Where Should my Voltage Gauge Read After...

[5-90]

5-90,

Yes, the huge hit happens during idle. As a quickie test today, I jumped in the XJ fired it up waited a few min for the engine to warm up then I switched on the A/C MAX (during idle) the Dashboard Voltage Gauge moved almost into the red area.

Then I reved the engine to about 1.5k to 2k RPM the above Gauge picked right up almost to 14V! And stayed there as long as the higher RPM's was maintained!

So, I gather that as long as I'm reving and not idling I can run most of my high-current accessories including the A/C!

****One last question, suppose I'm stuck in traffic and I forget to shut-off most of the accessories including A/C... will the Yellow Top drain all the way down and my engine shut off or conk out? Is this bad for the battery and alternator charging system etc? Hope I'm making sense.

One more thing - try turning everyting on, and gently twiddling the throttle until you get full voltage back. You should see that happen around 1000RPM or so.

The problem is what I suspected - your alternator can handle the load you're putting on it, but not at idle.

For your last question (which does make sense to me...) yes, it could drain your battery down, and yes, your engine could konk out and you'll need to charge tbe battery before you can start again (a jump won't do it - if you do get the engine to run, you're going to kill your alternator in short order.)

You really want to make sure you remember to turn off some accessories if it looks like you're going to be idling for a little while - say, more than 10 minutes (which isn't a problem here in the Ghey Area - traffic sucks from about 0500 to 2100 on weekdays - 0500-2300 on Fridays.) Just develop a habit if "panel sweeping" (checking your gages once every couple of minutes, like pilots do) and you can keep an eye on things.

If you decide to install an aftermarket voltmeter, I'd say to connect the ground to the chassis, and the "sense" lead (positive) to either the battery directly or to the main distribution point (start relay post on RENIX, PDC post on HO.) You don't need to fuse the thing, and you can use light-gage wire to hook it up (like 18AWG. It's really not going to see a lot of current.) That will give you a more accurate read on what's going on with your electrical supply - just be sure to calibrate the thing (there may be an adjustment - back-check it with a good DMM.)

 

[Blaine B.]

Regardless, his LCD screen is doing strange things......so whatever the volt gauge reads, something is wrong.

 

[DIGITRUCK]

Regardless, his LCD screen is doing strange things......so whatever the volt gauge reads, something is wrong.

Thx for reminding me.

The LCD is plugged into the cig lighter which powers two things an older model of EARTHMATE (GPS SENSOR) and the 12 inch LCD.

Could the Cig Lighter not be supplying enough current? And on that note I also have a smaller 5 inch LCD (used for backup cam) where the old remote thingy was above the rear view mirror on the headliner that also craps out when the voltage starts to get dicey.

Should I run larger power leads into these accessories? Would that eliminate the blanking effect?

Thx.

 

[langer1]

Even after you upgrade your wiring you will still need a high idle setup.
The 88 ECM don't have that option but you can use the A/C sense input.

 

[Shorty]

One more thing - try turning everyting on, and gently twiddling the throttle until you get full voltage back. You should see that happen around 1000RPM or so.

The problem is what I suspected - your alternator can handle the load you're putting on it, but not at idle.

been following along for a bit and it appears that 5-90 has the right answer (on this point-- good counter help is another issue).
an option not yet discussed is a SLIGHTLY smaller alt. pulley-- it will increase the speed at all RPM, but unless you're prone to spinning the engine to red-line, you can benefit from the increased output at idle without much hassle. The only setback might be a smaller-than-stock belt length.

I'm sure one of the less than qualified 'urinal jockeys' could assist you in finding both a smaller pulley and a shorter belt-- just explain what you wish to do and remember that it may take a few tries to get something that will fit and function nicely.

best of luck in your search
--Shorty

 

[5-90]

been following along for a bit and it appears that 5-90 has the right answer (on this point-- good counter help is another issue).
an option not yet discussed is a SLIGHTLY smaller alt. pulley-- it will increase the speed at all RPM, but unless you're prone to spinning the engine to red-line, you can benefit from the increased output at idle without much hassle. The only setback might be a smaller-than-stock belt length.

I'm sure one of the less than qualified 'urinal jockeys' could assist you in finding both a smaller pulley and a shorter belt-- just explain what you wish to do and remember that it may take a few tries to get something that will fit and function nicely.

best of luck in your search
--Shorty

RENIX uses a Delco CS-130 alternator, so March (Google them - I don't have the URL offhand. "March Performance" or something like that) might have a smaller-than-stock pully you should be able to use. Shorty is right - that should increase your alternator output at idle, but I don't know how much offhand. March will tell you they don't have anything for Jeep - so just tell them you want an overdrive pully for a Delco CS-130 (they mainly do underdrives - but I see no reason why they can't get you an overdrive as well.)

With care, you can even change the thing without removing the alternator - but it would be easier on the bench.

Worst case - a CNC shop can cut one on the lathe for you - but you'll pay for the "one-off" job doing it. It will help if you can dismount the old pully, measure it, and then shrink the pully so the circumference of the new one is about 15% smaller than the old one. Too much past that, and you risk going through alternator bearings like popcorn...

 

[Blaine B.]

Why not just hardwire the items?

Or go to walmart and get some cigarette plug thingies and hardwire thema if you don't want to cut the plugs off.

Then see if the problem still remains.

 

[Harlee&Tahoe]

Even after you upgrade your wiring you will still need a high idle setup.
The 88 ECM don't have that option but you can use the A/C sense input.

like high idle in "Police package" XJ models?

 

[5-90]

like high idle in "Police package" XJ models?

Pretty much, but I don't think the "Extended Idle" switch became an option in HO until 1995 or so. RENIX just doesn't have it - but the AC SEL option is a valid one - I just haven't had a chance to check it out myself yet...

 

[Shorty]

Pretty much, but I don't think the "Extended Idle" switch became an option in HO until 1995 or so. RENIX just doesn't have it - but the AC SEL option is a valid one - I just haven't had a chance to check it out myself yet...

I believe the idle compensation is through slightly larger oppening of the IAC when AC is selected-- probably wouldn't help much (if at all) since it would already be activated as his problems are mostly with the AC on. I would expect a "super-lean" idle unless ECU was programmed to compensate for extra airflow at closed throttle position-- just a thought-- I could be wrong

--Shorty

 

[DIGITRUCK]

The smaller pulley coupled with upgrading mains/grounds with 4AWG Wire did the trick!

I can now simultaneously run EVERYTHING!

Thank you All.