Hooking Map Sensor

[Rotax]

How do you guy's route your vacuum/boost line to the Map sensor?
The way mine is setup, is i start from the manifold with a 3/8 id hose to a "+" fitting that feeds the fuel regulator, The mondo Bypass valve, and finally the MAP.

Is that ok from your standards?

When i was running a stock computer with PMS, The map was hooked the same way, and was reading the same as my boost/vac guage.

Now, at idle i see ~10inHg vacuum, but in the Calmap software i only see ~5inHg.

Should i separate the MAP vacuun line from the others?

Thanx

 

[HighPSI]

I ALWAYS isolate the vacuum line to the MAP sensor. The more connections you have on it, the better the chances for a leak. All it takes is for one of the lines to blow off when under boost and the MAP sensor won't see as much boost. I even take precautions on my fuel and timing maps just in case this happens.

 

[Otto J]

Ditto I have mie on a single line only and its secured with small pull ties, And my Ve tables and Timing table are set in case the sensor or line ever fail it will run a clean pass.

 

[Rotax]

I had a fitting installed on my intake, used some 1/4 id Aeroquip 300psi hose and hooked the MAP alone with this line.
It still does the same thing. I used another 3bar MAP that i had laying around, still doing it...
The only way i can get this thing to show correct vacuum, is to configure it as a 1bar MAP, but i wouldnt try to get into boost like that...

Sounds like the mapping in the vacuum portion of the MAP sensor isnt right in the ECM under anything but 1bar setting...
What do you think?

 

[bruce]

You want a dedicated, short, rigid as possible hose.

Min cross section makes for min. signal dampening, unlike most everything else, in this case smaller is much better. Hard plastic, or copper (1/8" OD) with just 1" soft hose ends, is best.

In boost, a soft hose can even balloon and misreport the boost by several PSI. Obviously, you don't want that to happen to the FPR either.

 

[Rotax]

The hose is good for 20bar or 300psi, i know its hard enough.
The problem is software i think.

 

[bruce]

Originally posted by Rotax
The hose is good for 20bar or 300psi, i know its hard enough.
The problem is software i think.

You want a dedicated, short, rigid as possible hose.
Min cross section makes for min. signal dampening, unlike most everything else, in this case smaller is much better. Hard plastic, or copper (1/8" OD) with just 1" soft hose ends, is best.
In boost, a soft hose can even balloon and misreport the boost by several PSI. Obviously, you don't want that to happen to the FPR either.


You've already said you have 10 actual and 5 reported, that can well be the signal being dampened. The above could explain that.
I didn't just pull the above out of thin air, I've seen it happen several times.

 

[Rotax]

Listen, before i had a GEN7, i was running a PMS, and both my guage and display showed the same readings.(although the MAP wasnt on a dedicated line!)
That's the MAP i tried on the gen7 to see if the sensor was bad.

So youre probably right on the tubing size, but in my case it's not the problem.

I even hooked a second guage at the end of the Aeroquip line, and it reads the same as the other.