Recent Power balance test on 1993 Q45 with supposed bad injectors

[Infinitiguy19]

OK I did a power balance test using the laptop Consult with a 1994 Q45 ECU with TCS California edition.

------------------------------------------------------------------------------Power Balance Test Summary On 1/6/2009 4:20:35 PMCoolant Temperature: 176 Deg {F}Idle Air: 15 %

Cylinder # 1 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1081 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1051 Rpm Average RPM Drop Result... 30 Rpm Highest RPM Drop... 281 Rpm Amount Of Data Sampled When Cylinder Off... 192 Cylinder # 2 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1095 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1063 Rpm Average RPM Drop Result... 32 Rpm Highest RPM Drop... 295 Rpm Amount Of Data Sampled When Cylinder Off... 191 Cylinder # 3 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1103 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1072 Rpm Average RPM Drop Result... 31 Rpm Highest RPM Drop... 303 Rpm Amount Of Data Sampled When Cylinder Off... 191 Cylinder # 4 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1119 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1074 Rpm Average RPM Drop Result... 45 Rpm Highest RPM Drop... 269 Rpm Amount Of Data Sampled When Cylinder Off... 192 Cylinder # 5 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1114 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1088 Rpm Average RPM Drop Result... 26 Rpm Highest RPM Drop... 301 Rpm Amount Of Data Sampled When Cylinder Off... 191 Cylinder # 6 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1130 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1094 Rpm Average RPM Drop Result... 36 Rpm Highest RPM Drop... 292 Rpm Amount Of Data Sampled When Cylinder Off... 191 Cylinder # 7 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1125 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1085 Rpm Average RPM Drop Result... 40 Rpm Highest RPM Drop... 312 Rpm Amount Of Data Sampled When Cylinder Off... 191 Cylinder # 8 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 1130 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 1101 Rpm Average RPM Drop Result... 29 Rpm Highest RPM Drop... 280 Rpm Amount Of Data Sampled When Cylinder Off... 191------------------------------------------------------------------------------

Can someone help me make sense of this please?

[Q451990]

What version of ScanTech are you using?

From the results, it doesn't look that bad... but I'm not convinced that Isaac ever totally got the power balance test to a point that the results are particularly valid. My concern is that the ECU is still doing things to try to recover... opening the IAC, possibly timing advance?

How are your injectors ohm testing?

Heath

[Infinitiguy19]

Talked with Wes he said to disconnect the AAC which I will do then i will re run the test, And the injectors OHM fine when warm but I haven't been able to OHM them when cold on account of the cold.

[Q451990]

In my experience, they tend to ohm worse when hot than cold. What version of ScanTech do you have?

Heath

[Infinitiguy19]

The latest one available: 1.43, With the chick voice, Now I have a +1 on the Nissan Consult

[Infinitiguy19]

OK I have disconnected the AAC valve to perform both tests:

High beams, rear and mirror defroster and map lights on------------------------------------------------------------------------------Power Balance Test Summary On 1/30/2009 4:54:47 PMCoolant Temperature: 183 Deg {F}Idle Air: 10 % Cylinder # 1 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 804 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 770 Rpm Average RPM Drop Result... 34 Rpm Highest RPM Drop... 79 Rpm Amount Of Data Sampled When Cylinder Off... 187 Cylinder # 2 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 810 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 776 Rpm Average RPM Drop Result... 34 Rpm Highest RPM Drop... 72 Rpm Amount Of Data Sampled When Cylinder Off... 181 Cylinder # 3 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 813 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 780 Rpm Average RPM Drop Result... 33 Rpm Highest RPM Drop... 75 Rpm Amount Of Data Sampled When Cylinder Off... 190 Cylinder # 4 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 814 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 781 Rpm Average RPM Drop Result... 33 Rpm Highest RPM Drop... 64 Rpm Amount Of Data Sampled When Cylinder Off... 190 Cylinder # 5 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 817 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 781 Rpm Average RPM Drop Result... 36 Rpm Highest RPM Drop... 67 Rpm Amount Of Data Sampled When Cylinder Off... 190 Cylinder # 6 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 816 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 782 Rpm Average RPM Drop Result... 34 Rpm Highest RPM Drop... 78 Rpm Amount Of Data Sampled When Cylinder Off... 183 Cylinder # 7 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 814 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 781 Rpm Average RPM Drop Result... 33 Rpm Highest RPM Drop... 64 Rpm Amount Of Data Sampled When Cylinder Off... 192 Cylinder # 8 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 813 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 783 Rpm Average RPM Drop Result... 30 Rpm Highest RPM Drop... 75 Rpm Amount Of Data Sampled When Cylinder Off... 186------------------------------------------------------------------------------

Nothing on:

