(T) punto 75 sx wont start after new head gasket

my sisters punto 75sx broke down two weeks ago the rac said she had no compression so i put a second hand head on and a new head gasket put everything back together it turned over alot better but wouldnt run so i did the timing again and still wouldnt go it was turning over as it should but wouldnt go then it would tick over at about 500rpm if that but as soon as you pressed accelerator it died there is fuel getting through and there is a spark could it be the pistons the cylenders werent scored when i examined them. before it broke down it used to suffer from erratic revs any advice would be great as im at a loss now and she is on my back to fix it

First call is whether the belt was jumping one or two teeth.
What was wrong with the old head?
Did you skim and pressure check the second hand head?
Are you sure that the valves are not bent (sometimes you can't see it)?
It might sound patronising but are you sure all sensors are plugged back in?

most common thing i see on here is the crank pully not being put back rite, there is a little pin on the crank that goes into the little hole on the pully to make shre it goes on ib the right place, tis worth a look if you dont remember seeing it

If the pulley is 120, or 240 degree out it would not even tickover at 500rpm.

hi guys thanks for the info i changed the head for a good second hand one a put a new head gasket on to i havent done a compression test would it be wise to do one i knew about the bottom pulley from the last time i did the belt the belt was tight and hadnt jumped a tooth i have checked all wires and sensors and nothing out of place could it be the crank sensor that is doing it

The cranksensor can give trouble.
But going back to your second hand head. Was it skimmed or at least checked with a straight edge that it is not warped? Putting a second hand alloy head on without skimming goes in 9 out of 10 cases wrong.

i bought a complete engine that i heard running but i couldnt do a striaght swap coz my sisters car has power steering and the second hand engine didnt so i just swapped the head i have taken the pistons out of the spare engine and was just gonna put them in the old engine. it does sort of run but only about 300rpm very slow i followed the haynes manual for the stripdown and rebuild

If you take the pistons out you have to make sure that they are the same size. They sizes are A,B,C and D referring to the bore tolerances. Both are printed on the block and on the piston top. You can't just swap them.
Even if they are of the same tolerance in all four cylinders, which is rather unlikely you mated pistons with a crank shaft that have not been balanced together. This is most likely detrimental.
Finally you have to check the cylinder head to make sure that it is not warped because the headgasket can't take it up. We are talking about 0.1mm+.
Believe me I know what I am talking about I have done too many engines.

hi guys i got some sort of success today i changed both coils and ht leads and i took cambelt off and lined the timing marks up and it fired up but oil pressure light on at tickover but goes out over 1000rpm it does run but not 100% its abit hesitent and slow it keeps throwing water out of the rad (ive got the cap off to get rid of air pockets) could it just need timing up again in case the marks are slighty off?

if theres water being forced out the rad then i would say you've got a cylinder leaking into a waterway and pressurising the cooling system

head off, skim, new gaskets again, and new head bolts

did you get my pm?

who?