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** MegaSquirting a V8 - "Basics of How to" ... The A-Z Saga


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Crikey, curiouser and curiouser :blink: I don't wish to offend but are you sure all your wiring is up to scratch and you've wired the EFI loom in correctly?

:lol: Well there is a good chance that I've done the wiring wrong but as there are only 2 wires to make the Efi loom work I hope not.. but I could be wrong.. :P Let me rephrase that last statement as I may have mislead you. The windscreen wipers are on the original wiring loom so should be the same as before, what I was getting at is when I pulled the wash wipe stalk when the ignition is off and ticking that action stops the ticking and i was wondering if the switch has a constant live feed that might be giving the back feed to earth.

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I'm out and about in my 500hp Italian 2 seater at the mo but off the top of my head I changed the 86 on the 21 fuel pump relay, which is the W/S ignition switched live with the 86 on the 22 main relay which is a N 12v constant live. The MS is powered from the W/S ignition switched live. I've done this as when left it as in the diagram I was powering the fuel pump constantly and the pulsed earth from the M/S had no effect.

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  • 2 weeks later...
Remove Q20, Q4 & R39 ..................... replace with a TIP122 wired into the Q20 position ................ also remove D8 and fit a 1N4001 diode across the valve to stop the coil back emf (the solenoid is a large inductor) from causing the TIP122 to self conduct with possible destruction. Also protecting against back emf in this manner also will prevent the valve from a sluggish action ...............

http://www.msextra.com/manuals/MS_Extra_Ha...anual.htm#Fidle

:)

Ian

Fridge,

I've been going over all the things that could possibly cause the back feed in my circuit, my ECU came from P Ringwood so do you think its possible that a 1N4001 is missing as in the above post #184? Just a thought..

Jeff.

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  • 2 weeks later...

Some MS questions if I may.

I have a 3.9 serpentine which will receive the MS prior to installing it in the Dakar.

• The fuel rail has a sensor in it that I am assuming is a temperature sensor. Is there any function for this in MS?

• The fuel regulator would normally have a vacuum connection which would change the fuel pressure with engine load. Should this be connected or blanked off for MS.

• There are three sensors that would seem to be water temperature related. One of these would connect to the gauge on the dash but I don’t know which.

So I have a big one in the thermostat housing with 2 terminals that are so large they look more like a heater. On the front right of the inlet manifold is a 2 pin sensor and further in a sensor with a single threaded stud for a connection. Can anyone say which of these I should use and for what?

• I have the PWM valve to install but along with ‘Mad Pete’ the challenge is to find suitable hoses to plumb it in. The question is does the pipe size matter? I believe I can best route the pipes using 15mm copper pipe, bent and jointed to suit but would this be enough air flow considering the existing stepper and the new Bosch valves are larger bore?

Many thanks

Steve

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The fuel rail has a sensor in it that I am assuming is a temperature sensor. Is there any function for this in MS?

No although if you really really wanted you could probably connect it to the MS.

The fuel regulator would normally have a vacuum connection which would change the fuel pressure with engine load. Should this be connected or blanked off for MS.

Most people leave them connected although I don't see why you couldn't tune it disconnected in theory.

There are three sensors that would seem to be water temperature related. One of these would connect to the gauge on the dash but I don’t know which.

So I have a big one in the thermostat housing with 2 terminals that are so large they look more like a heater. On the front right of the inlet manifold is a 2 pin sensor and further in a sensor with a single threaded stud for a connection. Can anyone say which of these I should use and for what?

In the order you mentioned them:

BIG one with two terminals = Aircon fan switch as used in X-Fan etc.

Small one with two terminals = Connect to ECU

Small one with one terminal = Connect to gauge

I have the PWM valve to install but along with ‘Mad Pete’ the challenge is to find suitable hoses to plumb it in. The question is does the pipe size matter? I believe I can best route the pipes using 15mm copper pipe, bent and jointed to suit but would this be enough air flow considering the existing stepper and the new Bosch valves are larger bore?

Smaller bore may slightly restrict how much it can raise the idle by but it should work fine.

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  • 4 weeks later...

Quick addition.

I loose count now of how many people PM or phone me around the fitting of the trigger wheel

.....Its one of those things that can be a bit :blink: getting your mind around..........

