Leaking Injectors
 

I've been reading the related Threads on these Injectors.

Am i right in saying the Injectors can get stuck slightly open and when you turn the engine off they release all the Presurised Fuel from the Fuel rail into the inlet thus flooding it and making it hard to start.

Is this basicly how it works? can i check if they are working properly?(ie remove the Fuses and let it run out of fuel then leave it till its cold then put them back and try it?)

Can they be cleaned? or will fuel aditive (cleaner) do the job?

That's basically it.&nbsp Sediment and crud build-up can prevent the solenoid (basically what a fuel injector is) from closing properly.&nbsp This is how it leaks fuel and pressure after shut-off.

If the problem is "mild", an aggressive fuel additive will help.&nbsp My favorite is Redline Fuel Injector Cleaner.&nbsp Others are BG fuel injector cleaner (hard to find) and Chevron Techtron.

If the problem is "major" then the fuel injectors need to be pulled and professionally cleaned.




-Ted

Mine never leaked till I did the ATF trick, and dumped like 3 bottles of STP Fuel Injector Cleaner in there. Hmmmmm...WTF?

Did it work?

They never leaked untill AFTER I did the ATF trick! Now, flood, flood, flood. Oh well, at least she runs better now....if I can get it started!

Why would the ATF trick cause the injectors to leak? All you are doing is just pour the ATF into the engine. Is there a logical explanation to this? Anyone?

Jay

Yeah, theres no way the ATF trick could cause your injectors to leak. Maybe your hard start problem isn't because of flooding.

There's no way any sort of "trick" to rid of carbon in the combustion chambers. The ATF never passes through the injectors so it won't have any effect. It just might be a coincidence that your injectors are leaking or a weak battery? A slower crank will flood as well.

Maybe you never had leaky injectors. But after atf treatment, where the carbon used to give that extra bit of compression for a worn engine is no longer there resulting in harder engine starts. That's why some engines with 200K miles "never" seem to leak oil until they started to used synthetic oil(like atf treatment) and dissolves all that carbon that was there before to contain the oil in a worn engine compartment.

I have a TII and thought it was a leaky injector issue. I pulled them and they did not leak even a little bit. These Nippondenso injectors are really good.

The way to check if you have leaky injectors is to splice into the feed fuel line and run a fuel pressure test gauge, run the car hot and then shut the car off and watch the pressure, if the pressure leaks down to zero within 15 minutes you have one or more leakers. If it drops slightly and holds pressure they are not leaking down.

There is a way to check injectors!

1-You need to remove the upper and middle intake

2- Unbolt the fuel rail from the motor, leaving all of the lines still hooked up to the rail.

3- Wrap the injectors with some sort of wire, and attach them to the rail so they do not pop out when you pressurize the system.

4- Lay a towel down under your injectors; both fuel rails should lay down nicely so you can face the injectors at each other.

5- Place a piece of wire in the little yellow plug, located behing your air filter. It will have two prongs in it. You need to jumper the wire from one of those prongs to the other. This will activate the fuel pump.

6- Turn the car to the "ON" position, not start. Let the system pressurize itself for a few minutes. You'll hear the fuel pump kinda whine.

7- Now watch your injectors. If they are spraying fuel all over the place; they are in bad shape. If they just drip like once every 10 seconds, that is acceptable. If they do not show any signs of fuel leaking, then you probably just had them cleaned or they are brand new.

8- Remove the jumper wire, and turn off the car.

9- Determine whether or not you need to have your injectors cleaned.

Do you have to remove the hole inlet to get at the Primarys?

Turtle is right per the TSB from Mazda. The only thing he left out is that you have to test the pump for leakdown (back into the tank) first and block off the return line to the tank before you run this test. I have an '87 TII. It floods when hot if it sits more than a few minutes but always starts right up when cold. I had my injectors cleaned/rebuilt with absolutely no change in the flooding. I installed a cut off switch for the fuel pump at the relay (very easy). Now it starts right up every time. I've been using the switch for over a year with no problems. I changed water and air temp. sensors, plugs, wires, filters....nothing solved this problem except the switch. I suppose it could be bad compression but the car runs VERY strong and idles smoothly so I don't know what to think.

Todd

I left out one thing. I checked my injectors per the TSB when I reinstalled them and they still leaked down faster than the spec. even thought the cleaner / rebuilder said they were fine. New injectors may be the only answer here.

Todd

That's right if the pressure leaks down it could be the one way check valve in the pump. But if it does not leak down you know both will be fine.

Where is the best place to fit a Presure gauge to the fuel system?

At the inlet before the hardline. I got a Tee from Home Depot that had three of the same fittings as my fuel pressure teat gauge that I use on my LT1 Firebird. I then machined the ends to get rid of the threads so i could fit the fuel line over it.

can it be done tempararly or would i be as well to get one plumbed in permanatly?