starting a car with no alternator?
Discussion
Hi, I have a MK1 MR2, and I have removed the alternator as it's not charging and I'm going to recondition it, I'm just wondering if it's possible to start the car without the alternator. I was running fine before I took it out but did need jump starting, now when I turn the ignition it just clicks and the voltmeter drops. I have gave the battery a good charge before I try.
Thanks
Liam
Thanks
Liam
that's shocking.fake7 said:
I might be wrong but.......
until the car is running the alternator won't be turning, so you always start the car on the battery.
Yep but the alternator will be recharging the battery as you drive at any speed above idle. The only problem that will arise is that the car is more than likely to have electronic ignition and if I'm right coil packs or some sort of electrical discharge for the spark plugs. I wouldn't have thought the car would last too long without the alternator returning the charge to the battery to power these.until the car is running the alternator won't be turning, so you always start the car on the battery.
davepoth said:
But the chances are that it needs the alternator in circuit before it'll start. Plug it in but just rest it in the engine bay, and it should go.
The MK1 will run perfectly happily without an alternator.I had to do exactly the same thing...FYI, I did 80 miles and the battery meter was still in the 'ok' band
AndyFoo said:
Yep but the alternator will be recharging the battery as you drive at any speed above idle.
Small correction - the alternator will be be charging the car at idle. This is one of the key advantages of an alternator over an old-fashioned dynamo where the "ignition light" would typically glow red at idle to indicate no charge. (Alternator is better in many other ways too).I'm no expert, but:
Plenty of racing cars run without alternators, so in theory, yes, or course you can run a car without one. As said above though, there are some practical concerns: be wary if any important ancillaries are driven off the same belt, if removing the alternator breaks a circuit of any sort in the wiring loom, and a complicated car (probably not yours thankfully) may report errors if there's no alternator providing charge.
To answer the query about rpm above, most alternators have an excitement rpm that needs to be reached before they will start working (revs may then be dropped and the alternator will continue delivering charge). I don't know about road cars, but racing cars that run alternators usually have a pulley geared so that the engine needs to do significant rpm before the alternator wakes up and starts delivering charge. My old racing Metro was about 4,500rpm if I remember rightly. I don't know whether road cars have this issue or not.
Plenty of racing cars run without alternators, so in theory, yes, or course you can run a car without one. As said above though, there are some practical concerns: be wary if any important ancillaries are driven off the same belt, if removing the alternator breaks a circuit of any sort in the wiring loom, and a complicated car (probably not yours thankfully) may report errors if there's no alternator providing charge.
To answer the query about rpm above, most alternators have an excitement rpm that needs to be reached before they will start working (revs may then be dropped and the alternator will continue delivering charge). I don't know about road cars, but racing cars that run alternators usually have a pulley geared so that the engine needs to do significant rpm before the alternator wakes up and starts delivering charge. My old racing Metro was about 4,500rpm if I remember rightly. I don't know whether road cars have this issue or not.
sebhaque said:
Sorry to intrude with my lack of knowledge, but can't you simply bypass the alternator on cars and run the spark plugs off the battery? In which case I'm sure you'll be able to run the car (but probably only for a few minutes before you wear out your battery).
Yes, as stated above, a significant proportion of racing cars don't have alternators and run like this as normal.I geuss the battery is just fully dead then, last time I did have it running a few weeks ago it died as soon as I parked it up, I had to floor it to get to about 2k revs to get up the lil bump to my garagee, I guess I'll have to hurryup with the alternator so I can buy a new battery, no point in wasting money on one and then kiling it again.
Thanks
Liam
Thanks
Liam
Your main charging cable that bolts onto the 10mm post will be flapping about and grounding off the rear firewall if you don't insulate it.
On the Mk1 it's just the Alternator, nowt else on the belt unless it's a super rare AC model but IIRC that's on an outer belt again.
Anywhos, as mentioned above, if you remove the alternator and belt and insulate the charging cable then you can run the car until the battery dies.
Fine if you have to move it somewhere but if you're thinking of using it daily till the alt is refurbed then forget it.
On the Mk1 it's just the Alternator, nowt else on the belt unless it's a super rare AC model but IIRC that's on an outer belt again.
Anywhos, as mentioned above, if you remove the alternator and belt and insulate the charging cable then you can run the car until the battery dies.
Fine if you have to move it somewhere but if you're thinking of using it daily till the alt is refurbed then forget it.
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