[QUOTE=Jag4;1649717]WayneinAus, My mechanic isn't sure what the problem is..../QUOTE]

Hi WayneinAus, Any progress/update?

I am back tracking my steps while upgrading the fan module, tracing electrical stuff but nothing yet.

 

I had a similar experience with my 2006 3.0 just before the thermostat seals gave away... It was overheating - Once I replaced thermostat everything came back to normal

 

Hello All,

Should someone come up with a bad fan module I would love to have it to see if it can be repaired? As I am told it the power transistors that go bad.

I will pay for the shipping and do a post on what I find.

 

Larry, if you need info, let me know. I have the transistors sitting around my house. There are 4 of them, two different kinds of transistors are needed. Once you open it up, you will see where the problem lies as the transistors do not have sufficient contact surface to remove the heat. The 4 transistors are sitting side by side at the one end of the module.

 

Hi Jag & Chris,
I contacted the supplier but no answers from them that help so we are left to own devices again, Since it was working full speed with ign on I can at least use the car, it has developed a misfire occasionally so I replaced the spark plugs full set, old ones had a massive gap so probably not changed for years, anyway misfire still there but it is starting more readily, it also runs a little rough for first 30seconds from cold, might be air leak but since it still has a miss I am ordering a full set of coil packs and will replace these and the inlet manifold seals after my holiday in May so it will be a month before I get back to you with results, I am also looking for anyone wrecking one close to me who is willing to let me try bits from theirs like the module and ecm no luck thus far though.
I have replaced the top hoses as they were collapsing with pressure but no overheating or coolant loss (I flushed and am using Evans Waterless in all cars now) the temp gauge rises slowly as is normal and remains steady just below the mid range mark so I don't think the thermostat is at fault, it is quite bewildering to me at least but we will find the answers. I threw out the original so sorry can't send for testing.

 

WayneinAus, Thanks for the update. I am working on this with my mechanic and I have sent him the relative threads from this forum. I am dropping my car off this week - so we'll get to the bottom of it one way or the other.

I will be replacing the thermostat and seal so that's for sure.

About your coils: I have a old invoice - dated several years ago from the pervious owner - which had a recommendation to replace all the coils.

 

Hi Jag, I look forward to hearing what your man finds, the last comment about the coils is confusing, I expect you are talking about the last owner of YOUR car as I don't see how you could mean mine?? Did you replace them on yours and what was the issue and did it fix it??

 

Hi WayneinAus, Replacing all of the coils was recommended to the previous owner of [my] car. Since they (apparently) only replaced one of the coils. The car runs great though, as is. I did have the plugs replaced as they were bad; but haven't touched the coils, yet.

I mentioned the coils as an FYI, not sure it helps in any way though.

I have replaced a ****-ton of little things like plugs, water pump, thermostat, tensioner pull and belt (this is a known problem causing the car to run rough); top/bottom control arms front and back and the shocks and springs - all making a huge difference in how well the engine runs and overall handling. (Strut mounts disintegrated as they were removed, BTW). And all of the suspension related bushings were beyond shot. I will write all this up soon.

Thanks for following up. More to follow!

 

@WayneinAus Issue resolved -

When I replaced my 2002 fan control unit (known to be bad) with a 2004 unit, (known to be ok) I didn't fully seat one of the electrical connectors. Seems the fans fail to the open/full ON position.

Today I removed all of the related connectors, cleaned the plugs, and re-connected everything. After this I ran a battery of test sets to ensure proper operation - we're all good now.

Not sure this helps you WayneinAus.

 

Hi Jag what do you mean(Seems the fans fail to the open/full ON position) I replaced my old unit when it just ran the fans full bore with or without ign o& regardless of temp, the new unit (from china) is off when ign off but on full with ign permanently running with ign, ign off fans stop a few moments later.
I am away on holiday next week but am planning to replace all coil packs on return since it gained a misfire after changing plugs, the other day it was missing so bad I floored the pedal and check light came on code came back lean mixture on one bank, cleared code has not returned, also need to check any signs of air leaks, I will let you know how I go but will also check all connections when I do the above.
cheers,
Wayne

 

Hi WayneinAus, I mean...because one of the fan-control-unit plugs was not seated properly (in other words, not plugged in), the fans ran at full speed regardless of temp, AC being on or off. In this case, the fans would come on 10-15 seconds after the car was started, and would remain on until the car was turned off. (This is with the 2004 fan control unit installed.)

