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

[Richard Lane]

Gday all,

With great fascination I have sat here and read through this thread. My name is Richard, I live in Australia and own amongst many a 1984 110 Land Rover with a Leyland P76 4.4 V8 which is basically an early 3.5 V8 with a longer stroke and a taller deck height. My truck runs a Rover V8 front timing cover and a modified 3.5 V8 Dizzy. I have a Mega squirt Version 3.0 of which I would like to setup EDIS using ignition only with the long-term idea of going to Fuel also. The truck runs LPG and Petrol but mainly on LPG hence the reason for fuel only at this stage. Is this easy enough to do with the Mega squirt or should I throw it and get the Mega jolt. I have experience with Mega squirt, and a friend runs a system in a 1984 Hilux with a 22r engine.

Thoughts?

[Richard Lane]

fuel only at this stage

And I should have said Ignition only!!

Cheers

Rich

[bobtail84]

Just a quickie.... One of the MSed V8's PWM valve under my care has decided to stay wide open all the time it's plugged in. If I set the PWM setting for warmup only it reads 0% in mega tune and revs at 14 to 1600 RPM. If I leave it on closed loop in reads 65% on cranking the lowers to 40% which is the setting for tickover but is still 14 to 1600 RPM. I'm getting a resistance reading with ignition on from MegaSquirt. If I unplug the PWM the tick over drops to more or less normal and is fine to drive but a git to start first thing. It looks to me to be a short on the MS side but I wanted to see if there are any other theories or maybe a problem with MegaSquirt settings. I have looked and they seem good.

jeff

[steve_d]

Just a quickie.... One of the MSed V8's PWM valve under my care has decided to stay wide open all the time it's plugged in. If I set the PWM setting for warmup only it reads 0% in mega tune and revs at 14 to 1600 RPM. If I leave it on closed loop in reads 65% on cranking the lowers to 40% which is the setting for tickover but is still 14 to 1600 RPM. I'm getting a resistance reading with ignition on from MegaSquirt. If I unplug the PWM the tick over drops to more or less normal and is fine to drive but a git to start first thing. It looks to me to be a short on the MS side but I wanted to see if there are any other theories or maybe a problem with MegaSquirt settings. I have looked and they seem good.

jeff

I have completely failed to get PWM working with either of the two MS units I have. Moreover nobody has been able to come up with a reason why.

Steve

[bobtail84]

I have completely failed to get PWM working with either of the two MS units I have. Moreover nobody has been able to come up with a reason why.

Steve

Steve

Both mine and another in my care work fine but this one just stopped doing what it should. I will be having a good look at the problem tomorrow.

jeff

[waxen]

And I should have said Ignition only!!

Cheers

Rich

Richard I would think that the Megasquirt would have to be built with fueling in mind to get it to work properly. That being said I run my setup with dual fuel, the Megasquirt controls EDIS via dual mapping and an empty fuel table. I simply have the power feed to the injectors interrupted by a relay when on LPG.

You would need to hook up a MAP sensor regardless and the O2 sensor is handy for tuning.

Cheers

Wayne

[FridgeFreezer]

If you don't connect injectors to the MS then it's ignition only

[bobtail84]

Just a quickie.... One of the MSed V8's PWM valve under my care has decided to stay wide open all the time it's plugged in. If I set the PWM setting for warmup only it reads 0% in mega tune and revs at 14 to 1600 RPM. If I leave it on closed loop in reads 65% on cranking the lowers to 40% which is the setting for tickover but is still 14 to 1600 RPM. I'm getting a resistance reading with ignition on from MegaSquirt. If I unplug the PWM the tick over drops to more or less normal and is fine to drive but a git to start first thing. It looks to me to be a short on the MS side but I wanted to see if there are any other theories or maybe a problem with MegaSquirt settings. I have looked and they seem good.

jeff

right I've had the test meter out and..... Ign on I have a circuit on the earth side. Ign off and still have a circuit... Disconnect DB37 from MegaSquirt no earth circuit. Sooo there is no short on the earth to the chassis and my guess it's a problem in the ECU. Shall I load a new Msq or does anyone think I should try something else.

jeff

[waxen]

Sounds like the Flyback Diode or Tip 122 is faulty, I had a similar problem and it was the Tip122

[Richard Lane]

Richard I would think that the Megasquirt would have to be built with fueling in mind to get it to work properly. That being said I run my setup with dual fuel, the Megasquirt controls EDIS via dual mapping and an empty fuel table. I simply have the power feed to the injectors interrupted by a relay when on LPG.

