Type 4 starts but dies immediately

[AndyMV]

Having a really hard time getting my NA 2056 T4 to start on MS. It's run before sat on a pallet with wires all over the place, but just won't kick into life now it's installed and neatly wired. A few extra things like WBO2 and vacuum lines have been installed now it's fitted, but don't know if there's a connection.

Coils are LS2 and injectors are ASNU 300cc which have both tested OK through the MS test menus.

Plugs are wet with fuel, but dropping ASE & WUE has only made a minor improvement.

Comosite logger & tooth logger both look okay.

.msq & .msl files are here. The log has a load of starting attempts, where (at best) it sustains itself for just a moment before it dies.

Please help!

Andy.

[Clonebug]

Do a save as and then go into your Basic engine settings and drop your "required fuel" numbers a little at a time to cut fuel.

That might help and if not just remember where you started and put that number back in.

[Clonebug]

I looked at your log file and one thing I notice is your battery voltage is very low. 7-8 volts with 11 volts at one point.

When the voltage is that low in the log there is no injector action. You have no pulse width or DC.

Jump the battery or replace it with a better one and try again.

[AndyMV]

Thanks very much for having a look. I'd totally missed that. I'm still getting my head around understanding what MLV is telling me.

The battery is new and had been on charge just before that log was created so I wonder if something else is causing the voltage to drop.

I'm back in work the next couple of days but I'll try and post an update on Wednesday.

Thanks again for your help.

[Clonebug]

Something is drawing the current down then.

Maybe you need to move the MS ECU supply wire to a better source.

Either that or maybe your starter is drawing too much current.

It could be a few different things.

You could try to temporarily supply the ECU with power from a different battery to see if that helps.

Maybe your feed wire isn't large enough to handle the current draw. I have a 8 gauge wire running to the front of my buggy from the battery.

Check your connections at the battery and make sure they are clean and shiny.

I had the positive cable go bad and it would lose connection on heavy draw. I put a new one on and the problems went away.

[AndyMV]

The starter could well be the issue. It's a modern unit from something like a diesel Golf. It goes like the clappers but I hadn't given any thought to the additional current draw. When the engine ran on the bench it was with hooked up to a stock bellhousing/starter test rig. Maybe I'll stick a second battery in parallel and try again.

[Clonebug]

If my voltage is below 12 volts I have trouble getting the engine to fire too.

You need good voltage to make everything work correctly.

[AndyMV]

Unfortunately no success with some additional power. Had a large battery from a diesel hooked up in parallel with the original, but saw no change. Battery voltage during cranking dropped to 9V according to MLV, which seems a lot more reasonable.

[TZepeSH]

Voltage during cranking on modern cars could drop to 6V. That is a normal test condition for ECUs. Megasquirt has a 5V regulator inside, it should work properly even at 6V. Injectors and coils also work at that voltage, otherwise modern cars would not start... But maybe it is a known issue with MS that it needs higher voltage.
However, I think the problem is different, I would check sensors. Do you have VR or Hall? VR could have issues, there were some changes in MS schematic due to signal not read properly. Does it keep synchronization? What do other sensors say? For example if the Map shows 102kpa all the time, it could require too much fuel and go to stall.