so, the FRST is hunting on idle and missing a little under acceleration, have put new leads and coilpack on seemed to cure at first, still having issues

worth changing plugs? they were changed maybe 1500 miles back, but the car sat for a few months, whilst doing a bottom end rebuild

anything else i could be missing?

 

Check the breathers r clear and its worth cleaning the IACV out...
Failing that, maybe the plugs are alittle sooted up, take them out to assess...

 

CPS sensor - mine had this prob a while back - water ingress to the CPS caused it! it is at the front of the engine at the bottom (fly wheel side). un plug lead, undo single bolt then leave on radator overnight! Then try again, if this fixes it, replace it or dry again and seal the end with a smear of epoxy resin! - that got me home whern I was away for 2 days then I got a new one!

 

i have checked the wiring to the iscv all seems ok, can they be cleaned out? good call on the CPS have had issues with it in the past and have had to replace it, defo worth cleaning it up.... at the very least....

for what the cost is, i'm gonna put some new plugs in, and check out the CPS and go from there....

 

Mine Did the same when I had it, hunting in idle and a heavy miss on boost. Turned out the chip had worked itself loose on the ecu. Re plugged it back in. Sorted.

 

plugs changed, still appears to be no change

 

discovered what it is, the connection plug to the CPS has perished, so the connection isn't good, causing the miss....

try source a new one, unlikely that there still available from the dealer though...

unless anyone knows different??

 

I have part nos and may be a spare! pm me

 

you have pm dude

 

the FRST hasn't been chipped fella.....

 

My fiesta is doing this of recent too. I have changed the iscv, plugs and still eventually ended up back to square one. That was with and without a chip. So im thinking maybe my cos sensor is dicking about. Though whenever a cps gives up on a saxo vts, it doesnt actually fire up at all. Maybe its a underlaying problem elsewhere!?

 

when i had trouble previously with the CPS it was the sensor itself, and it would fire up and run, but when it was hot, and you stopped, it would not restart....
once it cooled, it would be fine....

this time, the connector plug appears to have perished, so the connection isn't perfect.... which i hope is causing the miss...

 

maxwell, if the cps aint quite dead or there is a bad connection somewhere to it the engine sort of works ie hunts a lot!

 

ok,so a bit of an update, i fitted a new connector plug to the CPS as mine had perished, things improved, but not completely, tracked issues to part of the loom, so was all stripped back, as there was rubbing wear on the rubber protective sheath, and 2 wires had worn through, so all were re wrapped, and then bound together.

next port was checking all the earthing points, i haven't done this since owning the car, what i found was under every earth point was painted surfaces, so contacts will be minimal. So as tedious and time consuming as re wrapping part of the loom, i undid all the earth points, removed paint, added come copper grease, re attach earth and cover in white grease to seal the damp out.

result appear to be much more consistant idle, no hunting at all, though still having issues from the breather set up i run, due to my original ford piece falling to bits....

new parts ordered, the whole crankcase breather set up can be ordered from the dealer still, though it is defo not cheap, but that in the pipe work as opposed to the actual pot itself....

 

ok, so just had a call from my ford dealer, all the parts order yesterday are obselete, so back to square one.....

fooked off is an understatement....