Fuel Injector Leaking Questions

[kxri318]

The injectors on my 1986 Ranger 2.9 are definitely leaking, but it seems like barely leaking. When I jump the fuel pump with the injectors not even plugged into the wiring harness, I can see a tiny bit of fuel coming out of the nozzle and everything gets a bit coated in gas and shiny. Not sure if this amount is normal, but it doesn't seem like enough to cause my truck to flood itself after maybe 3 tries cranking it and also getting 8.5ish mpg (when it didn't run so bad it could actually drive). The rich running also got worse over time, starting from 11-14MPG and starting good + running rough, to 7-10MPG and starting rough + running rough, to struggling to start at all. My fuel pump seemed to be making some weird noises too. The sounds are closer towards the front end.

I attached a picture of an injector after wiping it dry then turning on the fuel pump for maybe 6 seconds

Do you think these injectors are just old and bad or is that normal to see a small amount of gas? It seems like all of the injectors are doing this, but some seem worse than others.

 

[RonD]

There should be no leaking of fuel, its a needle valve and most likely all have had a bit of wear over their life so can leak a bit, not abnormal but not what you want

And certainly not the cause of 8mpg
Your 1986 2.9l runs Batch Fire injection, so 3 injectors open at the same time, 2 on one side and one on the other side of engine, the next rotation of crank shaft has the other 3 open, and they alternate back and forth to keep lower intake full of air:fuel mix
Not as precise as sequential injection needs to be, so a little bit of extra fuel would be compensated for by O2 sensor feed back
O2 is a VERY important sensor, only way the computer knows if it is calculating correct air:fuel ratio
And there is ONLY 1 on your vehicle
O2s last 12 years or 100k miles, and run out of chemicals, so like tires and brakes they wear out, only sensor that does


There is a fuel pressure regulator(FPR) on the engine, has the fuel return line connected and a vacuum line, check that vacuum line for gasoline, FPR can leak and raw fuel is sucked into the engine, that can cause flooding and 8mpg

 

[kxri318]

There should be no leaking of fuel, its a needle valve and most likely all have had a bit of wear over their life so can leak a bit, not abnormal but not what you want

And certainly not the cause of 8mpg
Your 1986 2.9l runs Batch Fire injection, so 3 injectors open at the same time, 2 on one side and one on the other side of engine, the next rotation of crank shaft has the other 3 open, and they alternate back and forth to keep lower intake full of air:fuel mix
Not as precise as sequential injection needs to be, so a little bit of extra fuel would be compensated for by O2 sensor feed back
O2 is a VERY important sensor, only way the computer knows if it is calculating correct air:fuel ratio
And there is ONLY 1 on your vehicle
O2s last 12 years or 100k miles, and run out of chemicals, so like tires and brakes they wear out, only sensor that does


There is a fuel pressure regulator(FPR) on the engine, has the fuel return line connected and a vacuum line, check that vacuum line for gasoline, FPR can leak and raw fuel is sucked into the engine, that can cause flooding and 8mpg

O2 is brand new, FPR is brand new and double checked for fuel in the line just in-case

I'm more concerned with the truck struggling to start and flooding itself out than getting bad mpg right now though. As it is, it's just being a useless hunk of junk because I can't drive it. There's so much gas going into it, it just drowns itself and dies when I try to drive it even backing out of the driveway.

 

[Uncle Gump]

O2 is brand new, FPR is brand new and double checked for fuel in the line just in-case

I'm more concerned with the truck struggling to start and flooding itself out than getting bad mpg right now though. As it is, it's just being a useless hunk of junk because I can't drive it. There's so much gas going into it, it just drowns itself and dies when I try to drive it even backing out of the driveway.

Do a little u tubin and do some testing on your injectors... if they electrically test good... clean and rebuild them... parts are very reasonable.

Beware of cheap rebuilt injectors... you get what you pay for.

 

[kxri318]

Do a little u tubin and do some testing on your injectors... if they electrically test good... clean and rebuild them... parts are very reasonable.

Beware of cheap rebuilt injectors... you get what you pay for.

What do you mean if they test electrically good? All of them seem to open and close fine with you put power to them. Isn't the leak from the needle internal though? So getting a seal kit wouldn't fix that, right?

 

[Uncle Gump]

Dirty injectors do hang up and leak.

Each injector coil should be checked for resistance.

You tube has many how to's

 

[kxri318]

Dirty injectors do hang up and leak.

Each injector coil should be checked for resistance.

