i've just got MJLJ up and running on my 2.0l mk2 golf running a single 45mm DHLA and 272 cam and every thing is working as it should and i am very impressed with the system so far but my MAP sensor is jumping from about 45 to 60ish at idle. is this excessive? it reads 99 when disconected. i'v had a talk to my local rolling road operator and am now thinking i should have used a TPS instead.
my inlet manifold is a crossflow design i,e one carb choke feeds cylinder 1+4 and the other feeds 2+4. My Vac take off is on one side of the manifold which feeds cylinders 1+4. do you think i would get a smoother reading if i had a take off on the other side of the manifold (cylinders 2+3)
or are there any other ways to to improve things?
(re-wire the board to take a TPS?)
Cheers Rob
Now thinking a MAP sensor the wrong choice?
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It's jumping around at idle
It's jumping around at idle because the MAP is pulsing. The other branch will do the same.
Why do you think you've made the wrong choice? Can you detect any problem other than what you see on the runtime display?
The 'problem' won't be so bad at higher rpm.
I have heard of people putting one of those cheap plastic fuel filters in the vacuum hose to the MJLJ to dampen the MAP pulses. Will have a small delaying effect on the MAP reaching the sensor inside the MJLJ - but probably not noticeable.
I'd stick with what you've got unless you/the rolling road can detect an obvious running problem.
BTW, it reads 99 when disconnected since normal air pressure is nominally 100kPa, so it's working pretty well!
Why do you think you've made the wrong choice? Can you detect any problem other than what you see on the runtime display?
The 'problem' won't be so bad at higher rpm.
I have heard of people putting one of those cheap plastic fuel filters in the vacuum hose to the MJLJ to dampen the MAP pulses. Will have a small delaying effect on the MAP reaching the sensor inside the MJLJ - but probably not noticeable.
I'd stick with what you've got unless you/the rolling road can detect an obvious running problem.
BTW, it reads 99 when disconnected since normal air pressure is nominally 100kPa, so it's working pretty well!
if you don't think it's
if you don't think it's fluctuating to much the there isn't a problem just wanted to double check. after talking to the local tuner he reconed it would have been better to us a TPS?
i was thing about conecting both branches at the same time to get a smoother reading (if that's possible)
i was thing about conecting both branches at the same time to get a smoother reading (if that's possible)
proper connection
for best results with carbs and a map sensor you should have both your manifold branches connected via a small tube with a t-peice in the middle, the map feed is then taken from the the middle via the t-peice, you shouldnt get much pulsing that way,. incidently for 2 twin carbs all 4 manifold inlets should be connected together and the map takoff taken from it
Thats what i thought. thanks
Thats what i thought. thanks