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Running issues

Started by Jm4635, 25 May 2024, 02:36 AM


Hey guys,
Finally got my 450 sel to start, issue is it doesn't idle at all and blows enough smoke to fill the neighbour hood, I can start the car with the fuel pump unplugged then when it fires quickly plug it back in and give it revs and it will stay running with revs but no idle
Bit of background is I bought the car from a guys barn, I've changed the injectors, fuel pump, fuel filter. I've compression tested the motor all good, but did find the screw infront of the fuel distributor wound all the way in, I have since wound it back to just above flush with top. I am waiting for my fuel pressure tester to arrive but if anyone has any ideas of what to check while I wait that would be handy, no idea is a stupid idea at this point


If you changed the adjustment screw you have to readjust while the engine is running , it makes sense that the car is not idling if that screw is out of adjustment , i would keep the engine running with as low revs as possible and adjust the screw until the revs go up and the farther until they go down again, the middle point is approximately where you want to be, but without a exhaust gas tester this wont be perfect.
The screw is very sensitive half a turn wrong can make the engine not starting at all.
But all this makes only sense if the fuel pressures are good and you don't have any vacuum leaks.


You might be referring to the mixture screw. However, sounds by your description you unscrewed (flush) rather the screw that covers the real mixture screw (allen hex 3mm). There's a visible cover screw (flat) and inside a "hidden" hex screw which is the real mixture adjust.
It sounds your mixture if off, agree. As mentioned above adjust that screw carefully by 1/4 turns each time.
CW richer mixture
ACW leaner
Good luck.


Thanks a lot, I will try all the above and keep the post updated 🤙🤙