In my Cossie the MAP sensor is in next to the ecu not its original place, the previous owner moved it there as he put a loom in it. Anyway I noticed that on the sensor itself one of the holes for the mounting bolts has a metal ring on it and was wondering if this is an earth point?? Obviously mine is not bolted anywhere as it is in behind there, therefore not earthed?? I will move it back one day.

Reason Im asking is because since I got the car it has never liked revving high and just misses as if its blowing out spark or not fuelling right.

Any input would be good, cheers folks.

 

i always earth mine, but im sure they dont need to be, also the sensor must be pipe down, they mis read any other way

however, the pipe running to the sensor from the plenum, should not be to long...there is a max length, and i would presume yours would ne too long....

 

Scrap it.....( and it will stop popping if ya switch ya anti-lag off....pmsl)

 

the map sensor must be positioned upside down and not near any high tension electrical items i do also believe it must be earthed also

 

it is an earth point yes, but there is a difference of opinion amongst those in the know whether it needs earthing or not.
one point I will say tho is from the factory the pipe to the map sensor is an exact length so if yours is overlong it might be actually reading low..

steve

 

beat you all lol!

 

bollocks my typing is too slow tonight !!!


steve

 

erm

fucking get your big usless punk ass down jacks on saturday so i can have a looksy at the new toy , !!

would you belive the other night when u went to jackos , i live literraly 1 min round the corner and the wanker forgot to txt me

lol i thought i heard fireworks ,

prob you and your als lol

beef

 

I remember there being a certain length of the pipe now its been mentioned and I thought it was an earth ring. Looks like its a job for the weekend then to re mount it in its original place then.

Cheers chaps.

Beef, Ill not be down in it again till its set up properly for its greys. I need to get it to run right first and fix the leak from the water pump it now has

 

Your only jealous old man

 

the length of pipe will not affect the pressure measurement, as the pipe will eventially be filled to the same pressrue as the rest of the inlet. it will however take slightly longer to react to these pressreu changes.

i doubt and extra 1ft would make that much difference tho.

 

mine is inside the car

 

Is yours earthed Andrew?

 

not sure, think its just an extra earth, prob helps eliminate any interferance cause by a bad earth

 

Pipe down? And what if i pull some g in a corner or brake hard, it misreades? As far as i know it's just a membrane on a variable resistance thingy, and is not concerned how it's positioned

 

it is critical i assure you

 

I got told it was to do with condensation ?

 

Jimbo, you cant quote "not affect" and "eventually be filled" in the same statement as its a total contradiction!

My understanding is that the sensor will work its best if the pipe is the proper length. Worth noting the standard pipe is also of solid plastic construction with rubber ends. I guess this is to stop and expansion issues. With all that in mind I am pretty sure a longer length of (I assume rubber) hose to the sensor could result in the ecu not reacting to pressure changes as quick as the MAP has been written for. (assuming its not been properly and fully re-mapped with the longer pipe).

I wont try to pretend I know about transient fueling and ignition but I believe its a function to cope with fast changes that sensors dont react quick enough too and maybe therefore affected by a MAP sensor pipe length?

Either shoot me down or give me a thumbs up someone who really knows!

 

Is was tony mannock that told me about the critiac length of the map sensor pipe, some 10+ years ago!
spent a full day with him in the workshop and learnt loads!
even how to reach into an engine bay whist wearing a bum bag without scratching the paintwork lol

steve

 

sorry what i said was confusing.

i mean the pressure reading will EVENTUALLY be correct. ie it wont read 10psi if youve really got 15psi (as someone said earlier), it will still read 15psi but might read it a few milliseconds slower than it otherwise would have

i have no idea what the real world imact is of going from a 1ft length to a 2ft length as i'm not an expert, but based on common sense and experience with devices such as boost gauges, i do not beleive that it will make too much difference (altho reading above if tony said its CRITICAL then it must be)