I replaced my plugs and cops. The engine is still running bad. I had Ford do a combustion balance test. Anyone want to take a stab at reading it?

 

hahahahha, damn that sucks! every cylinder is running bad

 

No engine codes? Is this just a snapshot @ 703 rpms? Looks like one full firing sequence at 703. Not sure what a healthy graph looks like but cylinder 6 sure sticks out like a sore thumb. What are the scales and did they not help explain it? Maybe Coobie can enlighten us.

 

I had no engine codes prior to this test by Ford.
I really don't understand why, but when I got my truck back from Ford after the test, the "service engine" light was on. code 306 came up.

 

Cylinder 6 misfire...obviously given the graph. Frankly it all looks fine except for cylinder #6. Of course I have no idea what engine you have or year sorry. Injector ok? p0301-0308 are misfire codes cylinders 1-8.

 

It's a 2000 4.6
Cylinder # 1 looks bad too, doesn't it?

 

Wouldn't that mean that cylinders 1 and 6 are good? Isn't a balance test where they kill power to one coil at a time to see if the RPM drops?

 

No, the ford service mgr. told me that 1&6 are missing severely.

 

yes, 1 & 6 are really bad, but a power balance test is where you hook up the ids to your obd port and navigate your way to the power balance test, then it tells you to engage your parking brake and put the vehicle into reverse and "load" the engine (rev up). Then it gives you that graph and it fluctuates like so.

i just did a power balance test on my truck at my friends shop, because i had a misfire, but the obd reader wasn't getting any codes (ended up being a bad spark plug).

to me, that graph looks all kinds of messed up, i don't remember getting values up to +40, but that may just be that they revved the engine higher than i did, however, cylinders 1 & 6 are the most troublesome.

 

That's correct. Each cylinder is individually shut down at the coil. Rpm drops are measured, then compared. Cylinders with the least amount of rpm drop would be at fault. Same scenario as the manual test that some of us use to pinpoint a misfire, by unplugging each cop or injector and looking for the cylinder that has no chance in rpm as the fault. With this test though, it can be tested under load, as apposed to idle. From what I see, 1 and 6 are good, as they show rpm drops...but I don't know exactly what that graph is showing.

"As each cylinder is shorted, a noticeable drop in engine speed should be detected. Little or no decrease in RPMs indicates a week cylinder. "

With that, I would say 7 and 8 look the weakest

 

two people are saying the complete opposite things

 

What's the deal? You had a test done then did not want the dealer to do anything?
Looks like they stopped when you did not want them to proceed, so your at where your at, hi and dry.
No info, no back ground, what are you looking for here?

 

Better ask, what plugs and cop's did you use?


"CYLINDER BALANCE TEST"

EEC-IV Cylinder Balance Testing Procedures
After you have performed the KOER test and corrected any problems you may now perform the EEC-IV Cylinder Balance test. This test checks all the cylinders in the engine for matched compression ratios. The Cylinder Balance test is designed to help isolate cylinders that have low compression ratios with respect to the others in the engine. This test is performed immediately after the KOER test has finished displaying codes.

To perform this test, the EEC-IV will bring the idle of the engine up to about 1,000 RPM. Once the idle has stabilized it will then shut off spark and fuel to one cylinder, during this time the decrease in RPM will be measured. The EEC-IV will then activate fuel and spark to the cylinder being tested, and will wait for several seconds until the idle stabilizes again. At this time it will repeat the process for the next cylinder, repeating until all have been tested. The results of the test will then output one or more of the following codes to your reader:

10 - Number 1 Cylinder Low
20 - Number 2 Cylinder Low
30 - Number 3 Cylinder Low
40 - Number 4 Cylinder Low
50 - Number 5 Cylinder Low
60 - Number 6 Cylinder Low
70 - Number 7 Cylinder Low
80 - Number 8 Cylinder Low
90 - Passed Cylinder Balance Test

After the first cycle of the Cylinder Balance test the EEC-IV will then perfrom the Cylinder Balance test again. The test will continue to cycle at twice the threshold of the previous test until the engine is shut off. Each time the EEC-IV finishes a Cylinder Balance test cycle it will display codes to your reader.

The following instructions will walk you through the procedures for performing the EEC-IV Cylinder Balance test.

Make certain that you have completed both the KOEO and KOER tests and have corrected any errors encountered during those tests to make certain that the Cylinder Balance test results will be accurate.
After performing the KOER test wait for the EEC-IV to finish displaying codes to your reader, do not shut the engine off!
Briefly depress the accelerator to WOT.
Write down any codes output by the Cylinder Balance test.
Wait for the EEC-IV to perform the next cycle of the Cylinder Balance test.
When you are through simply turn the engine off.

While the EEC-IV Cylinder Balance test is not a substitute for a compression check, it can help you determine where to start looking when diagnosing a rough running engine. It may also help to pin point impending engine problems.

 

i wish there was a video somewhere to show how a power balance test works. all there is, is a video of a recording a guy loaded and dubbed music over it. and a video of a completely different program that does a power balance in it's own way too.

 

Toyz,

He doesn't have an EEC-IV system, he has an EEC-V (OBDII system). Your post about the CBT doesn't apply as this isn't a CBT.

Clinders 1 & 6 are down with # 6 in worse condition.

We don't know what he has and until he identifies what he's working on, there's not context in which to interpret the graph he provided. I'm guessing it's a 4.6 with coil packs (pre-COP) and he's got a bad coil that drives cylinders 1 & 6.