Injector failure

[Q45denver]

If not too much trouble, could you check to see if there is a drop in current draw from the battery when the fuse is pulled? Do you get any current draw from the battery with everything off including the hood switch?

[Q451990]

If not too much trouble, could you check to see if there is a drop in current draw from the battery when the fuse is pulled? Do you get any current draw from the battery with everything off including the hood switch?

I'm not sure how to measure that... would you disconnect the negative battery cable and then measure between it and the negative post on the battery?

Heath

[Q45denver]

I'm not sure how to measure that... would you disconnect the negative battery cable and then measure between it and the negative post on the battery?

Heath

Yes, that should work. Do you have a milliamp setting?

[Q451990]

Yes, that should work. Do you have a milliamp setting?

I should... It's one of those Fluke meters that tries to do everything automatically unless you press the "range" button. If I can't figure it out I'll find another meter at my parent's house. My dad was an electroncs guy, so he should have some pretty nice test equipment if I can find it and figure out how to use it.

Heath

[Q451990]

For the heck of it, I decided to search the web sites of my local parts stores, and came up with new 94-96 style injectors for $114 ea. They are showing the mfgr. as "BWD Auto Parts"http://www.partsamerica.com/pr...Set=A

I'm wondering if they actually manufacture injectors, or if they just source them from the same supply as Nissan uses and rebox them? Any ideas out there? I saw some on another site branded as GP/Sorensen. I certainly ruled out buying from Joe, but at a $400 difference for 8, it's kind of difficult to be loyal if these parts are actually the same thing.

Heath
Modified by Q451990 at 1:02 AM 5/29/2008

[Q45denver]

JECS (Nissan/bosch) is only manufacturer I know of. JECS is stamped on injector. I believe the purple ones are the most recent version so most likely compatible with ethanol.

[Q451990]

Looks like the Nissan logo on the side of the connector. Their web site says they have some in stock locally... maybe I'll try to look at one in person and see what I can tell.

Heath

[sdkhalsa]

Is there someone who has run their pre-'95 Q with a battery isolating device for an extended period of time? Have we totally given-up on this idea of electrolysis being the cause of injector failure?

[Q451990]

Is there someone who has run their pre-'95 Q with a battery isolating device for an extended period of time? Have we totally given-up on this idea of electrolysis being the cause of injector failure?

As far as I know the theory was only discovered when Dennis posted this thread a week or so ago. I don't know if there have been enough folks in the Z community testing this to say if the theory holds up. Dennis has been unable to measure any current draw - but I have no idea how the chemistry works with electrolysis or how measurable the current draw would be. Has anyone confirmed that the 12V is switched on the 94+ Q?

Heath

[Q45denver]

Should be fairly easy to verify this theory if early injectors are in fact failing within a few months as some have stated.

Also, this seems to indicate that the changeout to the updated injectors occured for model year 1995 in other Nissan products?

This comes from a old 300zxtt forum. It is an interesting concept that the constant +12 volts on injector causes corrosion [ethanol with water conducts a little.The Q constantly supplies +12 and the rail is grounded thus some current could flow? I will test today and report. Easy as there is an injector fuse

"Well, now I know why I keep eating so many fuel injectors. Apparently it's normal for Nismo 555 injectors to last only a year in the 1990 to 1994 300zx...

http://www.twinturbo.net/net/v...35571

Some more comments from Greg @ SpecialtyZ:

We have had many,many,many nismo 555 injectors fail in the last coupleyears and nismo will not do anything. some of the early style injectors are only lasting a couple months. Since the fuel changed with alcohol content they are all failing extremely soon.

I feel for you that your experiencing problems with nismo injectors andyou are far from alone.

What is happening to the injectors is that they are corroding theinternal connection and causing an open circuit. The injectors are not getting shorted coils from running past their duty cycle.

