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

[bobtail84]

For reference: TIP122 Data sheet - Fairchild Semiconductor

The Collector (Pin 2, the one that goes to the PWM output) is internally connected to the tag on the transistor, so a short to ground strongly suggests that the tab is not being insulated from the heatsink properly - with the tab lifted off the heat-sink if you measure resistance from Pin 2 to Pin 3 it should be high, from Pin 2 to the tab should be short-circuit and from Pin 3 to the tab should be high.

Here's how the mounting should be arranged - you need to be bang on if a metal screw is used to mount it, plastic ones are not so much of an issue and preferable to use if you've got one.

Cheers Fridge I will check again.

jeff

[FridgeFreezer]

Pay attention to the mica insulator & shaped nylon washer - if the mica is damaged or the nylon washer is not sat properly in the hole in the tab, the metal screw can touch the metal of the tab and connect it to the heatsink or the grounded through-hole on the PCB.

[daftpooly]

First many thanks to HFH, FF and BBC for such an inspirational thread - I'm about to squirt/EDIS my Disco and can only [s][/s]blame thank you guys for giving me the confidence.

Now, to my very simple question - there seem to be many members who have squirted a serpentine lump - where did you put the coil packs and how did you mount them? Can I have some pics please? The build was going to start next weekend but I cooked the engine yesterday so it's coming out for a rebuild and whilst it's out the vr and trigger wheel can be placed without scraping more skin off my knuckles

[waxen]

Thanks, Nige & Fridge,

When I get Megatune running on this computer I'll work out how to do a screen dump and post. The issue is not that big a deal as it works fine after about 10 -20 seconds.

The whole PWM thing has been a bit of a nightmare because I built my own board, I followed the directions (or so I thought) in the MSextra manual for the flyback diode. 3 TIP 122's and 2 Diodes later it works. The pictures in the manual show the diode connected to S12 NOT S12C as it is written. that little issue had all sorts of ramifications. In the end the Flyback diode is now at the valve, works heaps better.

[FridgeFreezer]

Here's how I always do them:

[waxen]

First many thanks to HFH, FF and BBC for such an inspirational thread - I'm about to squirt/EDIS my Disco and can only blame thank you guys for giving me the confidence.

Now, to my very simple question - there seem to be many members who have squirted a serpentine lump - where did you put the coil packs and how did you mount them? Can I have some pics please? The build was going to start next weekend but I cooked the engine yesterday so it's coming out for a rebuild and whilst it's out the vr and trigger wheel can be placed without scraping more skin off my knuckles

I mounted the Coil packs behind the Plenum on the Firewall with the connectors facing down. The idea was to reduce the possibility of water getting in. This turned out to be a not so bright idea as the leads now dont have enough room to interlock with each other.

Here a couple of early in progress shots, mines a Range Rover but the Discoverys have more room behing the engine for the Coil packs

[Boothy]

Righty oh,

Here's a problem I found myself with, following a full rebuild, I have got a Kpa up at 70/80 on tickover, 800 rpm'ish which means with the old map it's throwing fuel in.

Same cam etc just re honed, reringed (although less than 1000miles since rebore, heads skimmed and recut etc, reground crank usuall stuff but nomajor changes.

OK I thought do a day in it and it will come back down, absolutely no time for re-mapping (which has to be done off-road),

so a full 7 hour Challenge took place, it run faultlessly but without any silly rev's used a full 70 litres of fuel on a very small site,it was difficult because it was sowet and cold totellabout smoke etc but all seememd well.

Tried the other day now running like a bag of nails and extremely rich and chuggy, laptop on and still up there at 70 or 80Kpa cold, plugs black and wet with fuel.

Question is, if I doctor the fuel map to compensate for the high Kpa I will have a very limited range, so to speak, how long should I expect the high Kpa, is it normal and expected, all other paramaters, settings, readings, temps etc look good to me.

