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Need help guys.

A few times this week, I've gone for a drive and as I've pressed the clutch, the revs drop to 0 and the battery light comes on. Sometimes, I'm able to release the clutch and the car springs back to life.

If it stalls, I have to pull over and depress the accelerator and give a few 3000-4000 revs and it drives like normal, no stalling or low idling.

What could it be? Prefer to do most things myself as I'm new to the car, I'd love to learn.

Thanks,

Russ

Is it worse with headlights on? Just thought it could be the regulator in your alternator. Anyone else got some better ideas?


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Come to think of it, with the headlights on it is a bit more sluggish... and more frequent

Experienced it tonight. Came to an almost stop in second gear and powered through, but it was slow. As in 5 km/h with accelerator depressed.

Ideas?

Check charging voltage. Have you got a multimeter?
Should be between 13 - 14 bolts roughly.

Google "idle dip" here and on miata.net.

ED_MX5 wrote:Check charging voltage. Have you got a multimeter?
Should be between 13 - 14 bolts roughly.

Thanks, I'll go buy one. Where should I be checking for voltage?

manga_blue wrote:Google "idle dip" here and on miata.net.

Played around with the idle the other night but will go over it again today

Check belt tension also, a loose belt can cause charging issues.
To check charge rate:
- engine off, connect multimeter leads to battery, black to black red to red etc.
Note voltage, should be approx. 12.4 to 12.6 approx.
Turn car on, connect leads again and note voltage, should be approx 13.5 to 14.5V.
If it is much lower, you probably have a bad alternator. Alternator also at fault if it reads higher, which means it's actually boiling the fluid out of the battery slowly.
Also be sure to check all connections on battery and alternator, make sure they are all tight and no excessive movement in the leads themselves.

Another quick test, is after you have checked voltage with engine running, turn on every electrical accessory you can think of, lights, radio, a/c wipers ect and re check voltage. If it is below the 13.5, you have a problem. the alternator cannot keep up properly
Hope this helps mate.

The battery/charging light comes on when the engine is turning so slowly that the alternator can't work. It's nothing to do with an electrical fault. Idle dip, or idle drop, is the single most common and most annoying fault of NA6s and NA8s. I reckon you've got it.

Try here for the cure: viewtopic.php?f=76&t=60434

In the short term, while you're trying to track it, you can avoid it a bit. When you're slowing to a stop leave it in gear until the revs fall below about 900rpm before de-clutching. The dip seems to result from a delay between where the ecu decides the engine needs no fuel and no air (i.e. as you're decelerating) and when it realises that you really just want it to idle and it hands over control of idle to the preset throttle bleed setting. It's not so bad when it's just transitioning from under 900 under ecu control to default idle control.

Thanks a lot guys, had trouble starting it today. Was cranking but engine wasn't starting. Go over it with a multimeter and see how we go. Hopefully it's just a belt or the alternator

Today will be fun!

Got my battery and alternator tested at Super Cheap Auto and pulling 14V


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Hmmm something is not right. Was the 14v with headlights on?
Cranking issue could be fuel pump but that doesn't explain your dip/stalling issue... I'm out.


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14v with headlights off, I thought between 13.5 and 14.5 was okay?

Found out that I didn't adjust the mechanical idle last time so I did it before and now the ecu idle and mechanical idle match, woooo!

But it hasn't finished. Started the car in the cold and drove straight away, accelerator fully depressed, only managed to speed up to 10kmh until I clutched in and it shut itself off / stalled.

I have no rubber cover on the negative terminal of my battery, would that be a problem?

I'm thinking the fuel pump could be the culprit...


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