You would need to hook up a MAP sensor regardless and the O2 sensor is handy for tuning.

Cheers

Wayne

If you don't connect injectors to the MS then it's ignition only

Thanks lads,

So I will be putting this thing together to suit MS1extra with mods for EDIS. I have the kit at home now and I will be able to solder it together ready for the fitting to the truck.

Rich

[tarmacshredder]

Update on my Landy as I haven't posted for a while as although I have been doing various bits to it I haven't got it going yet.

The main update is that I have moded the ecu so that it is now running Edis (Everyone seamed to thing that this would be the turning point and it would just run!).

A big thank you to Nige as this has then allowed me to send to Nige who has very kindly tried the ecu on his hybrid and much to my amazement it has started and run fine, with everything as it should.So it must be something that I have done wrong for it not to be running on mine! so suggestions on a postcard as they say, as to what I have not got right.

With the Edis on it will crank 2-3 times then fires and runs for 2-3 seconds and the first couple of times ran on all 8 cylinders then stops. If you touch the throttle it will not start and it will not run/rev. It always used to when it did run/cough into life before so this is abit odd.

After it has tried to start each subsequent time of turning the key, cranking firing running for 2-3 seconds it drops the number of cylinders trying to run untill it wont start and run at all. Removing the plugs cleaning and igniting the fuel in the bores helps as it appears to be flooding. Have tried dropping the values in the warmup wizzard but doesn't appear to help.

I have a modded 3.9 loom which is quite simple to adapt anyone had similar problems on a 3.9 loom they have modded?

As it ran on the Lucas a month ago that sort of rules out the fuel side with regards to injectors and pressure relief valve as they haven't been touched.

Vr would seam to be my next to try, I have already checked and checked the missing tooth and checked that tdc is at tdc on my pulley, checked the air gap etc. what else could I have got wrong?

All ideas greatly received

Many thanks

Glenn

[FridgeFreezer]

If you're getting RPM shown in MegaTune and sparks on the coils then the EDIS is working, so you're most of the way there. The wires for the VR sensor could be reversed, so that's a quick one to try.

If no joy - can you show/describe the mods you did for EDIS? A good photo of either side of the PCB would be helpful.

[Bull Bar Cowboy]

Sounds like its wired wrong ………….

From your description it would seem that you have a ‘cranking live’ but as soon as you release the key you don’t have an 'ignition live' to keep it going……….

IIRC on LR’s the 'cranking live' is a white /red and 'ignition live' is a white ………….

[tarmacshredder]

Hi John and BBC,

I am going to try the Vr sensor wires the other way round but then it did run last year though rough.

Nige has run the ecu on his so the mods to the ecu for the edis should be fine, the mods to the wiring I have made were feed to the module, pip and saw to the db37 plug pins 24 and 36. Earth to the other ecu earths and coil driver outputs to the existing wiring that I already had inplace for the direct coil drive setup.

The Ignition switched live I have tested in the past and it is continuous with cranking but will double check that it is when you switch off the starter.

I am going to try a different VR sensor and VR sensor cable to see if this changes things.

Any other suggestions greatly received.

Many thanks

Glenn

[steve_d]

Have you calibrated the throttle pot?

If this is wrong MS will be all over the place and may even think it is in 'flood clear'.

Steve

[FridgeFreezer]

Have you calibrated the throttle pot?

If this is wrong MS will be all over the place and may even think it is in 'flood clear'.

