mk4 fiesta 97 I have a problem and i'm now lost . i've fitted

new

oxy sensor

plugs

inlet manifold gasgets

fuel filter

swaped

maf

thottle body

coil pack

leads

air temp

crank case breather

all from my dads fiesta mk4 running fine none of this helped

today fitted injector rail complete from scrap yard

all pipes seem fine can't see any leaks

misses when cold then lack of power under load

inlet manifold seemed to be dirty with oil ?

have ordered new crank case breather valve for tomorrow

code still coming up p0171

any help please i'm now demented only bought car last week wish i hadn't now .

as you probably know, that code indicates a lean mixture.

one other possible reason for it that you might not have covered is low fuel pressure...either a bad pump or pressure regulator maybe.

can only be properly checked with a fuel pressure tester,

most common reason for that code is air leak.

if it has the ohv engine then also check the valve clearances

checked rail pressure best i can with a tyre guage 1.8 tickover about 2 bar blip throttle open ... i changed the hole rail yasterday ,and as far as i know the regulator is on the end of the rail...

today had live feed off my car and dads my timing only goes to 20* where my dads goes to 14.5 * when floored mine dies at 3500rpm under load why would the timing not advance /ret'd ?

note belt has been checked / belt timing ...

any ideas am all of the above its 1.25 zetec dohc.

timing is controlled by ecu, based on what readings all your sensors etc are supplying it...in other words, source the problem before worrying about timing as chances are once you get to the problem, timing will improve.

bearing in mind that im not sure a tyre guage will be accurate, {or safe for that matter} better off with dedicated pressure tester...might pay to try it on other car to see if you get better readout though...

that fuel pressure is quite low, would expect 2.5 bar min at idle....3 bar under acceleration

remove the vacuum pipe from regulator, at idle speed you should get 3bar...if you do then regulator is suspect...if you dont then fuel pump/fuel flow/injector leakage needs checking

may also be worth running pump with engine off, by bridging the relay and check to see what pressure, pump is capable of producing, would expect 3.5-4.5 bar, especially if you temporariily clamp off return pipe.

another test worth doing is getting an exhaust gas readout...CO/HC/CO2 and LAMBDA ideally

if possible, an exhaust back pressure test too, which would help indicate or eliminate a blockage in the exhaust system

also should add that if not done so, dont just rely on visual inspection, remove the breather pipes for full inspection for cuts or signs of collapse..these are the most common reason for that code to flag

done a compession test 195,195,195,165 dry not much improvement on cly 4 wet 175 could this be the problem

no back prassure on exharst pipe that i could read ( rear pipe has been renewed to front pipe ....)

I put the code reader i have on, it's a u480, go to i/m scrool through to o2 not ready and h2o not ready but the other day faffing about it came up both ready... thought grate what ever i've done for the better... but before i could try it i rescaned an scrolled the i/m and again not ready is it my imagination or did it happen ,,, it's a 97 model are they surposed to come up ready and if so is it a wiring fault . possible earth if so any idear where the earth post comes from on the harnes for this... or wher to look for a problem that would do this if it is surposed to read ready

compression is slightly down on that cylinder, though dont think its enough to cause a misfire...general rule of thumb is something like lowest figure is min of 75% of highest...

not familiar with the scanner your using, but your sending yourself up a blind alley with the readyness readings...ignore them

think your forgetting that fuel pressure was very low...first point of call needs to be get an accurate readout...not sure a tyre guage will cut it, but if that reading is actually correct, then low fuel pressure could well be your problem

thanks for the reply as to pressure readings , seem to fall in spec with haynes book... as follows

vac disconnected 2.7

engine running 2.1

hold 1.8 bars min

but still haven't counted it out as don.t know the flow . don't have a way of testing but iwould only of thought it would matter at full load but hesitates and tends to miss cold at low revs even sucks back blipping throttle the lean mix would possible do this i suspect but is it fuel ..... had a vac guage on today sitts steady at tick over ... it's a boost guage so scale not as good as a vac only ..but still think it drops to 0 to slow... and i can't find any vac leaks anyware thought it could be a sticking valve?

machanic that checked the timing belt is stumped he thinking it might have somthing to do with the ecu ...

hope it isn't a valve or the ecu..

ps thank for your input on this..

see if you can make head sence of this lot

st ftr mi % 1.5 - -4.6

lt ftr mi % -14.8

ign adv /deg/ 10.5 takes a while to drop from 20 at idle

??? ??/st 0.0000

abslt. tps% 18.00

o2s ?1 0.085 -3.1

0.500 -4.6

just checked the autodata..

states fuel pressure should be 3bar and regulated pressure is 2.7bar

this doesnt match the figures your giving from haynes

with regards to holding pressure, think that refers to pressure sustained with engine off.

maybe worth doing a bit more research on the www, ive got to go to work, but your pressure seems a little low to me

other possibles worth checking

engines had a common fault with corroded wires on the throttle sensor and MAF sensor..often gives the 0171 code

the idle control valve needs cleaning

would also recommend getting the CO etc checked, both at idle speed and at 3k revs...that could give a big help in pinpointing a problem [ideally a gas readout of CO/HC/O2/CO2 and Lambda}

forgot, sorry

will have to be more specific about the info you have given to make more sense of it as not sure what im looking at

was the corroded wires on the harness plugs or harness earths?

see if you can make head sence of this lot

st ftr mi % 1.5 - -4.6

lt ftr mi % -14.8

ign adv /deg/ 10.5 takes a while to drop from 20 at idle

mal tr/st 0.0000 (possibley)

abslt. tps% 18.00

o2s 1 0.085 -3.1

0.500 -4.6

this what was written on a bit of paper i have when it was getting live data off machanics code reader .. but mine is basic and has no live data .....

corrosion on the connecting plugs and the pins of the sensors

live data is very useful, but that printout is very difficult to follow not only for the abreviations are confusing but mainly because you need to know the conditions when it was freeze framed..