3.5 efi Flapper to Megasquirt conversion

[FridgeFreezer]

Not revving properly is likely just the ACCEL fuel values and the MapDot/TPSDot numbers, if you read the tuning guide it explains these and how to tune them.

Usually with the LED's:

- One is for warmup

- One is for ACCEL mode (will light up as you push the pedal)

- One is for either SQUIRT (injector pulse) or PIP (signal to EDIS unit), the one nearest the 9-pin plug.

[bodumatau]

which tuning guide?

[Quagmire]

Ms1 stuff here:

http://www.msextra.com/doc/ms1extra/MS_Extra_Tuning_Manual.htm

[bodumatau]

as Fridge so eloquently put it RTFM!!

getting there, albeit slowly, I think my PWM valve that Nige sent me is not working, it doesn't ever seem to open and my engine only idles at around 400rpm unless I open one of the small spare air inlets into the Plenum, then it idles at 1100 and is stable, so I am thinking the PWM is not letting enough air through at idle

my hesitating acceleration seems to have been my injector timing that was at 1.0ms, put it up to 1,2ms and suddenly everything started happening much more smoothly.

so I continue to and hope I can understand

[bodumatau]

tested my PWM valve by putting 12V on it and it doesn't move or budge or click or tick or ANYTHING, so I guess that might maybe be why I am struggling to get it idling properly...... also my idle grub screw on the plenum is so far closed the throttle butterfly all but SEALS the hole...... anybody have an idea what size the grub screw allen key is? I have tried 2mm= too small, 2,5mm= too small, 3mm= TOO BIG..... so I am stumped, unless there is an imperial in between I am missing?

for SKAULDY: here are some pics of where I put my EDIS and ECU and run my loom, bear in Mind that mine is a LHD so the heater box and brakes are swopped around..

thats my EDIS on the bulkhead, just below it is where my 3 power wires go to the MS system.

which are these 3, 2x fused power feeds (10A fuse working fine for now), 1 x switched power wire feeding the ECU, PWM, EDIS power and the main relay trigger (2A fuse working fine for this)

here is my main loom running under the right side footwell to the right seat box

and here is my ECU and relays under the right side seat box, ECU still needs to be stuck down, I pulled it out again because I thought the serial cable was causing problems (I had slightly modified it to save space) but in the end it was Megatune and not the cable

[Bowie69]

The grub screw is an air bypass screw, assuming have the right one, and has no effect on the butterfly, so yes it should be sealing well, if it doesn't then it is worn!

[bodumatau]

aha... Bowie, finally I think I have one up on you

if you look under the throttle actuator, at the plenum side, there is a tiny grub screw which pokes its head out and stops the butterfly from closing all the way.............it is there ...........I promise...........look

its the little pointy one my index finger is pointing at and not the blanked off one my thumb is on which is the air bypass screw (had a long uncomfortable relationship with this screw on my Flapper)

then having the luxury of having my Flapper plenum off I turned it around to find a LOOOOONG hole with a little grub screw hiding in the end of it, but I can't get my allen keys to fit or turn it......

for the mo I have done the bodge fix of tightening up my throttle cable to get the aprox right revs, but you know how cables are they never perform exactly the same way

[bodumatau]

two idiot questions if someone would humour me....

1. how do I see from tunderstudio if I am running to lean? or too rich for that matter?

2. my "rear bank O2 voltage" and Lamba gauges are often WELL into the red, Lambda reads very high voltages (over 1-1,1) and "rear bank voltage" also mostly in the red on the right side of the gauge 0,8-1,0 - what does all of this mean and how can I fix it?

[Bowie69]

Nope, you don't

That is indeed the throttle stop, but you do not set the idle speed with it.

Under your thumb in that pic is a cap, prise this out, and underneath is a 1/4" hex grub screw, THIS is your idle bypass screw, and is used to set the idle.

The tiny grub screw you point to is designed to stop the butterfly slamming into the plenum wall each time you let off, and wearing out both components, and probably shouldn't be moved from factory position -I can see no reason to do this.

[bodumatau]

it all started in a little town in South Africa called Mafeking.

first, Mafeking land rover won't start so I tore all the bits out and put a MS in....

now, because Mafeking PWM/EAV doesn't work I am trying to set my throttle butterfly a slight little bit open so the engine can idle higher than 400rpm....

I also read in one of the threads written by BBC (as part of Nigels original MS build thread) that he did this so that his PWM has less compensating to do each time he lets the throttle close, this hotwire throttle body closes the throttle valve a lot more than the old Flapper used to, so once it is closed the engine won't run at all if the indie bleed screw is blocked off.

BBC's logic is if I can get it to idle with the throttle butterfly at operating temp (or 100rpm under at say 700rpm) then the PWM valve doesn't have to move as much and there will be less lag in idle rpm settling.

[Bowie69]

Have you removed that cap yet and opened the bleed screw? You can get it way over 1000rpm with that open.

[skauldy]

That's bob. It's great to see pictures of how others done it.

[bodumatau]

Not if there is no air feeding to the bleed screw, my PWM is a tightly shut as a sharks arse.

Bleed screw is completely open anyway, if I take out the PWM and connect the bleed screw port directly to the stepper motor port then the motor idles at about 1800rpm.

[Bowie69]

I'm sorry, but I think you have a fair bit of the plumbing and terminology wrong, have you had a look at the RAVE manual for a hotwire vehicle?

