Quick injector Question - Diesel Forum

T5Bird · 05-11-2007, 01:40 AM

Pulled my injectors today ( I was doing a return line kit so I was halfway there already), going to get them tested but maybe I shouldn't even waste my time. 3 injectors were dry as a bone, 5 of them were wet from the tip to the threads. So the way I see it is I either have 5 good ones or 5 bad ones, LOL. Any input?

aceohearts · 05-11-2007, 01:46 AM

With good combustion, they shouldn't be wet...I'd say 5 bad ones.

LMJD · 05-11-2007, 02:16 AM

Wet tips mean nothing, as you shut the engine down fuel gets injected but doesn't really fire as the engine comes to a stop. You'll never pull any injectors out of any diesel and not find fuel on several tips. If you do decide to buy new ones, have them tested. Of the last brand new Stanadynes I bought, all 8 had below spec popoff pressure and less than perfect spray patterns.

jeffrall · 05-11-2007, 12:08 PM

LMJD,

The only way to shut down a diesel is to take away the fuel. Hence the Fuel Shut off Solenoid. Once all of the fuel is gone the engine quits. [img]/ubbthreads/images/graemlins/rolleyes.gif[/img] [img]/ubbthreads/images/graemlins/crazy.gif[/img]

All of the injectors should be dry in a properly running engine with properly functioning injectors. [img]/ubbthreads/images/graemlins/warmsmile.gif[/img]

T5Bird · 05-12-2007, 11:16 AM

Well had them tested and one injector was good. There were two others that were marginal but the wet ones were toast.

LMJD · 05-13-2007, 01:18 PM

[ QUOTE ]
The only way to shut down a diesel is to take away the fuel.

[/ QUOTE ]
That's quite true, but you still can get some slobbering on shutdown. After pulling heads for years on about every breed and size of diesel I never got excited about a wet tip or two after testing a number of wet ones and finding perfect patterns and popoff pressure. If the engine was running ragged then of course we'd test the injectors. Another diesel mechanic posted the same long time experience here about a month ago.

jeffrall · 05-14-2007, 01:46 AM

According to the ford shop manual the only way you can have allowable leakage (AKA Slobering) is with the injector on a test stand and pressurized to just below the popoff pressure. Leakage is allowable as long as it does not drip off of the injector in five seconds. The leakage we are talking about here is obviously ocurring with NO pressure in the lines.

As the member said the wet ones did not pass the test he had performed on them.

[img]/ubbthreads/images/graemlins/shrug.gif[/img]

agnem · 05-14-2007, 05:57 PM

The bench test is the only way to say if they are good or not. I'd agree that wet is a reason to raise suspicions, but I've seen plenty of dry injectors that were bad too.

jeffrall · 05-14-2007, 06:46 PM

Mel,

Thanks, Most people do not have any way to test injectors. Most (at least I) just replace them all especially ones that are wet. I would also agree that dry ones could be bad too. I would think that if they were dry (And bad) that they would not be firing at all.

my $.02