307 fast idle

[gnc]

hope some one here can help, 307. 1.4. petrol. twin cam 16valve. 06 reg just changed headgasket because of oil leak. ad now it wont idle beow 1500, coming up faults 153 /121/ 158. fitted another throttle body with throttle position sensor. were to go next without throwing lots of money at it.

[megamaniac]

It sounds like it has an air leak on the inlet,maybe a vacuum pipe off/split.

[gnc]

jv ordered a new MAP see how that goes

[Old Merc]

megamaniac said:

It sounds like it has an air leak on the inlet,maybe a vacuum pipe off/split.

I agree.
I take it the idle speed was OK before you did the head job? So before you start throwing parts at it have a good look round your job.

[bearman68]

It's a MAP sensor. Air leaks will result in higher idle. Try pulling a pipe off the inlet manifold and see what happens. (MAF meter idle will drop with a vac leak)

[gnc]

it had an eratic idle before the head job, not a lot of air pipes on this engine. disconnect MAP and it stops.

[bearman68]

gnc said:

it had an eratic idle before the head job, not a lot of air pipes on this engine. disconnect MAP and it stops.

The engine stops, or the erratic idle stops?

[gnc]

before head job ,eratic idle. after head job , fast idle, diconnect MAP, engine stops.

[gnc]

fitted MAP. still the same. then pushed breather hose on properly., seems ok now, so it was prob an air leak all along. thanks for help. gnc