Power Balance Test

[DenverQ]

I got the power balance test done, I was supposed to have the 1.3 hrs of actual consult time but thats all they did and charged me 120 bucks!! I am so mad!!! anyways

1. 144 rpm2. 142 rpm3. 120 rpm4. 92 rpm5. 101 rpm6. 104 rpm7. 107 rpm8. 107 rpm

I know there is not a 12rpm varience so what does it look like I need to do to fix? New injector? Spark Plugs? BG flush? Pull the plenum? Thanks for yolur help guys!

[Mayhem_J30]

That bites Tory. Obviously I had problems with my dealer service, but they gave me a full diagnostics for $90 which included the power balance test. Unfortunately it just costed me the extra$45 to give me results. Looks like something is going on there with those results. Do those mean that when stopped the rpm drops by that 'x' amount?

[Q451990]

Each reading is showing the contribution of that cylinder to the total idle. Consult holds the RPM at a certain base idle, then turns each injector off one at a time and calculates the RPM drop. If you see 0 RPM, that cylinder wasn't doing anything to contribute to the base idle. Usually this is the case with a failed injector.

Does your report show the coolant temperature and base rpm on the page - it should? All of the numbers look too high to me - as if the idle was being held higher than normal or the test was done when the car was cold.

In a perfect world, each cylinder would show the same number - and that's possible after a complete intake cleaning, injector flush, and possibly new spark plugs (according to how old they are and how much carbon has built up).

Your variances aren't that bad... My last rail flush was 9/17/01 at T3... here are the before and after results.

Before1 - 622 - 503 - 504 - 505 - 506 - 507 - 378 - 37

Base RPM 837 rpmCoolant Temp 188F

After1 - 622 - 623 - 624 - 755 - 626 - 757 - 628 - 75

Base RPM 1087Coolant Temp 185F

The actual number on each cylinder isn't that important - it's variance between them that tells you what's going on.

Dennis mentioned a new way of running this last summer... sort of a loaded test with the car in drive holding against the bakes at 1000 or 1500 RPM - which would give a more accurate view of what's going on under a load.

Heath

[DenverQ]

says 1163 rpm and 181 degress at the bottom of my little slip

[Q45tech]

Your test was done with a Consult II vs Heath's Consult I which only shows 12 rpm increments and rounds to the closes value.

I like to see perfectly equal but that is rare a 12 rpm +- variance would be decent at 1100 rpm.

I usually do the power balance test 2-3 times and average all the averages and meditate on the numbers a few minutes.

A 52 rpm or even a 40 rpm would show up as a less than perfect idle and might mean that the lowest dropping cylinder might [92/144] be producing up to 1/3 less power.........but remember each cylinder only produces 12.5% of the total so at high rpms we might see a 5% drop.

But the wide variances 144,107, 101, 92,etc lead me to suggest a BG rail flush and an intake runner fogging/TB cleamed manually before..........even with the so called more clog resistant 94 and above injectors. If you care about smooth idle and achieving as new power?

Mine are always at 87 rpm [1200 rpm/177F] [for all 8] even with 243k and 13 year old injectors.

[DenverQ]

The TB was cleand about a month ago I am going to call and scedual a rail flush/ fogger treatment.

I wonder if I can convince them to do another power balance test without charging me 120 bucks (grrrrr)

Yes I want perfect idle and as new performance!

[Mayhem_J30]

Let us know what your dealer charges for the rail flush/fogger treatment so I can subrtact 30% from that and get an idea what I would have to pay. Have them do the power balance test when engine is warm so you don't have to worry about the base idle declining while doing the test.

[DenverQ]

They told me yesterday 109, but I called today and now its 119. I am beggining to hate all dealerships! they drive me nuts!

I called and complained about the $$$ and the service manger lady said they bill for 1hr no matter what, but i was like I want my full hr!!!! so they refunded 40 bucks so it was 80 bucks for a power balance test and it will be another 80 if I want to do it after my Fuel injection service I think that is totally outrageous

I wish that comany would hurry up with that consult program I would buy one for the 400 bucks they ask!!!!!

PS, I called the dealership out here in Omaha NE (im in lincoln) they said 125 for the flush but only 30!!!!! to do a power balance test!!!! Now Im really mad I am calling the dealership and speaking with the GM today.

[Q45tech]

The Consult WON'T ALLOW most test until the coolant temp warms to 176F.

