sound. I moved the stethoscope back and forth among the injector couple of times to get the clear sound that it was supposed to make when it was working. Once you’ve located the HOWO truck injector giving issue you’ll have to remove the fuel rail to change it.