------------------------------------------------------------------------------Power Balance Test Summary On 1/30/2009 4:58:57 PMCoolant Temperature: 185 Deg {F}Idle Air: 10 % Cylinder # 1 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 810 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 779 Rpm Average RPM Drop Result... 31 Rpm Highest RPM Drop... 72 Rpm Amount Of Data Sampled When Cylinder Off... 187 Cylinder # 2 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 834 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 796 Rpm Average RPM Drop Result... 38 Rpm Highest RPM Drop... 71 Rpm Amount Of Data Sampled When Cylinder Off... 188 Cylinder # 3 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 831 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 799 Rpm Average RPM Drop Result... 32 Rpm Highest RPM Drop... 68 Rpm Amount Of Data Sampled When Cylinder Off... 190 Cylinder # 4 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 838 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 798 Rpm Average RPM Drop Result... 40 Rpm Highest RPM Drop... 75 Rpm Amount Of Data Sampled When Cylinder Off... 187 Cylinder # 5 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 836 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 798 Rpm Average RPM Drop Result... 38 Rpm Highest RPM Drop... 86 Rpm Amount Of Data Sampled When Cylinder Off... 189 Cylinder # 6 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 842 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 803 Rpm Average RPM Drop Result... 39 Rpm Highest RPM Drop... 79 Rpm Amount Of Data Sampled When Cylinder Off... 191 Cylinder # 7 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 837 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 799 Rpm Average RPM Drop Result... 38 Rpm Highest RPM Drop... 74 Rpm Amount Of Data Sampled When Cylinder Off... 190 Cylinder # 8 Cylinder On Stablized For 2 Seconds Average RPM When Cylinder Stablized... 841 Rpm Cylinder Off Sampled For 3 Seconds Average RPM When Cylinder Is Off... 800 Rpm Average RPM Drop Result... 41 Rpm Highest RPM Drop... 78 Rpm Amount Of Data Sampled When Cylinder Off... 191------------------------------------------------------------------------------The results seem pretty random.


Modified by Paul Wall at 10:53 PM 2/3/2009

[qship96]

It all looks as clear as chinese to me? I bet it took longer for you to type all that than to test it? If it runs good, it runs good.

[Infinitiguy19]

Bump

[Q45tech]

Normally on a Consult I, I like to see all rpms drops within +- 12 rpm of average drop as 12 rpms is 1% of test speed.

From a smoothness standpoint +- 25 rpm may be acceptable depending on test rpm.

Remember the Power Balance Test was only designed to show a dead cylinder not to discriminate between working cylinders as we try to use it. After doing thousands of them you gain some insight

[Johnny Rocket]

So if you had a little bity idle miss...hadly detectable..is the power balance test a waste?

Normally on a Consult I, I like to see all rpms drops within +- 12 rpm of average drop as 12 rpms is 1% of test speed.

From a smoothness standpoint +- 25 rpm may be acceptable depending on test rpm.

Remember the Power Balance Test was only designed to show a dead cylinder not to discriminate between working cylinders as we try to use it. After doing thousands of them you gain some insight

[Infinitiguy19]

In a way yes because unless you have a definite bad injector then its not the best way to tell.

But from what I can surmise, my injectors are clogged so my next steps are to change the fuel filter and power flush them the first way to see if there is a change:

"I have a trick which shows if a rail flush will help: Use non biting pliers to close off fuel return rubber line in repeated but very short [ a second closed then wait 3 and repeat 10-15 times to raise rail pressure from 34psi to 60-70 psi to force trash thru the injector screens ----- fleck off carbon/deposits from injector tip..............does power balance ratios change? It should get temporarily better.

Usually helps without doing much fuel pump damage [pump has it's own blow off high pressure valve]. After all the pressure rises to 43.4 psi under acceleration."-Q45Tech.

Then if that works I will try the BG Injector flush.

Hey Johnny are you still interested in the HVAC control unit?

[elwesso]

can you tell by FEEL what cylinder is dropping out..? IVe felt Qs that have a tiny bit of a shake but its nothing like when an injector is bad... my Q has a little shake to it sometimes especially when its cold out or hasnt been driven in a while and/or short trips, but unless youre getting a constant shaking at warm idle no matter what, then its an injector...

power balance shows that no one cylinder is showing a misfire. John, in your case I think itd show a cylinder thats weak (or 2?)

[texasoil]

It is a great balance report 36 average drop +/- rpm

It is possible you have gummed up intake valve tulips or spark plug gaps incorrectly set or? LOTS of very weird things can/will cause small power ouput variations at very low loadings. In my limited experience the Q45 engine will always have a little 'grainy-ness' in the idle. The engine mounts are designed to damp that out. If you have not replaced them--its time.

[Q45tech]

I always to a series of PB tests at different base rpms. One in drive foot on brake to load engine up, same with ac compressor on.

If you do enough different tests you will get a feel for which cylinders might be weak.