Engine problems

[shea]

im having a problem where my bus won't turn over unless I get a jump start, I've tested with a brand new battery and it still won't start. Once I manage to get it started it will die unless I keep the revs up. Now somedays I'll turn the key and the bus will start right up.

Anyone have any ideas what it could be or suggest a few places to start for diagnosing seems like maybe faulty wiring to me but I don't know where to start.

 

[BRAD]

I had that happen to me on the isle of wight ferry, it turned out to be after lots of over thinking it the spade connector being loose on starter motor

 

[dustrat]

It sounds from what you say it is an electrical problem. The spade connection to starter being loose would stop the engine starting but would not affect the engine ticking over. Does the charging warning light go dim or go out when you try to start with key ? if so check and clean the earth cable from battery to engine as well as cable from generator/ battery to starter. 9 times out of 10 these cables are the problem.
Robert

 

[newhippy]

As a matter of interest where is th engine to body earth wire?

 

[jonboylaw]

On the gearbox.


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[shea]

Thanks for the advice! I won't be able to get to the Bus until Friday so I'll check then and get back to you.

 

[shea]

Looked at the negative cable on the battery and it was pretty rusty so cleaned it up and bolted it back down but no difference. The oil and generator light dims when I turn the key but doesn't go out. I put a voltmeter on the battery and it measured 12.58v and then drops to 12.38 or so when I turn the key.

I went under the bus to check the engine cable and starter motor like you said, I found these two cut wires, not sure what they are

Hard to see here but there's a yellow wire that's been snipped

Any ideas on what else I can do?, I might take out the starter and check it on a bench.

 

[madmike]

Can only test starter (out) if the shaft is supported
clean all the connections, install new cable 'Earth' to bottom starter stud

 

[shea]

Thanks mike, can I test it in situ? I can only work on the bus on weekends but I'll clean it up, is the earth wire the one that's cut or the wire beside it?

 

[dustrat]

You can test starter whilst fitted but first of all make sure out of gear and handbrake applied. There are two wires going to starter motor. One is from from dynamo/alternator/battery which sould be alive. The other is from ignition switch. Check voltage to starter from former and you should have same reading as when checking battery.Disconnect the other cable and with a volt meter in place get some one to turn ignition key as if to start engine. You should get a good reading there as well. If not run a wire from + terminal on battery to the the terminal where it goes and starter sould turn over.If it does turn over you have a problem with wire feed from ignition switch or feed from fuse box to switch. If not you have a problem with starter or starter solenoid.
Robert

 

[shea]

Got it working! jumped the spade connector on the solenoid and the starter motor worked so stripped the wires and put new spade connectors on and it's starting again! Doesn't explain why it keeps dying but I'll move onto that next. Thanks everyone

 

[BRAD]

Fuel pump, rod, lines, filter maybe?

 

[shea]

Whats a rod? if you mean push rods the engine was rebuilt around 2k miles ago with a rebuilt carb and a new accuspark svda distributor. I replaced the fuel lines while the engine was getting rebuilt and put a big MANN filter in by the gearbox. How would I be able too tell if it's the fuel pump?

I haven't taken the bus out for a run since fixing the starter as it's up on jack stands.

 

[john the horse]

Think he means fuel pump rod

Jth

 

[shea]

Ah right I'll have a look and see if it's loose (that's what happens isn't it?) I have a spare pump I can use. I take it could be the alternator too? I'm going to check that when I'm back this weekend.

 

[lard]

Hi - one way to tell if it's the pump - check for excessive petrol smell in oil, may have split the rubber inside and it would be leaking down into the engine, tell tale sign if petrol is in with the oil in the sump - glad to hear you got it started - nearly there!

I checked mine when had cutting out issues and someone had put the rod upside down when installing it back - mine had a square end and a pointy end, square end should be at the top i believe with round/pointy end down against the shaft, changed the length of the rod and believe didn't give a full stroke on the pump - either way, worth remember which way round it was in when you take it out