broken nozzle (kinda ot)

bruce · Feb 11, 2015

Ok this actually pertains to a 3126 cat engine but since it's heui I'll post here. It's pour in white smoke and when you accelerate it pours black smoke. I think it's a broken nozzle. How do I determine which one it is? Any input is appreciated.

ghohouston · Feb 11, 2015

Do you have access to cats electronic technician software? Can you see fuel seeping from 1 or more of the 6 exhaust ports? Possibly an in fared thermometer on the ports?

Arisley · Feb 11, 2015

If it's a HEUI, unplug an injector. when the smoke goes away, you found the injector.

ghohouston · Feb 11, 2015

And funny enough, the 3126 heui injectors are physically identical to 7.3 injectors. Iirc, the nozzles are longer, and solenoids are a hair different though.

ghohouston · Feb 11, 2015

Arisley said:
If it's a HEUI, unplug an injector. when the smoke goes away, you found the injector.

I think he was trying to keep from pulling the valve cover while diagnosing, but yes, if it comes to that, he would know quickly. Iirc, it's just got 10mm bolts all the way around, and doesn't take too long to pull though.

DEEZUZ · Feb 11, 2015

If this has a fuel bowl, take the filter out, make sure bowl is full of fuel, crank engine over with a push-button starter and see if you have bubbles coming into the fuel. If no bowl, than put a hose a fuel line into a bucket of fuel

DEEZUZ · Feb 11, 2015

Basically your looking for compression feeding back through broke tip into fuel

Arisley · Feb 11, 2015

Good thing to remember for if you have a broken injector.

Do you count bubbles and divide by 8 to figure out which injector?

JK, I feel like being an a$$hole tonight.

DEEZUZ · Feb 11, 2015

Lol, no, but simply unplugging them doesn't always work, you still have fuel pressure running through that injector

Arisley · Feb 11, 2015

OK, real question. Honestly not sure.

I thought, the HPO had to fire the fuel before the nozzle. I thought once the fuel hit the nozzle, every thing that happened from there on was just atomization.

Please correct me if I am wrong.

mandkole · Feb 11, 2015

turn the power off, the inj is dead. Pull plugs until the smoke goes away. If that wasn't the case, just keying the fuel pump during prestart would flood the motor...lol

cleatus12r · Feb 11, 2015

Easy.

Infrared thermometer.

Find the exhaust port that's a wildly different (lower in this case) temperature at idle. There's your culprit.

bruce · Feb 12, 2015

I've done a cct and they were all pretty close to each other.

ghohouston · Feb 12, 2015

Done cct cold? The last 3126 I put an injector in was way low on power and hard to start, and when you would get it running, missed like hell. By the time you drove it around the yard to the shop, the engine would warm up enough that electronic technician wouldn't show a bad injector. We waited till the next morning and had computer all ready to go before first start. Finally found the bad injector

bruce · Feb 12, 2015

Yeah it was cold because et kept showin a warning about how its not supposed to do test at that temp

ghohouston · Feb 12, 2015

Hell I'd either do the in fared thermometer or pull the valve cover off.

04stroker · Feb 12, 2015

Arisley said:
OK, real question. Honestly not sure.

I thought, the HPO had to fire the fuel before the nozzle. I thought once the fuel hit the nozzle, every thing that happened from there on was just atomization.

Please correct me if I am wrong.

To answer your question obviously the HPO has to fire the injector so unplugging it does shut it off that is correct. But if it is a cracked or broken nozzle you still always have fuel pressure down to the nozzle so if it is cracked and not holding back the fuel pressure until the injector fires via HPO, then it will continue to flow fuel through the broken/cracked nozzle.

boggerr · Feb 12, 2015

If you don't have access to a scanner you have to pull the valve cover. You cold have a couple of bent pushrods. The lock nuts on the rockers back off. Pull the valve cover to start, has to come off anyway

PSD POWER007 · Feb 12, 2015

Arisley said:
Good thing to remember for if you have a broken injector.

Do you count bubbles and divide by 8 to figure out which injector?

JK, I feel like being an a$$hole tonight.

This made me LOL

bruce · Feb 12, 2015

I have cat et, it just didn't tell me much. Luckily the engine can be on the stand in about 15 minutes. I guess I'll bust the valve cover off. I might just take a known good injector and swap each one until i can get it to stop.