Another problem - Advice please!

Right, here is the situation. My Clipper has been fully serviced and is running very well indeed now. Had a new filler pipe fitted last week and cleaned out the tank of all debris and it has made a world of difference.

The car now idles nicely at about 1200 revs when started at cold and within a minute or two goes doesn to about 900 revs. From here it runs fine. However, this is only in the day time when virtually none of the interior electrical items are on!!

At night time (when the headlights are on, and often the heater, radio etc etc) the idle revs drop to about 400. The car can drive ok when this happens but when I drop it into neutral at junctions/roundabouts etc, it stalls and barely restarts.

If I turn off all the electrics, then it starts fine and idles at 900 revs again. Just to check my theory was correct, I just started the car now (10am) and let it warm up. Then I put the blower on to the highest setting and turned the headligts onto full beam. Sure enough the revs dropped down to 400 again!

It has a new battery and it seems to be charging properly, so I'm just wondering if this is an alternator problem?

Any ideas please?

could be. not sure if there is an idle control valve, if there is, this could need a slight adjustment.

but my main guess would be the alternator, use a multimeter at the back of the alternator to see what voltage it is giving out when there are not electrics on. then put your lights on an heater to take a draw from your battery, then see what your alternator is giving out. i'd expect there to be a fair drop in voltage.

usual alternator power output should be about 13-15 volts, then with lights on i's expect something from 12-14, (maybe 11) but anything lower than that i'd change the alternator.
hth

dan

I was going to do some testing this afternoon and given your opinion, I think the alternator seems the most likely cause of the problem.

I don't think the idle needs adjusting. The car is running fine and as above, this is not a problem unless the various different features are drawing electricity. I will do some testing with a voltmetre and get back. How expensive are alternators to replace?

Thanks

just put an ad in parts wanted, i'm sue someone has one they can sell you cheaper than a new one will cost.

dan

Sounds like the alternator is working fine, its doing exactly what it should - drawing a larger current when electrical devices are turned on.

Now, when it does this, it demands more torque from the engine, and it appears this isn't being provided properly, with the result that the revs drop. This will be down to:

- massively overrich mixture at idle
- massively overlean mixture at idle
- timing out
- some other unusual engine/transmission problem

I would recommend, check the timing, if this is good then get the mixture checked. AFAIK there is no idle valve (as a separate part) on a carburettor engined car - its a Clipper, unless its a very late model, it will have a carb engine. Can you confirm this?

Yeah, it's a 1.8 carb engine. What you say Paul sounds very logical. I suppose that fact that the revs are dropping when electrical items are on suggests that the alternator is doing exactly what it should. T

hink I'm out of my depth on this one, and going to need a specialist to look at the timing and set up of the engine. It is running very smooth and like I posted earlies idles at areound 1000 rpm with nothing on.

I doubt very much that the mixture is too rich but I suppose it could be too lean….any advice as to how I can possible rectify this myself before spending even more money in a garage with mechanics who have never dealt with carb engines properly!

Without a gas analyser I can't recommend fiddling with the mixture at all. Best leave it with a garage who are okay with carbs - is it really that much of a problem to find decent garages these days?

In a word - Yes!

One told me the other day that he wouldn't be able to tell me what was wrong with it until he plugged his laptop into the computer on the car and do a diagnostic of it! I thought he was taking the p**s and then sharpishly got out of there when I realised that he was deadly serious!

has this been sorted yet?

if the car is running fine then i wouldn't say the problem is fuel related.
there is not much of a pull from the engine when you put your lights on
ok the rev's drop a bit, but the running of th alternator should provide eough charge to the battery to allow the lights to work etc.
if your car came into the garage i work at, your altnator and battery would be the first things i'd check before moving onto anything else as yo say its running sweet as.

do let us know when you have this sorted as would be good to find out.

dan

Hi,

By way of update this has not been sorted yet. In the depths of this recession when money is tight, I am just resigned to the fact that the car will cut out when I use a lot of electricity. I am currently minimising the problem by using as little electricity as possible. At night for example, the heater is a definite no no and having the radio on is also a thing of the past.

I'm not sure what to think to be honest. I took the battery into halfords the other day for a test and they said that it was a good battery and was performing as well as it should. I suppose this leave the alternator as a potential problem, and I will check this as soon as I can get a damn battery to fit my voltmeter! However, I am sceptical that it is an alternator problem since the battery seems so well charged?

What you gys think? I'll check the alternator asap and get back to you.

Thanks for your interest and advice!

DB

I'm sticking with my original suggestion.

By the way, the mixture adjustment takes a much greater effect at idle, which is why it could behave like this at idle, but seems okay at higher power/load (it will still not be optimal, but not as far off). If your car is running lean and you leave it too long, it will suffer from overheating. If its rich and left like that, you'll coke up the plugs and use more fuel than you need to.

the wait continues!

Ok here's the situation….checked the battery the other day at Halfords, no problem, fully charged and working well. Just checked the alternator and it is working perfectlt as well….not that surprised really since the battery was showing no drop in charge at all.

1. The only thing that I was slightly concerned about electrically which I have now put to bed by reading some posts on here is that when the car initially starts, the bettery warning light comes on at idle, once reved, it disappears permanantly. I understand that this is entirely normal? Can we confirm?

2. After ruling out the battery and the alternator, I guess the only other potential cause is the fuel mix. I cannot even begin to consider this since the car seems to be running perfectly to me……? I am very confused as to how this can be the case yet it seemingly is the cause of my problems.

I cannot take to a garage at the moment since funds are extremely tight. It is my daily driver and I'm having to do the best I can with just keeping electrical activity in the car down to a minimum…..

Any further, non-expensive suggestions welcomed!

Many thanks

DB

you checked he alternator with the lights on as far as the car would let you before it dies?


got me stumped!