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Poor Running - Is It Coil/ht Leads?


Guest Ian Marr

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Guest Ian Marr

Car has been running well for 2-3000 miles since IVA, but recently it has developed an intermittent faltering under load - usually after giving it some beans, e.g. overtaking a lorry up a hill. Initially the fault self-cured itself after a few miles of dodgy running and less beans. The third time left me stuck at the roadside. Recovery fella was a capri nut and used to pintos and he suspected carb problem. It was recovered as neither of us could get it running for more than a couple of seconds roadside. But having spent some time in the garage over the weekend I am not so sure it is carb/fuel. It was not running hot.

 

Set up is ...

2.0 pinto sohc with ESC11 and a Weber 30/34 DFTH carb. All fairly standard using original wiring loom, don't use the vapour separator (was bypassed on the donor anyway), fuel route is tank to original mechanical pump near dizzy to filter with pressure regulator (about .4bar) to carb.

 

Things done so far ...

After getting in the garage, first few attempts at starting just same - few seconds running then dies. Took carb cover off so direct air flow - same. Checked a few leads - same for first few attempts then struck up and ran for a while (carb still on open air) choke stepper motor working and butterfly adapting to conditions - tick over was not stable ranging from near stall to 1500 and back. Would rev well. Ran for a couple of minutes then ultimately stalled.

 

Then, with no further improvement observed at each stage...

Checked all electrical connections and WD40 dotted about

Removed and checked and cleaned plugs

- No1 was bit carboned and damp (petrol)

- No 2 was better

- No 3 was as No 1

- No 4 was fine

HT leads do not seem especially good quality (think they are Tricky specials!). Not overly confident of connections to plugs and the metal connector ends on the HT leads seem 'loose' - i.e. they move, although appear to be in contact with the dizzy.

Tested coil. LT to HT terminal is okay with healthy 6600ohms (Haynes says 4500-7000ohms). LT(+) to LT(-) gives about 3.2ohms, but Haynes reckons 0.72 - 0.88ohms. That seems quite a bit out of spec.

 

My brain is questioning the leads (or at least some of them). This would equate to differing performance at each plug and, I assume, put overload on the coil especially under load. Would such a fault cause the coil to start to breakdown the primary windings and increase the resistance? The coil is not the original so may not be damaged, just out of spec? Some websites are selling coils with 1.5ohms or 3ohms for pintos.

 

Wanting to get the old girl down to Stoneleigh at the weekend, but don't really have much time. Current thoughts are to get new leads and a coil tomorrow.

 

What do you think?

 

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Guest Ian Marr

Thanks Bob. Going to change the fuel pump as think it is original and not overly expensive. Regulator has a guage and is indicating just over .4bar (6psi)

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Guest preeday

I had an issue just like this & it was the fuel pipe from tank to pump, it was collapsing under vacuum pressure due to its age & wear. It would run for a few seconds then stall. It was just luck I put my hand on the pipe & it was flat!! Changed it & it was cured!! Worth a look!

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Guest Ian Marr

Most of the pipe from tank to the pump is metal tube, but will check out the short connections.

 

I have bypassed the regulator and still getting the same fault

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My Bosch dizzy gave a wierd problem like that would run (lumpy tickover ) then after a few mins engine would cut out until completely cold then same symptoms autotune man said output was very low replaced dizzy been fine since (been to Germany and back twice)

hope you find it soon

Derek

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Guest lotusPaul

I had same problem with mine before I went EFI. I had left on ignition acidently which cooked the coil. It would manage about 5 miles of driving or ten mins idling before the heat and thus resistance would stop it working..

Go get a lucus sports coil or another high power coil and try it. You can even run bigger gaps with a higher power coil.

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Guest lotusPaul

As its Ford I'd think a blue coil from bosch, also used on various vw variants. Useful because you can get one from eurocar parts..to be honest any coil will do to test it and they're cheap too.

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Guest Gargoil

When it stalls, have you dribbled a little fuel down the carb? If it is fuel starvation the engine should leap into life. If it's ignition, dribbling the fuel won't make a difference.

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If the coil is faulty it will probably get hot to the touch. I had a coil go down on a petrol tractor on the way to a show once. Changed the points, condenser,filter, cleaned the fuel lines out to no avail until I put my hand on the coil. Bingo.

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Guest chris brown

As you see Ian several answers just to add to the list try a new rotor arm I had a very similar problem on the daimler new rotor arm fixed it.

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