Symptoms of poor power

[craigr]

Hi,

Just finishing installing my new ICE consisting of 1 x bridged 4 channel amp running the front and 1 x mono amp running a sub.

On the way into work this morning, with the stereo only on very moderate volume levels, the FD started doing some weird stuff.

At normal cruising speed (40 ish), the car appeared to lose power (running on the revs it had, but push the clutch in and the revs would drop to nothing). Pulled up to a junction and it died. Started up after a struggle and then it died at the next junction again.

Turned off the stereo, which would therefore power down the amps, and everything was fine for the remainder of the 30 min journey.

I can only therefore conclude that I am drawing too much juice and it is sapping what\'s needed to run the car for normal driving.

Do you think it is something as simple as a duff battery, and a replacement with more poke (Optima or similar) would resolve the issue, or am I going to need to go down the whole second battery/split charge system route ?

Also, if it has lost so much power that it makes the car die, will this have any effect on the mapping of my Apexi ECU ?

Cheers in advance, Craig

[NixRX7]

Should\'nt effect the PFC, as its been mapped to the units eprom or whatever it has, otherwise if you removed the battery etc you would lose the map.

Have you tried going for a drive and seeing if the same thing happens again ?
Where your lights/wipers etc on, those and two powerful amps could draw to much power, are they connected directly to the battery ?

I would try and borrow a higher amp battery and see if that cures your problem, if not check your wiring for shorts/crossed wires etc

Nick

[shaunwil]

Sounds like the alternator isn\'t charging on all its coils, so its only trickling a little back to the battery. What voltage does it show when the car is ticking over, should be able to call it up on the pfc. It should be over 14v with the engine on, any lower and its not charging properly

Hope that helps

Shaun

[craigr]

Thanks for the pointers. Only the stereo and side lights were on, nothing else. Dash lights didn\'t appear to dim. Tried it on the way home for half the journey, and no hiccups at all.

In terms of charge - still awaiting my Commander, so I can\'t currently tell. Car always turns over and fires fine, even after 3 or 4 days of going nowhere - so I can only assume the battery is in a reasonable state. I was thinking of getting a more pokey battery anyway, but the usual suspects that are recommended (Exide Maxxima, Optima Yellow or Red, Bosch Silver) do not appear to have RX7\'s listed.

Will run some tests over the weekend, evenings drawing in now mean no more after-work play time ! It could be something as simple as a dodgy ground.

I have heard people in ICE circles talking about running an uprated alternator - has anyone out there done this on an FD ?

[shaunwil]

I\'d just take a volt meter to the battery and see what it is running at. I\'d just take a tape measure to the area available and get the biggest silver calcium battery that fits. What amps are you running

Shaun

[craigr]

Just went out to Maplins and got a volt meter.

12.4v with engine off, 14.5v at idle. Didn\'t try various mixes of components such as lights, etc. That will be my next test.

[nikp]

Those voltages look fine. Check it with your AMPs on next - see what the draw is then.

[craigr]

Yep, that\'s the plan.

Shaun, running VIBE Blackbox III for fronts and VIBE Monobox for sub.

[shaunwil]

Those don\'t look too masive. I used to run similar amps in an axgt and that only had a 50 amp alternator.

What gauge cable are you using on both the positive and the negative of the setup ?? I\'d expect at least 8 gauge for the 4x100 amp and at least 4 gauge for the monoblock. Or alternatively at least 2 gauge to run both.

Either that or as somebody else said you have a short somewhere.

Shaun

[shaunwil]

oh, unless your battering the hell out of the system it shouldn\'t use silly amounts of power. The AX was good for 140 db !

Shaun

[craigr]

I know this is an old thread now, but I forgot to update everyone.

It turns out the problem I was having was the panel holding in the ECU in the passenger footwell had come adrift. As the ECU wasn\'t sandwiched in correctly, it was causing these problems - Doh !

Nothing to do with the stereo setup at all.

[cannibal]

I\'m in the process of installing a system and I\'m after ideas for layouts out teh equipment, have you any photos of your layout you could send me.

Cheers

Rich
R.Haus@agipkco.com

[craigr]

I have been meaning to take photos of it, and write up the install for another thread. I can do a camera phone job this afternoon if you\'re desperate, or some decent ones tomorrow.

[cannibal]

Some decent ones tomorrow will be fine.

Thanks

Rich

[cannibal]

This should give you an idea of what I\'m thinking for my FD.

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