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=jon=

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Posts posted by =jon=

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    OK- wired this up and tested yesterday, the idle valve now works as expected and it starts and ticks over very nicely on closed loop from cold when on petrol...

    However - when on gas it's not so happy - come up to a queue of traffic, stop in gear (it's an auto) and it will slowly get rougher and rougher and then stall. I think it's because it's a single point LPG system, and the IAC valve is essentially bleeding air past it, so it gets weaker and weaker, the MS compensates for the drop in revs by opening the valve more, until it stalls.

    I guess the solutions are:

    Only use the valve for warmup (which happens pretty quickly) when it's likely to be on petrol anyway.

    Find some way of disabling the valve when it's on gas somehow. I can't just disconnect it as it doesn't 'park' fully closed. Any suggestions?

    Thanks

    Jon

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    OK - so I found another link that has it wired up like you had yours on the MS Extra side - the diode is the flyback diode, but it should be easy enough to put back...

    It also looks like the transistor needs a mica insulator beneath it, if one isn't there it'll appear to be full short all the time - and I can't see one on the pic...

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    Yes pretty sure i did the mod, i remember ordering the TIP121.

    Hi,

    Comparing what you've done to what's listed at:

    http://www.diyautotune.com/catalog/megasquirt-pwm-iac-valve-control-tip120-39modkit39-p-134.html

    They say wire the big transistor across Q4, remove Q20 and D8, and jumper R39.

    Your MS has B & C connected, A is jumpered across R39, and there's a diode that goes back to S12 (which looks to be +12v)...

    Pic of the board at: https://www.dropbox.com/s/zw61sre1yww331z/2015-04-04%2016.31.01.jpg?dl=0

    Any pointers. My electronics skills are pretty basic compared to yours!!

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    Are you talking about the same things here? As far as I saw the Extra EFI web page (should we be quoting other forums without rference to them?) is about adding a PWM fitting in replacement of an IAC and this thread appears to me to be about a IAC which is a stepper motor in which case the votage is pulsed not variable so the bulb will stay the same brightness!

    Hi,

    The Thor IAC is regulated via PWM - so a square wave pulse of varying frequency. If you put a bulb across a PWM feed it'll flash on and off very fast (probably quicker than the human eye can see) - the slower the PWM frequency the dimmer it'll get :)

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    Its coming back to me a bit now i read this thread. I suspect i got to the same point that you are now.

    Good you have tracked it down to the signal.

    Hi Paul,

    Can you remember if you made the optional hardware mods inside the MS to drive an IAC? It appears you have to swap out one of the transistors internally:

    http://www.diyautotune.com/catalog/megasquirt-pwm-iac-valve-control-tip120-39modkit39-p-134.html

    If you can't remember I'll go check but it's a mission to pull all the centre console apart to get to it!

    Cheers

    Jon

    auto starter inhibitor wiring...

    in International Forum

    Posted

    Not saying it won't work without a relay, it will and many early vehicles didn't have a starter relay, just to me it's an unnecessary strain on fragile components.

    I *think* (but to be fair haven't checked) in my case that there's already a relay in situ anyway - the ignition switch triggers a relay down near the fuse board that switches the solenoid... My previous 90 was like that anyway, I'd imagine the 110 is the same...

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    Did some playing today - the IAC valve is working when connected directly to 12V - it'll open/close depending which pin you connect.

    However, it doesn't look like the output from the MS is working - I can force the duty to 10% / 90% in tunerstudio, but the bulb didn't change brighness at all, so it looks like something isn't wired up right...

    We blocked off the IAC valve and the idle speed dropped low enough that it wouldn't run, so we upped the idle and now if anything it runs better than with the IAC valve present but disconnected - I guess it had been set up previously with the valve present but slightly cracked open which was almost the same as having an air leak all the time...

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    Had another play with the settings, and no matter what I select in tunerstudio plugging in the IAC valve causes the revs to climb to about 2000 and hunt a bit... I've played with the valve settings, PID values etc and nothing changes...

    Doing a bit more digging - it seems that if you are trying to use PWM and you are using a relay board, you need to jumper out the relay:

    http://www.msextra.com/forums/viewtopic.php?f=94&t=30394

    Next thing on the list to try - although I don't hear the relay clicking as it suggests I should, but I'm not sure I would from the engine bay over the v8....

    Edit - just took the cover off the relay board - if the FIdle relay is closest to the DB connector, it's jumpered already...

    MS - 3.5 with Thor heads - IAC valve settings

    in MS-Megasquirt/Jolt

    Posted

    Just did some checking - it's a 3 wire one, and one of the pins is 35Ohms to earth. Plugging it in and selecting PWM closed loop in tunerstudio causes the revs to hunt, so it appears to be working...

    Does anyone have a set of base settings (idle speeds, duty cycles, PID values etc) to get me started along the right track please?

    Thanks

    Jon

    Shock lengths

    in Series Forum

    Posted

    Just had a look through my old orders - I think they are fronts not rears, and they may be britpart not armstrong (paddock didn't quote a manufacturer and I don't have them to hand at the moment to check)..

    You are still welcome to them though - let me know!

    Supercharger Question

    in International Forum

    Posted

    And the on off switch effect, great in reduced speed limits, reach the right revs and all of a sudden you are breaking the law and rushing towards something in front of you! As you can tell I hate turbos?

    Maybe in the 80's it was like that, or if you are chasing huge power with a small engine, but a modern well setup turbo has very little lag and will start making positive boost at a very low rev range. The old setup I had on my MX5 was a diddy little garret turbo - it started making positive boost at about 1200 RPM which would increase linearly as the revs came up. Driving it it was very much like a car with a larger engine, or just like a supercharged one but without the whine...

    Shock lengths

    in Series Forum

    Posted

    That is helpful thanks - I'm looking at fitting later series shocks to my 80" to keep the costs down a little.

    I have a pair of virtually new standard series shocks that are left over if you want them - I think they are standard armstrong ones.

    You are welcome to them if you have someway of getting them from Oxford to you!

    Thanks

    Jon

    Megasquirt Series

    in MS-Megasquirt/Jolt

    Posted

    One other thing to bear in mind while it's all out - have you considered a 2.5 petrol from an early defender? I had one in my old series and it was considerably more powerful than the 2.25 it replaced. Other than that it was identical externally other than the throttle linkage so dead easy to fit...

    They can be bought for absolute peanuts as well as nobody wants them...

    Megasquirt Series

    in MS-Megasquirt/Jolt

    Posted

    Nice project :)

    Would using a throttle body injection unit not be a huge, huge amount easier? You are going to bypass a massive amount of hassle getting each injector mounted / angled right / fed properly, and to be honest, the power / efficiency gains on an old engine like a series are going to be totally minimal...

    If you check out www.ep90.com, TSD from here did the same to a ford essex v6 with good results. I was going to do the same to mine, and even got as far as buying everything needed bar a fuel pump, but circumstances have changed and the 90 is for sale...

    If you are interested in a brand new professionally built MS2, trigger wheel, GM injection throttle body etc drop me a PM! (There's also EDIS 6 & Coils but they are of less use!). Sorry for the shameless ad! ;)

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