P0300 only when in tow/haul

[shegarty]

The injectors and coils balance inspection is a great recommendation as well.

I was able to find the injector test in the Tech2 but I don’t know where the coil balance test is - any suggestions?

 

[Fless]

I think it's only the injector or cylinder balance test, but I haven't looked lately.

One thing to do while you have the Tech 2 on it is a cam/crank correlation.

 

[MassHoe04]

I was able to find the injector test in the Tech2 but I don’t know where the coil balance test is - any suggestions?

I am new to actual use of the Tech 2 for many of the special functions, so I'll ask...

Does the injector test run with injectors in place? I thought I saw some kind of special contraption in my Field Service Manual (like a test spray box or something).
Just curious... Can you test injectors with Tech 2 without any weird procedures or special equipment only a shop would have?

If you did run the test, how did it go?

 

[shegarty]

I am new to actual use of the Tech 2 for many of the special functions, so I'll ask...

Does the injector test run with injectors in place? I thought I saw some kind of special contraption in my Field Service Manual (like a test spray box or something).
Just curious... Can you test injectors with Tech 2 without any weird procedures or special equipment only a shop would have?

If you did run the test, how did it go?

I’m new to the Tech2 as well but from my understanding you can use it to test the injectors in place. You need to connect a fuel pressure gauge as well - I assume that is to monitor the pressure as the injectors are cycled through.

 

[OR VietVet]

Coil balance test, IMO, is just seeing that the output of each is sufficient. I think the word balance is what is throwing you and even me. Is there a way to also measure that under a load condition?

 

[shegarty]

Coil balance test, IMO, is just seeing that the output of each is sufficient. I think the word balance is what is throwing you and even me. Is there a way to also measure that under a load condition?

I am going to pick up pressure and compression testing tools tonight on loan from the local auto parts store. The plan is to do those tests tomorrow along with trying the coil balance test as well.

 

[rockola1971]

I am new to actual use of the Tech 2 for many of the special functions, so I'll ask...

Does the injector test run with injectors in place? I thought I saw some kind of special contraption in my Field Service Manual (like a test spray box or something).
Just curious... Can you test injectors with Tech 2 without any weird procedures or special equipment only a shop would have?

If you did run the test, how did it go?

One of the tests is to shut off each injector (ONLY ONE INJECTOR IS OFF AT TIME) and see if the misfire or rough running goes away. This is basically equivalent to the "old school" test of pulling a spark plug wire off each cylinder one at a time to see if it makes a difference or not in the way the engine runs. If you pull a spark plug or shut down an injector to a cylinder and the engine starts running smooth then your problem lies in that cylinder, its coil, injector, etc. Could be that cylinder's piston, rings, valves, rocker arm, lobe on cam for that cylinder, lifter, etc.

 

[OR VietVet]

Or if the running engine does not change when kill a cylinder, that is the problem cylinder, correct? That means that cylinder is not contributing to the way the engine runs.....correct?

 

[rockola1971]

Or if the running engine does not change when kill a cylinder, that is the problem cylinder, correct? That means that cylinder is not contributing to the way the engine runs.....correct?

It really all depends on what is causing the cylinder to drag down the other 7. For example a injector that has a dirty nozzle and just isnt getting a good conical spray pattern and mostly dripping instead of atomozing the fuel and air mix when turned off will cause the engine to likely run smoother. But if a cylinder has a dead ignition coil then turning it off wont make any difference on how the engine is running while turning one of the other 7 cylinders coils will definitely make a difference.

 

[shegarty]

Alright, finally got a pressure tester that would fit and did a compression test - here are the results:

Fuel injector balance test
- all injectors powered up to ~59-60psi, dropped momentarily to ~40psi and the cycled down to 32psi

Compression test results
1 - 150psi 2 - 155
3 - 160. 4 - 160
5 - 155. 6 - 160
7 - 150. 8 - 150

All the plugs look the same, clean, free of oil and carbon with only a little bit of white residue. Plugs have about 25k km on them.

Good news that compression and fuel tests come back clean. What now though? Can position sensor?

I did spray some carb clean around the intake with no change. Now that I am looking a bit closer I can detect a very slight miss at idle that I never noticed before. Also regapped plugs to 0.055 - still no difference on startup.