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PostPosted: Sun Jun 30, 2013 5:12 pm 
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Joined: Fri Mar 20, 2009 2:19 pm
Posts: 215
Location: Redondo Beach.
It is an L20B. Manual Gear Box. 5 speed.

It idles and runs nice, plenty power. Driving in city or highway is great. But on a hot day, or after exiting the highway after a good run ( 30 mins or so.) , or upon driving in stop and go heavy traffic ( which warms up engine ) then car idle starts to misfire, gets lumpy idle.

Gets worse and worse. To the point I got to let the car cool off. If I ignore the signs and keep on driving, it eventually dies off. Once colder, it runs fine again.

I changed the points and condenser, cables, cap and rotor. Radiator and cooling system is great ( recently got radiator serviced and pro cleaned with new H2O pump and thermostat.)

Weird thing is only happens upon getting car warmed up after highway drive, upon exiting and mingling in with stop and go traffic. Or city driving after driving for a while sufficiently ( specially hot day ) and most commonly in heavy traffic.

Once the idle starts to mess up, there is no way back, worsens until it stalls. Usually I stop before that and let it cool off, but what I ended up doing is avoid taking the car on longer trips or traffic conditions.

A mate told me it could be a bad ignition switch, he said sometimes a bad ignition switch makes ignition act funny when warm.

Any insight is appreciated.


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PostPosted: Sun Jun 30, 2013 7:35 pm 
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Joined: Thu Jul 28, 2011 1:40 pm
Posts: 19
sounds like the fuel is vaporizing before it gets to the carb (heatsoak) where does your fuel line run? Is it near the exhaust on the under side of the car?

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PostPosted: Sun Jun 30, 2013 7:44 pm 
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Joined: Mon Jun 15, 2009 12:15 pm
Posts: 943
Location: Cairns
what carb or carbs are you running?


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PostPosted: Sun Jun 30, 2013 9:31 pm 
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Joined: Fri Mar 20, 2009 2:19 pm
Posts: 215
Location: Redondo Beach.
Howzit.

Got a Weber 38 DGES. The exhaust runs on the left side of car and the fuel lines from the fuel tank run on the right side. Will double check. :thumbsup:


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PostPosted: Sun Jun 30, 2013 9:51 pm 
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Joined: Mon Dec 07, 2009 6:03 pm
Posts: 1051
Location: Metung, Victoria
Has it got an electronic choke?
Also check your float level.
Did you set the points to the correct gap? Have you done your valve clearances?

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PostPosted: Sun Sep 01, 2013 3:35 pm 
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Joined: Fri Jan 07, 2005 5:28 pm
Posts: 228
Location: Hobart, Australia
Hi. I had a similar problem with my rally car. Died after 3-4 stages of hard driving, then left for 10 minutes and would start again for another 10 then die.

We thought it was the efi computer but it wasnt getting the signal from the distributor. We changed the guts of the distributor, put a recovery system on the radiator (to stop it loosing water and getting overly hot) and it seems to have worked. Make sure there is a gasket under the distributor to motor in case it is transferring excessive heat up and frying internals.

It may be the pickup in the distributor like your friend said. Replace distributor and report back if this fixes it. Ours has not failed since. Replace with electronic ignition distributor and kill 2 birds with 1 stone. For better reliability consider moving the module off the motor onto the body with a made up heatsink and proper paste under.

Mark


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PostPosted: Sun Sep 01, 2013 7:55 pm 
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Joined: Wed Mar 05, 2003 8:38 pm
Posts: 1137
Location: straya
I had similar symptoms with a dodgey bosch hec715 coil. Was fine til it warmed up then it would spark out of the coil and ignition woukd break down and car would die.
Fuel vaporising may also be an issue. That's my suspected issues. Easy to fix if its coil or fuel.


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PostPosted: Mon Sep 02, 2013 5:15 am 
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Joined: Fri Mar 20, 2009 2:19 pm
Posts: 215
Location: Redondo Beach.
Thanks mates.

Been busy with work and family so thing is I had been using my Datto locally to avoid this issue. By the time it starts acting up I am at or close by destination.

Use other vehicles for distance driving. But I got to fix it once and for all. The coil is an accell coil I bought 2 years ago. (New). The party I believe is at fault and only new ingredient is the used Weber 38DGES I got from a friend. Never trusted the source and it gave issues since the start.

I got a Dellorto DHLA 40 on a Links manifold I got from a member about 3 years ago And in apparently good shape. Time to call it on to duty. Looks good. I am purchasing a rebuild kit and float just in case. Will swap it in and see.

Also have on the line a electronic dizzy. In order to determine issue will swap in the carb first. Then dizzy.

Let me look for a couple photos of said items. Need some advise on e dizzy connections.

Cheers.


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PostPosted: Mon Sep 02, 2013 7:52 am 
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Joined: Tue Aug 07, 2012 5:44 pm
Posts: 171
Location: Northern NSW / Queensland
The problem may well be fuel or carbie related but I say check the coil anyway. Back when I used a large competition style accel coil for rallying, the instructions clearly said to use you existing ballast resistor in series with the resistor that came with the coil. I sourced a 100 watt aluminium heatsink clad wire wound resistor of the correct value, about 3 ohms from memory.
No need to go that radical for ordinary driving but I'd say check your ballast resistor and coil for overheating anyway.


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