Spark plugs?

[Spinal]

So, my car is (finally) getting restarted and back on the road after all the issues with insurance companies et al. Last night, I put the battery on charge, and this morning put it in the car. No result; I grab my voltmeter, and test it, just over 10 volts... hmmm. Grab a hygrometer, one of the cells is dead. Charming I think, then I read the side "4 Year Warranty". I rush upstairs, find all my receipts and find the one from halfords, its 2 .x years old! Wee!

I goto halfords, they quickly check it and replace the battery with a new one!:bannana:

I get home, pop the battery in and start the car... on the second turn it starts (I was VERY impressed). Problem is, the car now idles at just over 500rpm, while it used to idle at .7/.8k rpm. Also, when I turn on the heater (or high beams or any energy intensive equipment) the rpm's drop noticeably and in certain cases, the engine dies.

I though I'de leave the car running 10 mins (which I did), and retry. Same issue; DOH! I'm thinking the spark plugs might be fouled up, is this possible?

If so, how do I get to them?! I looked, scratched my hear, looked again, and wondered. The 4 spark plugs are behind a very interesting metal contraption, with wires and cables sprouting from it... (its a W202-pre)

Thanks in advance,
Michele

 

[DieselE]

I think that you're getting your hundreds and thousands mixed up. I doubt that the engine will rev to 7-8k never mind idle at that speed.

Does your ignition warning light go out? The symptoms you describe look as if the alternator is not charging.

 

[Spinal]

Hundreds? Thousands? 'Tis just a zero, zeros mean nothing

No warning lights (other than the low fuel light, I need to refuel) on the dash... Tomorrow I'll put the battery on the external charger and see if anything happens over a day or two...

I'm guessing that spark plugs are ruled out then?

 

[John Sweeney]

I agree with Peter - it does sound like your alternator is not able to handle the load that is being placed on it when you switch on the heavy current absorbing items. How old is your car?

John.

 

[Spinal]

The W202 is the old girl, "shes" 10 in January

 

[John Sweeney]

Might want to see if you could get a second hand alternator then? Mercedes breakers, perhaps?

 

[Spinal]

(hope I spelt that right...) I love my old gal

So I went down this morning, a little dreary thinking "MORE things to tinker with until they work (which is good) and MORE money to spend (which is bad )". So, I decide to give her one last try.

I sit in the car, notice how I have enough condensation on the inside of my glasses to relieve Africa's water crisis (or London's during summer ) - and turn the key. Vroom The car starts, idles at about 800 rpm. A little too suspicious to be happy, I turn on the lights. No change. I turn on the heating, the rear glass demister, and...uhmmm (well, I click every button, flick every switch and prod everything that is prod-able). The car still idles, no drops in rpms... VERY ODD... So I open the boot and notice that there is a loose fuse on one of the battery wires (no idea what this fuse is, its connected inline to the +ive terminal of the battery). I seat it properly and re-try, the car likes it. I remove it and retry, the car like it... Odd...

But, the car seems not too have any issues. My explanation? Being a technically minded person, I put forth a technical explanation, not for the faint hearted. The car has a mind of its own. She needed to meet the battery and come to know the battery better until she would let the battery offer her a drink (Don't accept drinks from strangers )

In the meantime, the monster I've been driving as a replacement (3.3lt Voyager) was in an "accident" (more of a scrape). My mother miscalculated the distance between the car and the wall in the parking lot, and now the car has a dent on the near-side rear door. Thats next on the list! (The paint doesn't seem affected, it seems "coated" with white-wall-paint which comes off when scraped with a fingernail... I'm thinking of using a soft rubber eraser)

Michele

 

[John Sweeney]

Cars are a bit like that - they have minds of their own! My first car was a 1990 metallic dark blue Vauxhall Astra Belmont 1.6 Automatic. I loved it to bits. It was the proverbial 'one old chap owner from new, full service history, always garaged car' and then some .