The early style injectors have positive 12 volts all the time. The fuelformula changed a few years ago and they started adding alcohol to thefuel. Since the time the fuel was changed the injector failures of cars withearly style injectors is through the roof, (brand new and original early styleinjectors we are replacing several a week). It is believed the alcoholand having power to the injectors is causing electrolysis and eating up theconnections internally causing the high failure rate. They are nothaving this problem in Japan and they make fuel the way we use to withoutalcohol. The injectors were originally designed for fuel that we do not have anymore.

The stock injectors use to last 10 years easy and we hardly ever hadfailures......Now we are having to replace stock injectors that havealready been changed in less then a year all the time as well as originalinjectors failing almost daily. The late style injectors are wired to the ECU differently and do not have power when the key is off.

By old style, I mean the 1990-1994 year style injectors.The new style injectors that were used in 1995 and newer Z cars arecompletely different in design and require different code in the ECU and donot have power going to them from the ECU until the key is turned on.They also require a different fuel rail to bolt them in.They are not directly interchangeable. It requires different fuel rails andmachining of the lower intake manifold to accept the newer style fuel rail.It also requires changing the injector electrical plugs and ECU chip.

You absolutely have older style injectors because that is all you can usewithout major modification and changing all the injectors to the late modelyear style.Your only option at this point is to replace the one bad injector unlessyour willing to go to the expense of replacing all of them and doing themodifications to change over to the complete new set up.

Nismo is aware of the problem now and we have a lot of documentation.We are hoping nismo comes up with a solution for direct replacements.

I am recommending to people doing upgrades currently to change over to thenew style now they we know there is a problem with the old style injectorscombined with our current pump fuels.For years the Nismo 555cc injectors were a great relieable injector.

Other company's selling injectors for the early application are assembledthe same way and the ECU program for the early style injectors has the ECUsending power to the injector all the time adding to the electrolysisproblem.

Mike Smith and JWT are looking into ways to help the injectors live longerby wiring the injectors differently. This is still in the testing stages andwe are hoping to offer at least a patch of some kind to help with peoplethat have these injectors.

I feel your frustration, I had to change 3 of the 6 injectors in less then ayear on my personal 300ZX that had the HKS 2530 turbos......I replaced themall with the newer style 740's and fuel rails when I put JWT 700 turbos inthis last year.I still have all my 555cc Injectors in my 280z that has the twin turbomotor and Greddy TD05 turbos. I did wire this car myself when I did theengine conversion and I do not have power to my injectors when the car isoff.This just happened by accident because I wired the car and the fuelinjection relay does not have power until the key is turned on.

[Q45tech]

Such a test would only be valid IF 25 owners used all brand new oem injectors from dealer...............that's not going to happen under controlled conditions.

Same problem with testing each gallon purchased to make sure it is E10 not E9 or E11 or worse oscillating between Ezero and E10.

Ethanol will not corrode copper unless there is water in the ethanol

This water is the fault of the service station.

I have made it a point to talk to [ 11] tanker drivers as they test the tank prior to dumping their load for residual water in each tank. They all seem very careful and always use the water test jell [changes color when exposed to water] on the measuring stick. After all they have to buy gasoline for their family cars and have been trained and retrained recently on what happens if water is in the tanks.

Silver Corrosion (3 hr@ 50 C)- ASTM D4814 Rev B 1Copper Corrosion(3 hr @ 100 C)- ASTM D130 1a

Silver Corrosion (3 hr@ 50 oC)- D4814 Rev B 1Copper Corrosion(3 hr @ 100 oC)- ASTM D130 1a

http://hawaii.gov/dbedt/ert/ne...e.pdf

[Q451990]

Here are the pictures of the "BWD" brand 94-96 injectors available at O'Reilly and Advance Auto (and probably AutoZone too). My hope was that they were just reboxed OEM injectors - but I don't think so. I didn't see any country of origin on the box or the injectors, and the purple color of the top doesn't look right... too deep vs. the light color that I have seen on the OEM ones. These pictures didn't turn out as well as I had hoped, but if anyone has an opinion on how similar/different they are from OEM, I would like to hear it.

