Intermittent Electrical Problems

[Snapperpaul]

I have had a hell of a bank holiday weekend, started with taking the kit to work on Friday and only getting halfway there before an oil cooler pipe came off at speed.

AA got the car back and over the weekend i have been cleaning it.

Then started on the intermittent electrical problems.

I have recently replaced the entire Megajolt system including VR sensor, plug, shielded cable, megajolt loom, megajolt, EDIS,seperate fusebox, coilpack, plugs. Leads replaced previously.

 

Found a dodgy earth and replaced that but still have an intermitent ignition fault.

This time not only do i get spark dropout but the guages seem to move for no reason, i.e. the water temp guage slowly moving from 80+ degs back to 60 then up to 80+ again.

 

I changed the alternator for a secondhand one a few months back and am now wondering if i need a new one.

Volt meter reads 12 to 13 at tickover, battery warning light stays on until engine reved then light goes off and voltage goes to about 13 volts.

 

Can't think of anything else to change but also don't know how to multimeter test an Alternator.

 

Any ideas

[stevedohc2b]

I had a prob with the lead on to the alternator on a tin top all the gauges would go mad. It was a braking lead to the alternator RAC man fixed it after I broke down in rush hour in the blackwall tunnel. So could be alternator prob I would expect 14 volts at battery when reving engine.

 

Stephen

[Guest sparkt]

I have had a hell of a bank holiday weekend, started with taking the kit to work on Friday and only getting halfway there before an oil cooler pipe came off at speed.

AA got the car back and over the weekend i have been cleaning it.

Then started on the intermittent electrical problems.

I have recently replaced the entire Megajolt system including VR sensor, plug, shielded cable, megajolt loom, megajolt, EDIS,seperate fusebox, coilpack, plugs. Leads replaced previously.

 

Found a dodgy earth and replaced that but still have an intermitent ignition fault.

This time not only do i get spark dropout but the guages seem to move for no reason, i.e. the water temp guage slowly moving from 80+ degs back to 60 then up to 80+ again.

 

I changed the alternator for a secondhand one a few months back and am now wondering if i need a new one.

Volt meter reads 12 to 13 at tickover, battery warning light stays on until engine reved then light goes off and voltage goes to about 13 volts.

 

Can't think of anything else to change but also don't know how to multimeter test an Alternator.

 

Any ideas

 

you should 12volts to 13 volts on tickover then as you rev engine it should go up to 14.2 volts , the warning light staying on on tickover is the diode pack, problem hope this helps

 

cheers

[Longboarder]

For a start you could undo and freshen all the electrical connectors in the charging circuit including engine earth strap/body and battery connections. Agree you should have 14+ volts with engine running above idle.

 

Nigel

[Guest salty_monk]

Light staying on till you rev it is not an issue though - that's because your idle is too low to "energise" the coils in the alternator. My first one used to do that. Speed idle up to about 1100 or so & it will cease to happen. Most older alternators need at least 1k revs to energise.

 

Dan