Common problem is needing to replace a 3-4-5 year old worn out thermostat which won't allow the idle to stablize up to 176F ....the idle temp goes up to 170F or even 175F but that's not enough for the Consult to allow the test.

Your car is brought in sits, cools, then driven in and the Consult connected, warm up time: who pays for the 10-20 minutes everybody waits while it tries to warm up so the test can continue. More of a winter time problem!

I sure won't do a Power Balance for $40 unless it was extra to another more profitable service!

[firstq]

Tory, my understanding is that the injector flush includes a power balance test by the dealership - I even have a coupon for $89 that states that.

[DenverQ]

Cupon!

I wish I had a cupon! Did you get it in the mail?

but its probably 100 for the print out of the test LOL

[DAEDALUS]

Q45tech, you once stated that a power balance test couldn't be accomplished by disconnecting the plugs, as the car would try to compensate. What if each injector were disconnected? Would the car try to compensate in the same way, or would this produce the desired results?

[Q451990]

You could do it, but how would you get to each injector connection? The other problem is accurately measuring the drop - but I suppose it could be done with some other test equip. - like an accurate tach.

Heath

[AZhitman]

The copy of the Consult printout is free at Scottsdale.

I'm gonna see if I can get them to run this test on mine since it's currently in the shop.

[DAEDALUS]

You could do it, but how would you get to each injector connection? The other problem is accurately measuring the drop - but I suppose it could be done with some other test equip. - like an accurate tach.

Heath

Yeah, I think an advanced DVM will soon be part of my tool arsenal. If a power balance test was something that I was going to do even once a year, it would be worth it to make a splice harness with switches. I would buy an injector harness (mine should be replaced anyway, then I could use the old one). I would get an engine sub-harness (with the connector that the injector harness plugs into) from a wrecking yard. Then I would splice the 2 together, keeping the length as short as possible, along with a box and 8 switches, while maintaining the proper pin-to-pin connections. Then every 6 months I could just disconnect the injector harness, install my gangleon creation, and perform the PBT. Just some thoughts here. I simply can't afford to do all diagnnostics at a dealership, and at $100/test, this thing would pay for itself after 2-3 tests. My concern is with the added resistance of the splice and how it might affect engine RPMs. I suppose I would need to compare engine RPMs before and after splicing the test harness to ensure that it isn't causing an RPM drop on its own.

[DenverQ]

I have talked to theses guys before and they said they were working on a q45 version, but I bet if they got some more interest it could help get us one sooner. I know I would buy one!!

http://300zx-twinturbo.com/conzult/

Dowload the preview its pretty cool

[Q45tech]

You can't stop the ecu from trying to compenstate for rpm changes [without a Consult] as it will try to vary the IAC first, if that doesn't work it will change ignition timing, if that doesn't work it will change the fuel injector pulse width.

The ecu job is to try to hold the idle speed steady!!!!!!!!!!!!!!!!!!!

The Power Balance locks the IAC open [why the jump to 1,000-1,300 rpm fot the test*] and freezes ignition advance and injector opening time to 2.2 msecs.........

* the NEW base rpm is a good indication of how clean the intake, IAC passages, and injectors are

For example when AC is turned on the HVAC sends a signal to ecu to get ready get set NOW add 0.3 millisecs of injector time to what ever the previous calculation was, same when power steering is turned [it varies with speed].......the ecu also monitors the battery voltage to injectors to compensate for lights heater defroster, power windows, etc............even a 0.1 volt change at the injectors MUST BE COMPENSATED FOR.

OBDII monitors fuel temperature and another dozen parameters to get the injection pulse as perfect as it can be

[DAEDALUS]

Rats. Thanks Q45tech, glad I didn't waste my time. I'd be in for a "Qonsult" too--the Z version is around $450 or so. How about a show of hands if you think you would seriously buy a Q version at the same price? We can plead our case again!

[cdiver]

Interesting idea, please do a posting if you are successful. Also, is there anywhere I could buy a Consult II or I unit? Would it also work on my Max?

Thanks,

Stephen

[cdiver]

BTW, "Driving mom's car?!!" not since I bought her 1970 Ford stationwagon when I turned 16!!!

[PalmerWMD]

BTW, "Driving mom's car?!!" not since I bought her 1970 Ford stationwagon when I turned 16!!!

All the new guys get that.Your title gets cooler as you make more posts.

Fred...