Injectors... One or All (1 Viewer)

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moose5280

moose5280

Joined
Oct 28, 2012
Threads
13
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Location
St. George, Utah
My land cruiser started running rough under load at around 2300 rpm's this past week so I ran some seafoam (full tank of gas) through it, no change. I then took it to my trusted mechanic, who's a LC guy. He hooked it up to the computer and the #3 cylinder is misfiring. He replaced the all the spark plugs, wires, and disti... which it needed, still no change. For kicks we ran some 44k injector clean through it (1/2 tank of gas) as a last ditch effort... still no change. He's certain it's a blow fuel injector in #3.

My question is.... while he has it apart to replace the #3 injector, would it be best to just have him replace all 6? Unfortunately new OEM injectors are just shy of $200 a piece. :(

I've read threads about sending them out and having them cleaned, but my LC is my daily driver and I can't wait a week to get it back on the road. BTW, it has 275k miles and I'm fairly certain these are the original injectors.

Opinions/advice welcomed.
 
Can you plan a few days, pull injectors & have cleaned, then pop them back in?

Borrow a friend's 2nd car, or rent a little econo-box for a couple days?
 
No need to replace. As others have said, they can be cleaned. Do all of them at the same time. RC Engineering in LA does great work, but there are likely others. Overnight, 24 turn-around, overnight return. Under $200 and three days turnaround. A single new injector will likely cost you more.
 
Swap the injector to a different cylinder, chances are it's on the wiring bundle or corrosion on the electrical plug.
 
newtomelx said:
Check the wiring harness where it passes next to the EGR valve, this was my issue for my misfire code!
Click to expand...

He checked the wiring harness and said it looked fine, no extensive wear. So he put in a piece of foam to insulate it from happening down the road.
 
Pop the connector off the injector (carefully so the old plastic doesn't break) and ohm it out. That will tell you if there's an open (I had #6 fail a few yrs back) or within spec. Easy to do and should be around 13 ohms.

I WOULD send all the working injectors in for cleaning/flow testing to a reputable shop. There's also 'cheaper' sources of injectors versus OEM new... But no need to replace them all if only 1 is faulty.

Here's my #6 fault finding experience: Injector Service

cheers,
george.
 
moose5280 said:
He checked the wiring harness and said it looked fine, no extensive wear. So he put in a piece of foam to insulate it from happening down the road.
Click to expand...

Ooops. We were talking about two different wiring harness points. A piece of foam was put in were it rubs coming in from the firewall, not near the EGR.
 
Like was said. Buy 6 used ones. Send them out and have them done right. Install them with new OEM plastic harnes plugs. Then sell the used ones. Should about break even. Or after you are done send you old ones out for the same service and then sell them. Inj plus cost of service. They might be easier to sell that way. Someone in your situation will want them.
 
*** UPDATE: First, thanks for everyone's insights. After a couple of suggestions to check out the wiring harness... I had a chance climb into the engine compartment this afternoon. The harness insulation was against the EGR tube and some of the heat tape was roughed up and slightly melted. However, upon removing the shielding, none of the wires appear to be damaged. No melted insulation or visible copper. I also pulled to glove compartment out and checked for wear on the lower bracket. No wire damage there either.

So I guess I'm back to a bad injector or injector connector.
 
I think you'll find that buying all new injectors is cost prohibitive.

Like others said - send them out for cleaning and testing. There are a number of reputable services. Might even be a local shop that can bench test them.

The rebuild service isn't what you'd imagine a rebuild being - almost all gas fuel injectors are not really something you can open up so they just clean them inside and out and replace the micro screens and install new o-rings and pintle caps.

They run a high detergent mix through them into a graduated cylinder so they can see if the whole set is spraying the same, and they can visually verify the atomization.

If an injector isn't working well they can back flush it and try some other things to clean it out. Worst case scenario they can tell you for sure that it needs to be replaced.

Cost per injector for this service runs from $12-30 per injector. Witchhunter Performance is the service the race guys trust. Premium Fuel Pumps of San Luis AZ is the cheapest I've tracked down (at $12/ea) but i haven't actually sent out injectors yet so i can't personally vouch for them.

There's a fair chance that there is a 4th generation bosch 4-hole injector that will be a modest upgrade for our engines, but so far I don't think anyone has figured out exactly what it is. Or if they have they haven't filled us in. Mostly it's a matter of getting the same flow rate (taking into consideration injection pressure) with the same physical dimensions.
 
As mentioned above swap it for another location and check if the problem follows the injector.

If you can pull the injector then you can pull and clean the bucket screen your self.... THEN:

For back woods / hillbilly dirt cheap project trucks that I don't want to invest a lot of $$$ in OR for those who have a weekend to kill and want it Tested / FIXED NOW while you wait.

I use a harbor freight sonic jewelry bath cleaner (with stainless tub) filled with your preferred heated solution cleaner. (I heat it outdoors on a Coleman camp stove and I prefer Sea Foam or POR-15 marine clean). I like to cycle the injector with a home made harness and a 9V smoke detector battery while it is in the heated solution sonic bath.

After cleaning ~ With a little additional back yard engineering you can set them up to flow water (most household faucet pressure is 30-60 psi) and while the specific gravity between water and gas is different, for testing purposes liquid flow and atomization is close enough to distinguish gross malfunctions (poor pattern / dripping / leaking). Thus you can often differentiate a bad injector using water.


*** Flush injector with gas before reinstall to remove or dilute any remaining water.

Work safe around any flammable solvents.


I'm far enough out on a tangent away from the average persons comfort zone that I will not get into DIY nozzle cleaning ~ But as these are not serviceable like the commercial diesel injectors and only cleanable from the face it's not difficult. Yes nozzles are fine tuned metering devices but the window of operation here on my old 3FE is fairly BROAD at 300K miles.

And why? Because throwing $$$ at a problem doesn't always make it go away. Pick up a wrench and learn what makes it work.
 
There are several options and I have done this exact job (mine was #6):
  • Order up 1 refurbished injector from Rock Auto now and have it put in- Cheapest
  • The labor to do one is nearly the same as doing all. If you do all you will see a 10-15% increase in performance after the ultrasonic cleaning
  • If you ask nicely I bet you can find a car for a week. I just let a woman at work use our 3rd car (I drove Cruiser) while she had work done for free.
  • Order up 6 Refurbs and put them in at one time
  • My truck was nearly un-driveable with the injector out
 
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