The enclosed pic(s) below is the one I found that made me understand what's what :)

Basically its viewed "From Behind" = ie turn yourself into a 'flywheel' at look twards the front

of the engine. Then look at the VR sensor, and where the gap is, for a V8 its 5 teeth to the gap

The way I did mine was to loose fit it all in place on the engine, marking the key points with tippex, then rotated the

trigger wheel to the correct place and marked that against the main pulley,

Then remove from engine check settings and drill right through the assembly,

then bolting up, I got 10.7 degrees when running, 2 minor moves

with a VR sensor on a slotted bracket got me to 10 degrees spot on - no trim required :)

I always think its best to have this correct as far as possible, then "tune" to 10 degrees spot on by having

and adjustable VR sensor, however you can remove the timing excess or deficiency by "Trimming" within the MS file

messy and not best practice but can be done, the trim is in the settings show here :)

post-22-1231064721_thumb.jpg post-22-1231064697_thumb.jpg

Hope this helps

Nige

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Whilst having a rummage around Mega Tune I found these....

gallery_3150_282_4917.png

gallery_3150_282_19187.png

As I run table 3 for my LPG I wondered if I need to adjust T3 or T1 is incorrect and I need to look at them both.. or do I just leave well alone. These are in the most currant MSQ that I'm using (thanks Nige it goes like poo poo of a stick).

HFH, FF, BBC anyone.... some advice please.

Jeff.

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Fridge: I like that AFR table, it's a lot smoother than mine. Is it safe to run upto 16.5 on a RV8? i've been a bit wary of going leaner than 14.7 but would be good to squeeze out a bit more economy on cruise.

Jeff: Err.. not sure when it's shown in volts, which Lambda sensor are you using or what's the AFR to Voltage relationship? (e.g. 0v=10:1 5v=20:1)

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Jeff: Err.. not sure when it's shown in volts, which Lambda sensor are you using or what's the AFR to Voltage relationship? (e.g. 0v=10:1 5v=20:1)

It's just a universal 4 wire N/B lambda from an Alfa OE Number 46523129. I only bought this one because the cable was 900mm long.As for the AFR to volts I have no idea yet but I will try and find out.

That AFR table FF posted looks like MS2 but I could be wrong.. I normally am.. :lol:

Jeff.

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Since I'm being a picky git, there is NO calibration between narrowband lambda sensor voltage & AFR, it is entirely dependant on factors such as EGT, the only point the thing is accurate is at 14.7:1 which is at ~0.454v. Wideband sensors usually output 2.5v at 14.7:1.

This sort of explains it:

wbvolts.gif

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I have just read this from start to finish (over two evenings :P) and i really cannot see my self ever being able to install this, I'm not to great at all with wires! tune/play around - mabye!

I have read this thread soooo many times now and I still find stuff I've missed and need. With the help and advice of people on this forum i have Mega Squirted my V8 and it's the best thing since sliced bread and I'm a lorry driver with no school quallies . All you need is there.

By the way take no notice of post #402 as they are W/B AFR tables, I had a look at the Mega Manuel.

Jeff.

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It's not a complicated thing, you have to remember this thread is not just about fitting MegaSquirt, it's about building a complete EFI engine loom from scratch for a custom motor. If you've got a flapper or hotwire EFI lump in your vehicle already it becomes a far quicker and easier prospect - I can do the conversion in an evening without too much hassle and some decent prep.

MPG wise you should get as good or better than factory EFI and significantly better than carbs, there's no precedent for a 4.6 109 but I get 15-20 depending what I'm doing and how loud I'm being. My truck is not really the ideal MPG test vehicle :lol:

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When my Range Rover was a 3.5 on carb's I was lucky to get 8 mpg and that was down hill with the mirrors pulled in :ph34r: but with the 3.9 and MS 15 mpg on a good day and if I keep the foot off the loud peddle possibly more but I haven't tried that yet... :lol:

Jeff.

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The Rover sensor numbers are:

-40 C 26371 ohms

30 C 1405 ohms

99 C189 ohms

So yes, you're close enough there. The full thermfactor.ini file is here for use in Easytherm.

GM Temperature Sensor Resistance

-40 C 100,700 ohms

21 C 3,400 ohms

38 C 1,800 ohms

99 C 185 ohms

So you're probably also right there.

Using the rover sensor calibration numbers - MT giving me lower temperatures than the ambient (independent temp measurement) and MAT reading (Delco sensor). After 2 days in garage - the coolant should be cca the same as air temp - but mine is reading 8degC lower (ie air 18, CLT 8). On the top end - when driving/cruising it settles somewhere around 77-78degC - only when idling it goes above 80degC. Isn't it too low???

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