Discussion in 'XJ Technical Chat' started by tabaka45, May 15, 2019.
how low is your idle? maybe 50 more rpm and it won't happen
I have thought the same thing, because when fully warm it idles around 1300, and cold less than 1000. I have not increased the idle because I didn’t want any higher idle when warm.
Check tbe case and frame ground connections. No paint or corrosion between the ring terminals and the mount points is best. Also make sure the battery ground wire is secure and there is no play where the wire is crimped.
you were having issues then changed fuel filter because old filter was cracked. adjusted mixture screws. have you installed the air box duct yet?
duct install may need some tune up adjustments as it does affect air flow.
Got the air duct and it’s in but I really had a chance to get it fully warmed up yet—hopefully today. Fuel filter is in.
Started it today. Battery reads about 12.6, and drops to about 10.10 when cranking. When cold at low idle, slightly less than 1000, battery reads about 12.27; at 1500 rpm it reads about 12.6; at 2000 it reads about 13.1; and, at 3000 it reads about 13.6. At cold idle if I hit the brake it drops to about 12.1 and may stall. At higher rpms it still drops slightly when the brake is applied but doesn’t seem to effect the engine. Any problem with those numbers?
I also think that I may be dropping a cylinder at cold idle, so maybe I am still a little lean on that cylinder—- no idea which one yet.
* approximately 500-2000 rpms: 1.8 volts gradually increasing to 14.2 volts
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all models except XJ700-X and XJ750-X)
If your charging voltages are too low, suspect the alternator brushes first, then perform the alternator stator and rotor checks as described in the Alternator Section.
your brushes need to be checked how to in this link.
The Ultimate Relay, Switch, Sensor, and Diodes Guide
Should I just go ahead and get new brushes or is there some way to check the ones I have?
you start by ohming the wires externally to alternator to see in it is needed to open up.
then measure length of bruhes 11mm is min. spec and rotor will need to be cleaned with hard art eraser and clean the crumbs with canned air and electronic spray cleaner do not overdo it.
the way I think, if I am going to open the cover the brushes are going to be changed. you may also consider replacing the brush holder
I have been trying to buy a house—unsuccessfully unfortunately—so I have not done anything yet. Not sure how to “test the ohms” and can’t find anything about it in my tech manual. How would I go about that and what reading am I looking for?
ohms from green and brown wire these wires are connected to the brushes.
ohm the 3 white wires
The Ultimate Relay, Switch, Sensor, and Diodes Guide
from above link read it is at the end it has trouble shooting advice
Checking Alternator Stators:
Measure the resistance across each pair (white1 to white2, white1 to white3, and white2 to white3) of the three white wires (white1, white2, and white3) at the connector; the specifications should be:
0.50 ohms +/- 10% for all XJ550 models.
0.46 ohms +/- 10% for all XJ650, all XJ700, all XJ750, and XJ900RK models.
0.37 ohms +/- 10% for all XJ1100 models.
0.40 ohms +/- 10% for all XS1100 models.
Note that the resistance specifications for the stators are extremely small; they should barely have any resistance at all (compared to most other electrical devices).
Checking Alternator Rotors:
Measure the resistance across the two lead wires (usually brown and green) at the connector; the specifications should be:.
4.5 ohms +/- 10% for all XJ550 models.
4.0 ohms +/- 10% for all XJ650, all XJ700, all XJ750, XJ900RK, and XJ1100 models.
3.5 ohms +/- 10% for all XS1100 models (field coil).
Thanks. I'll try to check it out this weekend.
I may have found my problem. I removed the alternator cover and found oil inside and the inside of the windings were coated with oil and although the brushes looked ok I am sure they are coated with oil. A couple of years ago I tried to fix the oil leak that was, and still is, coming either from the oil nozzle and/or the alternator shaft flange. I replaced o-rings on both and had also found a pin hole size imperfection in the inside of the flange where the o-ring fit and tried to repair it by filling it with rtv. Could that be the source of the low voltage from the alternator? I have not checked all the connections, but the ones I have have been fine.
oil will cause drag and also act as an insulator on the brushes to rotor
It's a light coat, but it's everywhere. How would I go about cleaning the windings?
Electric motor cleaner.
Not contact cleaner or any other solvent.
As for the leak, and the previously discovered imperfection, I think it would be wise to shop for a replacement bearing carrier. The only other thing I would reccomend is fixing it with epoxy, but given how inconvenient it is to pull the alternator rotor you may as well as get a carrier that does not have that imperfection.
I happen to have a spare engine sitting on the garage floor and my plan was to swap the bearing carrier, but still try repairing the old one with epoxy. I will see if I can find some electric motor cleaner, and replace the brushes at the same time. Hope that fixes the problem--getting to be a pain.
The spare engine has no brushes but the shaft flange is good with no oil leaks so I want to exchange it with mine that does leak. I got two of the torq screws out using an impact driver but the third one won’t budge and has stripped the star points so that the torq driver pretty much just spins. Any suggestions on how to get it out short of drilling it? I don’t want to damage the flange or the engine.
Can you post a pic? That would help this brain give you some better ideas.
Will the next size of TORX or Allan bit grab if you tap it in?
I know you don't TIG weld, but you could epoxy a bit into the screwhead. Use the steel-filled epoxy and let it set up overnight.
If you do hae to drilll it out, use a left-twist drill and size it so you can drill the head off, leaving the stub of the screw. I would not use an extractor on it.
Had to drill the screw and use an easy-out extractor, but it came out. Got the flanges exchanged and the electrical parts cleaned and polished. Unfortunately, I broke one of the brushes getting the holder out to clean it. But I suspect they were saturated with oil anyway. Brushes on order from Chacal.