Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[vitman]

ok me xj 4.0 1999 not charging have checked all fuses ok main wire from alternator out post to battery ok got one 12 volt feed to alternator on 2 pin plug .with engine running no 12 volt out on main post.have tested relays only relay u/s is cooling fan.there is a sensor on bottom of battery tray i take it a batt temperature sensor???.does the xj model have a charging relay? i been told ecu pulses charge to alternator.i need a wiring diagram to follow if someone may know to download or look at on the web.or any fixes pepole know of will be on the cases morrow ran out of light pissin winter here :banghead:cheers any info be a great help

[Panic mechanic!]

not 100% sure but think they have the same system as the wj , where the charging is controlled inside the engine management, there is a way round it,I am likely to be doing it myself or you can spend a few hundred replacing engine ecu and reprogramming.

[vitman]

thanks for replie is there any threads on the web bout by pass i take ecu sends 12 volt feed to alternator if temp sensor faulty will it stop charging ???also if ecu doesnt control it will put on mil on dash and give p code

[vitman]

i have alao tried another second hand alternator so can rule out that also

[Panic mechanic!]

sounds like you have the normal chargin problem  then, you need to bypass the internal voltage regulator, you can find out how on youtube

[vitman]

i take it internal voltage reg in ecu??? will look on youtube thanks

[Panic mechanic!]

yes or you may be lucky and have the type you can take apart and resolder, I would ned to see a pic of ecu to tell you if you can do that

[vitman]

i got a n reg xj where there is resistor on loom to alternator but mine has just 2 pin plug and main out post so mine must be in  ecu.if i got igntion feed on one wire and other must get feed from ecu cant i just feed that wire with  12 volts with engine runing to see if it will start charging??

[vitman]

http://www.ebay.co.uk/itm/EXTERNAL-VOLTAGE-REGULATOR-BOSCH-VALEO-12V-VOLT-VOLVO-FORD-BMW-MERCEDES-130675-/180984113664?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2a237e6a00
if it is ecu at fault cant i use this to bypass??

[Panic mechanic!]

not seen that type used but I don't see why not as long as you can work out what wires to bypass.

[bigjeepzj]

that one may work
the modern jeep alternator dose not have a regulator in them
you can fit this kit to get round it

http://store.alternatorparts.com/hd-external-voltage-regulator-conversion-kit.aspx

[vitman]

ok will check morrow but is there a quick way to check if ecu at fault?? i take it there should be 2 batt voltage at 2 pin connector on alternator when plug in and engine running is there a company in the uk to get that convewrsion kit in pervous reply???

[bigjeepzj]

one of the pins will have a voltage that will vary with load and engine speed if you have a perm 12v or 0 on both the ecu could be faulty
the 12v comes from the emergency shut down relay so it could be that if on 12v
the ECU controls the reg voltage on the neg side of the armature.

[vitman]

ok will check out morrow will cut out volage reg on n reg jeep i got to see if can use or will reg be in ecu to on 1995-1996?

[Jonny Jeep]

Regulator for 95 models is also in the PCM.

In 99 Dark green wire to alternator field terminals is from ASD relay but routed via the PCM and should be at 12V for first two seconds ignition is turned on or when engine is cranking or running. The green/orange wire is controlled by the PCM to cycle the ground to the alternator field circuit and regulate output. At cold temps the charging current is higher than when warmer so even if the battery temp sensor is bad or unplugged the system should still charge.

Not often but sometimes the regulator within the PCM does fail. I don't know if bypassing the PCM regulator with an external regulator could end up causing a check engine light and code.

[vitman]

ok spent coupe hours on jeep today found good 12 volt feed on green/orange wire checked found main wire ok to battery post.found green wire from ecu to alternator ok but when plug in engine running found high resistnace in wire traced to cooreded wire in loom just behind abs pump area cut plus soldered new wire in and now charging at 13.98 volts loaded.

[bigjeepzj]

good man

[isle of man]

Ding-a-ling!

[Jonny Jeep]

Well done.