hi, i have this 89 ke laser auto with a 1.6ltr carby motor. bought the car with a seized motor. i pulled the old one out and replaced it with a 2nd motor from a wrecker which had supposedly done 150,000klms.

now it has an inconsistent misfire which is driving me nuts as i can't work out what the problem is. so far i have:

- changed plugs am using gen. ford plugs (ive done this twice as the first set fouled right up like you wouldn't believe)
- replaced air and fuel filter

- gave it an oil and filter change but used 10w-30 oil as i had a few litres in the garage


i have checked the ignition lead resistance here are the results:

no1 - 3.54
no2 - 3.22
no3 - 2.83
no4 - 2.09
coil lead - 1.55

all of the above were measured with a multimeter set too 20k resistance

i have cleaned up the contacts on both the dizzy cap and rotor button

it idles fine when cold but when it warms up it develops a miss its not even a consistent one at the its very erratic.

ive set timing to 2deg BTDC as per the sticker under the bonnet

now would the 10w-30 oil be slipping past the rings and into the combustion chamber causing the motor to miss

are my ign leads rooted

perhaps the mixtures are right out of whack


any help with this is greatly apprciated and sorry for the long post.

cheers in advance

compression test it

idle circut in the carby is blocked.

if it's fine when the choke is one but carries on when the choke is open it's the only thing it can be.

run it and have a look down the carby if it's drawing feul from the booster discharge, you have to much idle opening, because you are trying to compensate for having no idle circut. you may also hear a crackling noise from the carby

main metering mixures will be fine, unless feul jets or air bleeds are partly blocked.

also set the timing at 6-8degress.

whoops

I'd try having a look at your leads in the dark. If you see blue flashing lights along the leads or sparks jumping to the body...she's stuffed.

is the plug fouling up with oil or fuel??
if its fuel i would just change the leads.

it take a few thousand Ks to oil foul a plug.

so they would be fuel fouled. but i'd leave the leads alone and work out why the choke is staying on.