It's not made by Lucas you know

If the throttle pot value hits ~255 it will go into flood clear but the rest of the time MS works on the rate-of-change of the throttle pot voltage (eg how quickly you're mashing the pedal) rather than it's actual position from the carpet.

You can tell if it's in flood clear or acceleration enrichment by the engine status (EG "CRANK", "RUN", "WARMUP", "ACCEL") in MegaTune.

[simonr]

Nigel (Hybrid from hell) - I'm told you are going into business selling Megasquirt in the UK. Have you decided on pricing etc yet?

One of my friends needs MS to get his truck up and running with a new engine.

Si

[tarmacshredder]

I have calibrated the throttle in megatune, also when you press the pedal more than 3/4 down it comes up as flood clear in the tabs at the bottom of megatune so that would appear to be working. Also my wide open throttle value is about 255 cannot remember off the top of my head the closed position value.

Glenn

[Hybrid_From_Hell]

you should aim for something low ie 20 +/-

Nige

[bobtail84]

Sounds like the Flyback Diode or Tip 122 is faulty, I had a similar problem and it was the Tip122

Waxen, it look's like it's the TIP122 that's at fault as "if the TIP122 has failed you would have a permanent short to ground" is exactly what has happened. Fridge passed on the prognosis so new TIP122 ordered and arrived today, well 4 for 90pence + P&P so I will fit a new one after luncheon tomorrow and see what happens.

jeff

[FridgeFreezer]

Make sure you don't break or lose the mica insulator & plastic spacer for the retaining screw, if they're fitted (most metal-tabbed TIP122's need them fitted) otherwise the smoke may escape.

[waxen]

Bobtail84, I will be interested to hear if the change of transister makes the PWM valve behave any differently. Whether it is coincidence or not........I had to change my settings a fair bit to get the valve to behave the same way, and while I was playing discovered the flyback diode was faulty as well. This brings me to a new query, it doesn't seem to matter what PWM idle settings I dial in I can't seem to get it to hold the idle immediately after a cold start unless the throttle is coaxed initially. I was wondering if it was because the warm up enrichment isn't rich enough to begin with. Mind I have been using some of the settings found on this thread, which would appear to be suited to a colder climate from where I am.

Cheers

Wayne

[bobtail84]

Make sure you don't break or lose the mica insulator & plastic spacer for the retaining screw, if they're fitted (most metal-tabbed TIP122's need them fitted) otherwise the smoke may escape.

Made sure the spacer was in place 'both' times I replaced the TIP122 and it still has a short to ground....

Bobtail84, I will be interested to hear if the change of transister makes the PWM valve behave any differently.

Naff-all difference...

When I've opened the ECU up I did find water dripping out, not a great deal but it was moist in the case. Where the TIP122 lives on Q16, it looks as if the blue coating has lifted a little next to pin 3 of the transistor. Would that cause a problem? The owner of said ECU opined that the rear window of the truck cab leaked... hence the moisture.

it doesn't seem to matter what PWM idle settings I dial in I can't seem to get it to hold the idle immediately after a cold start unless the throttle is coaxed initially. I was wondering if it was because the warm up enrichment isn't rich enough to begin with. Mind I have been using some of the settings found on this thread, which would appear to be suited to a colder climate from where I am.

Hopefully the tuning guru's HFH or BBC will be along and help you there.

jeff

[Hybrid_From_Hell]

it doesn't seem to matter what PWM idle settings I dial in I can't seem to get it to hold the idle immediately after a cold start unless the throttle is coaxed initially.

Cheers

Wayne

Hiya

Please post up the 2 x screen dumps of the PWM / loop settings and the engine spec for me to look at

Nige

[FridgeFreezer]

Crank / after-start / warmup are the biggest PITA to tune, and take up far more of the space in the ECU's firmware than the relatively simple business of keeping it running once it's up to temperature.

It can be the case that the PWM valve just can't flow enough air for a big V8, bear in mind most of them were fitted to a ~2.4l Volvo/Saab or similar at most. The TIP122 is rated to 5A so could drive two PWM's in parallel to double your flow, but that would be a rather extreme case.

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.