You tube has many how to's

Just went out and tested them. Also, when I went out there I noticed a couple fuel injectors completely filled the little divot from where the needle is to the top of the orange cover thing while some dried out completely. The injectors are upside down right now too. See pic for what I mean.
Cyl 1: 15.9 ohms
Cyl 2: 15.9 ohms
Cyl 3: 15.8 ohms
Cyl 4: 15.9 ohms
Cyl 5: 15.8 ohms
Cyl 6: 15.7 ohms
No idea what they should be but they all seem very similar.

 

[Uncle Gump]

I think that's what my spare set ohmed out as. At least they're all the same.

The next step is to clean them. You electrically activate the injector and shoot cleaner through them. Rebuild kits come with a new inlet screen... o rings... and pintle caps. They sell a tool to aid in cleaning.

After a good clean... see if they seal.

 

[RonD]

And you can smell the gas so you know its flooding out?
And it runs OK after startup/warmup?

Try "Clear Flooded Engine" mode, all fuel injection computers have this

Key on
Press gas pedal down to the floor and hold it down
Try to start
It should NOT START, just crank, fuel injector pulse should be off
(gas pedal to floor + 0 RPMs = "Clear Flooded Engine" mode)

That should dry out the cylinders
Then try to start

What about ECT(engine coolant temp) sensor, 2 wire 5volt sensor that sets Choke Mode, this can over fuel an engine if its running in Choke Mode all the time

 

[kxri318]

After a good clean... see if they seal.
[/QUOTE]

I think that's what my spare set ohmed out as. At least they're all the same.

The next step is to clean them. You electrically activate the injector and shoot cleaner through them. Rebuild kits come with a new inlet screen... o rings... and pintle caps. They sell a tool to aid in cleaning.

After a good clean... see if they seal.

This is already after I've taken them all out and sprayed carb cleaner through them. I just don't see how the rebuild kit would help the leaking as it's leaking from the needle which is internal and all the rebuild kit replaces is external besides the filter. I'd assume if it was clogged it wouldn't be running super rich, it would be running lean.

 

[Uncle Gump]

If you said you cleaned them already... I missed it.

For as much as a dirty injector could cause lean... if the injector won't fully seal because it's dirty... it will leak.

If your certain you have them as clean as they can be. Buy new injectors...

 

[kxri318]

And you can smell the gas so you know its flooding out?
And it runs OK after startup/warmup?

Try "Clear Flooded Engine" mode, all fuel injection computers have this

Key on
Press gas pedal down to the floor and hold it down
Try to start
It should NOT START, just crank, fuel injector pulse should be off
(gas pedal to floor + 0 RPMs = "Clear Flooded Engine" mode)

That should dry out the cylinders
Then try to start

What about ECT(engine coolant temp) sensor, 2 wire 5volt sensor that sets Choke Mode, this can over fuel an engine if its running in Choke Mode all the time

Yeah I can smell a real strong smell of gas while cranking and idling.

I put the pedal to the floor while starting without knowing that was a mode and it worked sometimes, but I usually didn't try to crank it long cause I figured it would just flood the engine worse.

It still runs rough when it does start like it did before, but it doesn't seem to drop the idle after warming up like it used to or at least it barely does. Though when I put it in reverse after letting it warm up, I got a few feet then it started bogging down and died on me. It also wouldn't start again after that so I had to push it back inside.

ECT is brand new and tested good on top of that

 

[Uncle Gump]

But beware... there are some serious junk parts these days.

 

[RonD]

If you want you can gap plugs a little wider, +0.003, above current gap, which is better for startup, but worse for RPMs above 3,500, if you run it that high
Current gap is 0.044" so change to 0.047"
Wider gap makes for a hotter spark for start up but also less time for coil to recover between sparks, which is why its better for start up but "less better" for high RPMs, lol
Narrower gap is "less better" for startup but better for RACING!
Vehicle makers pick a gap in the middle, so you can use +/- 0.005" if you want, kinda like the tire pressure thing, your tire so use the pressure you want

If ECT sensor tests at under 1volt warmed up then computer is most likely the issue especially if you haven't got lean or rich codes coming up
+1 on Uncle Gump, heads up on ANY "new" part, new used to mean "tested and working", new now means "YOU TEST IT, and we will replace it if it doesn't work"

If you can test running fuel pressure and its 30-40psi that OK, the fuel pump can do 80+psi, which is why it needs an FPR
While its a long shot, a return fuel line can get kinked or restricted, causing high fuel pressure, so if possible take that off the table with a test

 

[bobbywalter]

Sounds like a bad PCM if the injectors are spec.