Injector Cleaning.
 

I have not posted much for quite a while. Maybe it's about time, maybe it's too soon. :)

This really isn't a question. It is passing on an experience that might be useful to others. Mileage changes inferred from this are subtle and seem to coincide with seasonal gas changes so I would not may too much of the mileage variation. Last fall my mileage dropped more than I expected. The engine seemed to have a bit more roughness but had always missed a bit when running over 200 F IAT. This spring it started setting a CEL for cyl #3 miss. It only did this between about 100 and 130 deg. F water temp.

I could not pass the emissions test. They only read the code but while I could go for a few days without setting the light I never went long enough to get a ready state. Also I had forgot that I don't get a ready state with the IAC unplugged. I verified all ignition components but installed a set of spiral wound plug wires even though the old ones ohm-ed out fine. As some who have followed me know I have pushed the limits sometimes. I began to have thoughts of failed piston rings, burned valves, or a damaged camshaft. All those components seemed fine.

As a kid I watched my dad many times moderately rev an engine, cut the ignition, hold the throttle open and listen carefully as the engine coasted to a stop. If a valve or other factor is affecting the engine you can almost always hear it in the intake and exhaust sounds after the ignition is cut. if the engine just has an ignition problem it will smooth out as soon as the ignition is cut. My car passed this kind of test. Yes I know how to do compression and blow down tests. I have done those types of tests in other times but they almost never told me anything that was not obvious by turning the engine or listening too it. Anyway I still had a check engine light.

I pulled the injectors and sent them to Witchhunter Performance. https://www.witchhunter.com/

#3 injector was down 9% with a bad spray pattern. # 2 injector was down 5% with a poor spray pattern. The injectors came back calibrated within 1%. Cleaning and calibration was $18 per injector and $10 shipping. I am very pleased. Never set the CEL again and passed emissions shortly thereafter.

Also the engine is smoother at high intake temps that it ever was. I think my mileage is a bit better but I would not make too much of it.

The Scangauge has me right at 55 mpg at 65 mph now in the current warm temps. To get that good I need to draft a little bit. A good point I have read recently is that the Scangauge is a darn good tool but just because the overall average is correct it might not be accurate in all situations.

Just putting in an unpaid plug for WitchHunter Performance.

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I was also setting a fuel tank pressure is abnormal code. My voltage was dropping abnormally low. After reinstalling the alternator belt I never set that code again. Maybe it was a factor. I have my engine compartment sealed up pretty well. It turns out that a fairly new battery had a failed cell. This failure went on quite a while longer than it might have because even though the voltage dropped to near 9 volts the battery kept a respectable amperage output. The engine always started but cranked slow. Admittedly I may have damaged the battery by high under hood temps. If this battery fails early it probably is not a coincidence. Just fessing up a bit. This is certainly a known risk with the temps I am running under the hood.

Battery relocation may be required. That would make a nice area for a compact HHO generator. Just dreaming. If it gave me a 20% improvement by golly that would be acceptable mileage. ;) I do have a Smack copy nearly done. Still debating about frequency and magnetic coupling rather than finishing and installing.

Ernie

Several years ago I had my injectors balanced and blueprinted by RC Engineering. Three of the injectors spray patterns were poor and one was good. There were big differences in flow between each. Yet there was no apparent problem. It's just something that was recommended to me. Ever since then my O2 readings have been stable, idle has been stable, I made more power, and I got better mileage. Most of all my emissions improved (HC's and CO).

I did see some posts after engine teardowns to inspect parts after using HHO assistance. Clean plugs and injectors were part of the observations, so I'm hoping not to have to spend money cleaning things. Time will tell.

I wouldn't imagine HHO will do much for the inside of the injectors.

The way they clean them is to put them in a machine that vibrates them ultrasonically while firing them. It's a special process. It's not the same as spraying them down with carb cleaner or running some bs fuel system cleaner in your gas tank. It's a whole other ball game. In fact, afterwards they are actually better than brand new.

https://www.rceng.com/Fuel-Injector-C...yyOKdGvgp4X0gN

yea i did a decent injector cleaner on my s-10. its where you disable the fuel pump, disconnect the lines, and then hook up an injector kit to it where it uses compressed air regulated to your pumps PSI and allows the engine to run off pure injector cleaner.

I did this. It works.
https://fordfuelinjection.com/?p=82

This is who I have used to clean my other honda injectorsL https://www.injector-rehab.com/index.htm

I was very pleased with their turnaround and end product. If you mention you saw them on honda-tech.com it is only $12.50 a injector.

i did the one at the walmart oil change place. mpg jump several miles per gallon.

u let wally world touch your car? better have good faith in them...

The idea that one injector was "down" 9% is interesting. Everybody is worried about burning exhaust valves when you lean an engine out too much but who knows how many MPFI engines out there are running really lean on one cylinder.

Perhaps the injector flow decreasing with age is responsible for some older cars getting progressively better mileage...

The WitchHunter Experiment is on.

The Caravan has 140,000 miles and at least five of the injectors are original. I didn't want the Caravan downed for a couple weeks while the injectors were in work, so I went to the junk yard and relieved a similar (except for the bashed fender) 3.8L Caravan of its injectors ($4.50/ea.) and sent them. When they get back, I'm going to do a major tune up. A tune up on a 3.8L Caravan involves taking half the engine apart, so I'm arranging it so that I can take it apart and put it together all at one time. Remanned injectors, plugs, wires, pcv valve, and hopefully, the upstream O2 sensor. Sure hope this helps.