loss of spark ignition

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Hawaiis0
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Re: loss of spark ignition

Post by Hawaiis0 »

keith rhodes wrote:
Sun Apr 11, 2021 12:01
regarding taking the sir box off the access the distributor - the back end of the box looks like its bolted onto the inlet trumpets - i thought it might just be simpler to unbolt the whole inlet manifold and ease it out of the way?

I'll try taking the back box off and see if i can get my large hands in!
2 10mm nuts per trumpet - an easy remove. Have a magnet ready :D
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Re: loss of spark ignition

Post by Alan_M »

Definitely do as above. With just air box and trumpets removed you will still be able to run the engine to test. With manifold off - can’t do that. Also manifold has water jacket, so you’re going to need to disconnect from water, disconnect fuel pipes, throttle and choke cables vac pipe and need new gasket or risk air leaks.

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Re: loss of spark ignition

Post by keith rhodes »

Once again, thanks guys!

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pistolpete
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Re: loss of spark ignition

Post by pistolpete »

SO the symptoms you have described the stopping , starting a bit and then stopping again. leave it for 30 minutes it starts and goes for 20 minutes. I tried a load of stuff. But it was the rota arm. you just need to buy a quality one not made in China for £2.50. Its the rivet that makes them crack and short out. You just need to take the air box off its not as difficult as it seems

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Re: loss of spark ignition

Post by Pete Boole »

Don't forget you'll lose coolant if you remove the whole manifold - coolant coming from the head travels through it on the way to the thermostat housing.

Pete

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Re: loss of spark ignition

Post by Tanz »

Place an opened newspaper under and in front of the air box to catch the nuts and washers as they inevitably fall.
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Re: loss of spark ignition

Post by KevW »

Whilst I'd never advocate throwing new parts willy nilly at a problem without diagnosing the fault I wonder how old the ignition coil is? At under £20 for a new one it's easy and cheap to replace and if the coil is old worth doing anyway.
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Re: loss of spark ignition

Post by AndyC »

pistolpete wrote:
Sun Apr 11, 2021 16:49
SO the symptoms you have described the stopping , starting a bit and then stopping again. leave it for 30 minutes it starts and goes for 20 minutes. I tried a load of stuff. But it was the rota arm. you just need to buy a quality one not made in China for £2.50. Its the rivet that makes them crack and short out. You just need to take the air box off its not as difficult as it seems
+1 for that. I had it give me problems like running fine to the MoT test, misfire at station and then once really warm it broke down on a roundabout on the way home. New rotor arm (brass molded in not riveted) and job done. I think the crack wasn't even visible as it was likely direct between rivet and mounting spindle.

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CID
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Re: loss of spark ignition

Post by CID »

I've got also the 123ignition... and satisfied with it.

But indeed as Kev said I would also diagnose the problem to start with:
1- Does the fuel pump work? Is it ticking when pressing throttle before starting the engine. Or loosen a fuel-line if it has pressure.
2- Do you have spark? Remove a lead and put 1cm from ground to see the spark when cranking?
And with some spark indicators you can follow if it fires smoothly https://www.ebay.co.uk/itm/Laser-Tools- ... bFEALw_wcB

Without this no working engine....

RGDS Curt

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Re: loss of spark ignition

Post by keith rhodes »

Hi all,
I had already checked fuel line and that is ok, no spark detectable.
Plugs changed coil changed
so I have now removed the distribution cap and rotor and will be replacing those next.
a couple of questions- comments please.

having got the whole air filter box off i have found right next to the distributor a small "canister" shaped sensor bolted onto the crank case- i think this might be oil pressure reader? it has 2 spade terminals on it but its only got one wire connected to it though (white with red band) -is this correct? I am assuming the other is is an earth connection not on as the block will be earthed ?? if not I'm missing a wire altogether as I can't see anything locally hanging loose.

Also - a strange metal box about the size of a large match box, with a plastic bottle on it , it says forendit SPA on the bottle, two plastic hoses come off it but hang loose - open ended. the open ends are not neatly cut but look more like fractured and some part has fallen off. If I put the two damaged ends together they have similar but not exact fitting fractures. I'm wondering if this should be one hose connected together? there's a couple of wires off the metal box going into the loom via a connector block. What is this component for??

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Lotus-e-Clan
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Re: loss of spark ignition

Post by Lotus-e-Clan »

Oil pressure sender only needs the one wire ... it sinks to earth through the sender (variable resistor) ..the block being earthed so you needn't worry about that.

The other plastic device is the "air box purge pump". There is a motor pump inside the plastic cylinder with one hose outlet to the underside of the airbox and the other hose drops down below the chassis as and outlet to free air,

The idea is to pump hot petrol fumes out of the air box when the ignition is off to aid hot starts. If this isn't working your mixture will be too rich during a hot restart and you will have to churn the starter to clear the air box of fumes before it will start (which is embarrasing.

The pump only operated witht the ign off and the engine temp above 73C. There is a temp sender in the back of the cyl head as part of this purge system.

Problem is thepurge pump motors overheat inside that plastic barrel (it not vented) and stops working. I've replaced mine with a washer pump motor ..others do it differently (search on this forum for 'purge pump" theres loads of info on fixing this system....other just do without and churn the starter when hot (no shame)!
Peter K

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Re: loss of spark ignition

Post by bash »

I had a couple of fail to proceeds that mysteriously fixed themselves after a few minutes and it took a bit of tracking down, it turned out to be a bad wire in the harness near the coil. I only found this because when the car was ticking over I jer jer jiggled the wiring harness and it cut out. I ended up replacing the wire and it has been fine ever since. Im not saying yours is the same but its worth having a look.
Bash
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HC180
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Re: loss of spark ignition

Post by HC180 »

I had a similar thing to Bash.

One of the two wires from the Distributor pick-up to the AB14 had a weak connection on the back of the bullet connector. Iit was inside the rubber insulation and only apparent when jiggled.

Interestingly, my original genuine AB14 had a stronger spark than the new replacement

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