There are four small holes in the plate that you can't see on the tip.

[Q451990]

As a side note, I emailed Keith Bowers (TexasOil) and asked how his 96 injectors were holding up in his 92Q. He says they're doing great and mentioned again how silky smooth the idle is with them. I specifically asked him if he thought they were superior in design or performance to the pintile style 90-93 injectors and he said yes. Just one man's opinion, but it's one that I trust enough to pass along.

At this point I'm considering trying to find a set in a lower mileage salvage vehicle, flush them and toss them in. I got the injector "death bounce" again for a few minutes today

Heath

[Q451990]

I got the injector "death bounce" again for a few minutes today

Ohmed them today... now #5 reads 100 ohms and #8 reads 20. Before the drive #5 was at 16 ohms and the others were normal. That's a lot of damage for 63 miles of driving yesterday.

I noticed that my temporary dead miss seems to show up after the car sits in the sun for 15-20 minutes in a parking lot. I wonder if the heat speeds the swelling, electrolysis or whatever mechanism is killing them?

Heath

[jimbyjimb]

If it is the water that's killing them could we just run fuel-system dryer through them? Like what you'd do for a diesel or a 2-cycle... less than 3 bucks a bottle, less than a gallon of fuel.

[Q451990]

Ethanol will not corrode copper unless there is water in the ethanol

and

If it is the water that's killing them could we just run fuel-system dryer through them? Like what you'd do for a diesel or a 2-cycle... less than 3 bucks a bottle, less than a gallon of fuel.

My understanding is that the system dryer breaks the water down into smaller particles and bonds with them... so it doesn't really remove it, just makes the water more easily digested and burnt by the engine.

Dennis and anyone else that wants to comment, do you think something like this could work?

http://www.performanceoilnews....shtml

The literature says that it should be installed before the fuel pump, but I don't see how that's possible with the Q's design unless it is spliced in between the "sock" and the fuel pump within the tank. My first thought is that this could be teed in somewhere under the car where the metal tubes from the fuel pump turn in to rubber, and then the water separation filter would be mounted in the trunk.

Any thoughts?

Heath

[Q45tech]

Important to understand that ISOHEET [IPA= Isopropyl Alcohol] works the same as Ethyl Alcohol in making a mixture of the water and alcohol so the tank water can be injected into engine.

Once the Alcohol whatever type is OVERLOADED with water the same thing ocurs.

Don't confuse trying to remove <11 0unces of water from the bottom of tank with trying to 100% remove water from the ethanol/water solution!

Study how ethanol manufaturers remove the water from ethanol!Sodium metal or sulfric acid will create explosions if not done correctly and should never be mixed with gasoline.

One thing to consider is the fuel pump sock may sit too low in tank to deal with the cumlative amounts of water possible with ethanolized gasoline.

Only periodic examination of bottom of tank with tell the tale via rust and corrosion in the sock dish.

The next failure will be an increased problem rate with the fuel pumps from corrosion......................no more 7-10 year pump life!

[jimbyjimb]

Instal a petcock in the lowest point of the tank, where the water will be.

[Q45tech]

There are 3 types of water in tank: the water at the bottom, and the water mixed with ethanol separation layer, and the water suspended within the ethanol/gasoline mixture. [this is the water that gets to the injectors].

Experiment with 100 proof Vodka and devise a method to make ABSOLUTE [99.99 alcohol] ...........199.98 PROOF.

You can process the gasoline before putting in tank with zeolites to remove water.http://peswiki.com/index.php/Directory:Zeolite

[jimbyjimb]

Wait. I have the solution! Make the Q run on water. That's right people, the steam-powered Q. Probably a little easier than a plenum job...

[silkysmoothyjud]

Removing the plenum should be second nature to a Q owner. After doing it so many times, I no longer need light to do it lol....