So all i did was to reduce fuelling on the higher Kpa's to weaken it, but that also causes me concerns.

What do you think boys.

Chris

[waxen]

Righty oh,

Here's a problem I found myself with, following a full rebuild, I have got a Kpa up at 70/80 on tickover, 800 rpm'ish which means with the old map it's throwing fuel in.

Same cam etc just re honed, reringed (although less than 1000miles since rebore, heads skimmed and recut etc, reground crank usuall stuff but nomajor changes.

OK I thought do a day in it and it will come back down, absolutely no time for re-mapping (which has to be done off-road),

so a full 7 hour Challenge took place, it run faultlessly but without any silly rev's used a full 70 litres of fuel on a very small site,it was difficult because it was sowet and cold totellabout smoke etc but all seememd well.

Tried the other day now running like a bag of nails and extremely rich and chuggy, laptop on and still up there at 70 or 80Kpa cold, plugs black and wet with fuel.

Question is, if I doctor the fuel map to compensate for the high Kpa I will have a very limited range, so to speak, how long should I expect the high Kpa, is it normal and expected, all other paramaters, settings, readings, temps etc look good to me.

So all i did was to reduce fuelling on the higher Kpa's to weaken it, but that also causes me concerns.

What do you think boys.

Chris

Sounds like a Manifold leak, Your idle MAP should be somewhere between 30-40kpa. A kpa of 80 or so is like a wide open throttle. An easy way to test it is to disconnect the vacuum line to Megasquirt and see if it is running the same or similar.

[Boothy]

Waxen, you've given me food for thought there, because I was thinking the higher the figure the greater the vacuum but thinking about it it's the opposite way, oohher.

[Hybrid_From_Hell]

Boothy

Check all hoses for any splits air leaks, spraying wd40 around the engine if then sucked

in will raise revs and give you a clue, just don't set fire to ywerself

If you have an air leak the table will raise and that cell will be a richer cell, and

thuis the engine will seem to be rich, similarly, yes I know its daft, check CTS and MAT plugs aren't misconnected,

but the clue is the high Pressure showing - go air leak, missed pipe / split pipe etc huntin'

Don't forget the obvious too, disconnect both the throttle cable AND xcheck the mechanical stop too

Nige

[Max_torque]

Assuming you have the MAP sensor line connected downstream (plenum side) of the throttle plate, then if you have a genuine 80 kPA in the plenum (due to open throttle or air leaks etc) then your engine IS at high load and would rev to the limiter in neutral!!

so, assuming this isnt happening you either have

1) dodgy MAP sensor

2) dodgy ground to MAP sensor

3) air leak in PIPE to map sensor

If you check the MAP with the ignition on, but the engine NOT running MAP should be at atmospheric pressure, roundabout 100 kPa

When the engine starts, this will fall rapidly to around 20 to 40 kpa at idle depending on the cam setup/idle speed / ignition angle etc

[Boothy]

It's gotta be option 3, dodgy pipe somewhere in line to MAP sensor.

Nothing has changed except engine out, rebuild, engine in.

But what I did is to have a massive rationalisation of pipe/wiring, making things much neater and hopefully more reliable, including a serious re-route of the MAP pipe.

So there I think my problems lie.

I've had Megasquirt a long while now and forgot my basics really, I was looking at tight engine being the problem but now it's all coming back and I remember 100Kpa at rest with no engine running therefore the lower the reading should be lower not bleed'in high.

Back to basics and check the pipes tomorrow.

Thanks Lads

Chris

[Richard Lane]

Hey Boothy

Just a thought from a bloke in Australia...

Why don't you get yourself a vacuum gauge and plumb it in near the map plug on the ECU and see what its reading. That way you will get good things for testing.

1. Be able to confirm the reading of vacuum in the MS is the same as the gauge.

2. Be able to monitor the gauge whilst chasing vacuum leaks...

Sometimes its good to be able to confirm what your seeing on the laptop screen.

