intermittent starting problem

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intermittent starting problem

Postby colouredFunk » 10 Oct 2018, 22:01

Help! I’ve got a really strange intermittent starting problem - this used to happen 5 ish times a year, but now it’s getting increasingly frequent, making the van a complete unknown whether it will start or not.

So please bear with me, it’s a bit long winded but it all hopefully makes sense.

Turning the ignition, the starter motor spins nice and freely but the engine just doesn’t catch. Repeated tries cause the same effect. Then one attempt out of many the engine will seem to be almost catching, but still not firing up completely, and oddly it sounds like it’s almost there, but continues as long as I keep the ignition turned. Another attempt foot the floor the engine sort of fires up, but at really really low revs, pumping the accelerator has no effect and just maintains a low rumble. Now at this point, it might suddenly take and respond to the accelerator, or it can just keep its low rumble until I release this key. The other scenario that normally happens; I take the engine and pretend to know what I’m doing, fiddling with cables, making sure fuel is coming through, with another attempt at turning the ignition it fires up, probably not initially responding to the accelerator but after 5 or so seconds it behaves! What the blithering heck!?

As I said this used to happen a few times a year, and mainly on wet days, so I’ve always thought it was electronic, but now I’m not so sure.

I’ve recently had the injectors cleaned, and pretty much all electronic components are fairly newish (ecu, coil, amp, flow meter, idle control unit, fuel filter and fuel pump)

So anyone got any ideas? It’s quite hard for mechanics to debug as previously if I’ve got towed to them, when they’ve come round to looking at it, she starts!!


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Re: intermittent starting problem

Postby Da dan » 10 Oct 2018, 22:44

Fuel, spark or air leak.
Pump or air leak my moneys? More wise people will answer though.


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Re: intermittent starting problem

Postby ajsimmo » 10 Oct 2018, 23:53

Ignition switch. Could be losing feed to the coil on cranking.

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Re: intermittent starting problem

Postby ajsimmo » 10 Oct 2018, 23:57

Almost certainly isn't air leak. Unlikely to be fuel pressure, but worth checking fuel pump runs at key-on and cranking. Could be hall sender or wiring. Corroded earths on left hand head?

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Re: intermittent starting problem

Postby colouredFunk » 11 Oct 2018, 06:00

Based on the scenario where that van starts but at really low revs with the accelerator not having any effect, does not rule out the ignition switch?

I’ve also had this fitted last year - Distributor Repair Kit - T3 / With Vac Advance https://www.brickwerks.co.uk/distributor-repair-kit-t3-with-vac-advance.html
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Re: intermittent starting problem

Postby ajsimmo » 11 Oct 2018, 21:32

colouredFunk wrote:Based on the scenario where that van starts but at really low revs with the accelerator not having any effect, does not rule out the ignition switch?


Ah, missed that bit. I read that it turned over at different speeds but just didn't start. Soz.

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Re: intermittent starting problem

Postby colouredFunk » 14 Oct 2018, 09:05

Does anyone have any tips on how to diagnose any of this if they are on their own? As now the van won't even start at all.
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Re: intermittent starting problem

Postby 300CE » 14 Oct 2018, 14:06

Could possibly be the ignition control module - might be worth seeing if you can swap with a known good one to see if that makes a difference.
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Re: intermittent starting problem

Postby colouredFunk » 14 Oct 2018, 14:18

So today I got it started again! I temporarily unplugged the ECU, tried starting it and it fired up straight away then died after about 5 or seconds. Apparently, this proves it was over fueling and uses the fuel left in the bores?

It then wouldn't start again, I plugged the ECU back in, still wouldn't start. I then removed the air pipe off the back of the Vac advance and blocked it up (with a chopstick (after watching this video https://www.youtube.com/watch?v=E-kQNkswGgY)) She then finally started!

So I've no idea what this proves? Dody ECU? or Vac Advance?
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Re: intermittent starting problem

Postby bonus999 » Yesterday, 18:23

Pressure regulator?
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Re: intermittent starting problem

Postby colouredFunk » Yesterday, 18:53

Anyway of testing my current one, as they are £130 from Brickwerks
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Re: intermittent starting problem

Postby bonus999 » Yesterday, 21:57

I don't know too much but if there is a vacuum pipe connected you could check it for signs of wear and pull it of to see if there is fuel in the pipe. If there is, then the diaphragm is likely gone. I don't have that engine so I'm not sure of the exact setup.
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Re: intermittent starting problem

Postby ajsimmo » Yesterday, 22:17

Time to follow the diagnostic procedures in the protraining manual. Check everything methodically, don't miss any steps, and assume nothing. I have paper versions, but I know they're available online, somebody might have a link.

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