Amp Cuts Out When Engine Starts

Hi All,

Just bought a FIAT SEICENTO 1999. I have added a good quality VIBE Amplifier and some VIBE 6x9's with a Sony Head.

I have run the power cable from the amp throught the bulk head with grommet yada yada etc etc.

All working fine with the ignition on. Remote cable fine etc.

Problem being, as soon as the engine is running, the amp will not stay on constantly. Instead the power light flashes, slowly lighting, slowly dimming. No sound from speakers.

Turn off engine, turn ignition back on and it works fine!!!

Any ideas???

Welcome to FF

What's the earth like?

Are the power leads running down the same side as the speakers leads or are they on opposite sides?

as a wee guide to help us help you.....


1. you are running the positive from amp straight to battery positive?
2. have you taken earth from amp to bolt on body somewhere?
3. have you takken remote turn on from stereo feed such as amp on or aerial wire?
4. you say that you have to turn ign back on for amp to come on.....does ur stereo come on with ign or can u turn it on without??

Thanks for your replies. Just done some further testing.

OK. Power cable direct from positive battery then fused (within 6") then straight to the boot of the car where the amp is screwed to the back of the seat.

Remote cable direct from the appropriate blue amp / ariel cable on back of the stereo. In asnwer to the question posted previously the stereo goes off when the ignition goes off. only works when the ignition comes on. There didn't seem to be a switched feed in the standard loom (is this normal??) so i took a switched feed from the fuse box. Now it comes on and goes off when it should (no risk of flat batteries because of forgetting to turn stereo off!)

Earth from amp to the 6mm hex bolt just behind the seat release switch on the drviers side of the car in the boot.

I'm thinking that the earth must be okay as it works when the ignition is off.

As an experiment and to eliminate the remote wire as a problem i bridged a cable from the main power lead onto the remote terminal of the amp. The result... no change. This only leaves the main power cable, the engine/altenator, the earth.

Any other thoughts? where have you earthed your amps?

never ever had this problem before. Would love to work it out.

Thanks again.

on my cinq i (and a few others)used one of the bolts on the fuel pump cover under the rear seat

its normal for fiat stereos to be constant live.easy to change to ignition live as you found

I will try re routing the earth.

Is there any engine / electrical guys out there that can think if the engine running would make any difference to the amp coming on and off??

OKay Re routed the earth. As suggested i got some new cable, new connectors and bolted one end of the cable to one of the bolts on the fuel pump cover under the seat.

other end to the amp. obviously.

Same Problem....

Anyone think that there may be an altenator problem? can you get any rectifiers or something?

HELP HELP HELP!!

please don't give up on me!

you need to run a multimeter over the battery with the engine runnig.should show 14 and some volts when charging(nothing electrical running) to check charging.

do you know the amp isnt faulty for sure?also are you using heavy gauge cable?

I'm using 8AWG cable - the amp works fine when the engine is not running. so don't see that it would be faulty.

How can it tell if the engine is running or not?? Confused!

I've just sent a mail to VIBE to ask theyre' advice.

you need to see what voltage is runnig to see what the volts the alternator is oushing.also to rule it out it may be worth putting a constant live with switch to the remote connection on the amp to rule this out.(temporarily)

ok, so if your saying the amp works ok with engine off, but then cuts out once you've started the car then it sounds like a fualty amplifier!


try leaving stereo off, start car then turn stereo and amp on and see if this makes a difference! if not, faulty amp it is!!

Problme SOLVED!

Tried another amp. works fine. Faulty amp to start with! Weird fault though!!!

Thanks for all the time you spent helping.

Cheers..