Problems with newly fitted stereo

[Irvy]

Hope someone can help here
i purchased a 2nd hand unit from a member on here and fitted it yesterday. Used a halfords iso loom - the 17-4 one and it fitted directly into the pins down the centre console. the only other lead to fitted was the ariel. put the car back together and hey presto the unit worked fine.
went for a drive today. As soon as i started up the car the speakers hissed and popped and made squeeling noises till i turned the volume to almost zero when i then heard music again.
Tried listening with the car turned off incase it was a battery issue but same thing. i have alpine speakers in the back and focal 165 in the front so dont think its a speaker isssue.
i changed the oem unit as it was overheating, spitting out Cds and wouldnt turn off at times. i am now wondering if there can be a wiring fault with the car itself as the new unit worked yesterday.
anyone with any thoughts?
cheers
Irvine

[Ric]

do you have the active speaker amp?

[Irvy]

do you have the active speaker amp?

where would that be?
the cars a GZ model with the rear speaker also

[Soonto"HAS"soop]

It would be under the passenger seat, should remove it if going for an aftermarket stereo, as the aftermarket unit will be of a higher spec output than that of the original unit.

[geoffvalenti]

Look under the passenger seat

[Irvy]

just did a search. i asume i will have it. how easy is it to remove?
and do i have to connect any wiring left over..couldnt find a previous post that explains it well enuff:(

update - lloks like theres an amp - easy to remove?
the new stereo is definitely 50W

just another thought - but havent i just bipassed this amp by using the pc2-17-4 loom and connecting this directly into the two white plugs down the left side of centre console? or am i talking pants? :)

[Jim_1979]

yeah.. you doing that should have bypassed the amp mate.

[Irvy]

yeah.. you doing that should have bypassed the amp mate.

i thought that too
well been out in the dark resetting the unit to stock settings but the sound is still buggared. i also fitted the disc changer to find it has no power and isnt working or recognised by the unit.
will go back to seller methinks
Irvine

[Irvy]

update:
and any info would be beneficial:)
the chap i bought it off says it worked fine in his car. i am gonna wait till the weekend and undo/refit and check all the connections again. :(
some questions for anyone that might know.

after fitting the new stereo i had nowhere to plug the small male connector that came out of the rear of the oem stereo. Is this ok?

Only things i did fit were iso loom and the ariel. Is this right?

there's no earthing considerations?

cheers
Irvine