Hotstart relay fix

Been tinkering in the garage again? Post it here.
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spikeemikey
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Hotstart relay fix

Post by spikeemikey » Sun May 09, 2010 11:58 am

Hi Guys

Here is my attempt at curing the infamous bus starting problem of the solenoid not pulling when its 'heat soaked' after a long journey. Helga has been doing this since she was imported in 2006. Usually after a good hour or so on the motorway. The problem is the old bus wiring from the front of the vehicle drops a few volts before getting all the way back to the solenoid, and with the current/voltage it needs to pull when hot ... well it just doesnt manage it.

I think there are kits to do this, but just picked up a 30A fused relay from Halfords and some plumbing couplings to make it water tight. The solenoid then takes power from the heavy guage wire supplying the main feed from the battery, and the wire just supplies a couple of hundred mA from the ignition switche to the relay. The unit is cable-tied between the solenoid and starter which saves have to run long cables about.

It seems to work great, but it seems to have rung the last life out of the solenoid, cue another starter! Well the new one is nice and shiny!

Mike
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Dubmatix
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Re: Hotstart relay fix

Post by Dubmatix » Sun May 09, 2010 7:05 pm

Nice one Mike, i like the waterproofing.

My first line of offense on this problem is to remove the solenoid from the starter and then remove the plunger from the cavity and meticulously clean both and ensure there's no oil or contaminants on them. Clean and lube the pivot lever with some light grease before reassembly. I have done two bug ones, a fiat Panda and my bus and all are completely cured of this issue.

Whilst the starter is off (with the battery off naturally!) wirebrush all starter contacts and terminal rings before assembly. that spade terminal on the back of the solenoid is often well corroded as well as the spade terminal itself. If so try dipping the end of the cable in a popular full fat Cola overnight...it's fun trying to suspend the container however!

Then if that doesn't work then try the hot start relay.

Basically if you do it this way round, you are attacking it by removing some sources of friction and resistance first which could well be enough to effect a cure.

If you getting the same problem after fitting hot start relay then there is just too much friction for the solenoid to overcome (or the solenoid coil is toast!) so dismantling is worth a shot before replacing or if you already bought one, strip your old one (unless its exchange) and have a look. the hardest part is removing the two slotted screws! I found the best way is to put a big screwdriver in a vice and then apply the screw to the screwdriver and rotate the unit whilst pressing firmly onto the screwdriver blade.

My bus developed this fault in 2008 after 2+ hour runs on the Autobahns. I stripped cleaned the solenoid and have done some lengthy runs since and not had any issues.

I do agree with the many forum threads on this issue that the start switch contacts can get burnt over time and exacerbate this problem, i just think that happens less often than people think and that it's the total combination of 'resistances' causes the hot start issue.

Keep us posted on your continuing saga!


John

spikeemikey
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Re: Hotstart relay fix

Post by spikeemikey » Mon May 10, 2010 11:30 am

Hey John

I agree totally. Trying to fix the mechanical side of things makes sense and is the nicest and longest-lasting solution. I changed the crimp connector on the ignition cable wire and cleaned the terminals up (though not with Coke ... I guess Deox gel would do same .. its phosphoric acid in both?) In slight defence when I pulled the starter to give it a quick look over before trying the hotstart fix, it seemed to be moving quite freely. So that is what stopped me taking the thing to pieces. The fact the hotstart problem went from occasional, to even after a trip to the shops on cool evening, a month or so after Helga returned into regular frequent use was probably a hint the solenoid was on the way out.

I had a quick hunt around the net for a supplier of just the solenoid. I think I found one in the US. Does anyone know of one more local? And if your after a whole recon starter .. GSF charge a huge core charge (70 pounds?) for you to return your old unit when bought through their main website, but only 20 pounds thru their Ebay shop.

Ohh the nice thing about those plumbing couplers as a housing is they are watertight (with gaskets) but unscrew easily if you ever need to change the fuse.

Cheers

Mike

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Dubmatix
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Re: Hotstart relay fix

Post by Dubmatix » Mon May 10, 2010 1:40 pm

Hi Mike
Yeah, i reckon Deox gel would do the same, i think it is Phosphoric acid in that too as you say. The info on that seems to be harder to find than you expect!
I used coke on the 10 Way Eberspacher relay plug as there was no way to remove it and it was well corroded after having water splashing on it from the leaky screen surround. it came up a treat and was shiny brass afterwards.

I have a solenoid (used but good) if you want to have a play with that. It's a bug one but i think they are the same.

Your plumbing fittings. Is that drain pipe (sink drain) with blanking caps in both ends? Being cylindrical it works well strapped to the side of the solenoid! Did you cut/frill a cable access in one blank and fill the gaps with silicone sealer? Would look good in orange too!

Cheers

John

spikeemikey
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Re: Hotstart relay fix

Post by spikeemikey » Mon May 10, 2010 8:36 pm

Hi John

It's a 40mm waste pipe compression universal connector, and two flat blanking plugs. http://www.wickes.co.uk/Compression-Uni ... nvt/431902 I find Wickes are better than B&Q and Homebase for those as they always seem to have them.

Yeah drill a hole in one end for the wires, seal with silcione sealant. I used a couple of big cable ties inside the blanking plug to act as a strain relief, and a put a bit of hi density foam inside (ex girlfriends yoga mat!) to stop the relay rattling about. Snug fit, and as you say easy to secure. I had previously made a halogen bike light from similar fittings so the design came to mind.

Thanks for the offer of the solenoid. I have a 'new' recon starter to fit. Hopefully this will cure the starting probs. I am just hoping the teeth on the flywheel are in reasonable shape. A couple of misengages/disengages lead to some nasty metallic noises.

Cheers

Mike

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