Rich

My two bobs worth.

[teslo]

Hello,

yesterday i again spent some time with trying to setup MS ans EDIS conversion on my 3,9V8. Few weeks ago i give up first battle with new system and put it all back to original Hotwire setup( now it is working great again). I had massive misfire to exhaust which i couldn't identify why. Yesterday i installed just EDIS with coils for test with rover ECU. And it did misfire again. Wiring is 100% correct( based on informations from extraefi). Timing is solid at about 10 degrees. EDIS module is working in different car with no problem. Do you think that cause of problem could be camshaft?

thanks

ET

[Hybrid_From_Hell]

Camshaft ?

Why ? If the Engine works on Lucas system, and not on MS then there is an issue with MS

I would suggest a "Massive" misfire look at coil a b c d and wiring to edis 8 and also

plug leads on coil packs

Is this a Hand made new loom, or a change to existing Hotwire / flapper loom

Nige

[teslo]

I cannot count how many times i have checked wiring with scheme from extraefi web page( for EDIS8).

In yesteday's test i've connected just EDIS and coilpacks. So i didn't change wiring for ECU. But few weeks ago i've tried to use existing wiring from hotWire system. but without success. In my first attempt i installed whole system in one moment( EDIS, MS) using Hotwire loom. As i couln't find why it is misfiring i decided to put it all to original state and start again with smaller steps. First step was EDIS and coilpacks.

EDIS, coilpacks and connectors are used from triggerwheel( but working in othar car)

plug leads are new from triggerwheel

Massive misfire means:

-idle is bit rough but acceptable, misfires only once a time

-when engage gear( automatic transmission) it starts misfire massively

[Bowie69]

I would be tempted to stick it in gear, get it mis-firing nicely and start pulling off plug leads one at a time(wear rubber gloves!) to see which cylinders are affected.

My money is on you having a pair of leads in the wrong places.

Can you post a pic of the coil packs and an indication of which is ABCD? An extra pair of eyes is often helpful

[Richard Lane]

Megasquirters,

I have a question for you all. For those of you who have converted your V8 to MS and potenially EDIS, are you seing better fuel economy as a result? Has anyone kept tabs on economy and have figures for the osrt of litres per 100k's or MPG you are getting?

Would love to hear

Rich

[Boothy]

Boothy here, I haven't got a vacuum leak, thank god, what I have got is a kink in the pipe restricting flow, so it's only half my fault, although I have not tried it yet.

I use plastic air pipe with rubber jointers at each end,it's the rubber thats kinked and flattened on a corner.

Thanks for the pointers they are a great help,

Richard, I only have 2 gauges in the motor one for oil pressure and one for water temp and both are mechanical capillery gauges, oh and a fuel pressure gauge under the bonnet. I get confused by all these clocks and things.

Seems strange I use an Austrailian forum for my Nissan Patrol Y60 4.2 and you use a British forum for LR etc, doesn't it make the world a small place.

Teslo,

When I re-wired mine I checked using a multimeter the coil pack wiring from the ecu to the plug on the coil pack, checking a,b,c,d etc, and in doing this caused myself a problem due to the fact the meter leads I was using to check for continuity (just on the resistance scale) had forced the crimps (connectors) apart slightly on the coilpack plugs, so when metering everything seemed good good but in practice it was missing and banging and driving me mad due to the poor or no connection, even though the plug seemed to fit securley.

So it was just a case of carefully retightening the crimps with a very sharp small screwdriver and all was well again.

Hope that might help.

[teslo]

I would be tempted to stick it in gear, get it mis-firing nicely and start pulling off plug leads one at a time(wear rubber gloves!) to see which cylinders are affected.

Good idea...will do

[FridgeFreezer]

I have a question for you all.

Rich - that's a tricky one since most people's cars aren't standard, so comparisons are tricky.

