Ethanol Damage to Older Automobile -- Nissan 300 ZX '90

My vintage sports car, which had only 49,000 miles on it developed several injury/injector trouble(200 HzPower-V6) I went to my mechanic who has handled it for 10 years and asked him to look at it. He told me after an examination that when he pulled the injectors, he found that they would not operate correctly. He also told me that he had serviced early 90’s Nissans and had an injector problem with about 20 of them. He could not confirm that the problem was related to ethanol; but he seemed to feel that because they all fell within the early 90’s and they seemed to be related to only Nissan vehicles that the only thing he could think of that might have harmed them is the government changing to E85 or another ethanol mix.

This mechanic has serviced 5 automobiles for me over the last 15 years and is as honest as the day is long. He may have an incorrect conclusion; but he has always treated my repairs etc. at a reasonable rate and with the care any auto owner would want. Thus, the issue is "Do past history since the use of ethanol support his conclusion.?

I you used E10 as a fuel for the vehicle, there shouldn’t be any problem with the fuel system. However, if E85 fuel was used in the vehicle this most certainly can damage the fuel system.


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The only trouble I have heard with ethanol and older cars is the older rubber components were not designed for use with ethenol, and there were rubber component problems, those cars I know of were of a much earlier vintage.

Your mechanic probably just has a beef with the government. The government has not changed all gas over to E85, which is 85% ethanol and will corrode fuel system components not designed for it. Many states have required up to 10% ethanol in gas to reduce emissions and though some people have seen reduced mileage, it’s not a high enough concentration to damage fuel lines and other rubber components unless they were already on their way out anyways.

It’s probably just something with 20-year old Nissans.

It’s 18 years old. NOTHING lasts forever, especially rubber parts like fuel lines. An 18 year old car with only 49K miles does not get driven very much and perhaps the problem is stale, degraded gasoline plugging the injectors. Modern gasoline does not age very well. Perhaps a product like “Stabil” would be of benefit to you…

I recently helped a friend change the injectors on his 1992 300ZX non-turbo. It was quite a bit of work. Anyway, we live in southern California and ethanol had no role in his injection failure. Earlier in his Nissan’s life, the injectors were replaced by the dealer under warranty and so this time was the second failure. If you peruse the internet for Nissan performance oriented boards, you will see that injector failure is common to the ZXs and some Maximas of this period.

If ethanol did anything to your engine, it was on top of it’s known injector weakness. By the way, I recommend replacing them with NEW injectors rather than remanufactured.

No. First E-85 has not been required by any government I know of. That car should be able to handle E10, which is mandated in some situations. It is not likely that E-85 it would have done anything to the injectors, but it could damage rubber seals.

You mechanic may be on to something however. I would be possible that early 90’s Nissan’s may have have some problems in that area, unrelated to the fuel used.

I haven’t heard Tom and Ray mention this, maybe they will now.

I have a '89 Toyota Corolla wagon with manual 5 speed and a 4-AF engine (175K miles). It has a carburetor. As soon as we started using E-85 or the 10% mixture the gas mileage dropped about 10%. No surprise. But I’ve discovered somethings that effects ALL these old cars. I learned it from the man at the local hardware store where he deals daily with poorly running (or not running at all) gasoline powered gardening equipment.

Ethanol is a solvent of gasoline sludge, sludge that’s been accumulating for 20+ years. So when you start using ethanol blended gasoline, all of this sludge gets back into solution and proceeds to clog fuel filters, carburetors and fuel injectors.

Ethanol is partly water which rusts metal gas tanks. My old Toyota has a steel gas tank. The consequence is that each week I must back wash my clear plastic fuel filter. I do this by pulling off the fuel line that goes to the gas tank and shaking the fuel filter into a container that has a coffee filter in it so I can see what I’ve caught. Weekly I get about 1/4 to 1/2 teaspoonful of powdery rust. If I fail to do this for about a month the car will start to run very poorly, gas starved by a clogged fuel filter.

I pass this along: If you’re old car has a steel gas tank and a carburetor, you can run E85 by changing your fuel filter frequently or by back washing it.

