Hey guys , trying to figure out which injectors are bad. I have a dp tuner and ran a buzz test. Sounds like 2 injectors are bad. I read somewhere that if you do a cylinder contribution test which i should have on my dp tuner that it will tell you which injectors are bad. I couldn't find cylinder contribution test on tuner, but did a cylinder balance test hoping that was it. Unfortunately it almost immediately post a code about my a/c. No luck there. Can anyone tell me how to figure this out? My exhaust manifold on the passenger side is 50 degrees cooler than driver side, so im assuming the bad injectors are on the passenger side? Thanks for any help

 

Have you checked your UVCH? Bad connections there can have similar symptoms / results

 

I thought the same thing , do I need to do the $0.50 mod first? And then run a Buzz test? Was hoping to only have to take the valve cover off once and wanted to figure out if I have bad injectors and replace those at the same time

 

Also I am getting rough running on cold starts, but runs fine after about 10 minutes. I have been pulling some codes. And I have those posted along with the symptoms on another recent post

 

So you have an EGT probe on both banks?

3, 5, and 8 will often show as "bad" on a cylinder contribution test, but that is generally due to CPS and completely normal.

Running better when warmed up is a good sign of tired injectors. You can try synthetic oil that often helps tired injectors for a while.

Please post the codes on this thread if you want help on this thread.

If I was gonna do two injectors, I'd do them all. And go singles if you have stock splits.

 

Some things to keep in mind....

A buzz tests mainly checks the electrical side of the injector. That's not necessarily a tool to diagnose bad injectors.

Cylinder contribution tests won't tell you which injectors are bad, they simply tell you which cylinders get a differing rotating velocity. Tuning can affect the readings. Heck you could have 7 perfectly healthy injectors, and one firing a bit stronger, and get a failed CCT. Just because a cylinder pops up under the CCT, doesn't mean it's THAT particular one with the problem. The tool doesn't tell you if that injector is firing weaker or stronger than the previous one.

Diagnostic tools are nice, but understanding how to read the data becomes extremely important. Without understanding how to read the information you have, you're right back to parts swapping and hoping for the best.

I think a little more info into what's going on would be helpful so that others here can lend a hand.

 

Codes are p1316 , and p0605. Pretty sure the p1316 is pointing to the UVC Harness, but it is now not showing up for some reason. I thought of doing the 50 cent mod but after doing research, i started realizing that i could have bad injectors (or tired) since the running condition gets better when warm. I have 160,000 miles and found that many injectors start getting tired at this time.
Should i try the 50 cent mod first?
Would rather only pull the valve covers once, so i was trying to figure out a way to test injectors. Not sure what to do, and what order to do it.
As far as egt probe, i only have 1 on driver bank. I was shooting the manifolds with an infrared temp gun.

 

Think you found a couple of "gotchas"

1. You should have your climate control turned OFF before running the test. Probably said out of range or something like that and fails?

2. Buzz test only tells you the FIRST bad injector (electrically). When the test encounters a bad injector that buzzes softly, the test will continue but only buzz the rest softly. {This comment corrected by others below, keep reading}

 

Thanks for the input John , I will try the test again with the AC off. Is the cylinder balance test the same thing as a cylinder contribution test?

 

Depends on the year of your truck.

IIRC, the cylinder balance test is for later years (I saw it on the 6.0's but not sure if it is year based or 7.3 vs 6.0 based? )

If I were betting on it, I'd say cylinder contribution test is 7.3 and the balance test is 6.0, but only done it on a couple of trucks, so can't say for certain.

 

I buzzed a truck yesterday, seven was soft but eight was strong like the others.

 

[QUOTE=jstihl;16315255]Codes are p1316 , and p0605.

I'm pulling a p0605 code on my truck with superchip installed. Remove superchip, code goes away.

 

Thats what I got this morning when the engine was cold. Ran another Buzz test and number 7 was open. I plan on running another test after running the truck for a while to see if there is a difference. Change one or two injectors or all of them?

 

Original UVC harnesses and glow plugs?

 

Also check the wire harness on the drivers side valve cover, over time the engine vibration can rub some of the wiring insulation off.

160,000 miles is kinda early for injectors to go. 200+K is more statistically the mileage rang. But a lot can depend on vehicle us, for example Jason (HKusp) had his go around 160K but he used his 7.3L for plowing.

If pulling the VC's I would change the the UVH Harness(s), glow plugs and test the 42 pin connector first. If all that checks out then look at injectors.