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Still problems with my Sierra 1.8L CVH engine
novicebuilder - 9/8/16 at 06:22 PM

I have a Ford Sierra 1.8L CVH engine from my donor car in my Haynes roadster. Engine, wiring loom, coil all came form the same donor car. I replaced the starter motor, HT leads, plugs and rotor arm for new during the build.

Engine ran fine during the build, but now on the road problems have developed. Initially started every time and ran fine.Then with further use engine wouldn't restart from warm on occasions. Plugs were sooted up and when I cleaned them they re-sooted up very quickly and give no spark.

I am using the Pierburg carburettor and original engine driven fuel pump. Previous answer on this issue suggested carburettor fuel bowl was flooding and to start car with plugs out and accelerator pedal fully down. I did this and it all started fine.

Now using the car a bit more and find that it would start fine,but engine would stop after a while and then I can't restart it. Currently can't star the car at all. It turns over fine but will not fire.

I have inspected plugs and they are all sooted again and don't spark. I bought new plugs and have tried one of these an there is no spark with the new plug either. All connections are good and nothing loose since build (car has only done 45miles!). I measured the primary and secondary coil resistance and I think it is OK??, but my multimeter is not very sensitive, so difficult to be sure of very low residence measurements.

I checked the emissions at a local garage when car was working and they said it was fine and engine was running smoothly. I have never touched the fuel air mixture screw, so this should be as originally set.

Clearly there is a problem with correct fuel burning (Sooted spark plugs) and now there is a complete ignition failure. Can anyone link these symptoms to find a single realistic cause. It is so frustrating having got this far and the weather is great and I can't use the car.

Help gratefully received from those who know more than me. - Thanks


ian locostzx9rc2 - 9/8/16 at 07:05 PM

If it's running a std 1800 cvh distributor you need to check the cap and rotor arm as there common failures or could be a faulty distributor ?


novicebuilder - 9/8/16 at 07:19 PM

The rotor arm is new and the cap was one I found on ebay as the newest one I could get.

I have checked it all and it seems fine. I note the HT lead contact inside the rotor arm cover is a small metal ball which rotates in its housing to maintain contact as the rotor arm go round. It all looks a bit vulnerable but it has been there from the beginning, and I can't understand why it should not work now?


rusty nuts - 9/8/16 at 07:47 PM

Been a while since I worked on a 1.8 CVH but the first thing to check would be the cam belt, if that is OK have you pulled the King lead from the distributor cap and checked for a spark ? If there is then it could be a faulty cap or rotor , I seem to remember having problems with a rotor on one,


r1_pete - 10/8/16 at 06:34 AM

Does the carb have an automatic choke? if it does, that would be the first point of investigation, but like Rusty I've not touched a CVH in years..


nick205 - 10/8/16 at 07:55 AM

quote:
Originally posted by r1_pete
Does the carb have an automatic choke? if it does, that would be the first point of investigation, but like Rusty I've not touched a CVH in years..


That sounds reasonable to me - from your description it sounds like the engine is flooded with fuel when trying to restart when warm.


40inches - 10/8/16 at 08:25 AM

quote:
Originally posted by r1_pete
Does the carb have an automatic choke? if it does, that would be the first point of investigation, but like Rusty I've not touched a CVH in years..


I removed the choke from mine completely, they can be a Royal PITA. Started OK with a bit of throttle pumping.
Or you could fit a manual choke conversion.


novicebuilder - 10/8/16 at 03:59 PM

Thanks for your help. Yes it has an automatic choke, which I replaced with new bimetallic strip housing during build.

Automatic choke seems to work fine,I have run car with air filter ogg and see that the butterfly valve on the air intake is almost closed at start and gradually opens to fully open when engine is hot.

I fitted the new bimetallic housing and presume that the butterfly valve needed to be just open at start and as strip expands it moves the pin anticlockwise to fully open air intake valve. However I did not measure any gap for initial setting of air intake? it feels like there is a slight ridge that holds the valve just open and I presumed this was the mark to set it at. I can push choke lever beyond the ridge but this would close valve completely. Hope this makes sense.


Davedew - 10/8/16 at 04:07 PM

If you've got no spark at all, have you checked the crankshaft position sensor?

The 1.8CVH from the Sierra has it fitted to the bottom of the cambelt cover.
The toothed gear is on the back of the bottom pulley.

Could be the sensor has come loose or is faulty?

If the choke butterfly is open as the engine warms up it sounds as if it is working correctly.

HTH