I wonder if fuel injected or throttle body injected cars with steel gas tanks can really be run using E85, or the 10% mixture. The fuel filter is in the gas tank with the fuel pump and is an expensive hassle to replace. Or are there no such cars (they’ve all stopped running and have been scrapped)?

Everyone who drives a 20+ year old car needs to know if it has a steel gas tank or whether it has a plastic one like my 78 dodge truck. A magnet will let you know in an instant.

The man at the hardware store recommends that people use 89 octane gas in their lawnmowers because it is a different mixture that contains less ethanol. Works for me. (My hedge trimmers had a rotten rubber part in the fuel tank, BTW.)

Ethanol is NOT the problem. Age and neglect are the problems…NOTHING lasts forever, especially carburetors and fuel injectors…

Ethanol was unlikely to be the cause of the problem, old age likely was.

I’m not a fan of ethanol. It’s made of 99.997% bull. Pure politics. An attempt at another farm subsidy. But 10% ethanol is harmless to car engines. It’ll lower both your mileage and your cash reserves, but it’ll do no real harm.

But old age will…

JECS injectors (used in Nissan '90, called Phase 1 injectors) are known to failed with E85: the resin insulating the coil of the injector gets dissolved with ethanol and injector fails. Moreover, in these cars, injectors gets powered with a common and permanent +12V: an electrolysis phenomena appears when engine is off, some current flow from the +12V to the injector body (ground) thanks to ethanol conductivity.
Solution: go for JECS phase 2 injectors (structurally differents) and go for a switched with ignition +12V for the injectors power supply.
Btw the fuel hoses used by Nissan at this time are ok for ethanol, the only problem is this engine gets very hot so go for E85 compatible fuel hose (Gates Barricade / GoodYear R9)

I run E85 since 2007 and I have more than 80000miles on 300zx with it.

  1. This thread is over 10 years old.
  2. Ethanol does not conduct electricity.
  3. Why would you use E85? The loss of fuel economy more than offsets any price advantage, and other parts of your fuel system re subject to damage from this mixture.

Actually both gas and ethanol conduct electricity but differently. Sensors used on flex fuel vehicles use this as a way to determine the ratio of ethanol to gasoline.

Hm. I wonder if there is something other than simple conductivity.

There are materials called di-electrics that don’t conduct direct current electricity, but do conduct alternating current. The pulsing of the injector is alternating current so maybe that’s part of the explanation. Just noticed the link above provided by @Mustangman , and that does seem to be the explanation.

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Then the proposition posed by didier.gg_154544 about an “electrolysis phenomenon” makes no sense.

Yeah, it doesn’t seem like that’s possible, at least not when the engine is off. Ethanol could conduct DC electricity if it has the right impurities in it though. This AC conductivity discussion reminds me of the fellow who “invented” a welding machine. The input was the mains AC, and it used a pot of water as a resistor to limit the current to welding levels. Not recommending this technique mind you … lol . but it worked b/c water isn’t so good at conducting DC, but is able conduct AC electricity .

The electrical conductivity of gasoline is 10^-14 mho-cm and the conductivity of ethanol is 10^-9 mho-cm. Various mixtures of the two liquids will have conductivities between those values. Because the difference is 5 orders of magnitude, it’s easy to measure the conductivity and tell how much ethanol is in the gasoline.

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If you’ll allow a clarification @jtsanders , electrical conductivity is expressed in mho/cm rather than mho-cm. Gasoline’s conductivity is 10^-14 mho/cm which means a cube (one cm on all sides) of gasoline would measure 10^14 ohms between two opposing faces. The same size cube of ethanol would measure 1000 MOhm. A standard ohm meter isn’t able to measure resistances that high, would require special instrumentation.

The dielectric constant for gasoline is 2. The same cube would therefore have a capacitance of 0.18 pF between two opposing faces. At 1000 Hz it’s resistance* would be 900 MOhm. At 1 MHz it would be 900 K-ohm. That would be easier to measure.

@George_San_Jose1 thanks for taking me back to Emag class, a scary place.