Faulty injectors?

[JamesMichael]

I have an Isuzu MU7 and would like to know if there are any places that specialize in testing injectors. I don't want to change them all if only one is faulty.

[joepai]

Does the Isuzu dealer not have a test rig ?

[BillaRickaDickay]

I have an Isuzu MU7 and would like to know if there are any places that specialize in testing injectors. I don't want to change them all if only one is faulty.

Maybe you have done this already!
Symptoms? Miss fire, Lumpy running?
Start with :-
Diesel filter/s changed? Maybe crap in the Fuel Tank, drain tank and flush.
Diesel additive to clean Injectors?

[JamesMichael]

It starts up fine, runs smooth,normal driving no problem. The problem is when i put my foot down to pass somebody it blows black smoke.

[BillaRickaDickay]

It starts up fine, runs smooth,normal driving no problem. The problem is when i put my foot down to pass somebody it blows black smoke.

A bit basic and should be part of your routine service as you probably know, clogged air filter can cause black smoke on acceleration.
If as you think Injector/s, I dont know of a Diesel specialist but I use Srisook Garage on the Srisook road in Udon for most of my maintenance work, they may be able to diagnose the problem or point you in the right direction to someone who can, they speak English and very reasonable on price.

[Colin1a1]

If it starts and runs fine, then start by changing the air and fuel filters and putting a bottle of fuel system cleaner in the tank. Remove and clean the MAF sensor with carb or brake cleaner.
Common rail Diesels need 300 bar pressure on the rail, so if you had a bad injector it would affect the others and make it hard to start .
Is the engine management light on, and how many KMs has it done?

[Potamoi]

Black smoke can be from a few different causes. Intake hose collapse when you goose it is another possibility as is a sticky EGR valve.

My 2.8 liter Duramax on my Colorado (may be the same motor you have) had the former which was diagnosed in the driveway by a service advisor that is not known for his tech skills typically so it may be pretty common. I think this was at about 280-300,000 km. If you are rocking the Duramax, check that top intake hose carefully visually for creasing then look at it with the hood up and someone hitting the throttle a few times.

My 3.2 liter Triton on my Mitsu was beltching the black smoke but the in this case the EGR was sticking so changed it but I also ran some diesel spray cleaner through the intake as well. Every 50k or so I also clean the MAF with some trusty brake clean or throttle body cleaner for good measure (this can trigger the 'money light' (a.k.a. check engine light). In both cases the fuel economy suffered which I keep fairly close tabs on with Google sheets every fueling.

In extreem cases, even a very clogged air filter can cause the same symptoms. I'd say start with the easiest checks first rather than jumping straight to injectors as some may wish to make the easy sale then fix the real issue while changing injectors or selling turbo parts.

One last thing to mention is after I changed from exclusive PTT fuel, my fuel filters dont seem to need changing as often. Its a shame as their restrooms are certainly better than some.