Best Way To Stop Pulsing On Map Sensor?

[pugpete1108 62 1 Cars]

as the title really, i have my map sensor (300kpa one built into the ms ecu) but since i moved its takeoff point from the gti6 vacuum pump to a t piece off the top of the maifold which also feeds the regulator i get pulsing at idle which is causing hunting (well i hope that is why its hunting) as when i close off the map hose it stabilizes.

 

it has been suggested to use a small fuel filter such as from an nitro rc car or similar due to the small hose diameter.

 

just wondering really if anyone has any better suggestions? one way valve maybe or would that not work with the sensor?

 

 

[welshpug 1,621]

many pugs and citroen's with an ecu mounted map sensor used an inline damper.

 

 

1957 46 is the one from the S16, its about a tenner.

 

it wont stop the pulsing but will damp it.

Edited May 28, 2013 by welshpug

[hcmini1989 16]

Might be worth tapping into all four branches on the inlet manifold i think someone else done this to solve the vacuam problem are you sure this is the problem ?.And not an air leak thats causing the hunting?

[welshpug 1,621]

no need to do that as he's using the inlet plenum not ITB's.

[petert 549]

You don't want any valves etc. in the line, as this will delay the MAP sensor in reading the true load of the engine. I'd try another point if it's pulsing too much. The work around for such problems is to have a "zero throttle map". Meaning that when the throttle is at 0%, the ecu will read a fixed injection time.

[pugpete1108 62 1 Cars]

My tps never reads 0% fully closed its around 25-30 even after calibration (ranges 30-320) I guess this is not a percentage just a figure from the ecu.

 

And I'm not sure where else I can move it to? Was fine running from the vacuum pump but the xu7 doesn't have one hence teeing off the regulator supply.

 

Ill go over the lot again to check for leaks before buying a damper valve like mei suggested.

 

I'm getting a fluctuation of about 3 kpa whilst on idle

[Vili 17]

Fit a carb fuel filter in the vacuum line. It works as a damper in the line exactly like the OE damper in for example 306 S16 vacuum line.