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[Dingleberry]

Hi, i have been advised to ask this question i nthis area  

After fixing the starting problems with a new battery the seny ran fine for a month or so until last night . . . i went for a short drive to the shop  and had the heated seat on/screen and the front screen demister, i get to the shop go in come back out about 2 mins later and the battery is dead, i get it restarted and got it home and ive found that at idle if i turn all the above on everything goes real dim the battery voltage drops and the rev counter goes funny then i turn it off and it wont restart, get it started again and leave all the above off at idle and nothing plays up and it will restart when turned off, also if i rev it and hold the revs at 2k the dont stay there they hover around 2k

Any ideas ?




Cheers

[theolodian]

Yeah, that's what today is all about for us, trying to fix Senator problems, and Representatives, etc.

Oh, you mean the car!  

Sounds like a main power connection is overheating and the resistance is spiking.  Can be an internal short in the battery, or a bad alternator, but also could be fusible link, fusebox, or other main power connection.

If voltage at the other end of the system from the battery is marginal then strange things start to happen like the ECU is fine until you start cranking and then the voltage drops enough for the ECU to shut down.  So even though it cranks you have to bump start it  

[Dingleberry]

Meant to add that it has had a new battery, have yet to check fues etc and i dont really want to have to change the alternator for cost and how difficult it looks  

[CaptainZok]

Have you tried switching things on one by one to see if you have something shorting?

[theolodian]

Meant to add that it has had a new battery, have yet to check fues etc and i dont really want to have to change the alternator for cost and how difficult it looks  

New battery doesn't mean no internal short    Don't rush to change the alternator, and fuses aren't the problem.  Start with a voltmeter.

Does it not start or not crank at all when playing up?  Read the voltage at the battery when cranking and then go from there.  Check connections and fusible link if any.

[Marks DTM Calib]

Sorry guys, sounds like a goosed alternator.

Get it started and rev the engine whilst measuring battery voltage and report back....I suspect its not charging......hence why a new battery worked for a while but, its now pretty flat....

[Dingleberry]

Does it not start or not crank at all when playing up?  Read the voltage at the battery when cranking and then go from there.  Check connections and fusible link if any.

Basically it cranks but very slowly and gets slower and slower until theres nothing left




What sort of readings should i be looking for when measuring the voltage ?

[theolodian]

Mark's probably right about your alternator, although you may also have just drained the battery with short trips and too many power users.

If the battery voltage is dropping while cranking, from 12+ to 11 to 10 or less, then your problem is not enough juice in the battery or internal short.  If the voltage is staying over 11 and the motor cranks really slowly then you have an electrical problem somewhere else, check at the other end with the starter.

It sounds like a combination of a weak alternator and driving habits.  In general cars don't charge well at idle, you need to drive them for 20 mins or so above idle to get any real charge in the battery.

[Auto Addict]

I thought Senators had a voltmeter?

[Pete Elite]

They do on a digidash

[Big Rod]

I'm with Mark on the alternator theory.

I'm intrigued about the 'holding the rev's at 2k' statement.

Are you saying that the engine 'hunts' if you try to hold the engine at a certain speed or is it just the dash that's acting up?

If it's just the dash then a new alternator'll sort that, but if the engine hunts, get a new lambda sensor!!

BTW, where are you? I'm in Fife and I should be able to dig a decent alternator out for you if you want and it's possible to get it to you.

HTH.

[Dingleberry]

Sorry yes it does have the digi dash and i have noticed that when all the ancillaries are turned on the voltage drops at idle and things start to go dim as soon as the revs are raised it all lights up abit but once all the ancillaries are turned off the voltage goes up and everything gets brighter  :-/


Edit : Yes at 2k it hunts a little bit not lots but you can hear it, im in portsmouth . . .  quite away from you  

[Marks DTM Calib]

Ah yes, the classic Senator surging problem.

Still alternator in my book, regulator diode goosed causing low output.

When revving, the battery voltage should be above about 13.5V......

[Admin]

No question it is the alternator.

You should not have too many problems getting hold of one. If Rod will post his, that will sort it (courier will probably be £20 but worth it).

As for changing, it is not that bad at all...

By the way, 12 or 24v beastie?

[Dingleberry]

Well havent got round to testing the voltage yet but will do when i get home from work  


Thanks for the offer Rod   is it ok if i get back to you ?


And its a 24v