Note: The behavior I just described should not be confused with the behavior which led to my replacing the 2002 fan control unit (see above in this thread). Then - with the 2002 fan control unit installed - the fans would come on only after driving the car for a while but would remain on FULL regardless of temp, AC, etc. Once the fans came on, they stayed on until I turned the car off. I could then restart the car right away and the fans would remain off for a while. I hope that's clear.

Let me know how the coil replacement goes, I hope to do this myself. Better if you provide the pics and details worthy of someone mechanically minded but without much experience - like me.

Chris

 

sorry Jag I'm confused, if either of the plug connector was not connected then how were the fans running at all??
i.e. not connected = no power = not running

I had another issue appear gain yesterday, I had just ran about ten minutes to pick up G/kids from school, when we came out and I started the car the alternator light stayed on after starting, it did this before so I replaced the alternator and trust me with AC this is a bummer of a job, anyway I thought that would fix it but every so often it stays on, not indication of battery issues I did a drop test and it passed, all cells show healthy so I don't know why this happens but I am told it has a strange charge method what ever that means? battery always has heaps of power. very odd

 

WayneinAus, To clarify, only one of the fan control unit (FCU) plugs was not connected.

I believe there are a total of four FCU plugs in all; two of the four plugs connect just under the FCU. I noticed one of these plugs, the bottom plug, was not fully seated. I believe this was my problem. I can send pics.

I've been running the Jag a few days now and it continues to run as expected.

Sorry for the alternator issues. I will stay tuned for that resolution as well. I will be turning over this X Cat to my son, once I buy my XK.

Chris

 

Ok back from holidays, stripped and fitted full set coil packs and checked all seals etc for air leaks, only found one when I moved the intake manifold I broke the plastic T piece joining brake booster, intake manifold and a pipe going off under battery so I replaced the T piece and as the pipes used were hard as nails I used new pipe, so new plugs, new coil packs and zero air leaks (that I could find) started and after a moment ran without issue, road test after clearing codes went well all power no missing.
The cooling fans still operate full with ign on and still stop a few moments after turning off, checked all leads going to control unit and fans, nothing loose or disconnected so its still a mystery.
car ran well for a day then when I hit accelerator yesterday it had acouple of big coughs and splutters before settling down and initiating check engine light, same codes 03\07\00 lean mixture bank 1, the others mean nothing apparently.
cleared codes and all seems ok again at least for now, it is just a tad lumpy at idle especially from first start of day but quickly settles, feels like an air leak but if it is I haven't found it.
I have ordered a new fuel filter as this is the only one I personally have not changed and if restricted could be causing the weak mixture (but only on bank 1 is odd), not happy days but at least I can use the car pretty much normally, will let you know if filter fixes anything

 

Try checking your coolant level, thermostat or temp sensor. Car keeps fans on because it detects the engine has "overheated"

 

Hi Freddy thanks for the input, the fans come ON with Ign even first thing after standing all night, I have replaced hoses and flushed coolant and now use Evans waterless, the temp gauge is zero until it climbs to below mid point as engine warms up but never goes above and there are no leaks and the coolant level is steady at correct marks.
it makes no odds if I disconnect sender connector unless I am missing something I am at a loss, I have replaced the fan controller and when I turn ign OFF the fans shut down moments later.
I agree somewhere it must be getting a signal telling it to keep them running but I don't know where from, I am tempted to just install aftermarket sender in hose and power to module through it to circumvent issue.

 

Did you replace the fan module? if not try that, also replace the temp sensor just incase they are not that expensive.
We can also rule out the thermostat because it only faults when running the car for a long period of time.

 

Hi WayneinAus, Have you tried a different OEM fan control module?

 

hi Jag, no I haven't I bought two replacements from China, they are supposed to be the same units later marked OEM but I haven' bought one from a jag dealer as they are not cheap and do not just let me test a theory before buying, there aren't enough wreckers here to have one in stock, E-bay have S/H but then it isn't guaranteed, the original was working fine until it didn't and it stayed on regardless of temp or ign status till battery died.
at least at the moment they only run when ign is ON but this is going to cause prem wear to motors not to mention annoying hearing them run all the time lol

 

it would appear I have changed te coil packs for no reason, the same intermittent miss is still happening, for all my years it feels like a break in main ignition on an old car I would have said coil HT or somewhere like that.
It started after I installed new plugs so I am only guessing I have disturbed something in that process, most of the time she runs pretty sweet from start up, idle to full throttle going over 5000rpm I back off but when it misses there is no obvious reason no bump in road, change of fuel so it has to be a dumb electrical issue, the ODBC I have only basic maybe I need something I can plug in that monitors the whole system
I will scout around the wiring see if I can shake the devil loose.

cheers fella's