cleaning fuel injectors

[Seevee]

All,

Recently read a lot about cleaning injectors, which I didn't know needed cleaning at all.

I have a rough running engine, cylinder 8 is not firing right, and my mechanic says it's more than likely the injector. (He's tested compression and ignition).

First, is this common? And how often does one need to clean injectors?

Would it pay to just clean the one that's the problem, or should one clean them all?

I assume cleaning is a job for one with specialized cleaning equipment and flow measuring stuff.

Comments?

 

[gm280]

Re: cleaning fuel injectors

Yes injectors can be cleaned, but you have to understand how the injectors work first so you can understand how to clean them. As with all fuel system components, injectors get a buildup of deposits from the fuel flowing through them. They are basically little valves that open and close per electronic signals. So fuel deposits build up over time and cause them to provide less of a fuel charge and that pressurized fuel charge is not in a fine mist as it should be. So remove the injector and use some injector cleaner on the inlet AND outlet portions of each injector. If you had a pulsed voltage supply and a pressurized delivery setup you could see the difference between a dirty injector and a cleaned one…

 

[Seevee]

Re: cleaning fuel injectors

gm280,

Are they hard to clean, require special equipment? I'm use to aircraft injector which are really simple, no pulse, valves or anything.
Does it pay to have a pro clean them? Overall, I would think it would be pretty simple to do it yourself, unless one wanted them flow tested. Thoughts?

 

[NoExcuses]

Re: cleaning fuel injectors

To do all the stuff these guy do, you would need specialized equipment.

https://www.injector.com/injector_process.html

 

[gm280]

Re: cleaning fuel injectors

gm280,

Are they hard to clean, require special equipment? I'm use to aircraft injector which are really simple, no pulse, valves or anything.
Does it pay to have a pro clean them? Overall, I would think it would be pretty simple to do it yourself, unless one wanted them flow tested. Thoughts?

As per NoExcuses provided, there are companies that do such cleaning and I'm sure do an extremely good job, especially providing balanced injector sets for any engine. BUT, with that stated, that type work can quickly cost more than new injectors for an everyday driven vehicle. Think of fuel injectors as simple electronic valves that are under a high pressure fuel rail. When the computer sends a signal to open an injector a pulse voltage is sent to the coil of the injector and it forces it to open for a very precise time period. And since the fuel flowing through that injector is under high pressure, it mists out to the cylinder it is feeding. So as with anything concerned with fuel, they get deposits built up on the openings and restrict the fuel flow in both amount of fuel supplied and the type of fine mist provided, and your engine doesn't run as it used to. So you can take them out and have a company clean them OR use some cleaner sprayed into the supply side AND the output side going to the cylinder(s). It isn’t as good a job as professional injector cleaning companies can do, but it does help and can fix a lot of engine problems with very little cost… I’ve removed and cleaned injectors before and still running the original injectors after 150,000 + miles. So you can do it yourself and fix injector problems too… I have the equipment to provide a pulsed injector voltage and a strobe light to see the mist too, but I have never really set it up to monitor injectors because I presently don’t have the need… But it seriously isn’t rocket surgery either… Don't be afraid to try new things...that's how we all learn...

 

[NoExcuses]

Re: cleaning fuel injectors

I looked into replacement but at $280 per injector for factory parts, the $25 per injector that I spent was a heck of a lot cheaper than replacement. The injectors that I sent to Marren were very dirty, my theory is paint from the fuel pump assembly. Can you find a cheaper after market? Probably, but the technician from another shop out of Annapolis that I had clean the other engine's set of injectors told me that exactly matching an injector's specifications for a Volvo could be a difficult task since Volvo is such a small segment of the fuel injector market.

 

[gm280]

Re: cleaning fuel injectors

I looked into replacement but at $280 per injector for factory parts, the $25 per injector that I spent was a heck of a lot cheaper than replacement. The injectors that I sent to Marren were very dirty, my theory is paint from the fuel pump assembly. Can you find a cheaper after market? Probably, but the technician from another shop out of Annapolis that I had clean the other engine's set of injectors told me that exactly matching an injector's specifications for a Volvo could be a difficult task since Volvo is such a small segment of the fuel injector market.

Matching injector output can be a tedious job. For starters you have to find injectors with the exact same orifice openings and thicknesses. So they have to find injectors that literally provide the exact same output in both spray pattern AND volume per cycle pulse. That means you go through many injector of the same type and match their abilities. But it goes well beyond that too. An injector can vary from one pulse output to another. So a match injector at one pulse width can be wrong at a narrowed or wider pulse cycle. So they also have to match ramping pulse widths throughout the entire range of pulses and voltages. Now you are talking about a ton of work… With normal highly used injectors there are millions to work with. But on some unique engines they are held to a lot less injectors to work with… Matching and blueprinting injector is best left to high performance engines and let everyday injectors do their mundane jobs as best they can…