[murcod]

Would an XL-7 owner please be able to check what the normal idle speed is when both A/C units are on flat out in hot weather?

I'm trying to work out why the battery isn't charging in the wife's XL-7 (2004 model) and want to rule out low idle speed before changing the alternator. (The idle speed doesn't seem to increase at all with the A/C on.)

[SuziBlu]

No sure with an X7, dont use aircon, hate it, but when things go on, normal is no change, or very slight increase.

If everything is off and you switch things on, if the engine is not set up right, and its charging, the extra load will make revs drop, no so much go up.

Best way to test is with a multi meter, if your wifes car is not charging it will be a flat battery in no time.

[murcod]

Hi, it did actually have major electrical problems yesterday and wouldn't start. Even after being jump started by the RAA, it wasn't running right. Electrical items were not working or misbehaving with the engine running.

I thought it would just be the 6yr old battery. I have checked with a multimeter and with the A/C running flat out the voltage slowly drops at idle speeds (to like low 12v levels)- that's with a different battery fitted. Rev it a bit and it recovers- that's why I was curious about the idle speed. Going by the tacho it's only sitting at around 600rpm.

I'm beginning to think the alternator is on it's way out? It's a great time of the year to be trying to get parts like that for an XL-7!

PS: She's out driving it today so I can't do any further checks. I did warn her everything wasn't okay.....

[GeckoXL7]

Its around 780 but will confirm It increases by about 60-100rpm

Whats the battery voltage when engine is running?

[murcod]

Thanks for the RPM figures. I was asking because I've modded my IAC circuit to reduce the initial start up revs on cold mornings - it's been like that for 3-4 years with no issues (but I can't discount it not helping.) I'll check to see if the revs increase at all with turning the A/C on/ off. I didn't notice an increase last night so might have to reverse the mod and see if that changes. It's also got twin electric thermo fans fitted - no viscous hub cooling fan. Once again, it's been like that for 3yrs or more with no prior problems.

With the electrical loads low (ie. A/C off, thermo fans off) it's around 13.9v at idle. Switch the A/C on flat out and that starts decaying steadily. It's fine with the thermo fans running on low speed- and maintains the voltage at idle. They didn't cut in on high speed last night while testing things. With the A/C on flat out it needs to be revved to get the alternator to keep things at 14.1V

My gut feeling is the alternator (brushes perhaps) on the way out? It's done 110000km- so not high mileage for the age.

[GeckoXL7]

Mines stays at between 13.i6 to 13.9

Idle is around 680 to 760.

Engine should idle up if turn lights on too or blower with out Aircon?

It's possible the load sensing circuit isn't functiong correctly so won't idel up or tell the alternator to up the amps output.

[murcod]

GeckoXL7 wrote:

It's possible the load sensing circuit isn't functiong correctly so won't idel up or tell the alternator to up the amps output.

I'll go out and check the idle speed - she made it home okay.

The idle load circuit- I assume that's controlled by the ECU opening up the IAC valve in the throttle body? (It's a 2004 model with the IAC built into the throttle body.) Or is there a separate valve that opens somewhere that I'm not aware of?

[GeckoXL7]

Nah iac is in the throttle. If the battery falls bellow and stays bellow 13 then you have a lorblem with the alternator. Mine had dropped to 12.6 then charged and went up to 13.6 not long after. Ecu can switch alternator off to reduce load.

Useually the engine light would come on.

[GeckoXL7]

Ecu controls iac too it's the motor looking thing on the throttle body

[murcod]

I ended up pulling the alternator out and stripping it down. Everything checks out okay - there's even plenty of length left in the brushes. The only bit I couldn't check was the regulator. So I reassembled it and put it back in. I did clean the ignition and dash light plug terminals as the dielectric type grease in the plug had gone hard and was well past it's useby date.

I then pulled the IAC assembly off the throttle body and removed the "mod" where I'd partially blocked off the coolant idle control valve and IAC itself. It's back together and I went for a quick drive to bleed the coolant system and check nothing was wrong. That mod had been in there for over 3yrs so it would be strange if that was the cause?

I'll recheck the voltages again tomorrow. I did notice a slight increase in revs with the A/C on and when the headlights were switched on. Hopefully it's back to "normal".....

Regarding the alternator, I've read all sorts of things about it being controlled by the ECU in the updated models. The reality is I can't see how - it's got the usual battery wire and two small gauge wires for the dash light and ignition feed. All the documentation I've found also indicates both XL-7 models used the same alternator. I've got the service manual for the pre 2003 series and the wiring diagrams confirm what I mentioned about it being a standard alternator. Has anyone got the wiring diagrams for the post 2003 models?

[murcod]

For future reference, the part numbers off the 2004 XL7 alternator (Denso made) is 104210-8140 and 31400-52D10 .

[GeckoXL7]

Its got a smart IC regulator, but i did read somewhere that the ecu can control Output to reduce load at certain times, or increase output when needed, i have a AMP and Voltage meter permanently connected AMPS and Voltages vary constantly, eg at start its around 60amp then drops down to 16 and then after about 10min to around 1-10amps If accelerate hard it would briefly go up to around 30amps, Same if aircon or lights get turned on amp output will go up to a certain amount.

Im not sure if its it but there is a black white wire that connects to the IC Regulator and goes to a 20amp fuse and the IG Meter(?), then to the ECU, ICM and to the Dash light and then there is a White/Red wire that goes to the dash Charge light and white that goes to the battery via a 100amp fuse and the Case of the Alternator is the ground.

Looking through service manual these are the specs.

Type 105 A type
Rated voltage 12 V
Nominal output 105 A
Permissible max. speed 18,000 r/min.
No-load speed 1,150 r/min (rpm)
Setting voltage 14.2 to 14.8 V
Permissible ambient temperature –30 to 90 °C (–22 to 194 °F)
Polarity Negative ground
Rotation Clockwise viewed from pulley side

[murcod]

Thanks for the info.

It's cranking over faster than it has for a long time - so the battery definitely wasn't helping. I'll wait until we get another hot day and check the idle voltages with the A/C on- for now it's running perfectly.

PS: I hate the start up revs with the IAC mod removed. It spiked to over 2200rpm on start up yesterday (that can't be good for a cold engine, before the oil has started flowing!)

[GeckoXL7]

Mine sits that high but only briefly for around 20-30seconds then drops if engine is cold.


Idle speed in manual says Ideal RPM is 700+-50RPM with AC on 750 +-50RPM

Engine idle speed:
A/C OFF: 700 ± 50 r/min.
A/C ON: 750 ± 50 r/min.
IAC duty at specified idle speed:
5 – 40 % (at A/C OFF)

Engine idle speed: 700 ± 50 r/min. 750 ± 50 r/min.
IAC duty at specified
idle speed: 5 – 40 % (0.7 – 5.6 V when battery voltage is 14 V)

[murcod]

An update on the battery - I charged it after removal and it appeared to charge okay. It's been sitting disconnected from the charger since around 24th December and when I checked it's voltage today it was 10.4V - so definitely dead. My guess is it was possibly dragging the electrical system down.