help needed!

[onedayTM]

hi guys dont know whether you might be able to help me. My sons fiesta M reg 1.1 petrol HCS engine with single point injection has been running with what would seem like a sticking throttle, you can take foot off pedal and it keeps going, not all the time, now and again. He never sorted it and now it keeps cutting out. It will start and run but as soon as you try to put your foot down it dies and then will not restart for some time. took it to garage and had it tested, no air leaks but map sensor fault was showing on system. He suggested a replacement but wouldn't say it would fix for sure. I put new sensor on and still the same, any of you guys got any suggestions?
cheers
tony

[baz-r]

Map sensors measure pressure in inlet manifolds to calculate fuel load so can give all sorts of running problems if Thay give the ecu wrong information

[onedayTM]

cheers bazr, but having now fitted new map sensor would I have to take it back to be diagnozed again. the fault was cleared off system but my son drove it back home about 1mile on the old map sensor, in that time would sytem pick up any problems again and therefore make the new one useless.
tony

[flyerncle]

Map sensor code is a "Hard fault" and will stay in the memory untill cleared and leave the light on.

If it is fly by wire throttle body it may pay you to re-learn the settings and adapt the throttle position.

It's worth noting that a code reader will point you in the direction of the fault and testing before replacing will always pay dividends and save the punter money in the long run.

Quicly replaced EGR solenoid the other day to have car returned 3 days later!!!!!!

Tiny piece a crud in vac line was the fault. !

[onedayTM]

cheers for reply,
no its not fly by wire, its normal throttle cable auto choke with a carb like unit but with a central injection unit in from the top, it also has the following connected to it; fuel pressure regulator, intake air temp sender, throttle position sensor, throttle plate control motor. would you suggest taking unit off and giving good clean out, also where can I get fuelpressure gauge that can be fitted in line so i can check to see if getting right pressure.
thank
tony

[flyerncle]

Somtimes cleaning the throttle plate will alter its position and the stepper motor may alter the idle position up and down on its own.

Testing is the best way to go as I said previously to sort out exactly what the fault is.

Not 100% sure of exact fuel pressure but in the region of 30/40 psi is about normal and fit guage in feed line to check,purpose made kits are expensive and not viable for a one off check.

[onedayTM]

ok cheers for that.
tony