[jonost24]

Nope, you don't

That is indeed the throttle stop, but you do not set the idle speed with it.

Under your thumb in that pic is a cap, prise this out, and underneath is a 1/4" hex grub screw, THIS is your idle bypass screw, and is used to set the idle.

The tiny grub screw you point to is designed to stop the butterfly slamming into the plenum wall each time you let off, and wearing out both components, and probably shouldn't be moved from factory position -I can see no reason to do this.

I read somewhere that there should be a 0.004" gap approx between the butterfly and the housing. Is that the case?

[Bowie69]

Sounds about right, figure will be in rave.

[bodumatau]

Bowie have a look at this topic, http://forums.lr4x4.com/index.php?showtopic=15317&page=9

page 9 reply #180 from Bull Bar Cowboy: some extracts from his post ->

"For me the inclusion of a valve was going to serve two purposes……..

1. Provide a fast idle with a linear degradation to operating temperature.
2. It seemed good idea that if I could get it to work in closed loop mode then in some off road situations it would allow me to idle over obstacles without intervention of the throttle……..

So … to set the base idle I used the following procedure ………… disconnect he valve from the plenum and blank the plenum air inlet. Then set the base idle (using the throttle body butterfly stop) to a value that is just below the required controlled idle ……… I set mine to 800 rpm as I wanted a controlled 850rpm……

Reconnecting the valve and test driving, confirmed that the stalling issue was resolved and the idle was perfectly stable @850rpm…………."

and I have to agree with his thinking, why let a little slave valve which has to wait for a signal AND then open and close to get the REVS right and all of that only causes lag and delay? rather set up the system to perform almost perfectly and let the little valve just do the fine tuning.

my terminology:

Throttle butterfly valve = the brass valve inside the throttle body

PWM or EAV (extra air valve) = Bosch air regulator solenoid that comes with the MS kit from Nigel and is tapped into the old stepper motor port on the hotwire plenum

what else is there I might have misunderstood?

[Bowie69]

Pretty sure BBC used a flapper inlet, so slightly different.

Either way, the way to set the base idle is via the bypass screw and NOT the throttle stop. The bypass screw is entirely internal to the plenum, it does not go via the idle valve, and as its name suggests, bypasses the throttle butterfly.

The bypass grub screw does not leak air outside the plenum to the ISV/EAV (PWM actually has NOTHING to do with an air valve btw...), there is a machined channel inside the plenum that feeds air around the butterfly into the trumpets area of the plenum.

I agree with BBC's thinking for setting the idle, however not the method, certainly for a Hotwire setup, to set the base idle -that should be done with the bypass grub screw (under the anti-tamper cap in your photo)

[bodumatau]

ok thanks for your input Bowie.

some questions:

1. why is it more desirable for the idle air to bleed via the bleed screw and not through the throttle butterfly? is it mainly because the butterfly is only really adjustable in "big increments" compared to the little grub screw?

2. PWM, I haven't gotten my head around it yet. can you explain it in layman terms? (I understand that it isnt the EAV but the PWM is used to "drive" the EAV, I have only been referring to the whole thing as a "PWM" cause Nigel sells it as this in his kit)

3. If I set my idle bleed screw then I need to set it for a completely cold start (i.e. a LOT more open than at warm idle) and then let the EAV "close" down the extra bleed air to manage the warm idle? is this the right thinking?

[FridgeFreezer]

As your last post popped up as I was typing:

1) I agree with Bowie in as much as the idle screw is likely to give a finer adjustment and be more reliable as it' doesn't get disturbed every time you press the pedal.

2) PWM is the electrical method used to drive the valve (varying voltage by using fast on/off pulses), it does not describe what the valve does.

3) I'd set the idle bleed screw to about the minimum air required so the IAV can add more as required, or possibly a little less.

[Bowie69]

Thanks fridge

For setting idle, I get the engine *hot*, block the two pipes to air valve (even when closed it is not truly closed), and set idle speed to around 800rpm.

Then idle valve has half a chance of working once reconnected, as a cold engine will only ever require more air.

[bodumatau]

ok so now I am confused, the idle bleed valve controls the air coming into the pipe which comes from the stepper motor/extra air valve? or not? or does it allow air to pass around the butterfly in another way? I haven't seen any other bleed holes that allow this????

[Bowie69]

Hose #27 - you will have cut this and put the EAV inline, the stepper motor on the other end is likely removed and a plug inserted if using nige's kit.

Grub screw #8, anti-tamper cap #33 - this is the idle bypass screw, there is a channel from one side of the butterfly to the other, but this is internal and you cannot see it.... look into your plenum and you will see the two ports though. Your cap is still place, and needs removing before you can see the grub screw.

They are separate circuits, so no, the idle bleed valve does NOT control the air going to the stepper/EAV.

[bodumatau]

thanks Bowie, I had a good look at my old flapper plenum and saw the channel the bleed screw feeds air through, it is machined parallel to the throttle body bypassing the butterfly.

and while I was doing that the postman arrived with my "new" EAV, which I plugged in and SUDDENLY....... I can start my V8 without a dance on the throttle, the one Nigel sent me was not working..... bit irritating really......as I would expect him to check whether it works before selling it on to someone....

so now I can finally start fine tuning an engine that starts and doesn't die on me......

[Bowie69]

...and the first thing to do is to set the base idle(!)