engine flat spots,then goes!

[stag76]

hi lads,bit of a odd one here,or is it

got a littlesilver 91 1.6 off robert, she has been layed up for over a year.

she starts ok,a bit of a struggle,few turns of the key and peddle pumping

when started she seems to idle ok,and no bad noises.

now on driving with lite peddle pressure she pulls ok,not great slight hesitation,as you go quicker say 25mph and slowly increase in speed she seems to gentle serge,go then gentle loose power then serge then loose power etc etc.

collected car tonite,very hard to start in cold weather.she drove ok up the road,then this power no power,power etc.

then i noticed when id go around corners or round abouts on the exit it would die,splutter then just stop!

ah i said fuel,put 20e in,still the same.

drove her home along m50/n11,good 30mls ,had to gentle wind her up to 60 with genle serges,but if i came to hill and pressed gas peddle gentle on off on off of power again!!

at end of journy i had to go over speed bumps and she coughted and spluttered as if she out of petrol.

any ideas??? its as if she running out of petrol,but if driven very gentle she sort of ok,or when she splutters and you give her a chance to sort herself out she will pull like a deamon,and then the gentle on and off of power.

its not a loose wire i dont think,if it was it would be more jerky,so not loose leads or ignition wireing

petrol pump not up to standard,weak pump,problem with fuel tank,fuel filter????

the pulsing of the power feels like the pulse of the pump pumping,or not maybe

so to recap gentle power loss and then normal again,and fuel starvation on bends and roundabouts,speed bumps

we swapped out thairflow meter,no change

any ideas would be great

car bought as a trade sale job/do'er upper from robert

[pjmazda]

Hi,I had similar symptoms with mine, my issue was dirty/blocked fuel injectors.
No cost/simple job to sort this but remember to depressurise fuel lines first.

Rgds,
PJ

[MX5Spares]

Fuel or air problem.Is there any chance of dirt in the tank. Years ago I had similar issues with a mk2 escort and wait for it.....there was a rag in the tank. Some gobshite stuffed itbin instead of a fuel cap. Jason lift out the tank unit behind the seats under the carpet. Takes about 5 minutes to check the tank.Definitely not elctrical problem as its a surging thing not a jerky. Thing

[MX5Spares]

Just thinking there could the cat be blocked ad thisvwould cause these symptoms

[stag76]

hi robert,yes i agree with you,its not electical,its a fuel problem.

as you say could be a blockage at pump end of things,hopfully not a rag

the cat idea mite also be a problem???? anymore ideas lads

its the coing around corners and roundabouts and 20/30 feet up the road she acts as if she just running out of petrol,even 2 speed bumps put her off her tea

injectors,she seems to run fine on all 4cyl,but worth a look,how did you clear/clean then?

if it was the cat id say after the 30mls she would have blown manifold gasket.

thanks for the input lads,il keep you posted

i should have bought the auto 1

thanks all jay

[ger]

if you dont know when the fuel filter has been changed then stick in a new one, they are cheap, ive opened one that was on a car for years and it was very dirty.
swap out the pump with another owner and test. Also you can make the pump run from the diagnostic box, think its gnd and FP, you could pump petrol into a container see if it has constant pressure.

[stag76]

hi ger,good to hear from you.

yes a filter change would be the first job,and yes again to seeing if the pump is giving a constant flow of petrol.

it mite be pulseing,and thats what mite be giving the surging.

yea,and i mite swap the pump from 1 of my other cars.

thanks jay

[Steve]

yeah change fuel filter and ignition leads, see how it is then.

[stag76]

ill get a new filter 2moro and pop it on.

very sure its not leads,doesnt miss fire,just a very smooth power for 10secs then a gentle reduction in power,then a gentle increase to power again.
its not a jerky stop go stop go.

as she does this she always on 4 cylinders.


its the going around corners,and going over the speed bumps has me stumped,has to be filter/pump/crap in tank.

leads wouldnt act up on corners,nore would airflow meter or any other ignition item.

il give it a good going over during the week

thanks jay

[charged_rs]

id suspect a failing airflow meter or CAS

[stag76]

hi charged,thanks for the message.



yea when i went to look at her up at roberts,i had a look around it and it seemed ok,so i took it for a test drive.

as soon as i drove her she had the surging problem,high low high low power output.

brought her back,mentioned it to robert,he said airflow meter,so we changed it for another 1 off his shelf,went for a drive,exactly the same as before.

whats a cas?? a crank shaft sensor?

its realy the corners and around roundabouts and she dies its a fuel problem,and maybe a dicky sensor.

would it be the ecu advancing and retarding the timing because of a faulty sensor.

it is said that the car hasnt been used for 2yrs,this is maybe why she laid up


thanks again for ideas,keep them coming

thanks jay

[sidewaysreilly]

check all your earth leads from engine gearbox etc etc.........

[stag76]

hi sideways,yes ill check the earth leads and make sure there good.

still its the going around corners,as if the car running out of petrol,cant wait to get to motor factors and the car again,so i can try all these ideas.

thanks lads

jay

[MX5Spares]

Still worth checking that there's not a floater in the tank 'blocking the filter on the bottom of the pump. Or wrong fuel cap, which is unlikely, causing no ventilation in fuel tank. Leave fuel cap off for a few minutes and se if there is any difference.

[stag76]

hi robert,yes il do that also.

just ordered a fuel filter there,all going well should have it 2moro. ill keep you all posted with the out come

thanks jay