Anyway, after two years of trouble free motoring, I was showing a couple of friends how relaible it was. I put my foot down and the dashboard went pop - all the gauges stopped, apart from the speedo (cable operated) and the alternator and oil pressure lights both came on.

So, I stopped, feeling that I should have known better than to tempt fate, I replaced the fuse... the car was fine. Then it blew again later, then fine for a week, then 'pop'. I know it was a short circuit, but I checked everywhere on the circuit and I could find nothing . In the next two weeks, the car was driven into twice (written off once by a bus ) and put me through a hedge while I was pootling round a corner at 35mph . It also decided to pee petrol all over the exhaust manifold (luckily on a coldish engine!) I scrapped it the next day - it think it was annoyed at my complacency or something. Poor car...

 

[Glenn Smith]

I agree with Peter - it does sound like your alternator is not able to handle the load that is being placed on it when you switch on the heavy current absorbing items. How old is your car?

John.

I disagree, why not check the alternator output before condeming? low idle speed is probably due to new battery being fitted, the car will need a run before it settles down, also the idle valve maybe sticking due to the car standing for sometime.

 

[Glenn Smith]

But, the car seems not too have any issues. My explanation? Being a technically minded person, I put forth a technical explanation, not for the faint hearted. The car has a mind of its own. She needed to meet the battery and come to know the battery better until she would let the battery offer her a drink (Don't accept drinks from strangers )

Your "technical" explanation is probably closer to the truth than you may believe. modern cars now have to have systems that can monitor and adjust to compensate for operating conditions and wear and still give clean emmissions, and warning systems to alert to conditions outside of it's scope eg faulty sender or switch, the ecu stores "learned" adaptation values removing the battery will erase these values, these will be relearnt on driving (may take sometime) during this time misfires and uneven running including idle problems are common.

 

[John Sweeney]

I disagree, why not check the alternator output before condeming? low idle speed is probably due to new battery being fitted, the car will need a run before it settles down.

Sorry: , I forgot to mention that that bit should come first!

 

[Spinal]

Wow! I got one right ... well, sort of Now I've found a mecchanic to do the suspension ball joints and he had a quick check at the alternator (I am driving 2000 miles in a month or so... might be safe to make sure everything it in tip top condition!). He found nothing wrong with it, AND I'm booking in for changing the suspension ball joints on the 13th (which is no longer an unlucky day since winning my court-case on friday the 13th of october Thanks for all the input

Michele

 

[fredfloggle]

Would certainly not condemn the alternator - the fact that it is pulling down the engine rpm at idle suggests that it is doing its job of converting mechanical energy to electrical energy - however something is preventing the idle speed from being maintained .

Generally the alternator wouldn't be capable of knocking out a hard charge at idle speeds .
If you have a multimeter you cancheck the condition of the alternator in a couple of minutes .

 

[Dieselman]

Spinal I suspect the problem is either damp HT leads or stuck idle compansator. The heat of the engine has dried these and they now work properly.

 

[Dieselman]

It also decided to pee petrol all over the exhaust manifold (luckily on a coldish engine!)

Petrol on an exhaust manifold won't catch fire as it evaporates and petrol needs a spark to ignite anyway.
Car fires are caused either by an oil leak or brake fluid on a hot manifold.

 

[John Sweeney]

Petrol on an exhaust manifold won't catch fire as it evaporates and petrol needs a spark to ignite anyway.
Car fires are caused either by an oil leak or brake fluid on a hot manifold.

Thanks - I didn't know that. Neither did my Mother - she wouldn't travel in the same car as me for six months. Especially since the replacement car, a 1986 Vauxhall Senator (old shape) decided to repeat the trick! It had LE Jetronic injection with circlips to hold all rubber pipes between the injectors. Reallt crappy. No wonder the fuel economy was so bad - it probably urinated half of it's fuel onto the exhaust manifold!