hey everybody, i ran an injector buzz test on my truck (99 f350) and i noticed the 6th injector that buzzed sounded weak. now my question is, when the injectors are buzzing do they fire in cylinder 1 then cyl. 2 and so on, or do they fire according to the firing order 1-2-7-3-4-5-6-8? and also during the cylinder contribution test cylinder number 8 fails... any idea as to what this could be? ive been told i need new injector o-rings due to high pressure oil bleeding down overnight and as a result making the truck crank forever before it starts, but i cant imagine those causing these problems...sooo yeah any help is GREATLY appreciated! <!-- / message -->

 

The buzz test runs in cylinder order not the firing order.
If your truck had the CPS recall done at the dealership then your #8 cylinder will read funny.

 

Did you do the CCT test?

 

Are you using AE to run the tests? Did you get any codes after doing the buzz test? Did your do the buzz multiple times to see if there was an improvement on #6? What cam sensor are you running? A gray cam sensor, along with LL#8 injector, can show some higher rot vel %'s. Have you ck'd the rotational velocity %s ? What % did you get? Sorry for all my ???s, just trying to get more info.

 

Cylinder Contribution Test? yes i did thats how i came up with number 8 cylinder failing.

 

I am using a SNAP ON Solus Pro scanner to run these tests. and yes i buzzed it 3 times to see if there was an improvement and there was none. and i dont believe i can check the rotational velocitys with this scanner so i can't answer that one.. and im not sure what CPS is in there but it LOOKS like a grey one.. but ill try to get a closer look later today. Thanks!

 

My #8 fails every time I do the test. I know there is nothing wrong with my injectors. It is the gray CPS that is doing this. Usually it effects #3 and #8. If the engine is running good, don't worry about it.

 

not to change the subject, but what is the reasoning for the grey CPS causing cylinders 3 and 8 to fail the CCT? is it because their the last set of companion cylinders?

 

Wanted to explore the questions raised in this old thread a bit more. I'll add my data on Cyl Rot Velocity this evening. I had the grey CPS and was getting about 6% on #8. Now have the black CPS installed, and still #8 is 5-6%. Truck runs well. I would like to improve the #8 contribution if possible. Might that have to wait for new AC sticks down the road?

 

You've go the mods, the rest is up to tuning, oil, sticks, and alignment of the planets.

 

Oh, I was off by an order of magnitude. I dont think I saw the PERDEL1-8 pull down in the choices. Just Cyl Rot Vel 1-8. Same thing?

 

Naw... you've got it right, but it displays in Perdels. However... I'm going off memory on this one because I don't check that until I need to.

 

That's it. Displays in PERDELs. EOT had to get over 122 before these meters would start reading.

 

I know from your visit that the Perdel on 8 is pile of bovine bombs, your idle is smooth and I have felt an honest Perdel of 6... not the same.

 

Ok. Besides setting up these meters to measure CRV, I ran the CCT on the Test Onboard System tab, and it came up clean - no reported cylinders. From a search on google, A Beans fellow mentioned not to take the CRV tests in AE too seriously, but rely on CCT.