Auto Parts: 92 Honda civic fuel injectors, copper windings, summit racing

Question
QUESTION: I'm looking to replace the injectors in my 92 civic LX engine D15B7. The car
has 217K and I think they are OEM. I have been getting oil analysis, and the
fuel dilute is high. Also sometimes won't start when warm unless throttle
held wide open. My question is what is a good brand/type? Are
remanufactured units just as good? New items are about $100 each, remans
about $100 for four. The parts rep at Summit Racing said because I'm in
California, the high flow ones won't pass smog. OEM flows 235 cc/min the
high flows flow 255 cc/min. BTW all other tune items are new (plugs, wires,
dist cap, rotor, etc.). Honda dealer parts catalogs list two numbers for
injector sets, any idea the difference?
Thanks for any help,
Bob

ANSWER: Hi Robert,

Compression test that engine before replacing the injectors. Sounds to me like the engine has low-compression, and with over 200K on it, I can see why.

Thanks for the question, I hope this information was helpful to you.
Fred
www.knucklebusters.us
570-453-0910
"Re-use is the best form of recycling" Help us recycle by purchasing used parts from us!
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---------- FOLLOW-UP ----------

QUESTION: Thanks for the reply Fred, I guess it's just an old, tired car......

To your knowledge, do injectors EVER wear out? People trying to sell them
say they do, techs who install them say they don't. What's your take on it?

Bob

ANSWER: Hi Robert,

I have yet to see an injector wear-out. I've replaced them because they were broken, but never worn out.

There really is nothing to wear out on them. All an injector is is a stainless steel pindle that floats inside of a tubular magnet with some copper windings around it. When energized, the pindle moves up and down against stainless steel stops at a pre-set rate, like 60 cycles/second. Fuel is sent through the tubular magnet under pressure and when the pindle opens for the 1/60th of a second, fuel sprays into the intake or directly into the cylinder depending on your injection style.

Obviously anytime you increase the amount of fuel an engine is getting, it will produce more power. Aftermarket injectors are usually machined better than stock ones and are more efficient, but that efficiency will cost you more in fuel and only marginally give you more power. As part of a race-upgrade, injectors would be recommended but for your average daily-driver, you'll never feel the difference between OEM and Aftermarket injectors but you most likely WILL see the difference in your fuel receipts.

Thanks for the question, I hope this information was helpful to you.
Fred
www.knucklebusters.us
570-453-0910
"Re-use is the best form of recycling" Help us recycle by purchasing used parts from us!
Looking for an ASE Certified shop near you? ASE Certified Technicians are the BEST of the BEST!
Click here: http://www.ase.com/bluesealsearch/locator.php

---------- FOLLOW-UP ----------

QUESTION: Hi Fred,

Thanks for the tip, good to know. I read the propaganda about replacing injectors every 100K as a maintenance item,
and wonder why. They say they can leak and drip fuel into the manifold......

So, the fuel dilute can probably be attributed to blowby, I would guess. The car is due for a smog check so may get
some insight then. The head gasket was replaced recently, so that could have contributed to excessive ring wear. Fuel
economy is good, 26-28 average.

Any comments?

Thanks again,
Bob

Answer
Hi Bob,

True. Injectors, when they get old sometimes leak-down into the intake however, those style of injectors were American-made designs that used stainless steel pindles with brass seats. The brass seats pitted from years of fuel pouring over it and failed to seal properly after that. Most European engine designs use Teflon-coated titanium and almost all mid-eastern engines used stainless steel, like yours. American manufacturers NOW use Stainless on stainless because it has proven to be not only superior to the brass design, but inexpensive as well.

Anyway, the leak-down was minimal because older EFI systems bled-down fuel-rail pressure a few minutes after the engine is shut down using a vacuum switch or regulator so the amount of fuel that actually dropped into the engine was of a minimal amount, surely less than an ounce of fuel for ALL of the injectors combined and nothing to be extremely concerned with and typically the fuel that did drop into the manifold dissipated prior to the engine being re-fired and caused no harm. The fuel can ONLY reach a cylinder that has an open intake valve and chances are that your engine only stops with an intake valve open on average once every 6 times you shut it down. And even if it happens more often than that, as soon as the engine loses oil pressure (from not running) the hydraulic-lifter pumps-down and closes the valve. On top of that, even if you have a direct injection system there is STILL a pre-combustion chamber that is separate from the cylinder and it has a small 'belly' in it that can catch any accidentally released fuel.

Let me be clear, fuel leakage does NOT cause rings to wear out, years of scraping the side of a cast-steel cylinder sleeve cause that. The piston rings in your engine HAD an electroplated layer of CdFy (Chrome Molly) designed to reduce wear of the rings. After 200K, I'm sure that thin layer is no-more and that is what would be causing low-compression and probably contributing to the contamination of your oil by fuel, if I am reading that correctly.

Thanks for the question, I hope this information was helpful to you.
Fred
www.knucklebusters.us
570-453-0910
"Re-use is the best form of recycling" Help us recycle by purchasing used parts from us!
Looking for an ASE Certified shop near you? ASE Certified Technicians are the BEST of the BEST!
Click here: http://www.ase.com/bluesealsearch/locator.php