U have an FCD ? - what PSI do u run ?
#1
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I was running at 18 psi a few days back for about 2 weeks. I only put it down back to 10.5 psi because :
(a) john banks got me paranoid and am now waiting for an AFR
(b) Fuel consumption went up dramatically
edit ~ I'm not worried of the engine block as its a closed deck (MY 93 early model ain't it) but the pistons are another story all together.
[Edited by Katana - 6/3/2002 12:11:05 PM]
(a) john banks got me paranoid and am now waiting for an AFR
(b) Fuel consumption went up dramatically
edit ~ I'm not worried of the engine block as its a closed deck (MY 93 early model ain't it) but the pistons are another story all together.
[Edited by Katana - 6/3/2002 12:11:05 PM]
#2
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The Max I can run on an MY94, which uses a different MAP to the Post MY97, is just under 17psi.
That's If I want the fuel cut to still work.
The FCD is set to 'step-in' at 4.05V (11psi approx) and 'step-out' at 4.75V (16.5psi approx), car runs approx 14psi with PPP.
If I set slightly above 4.75V for some reason it won't 'Step-out' even if 4.96V is applied. Which is a bit strange, but will do for now.
This is only experienced when fully connected to the car and pressure applied to the MAP sensor.
If it is bench tested using a power supply to provide the varying MAP voltage it works fine. My thoughts are that maybe something in the ECU is loading the signal ?
I might try bringing up the lower level by 100mV to see if I can gain another 100mV at the top end.
[Edited by Scott.T - 6/3/2002 12:23:25 PM]
That's If I want the fuel cut to still work.
The FCD is set to 'step-in' at 4.05V (11psi approx) and 'step-out' at 4.75V (16.5psi approx), car runs approx 14psi with PPP.
If I set slightly above 4.75V for some reason it won't 'Step-out' even if 4.96V is applied. Which is a bit strange, but will do for now.
This is only experienced when fully connected to the car and pressure applied to the MAP sensor.
If it is bench tested using a power supply to provide the varying MAP voltage it works fine. My thoughts are that maybe something in the ECU is loading the signal ?
I might try bringing up the lower level by 100mV to see if I can gain another 100mV at the top end.
[Edited by Scott.T - 6/3/2002 12:23:25 PM]
#3
Scott,
As always you're one step ahead of me I was intending to run 15.5PSI.
My FCD works fine on bench but not tested in car yet.
I assumed the ECU would have a very high impedence & thus would work as expected so I'm surprised to hear you get different results when on the car
I assume you're using something to supply pressure to the MAP (big syringe?) - Did you manage to simulate above 18 PSI & does your MAP sensor give the readings we expect at the top end?
Just a bit concerned that maybe the MAP is not capable of producing above approx 4.8V & so it never steps out?
Hopefully will get a chance test this on the car one night this week & will post my results.
Any thoughts on the above?
Cheers,
Chris
[Edited - to say just re-read your post so dis-regard questions over MAP working above 4.8v]
It appears that you have already tested the MAP Senor up to 4.96V so that is probably not the problem.
Just a suggestion - It might be worth checking/changing the impedance around the circuit?
Will still do all these checks & post my results.
[Edited by Chris.Palmer - 6/5/2002 8:50:01 AM]
As always you're one step ahead of me I was intending to run 15.5PSI.
My FCD works fine on bench but not tested in car yet.
I assumed the ECU would have a very high impedence & thus would work as expected so I'm surprised to hear you get different results when on the car
I assume you're using something to supply pressure to the MAP (big syringe?) - Did you manage to simulate above 18 PSI & does your MAP sensor give the readings we expect at the top end?
Just a bit concerned that maybe the MAP is not capable of producing above approx 4.8V & so it never steps out?
Hopefully will get a chance test this on the car one night this week & will post my results.
Any thoughts on the above?
Cheers,
Chris
[Edited - to say just re-read your post so dis-regard questions over MAP working above 4.8v]
It appears that you have already tested the MAP Senor up to 4.96V so that is probably not the problem.
Just a suggestion - It might be worth checking/changing the impedance around the circuit?
Will still do all these checks & post my results.
[Edited by Chris.Palmer - 6/5/2002 8:50:01 AM]
#5
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Hehe, I got an FCD from a friend. Its not the DIY one. Once my AFR has arrived, I'll see how it runs at 18 psi again. My engine should be able to take it if I take a few precautions.
#7
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Chris,
The MAP can produce upto 4.96V when the engine is running or 5V when 'just' the ignition is on.
So I am a bit miffed why I can't set the 'Step-out' Value any higher than 4.75V. Perhaps the Potentiometers are pulling down the signal being read. But then if they are I would of expected to see this when bench tested.
I used a foot pump, with gauge attached to the MAP sensor input. Not very accurate, but I could see the 'Step-In' working at 4.05V and then 'Step-Out' at some point, although due to the crude method of applying pressure, could not really determine exactly where, but it looked to be around 4.7-4.8V.
Anyway, this morning was the 1st chance I got to try this (on the way to work) and managed to get a bit more boost with the Actuator shortened by 2 turns. I'll see what it settles at over the next couple of days, once the ECU had re-configured.
The MAP can produce upto 4.96V when the engine is running or 5V when 'just' the ignition is on.
So I am a bit miffed why I can't set the 'Step-out' Value any higher than 4.75V. Perhaps the Potentiometers are pulling down the signal being read. But then if they are I would of expected to see this when bench tested.
I used a foot pump, with gauge attached to the MAP sensor input. Not very accurate, but I could see the 'Step-In' working at 4.05V and then 'Step-Out' at some point, although due to the crude method of applying pressure, could not really determine exactly where, but it looked to be around 4.7-4.8V.
Anyway, this morning was the 1st chance I got to try this (on the way to work) and managed to get a bit more boost with the Actuator shortened by 2 turns. I'll see what it settles at over the next couple of days, once the ECU had re-configured.
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