However, when I had my standard 3.5 RR the MPG was slightly better on MS than flapper, even with my terrible tuning

The 109 with 4.6 V8 does 15-18mpg, 10 if it's towing something heavy. Then again, it's very under geared thanks to the portals.

[Bowie69]

I went from 13-14mpg on a run, just on my tod, unloaded on 235/85 BFGs, to 15.5mpg on a run, fully loaded with people/camping gear, and towing a 600Kg trailer tent, an added roll cage and an upgrade to 33x10.50" Simex JT2s...

Personally I was astounded it went up given the weight I was carrying, train weight must have been close to 3T...

Oh, and that was on a 100K mile 3.9 V8 with a slightly knackered cam...

[Hybrid_From_Hell]

^^^

The old 4.5 system (Lucas ECU with "Adjuster" and JAG AFM and Injectors, gave me 8-9 gentle, and about 4 "Having fun"

Off road even worse

Now with MS and 3.9 / 4.6 RR Injectors, 15-20 gentle, 12 "Having fun", so yes more than chuffed, improved again with new 4.75 CWPs to correct slight overgearing (were 4.1s)

Nige

[red90 driver]

I'm just started collecting parts to MS and EDIS a 1994 3.9 Lucas Discovery (hotwire?) setup.

This is going to be controlled by a MS 1 running MS extra code, therefore I can't use the 4 wire stepper IAC for idle control that is standard fitment.

After looking through a lot of info on various forums, we need a 2 or 3 wire auxilliary air valve. The one that I've found mentioned is a Bosch 0280140505 valve, this was recommended on the ExtraEFI site. This valve is quite expensive to aquire, and other similar valves are a lot cheaper i.e. Bosch 0280140516. Whats the difference? Will any of these alternatives work OK?

Does the fast idle control only switch on when the engine coolant temp is below the threshold set in MS? I've been told that on standard EFI systems the fast idle valve also operates on the overrun and under certain other conditions....

Should we go with TPS or MAP sensing? If we go MAP, then where and how do I attach the vacuum pipe on the plenum?

Does the standard exhaust 'Y' piece have 2 lambda sensors as standard? If so, do I need to move one Lambda sensor so that it is getting a readout from both banks rather than 1 and connect that to the MS?

Would a wideband lambda sensor be robust enough to leave in place all the time? I have been told that they do not like getting dunked in cold horrible muddy water...., and seeing as thay are about 3-4 times the price, should I just rely on the narrow band for fuelling?

Could anyone send me a base map for ignition and fuelling for a standard 3.9 running EDIS?

[FridgeFreezer]

Red 90 - Most of your questions have already been covered in great detail in this thread.

After looking through a lot of info on various forums, we need a 2 or 3 wire auxilliary air valve.

Part numbers & photos & sources (EG eBay) have been covered in this thread. I suspect the other part numbers are for smaller engines & will not flow enough air.

Does the fast idle control....

It's all in the manual for setting up the MS'n'S-Extra firmware and has been covered in this thread.

Should we go with TPS or MAP sensing? If we go MAP, then where and how do I attach the vacuum pipe on the plenum?

TPS sensed is for insanely lumpy engines & other special cases, the MAP sensor is there for a reason. The connection options have been covered in great detail in this & other threads.

Does the standard exhaust 'Y' piece have 2 lambda sensors as standard?

Yes, try looking under your car

If so, do I need to move one Lambda sensor so that it is getting a readout from both banks rather than 1 and connect that to the MS?

It's nice but not essential, once your're close with the tuning it's worth checking the radout from the other bank just to make sure they're not wildly different.

Would a wideband lambda sensor be robust enough to leave in place all the time?

No - not if you're going off-road. And since the subject has been discussed on this thread and the verdict is that you don't need one these days with the MS tuning software, you needn't worry anyway.

Could anyone send me a base map for ignition and fuelling for a standard 3.9 running EDIS?

Again, read back through the thread, lots of good base maps have been posted.