Technical (Another) car isn's starting right thread

[CharlieSheen]

Hi,

I have searched the form and the recently resurrected thread about this
wasnt sure whether to add to that or post a new one as it was from 2009 originally and there wasnt really a conclusion to it.

Anyway, I am really short of ideas for this problem and am wondering if anyone here can offer me some words of advice.

My my 56 GP sporting has an intermittent fault where sometimes you turn the key and the car will not start. When this happens there is no noise and as far as I can tell any movement from the starter motor. If you keep trying to start the car (sometimes for over half an hour!) the engine just kicks into life seemingly without doing anthing to get it started. I cant however work out what is causing this..

So far I have looked at issues relating to the battery, immobiliser, cables from battery to the starter motor, the start motor itself, but cant pin the problem down to any of these..

Every time the car has been to the garage, it has started fine being an intermittent fault so they are unable to diagnose the problem!

Does anyone else have any experiece of this?? or can anyone help? please!! :bang:

 

[dirtyhands]

what you need to do is find the solenoid wire which powers it up to see if it gets 12volts,dirty connectors can lose voltage,or if your lucky and have an extra pair of hands is to get someone to hold key in crank position [car out of gear ] when not starting and tap the starter with something heavy broom handle,wheel brace [not the + one] and if car turns over its a starter motor problem

 

[CharlieSheen]

Thanks fo the tip! I'll give this a try next time this happens!

 

[Spyder Punto]

Hope you don't consider this as a hijack: I'm investgating what may be the same problem.

Looked at a PG today. It had a problem with a noisy starter a few months back and the starter was replaced. It worked ok for a while then intermittantly it wouldn't start with just a click coming from the solenoid. I checked the voltage reaching the starter and decided that a new battery wouldn't go amiss. Problem remained. Suggested getting the starter motor replaced under warranty. That was done, problem went away for a week now back with avengence.

I stripped down the starter from the engine checking and cleaning all the V+ connections. Checked the iR drops in the feed and return, nothing greater than 0.1v. However, the solenoid contacts were open-circuit under fault condition. While the starter motor was out of the car I tried it across the battery terminals: good healthy spin every time. Then I checked the feed voltage to the solenoid: under starting conditions, the voltage dropped by 0.7V. The earth rail rise was only 0.05V so no problem there.

I read that the solenoid is powered from the ECU. I can't find if the voltage drop is internal to the ECU or before it. I've also read that a firmware update will solve this problem. How do I determine what revision the ecu is?

None of the wires from the ecu look heavy enough to carry the solenoid current. Is there a relay in there somewhere?

Tomorrow I will double check the chassis earth connection is good.

Anybody any ideas?

 

[dirtyhands]

i would have thought it came from ignition switch all heavy wires,next time it happens wiggle your key and if it starts its a switch problem,solenoid should get 12v,also try jumper cable from - on battery to engine to rule out bad earth.

 

[Spyder Punto]

No it definitely doesn't come directly from the ignition switch: there's a time-out if you hold the IS in start mode for too long.

Good suggestion on earthing though.

 

[Spyder Punto]

Should made clear it's a1.3 GP 2008. Tried the earth/jump lead check with no difference.

 

[Spyder Punto]

Thought I'd wind this one up: firstly, there are two relays in the current path for the starter motor. They are both contained in the engine compartment fuse box. One is enabled by the engine mangement unit on the rt hd end of the engine and closes when all the engine checks have been performed, the other is controlled directly by the ignition switch. The wiring from these relays is substantial and more than adequate for the ~10A solenoid current.

I ended up hot wiring the solenoid and the problem remained.

I then removed the starter and stripped the solenoid. The cylinder the iron core moves in is lined with a brass sleeve which had a faint witness in it and some debris. The button for the main starter contact was "gritty" and didn't move down freely. In desperation, I applied some WD40 to the internal button area which removed all "grittiness". I've since re-assembled the starter and the car has started flawlessly ever since.

I'm prepared to replace the "no name" exchange starter motor as soon as any problems re-appear.

HTHs.