MSefi.com read only forum (Jan.15,2018)

Hi there,

I'm new to this forum so i hope i'm posting this problem on the right forum...

I'll explain the situation:
I have a 1985 chevrolet camaro iroc-z28 (305 TPI-setup) took apart the engine, put in new pistons, blower ready camshaft/valves/springs. new low intake manifold with a blower which comes from a ford (suited for 5 liter engines).
I'm using the stock HEI module (7 pins) in the stock distributer. And stock injectors.

A buddy of mine assembled the MS2V3.0 (uses bowling & grippo V2.11 code) tested it, and it worked ok on the stim. I connected it to the car and it looks like all signals are present.

Now for the problem..
When i try to start the car it cranks, alle the signals are present for as far as i know. sometimes it allmost fires up, have some logs for those who want to take a look at that. At first the spark plugs were quite wet (of gas), but after some contact with a guy i know there not anymore(gave it a bit too much fuel, though if i pull out a plug i can see the ignition works). still the car doesn't start...

Because i'm not that great in wiring and stuff the guy i know assembled the megasquirt and helped me do the wiring, but today i was checking the HEI module and found out it was a 7 pins module, looked it for the ignition settings in the manual and found that some settings were not correct for the 7-pins HEI.(like ignition input must be rising edge and cranking trigger must be trigger rise) could this be a problem? still the engine almost fires up at some point with these settings wrong(i suppose)..?

I also discovered in the notes the guy made assembling the MS2V3.0 that at step 65 of the assemblymanual he chose to install the high current ignition driver instead of the first optiom which lookes to me as the right option... Could this be the problem?

Again i'm not a specialist in electronics and wiring but learning fast the past few days... Hope that someone here can help me solve the problem, hope i provided the necessary info..

thanks up front for anybody with good tips!!

Edwin

The high current driver won't be a problem unless it is also jumpered in; if nothing is connected to IGBTIN and IGBTOUT, the driver is just sitting there. I would first try making the truck start and run with the B pin disconnected, then get the ignition straightened out.

Matt,

Sorry for the late reply, been very busy doing other things lately... Disconnecting the B pin from the HEI I suppose you mean? What does this do to the ignition settings? Does this set the ignition timing to a fixed value??

Thanks,
Edd

Correct, that causes the HEI module to control the timing instead of the MS.

Guys,

After a lot of troubleshooting and searching for the problem I had the car almost starting... It fired up for like one second and after that no fuel was ignited...Then after some more searching I found the problem... The pully from the blower I bought was not connected with (I dont know the exact translation of the dutch word "spie") a cotter pin to secure it properly.... Bottemline was that the blower didn't turn during cranking...No blower means no inlet air... At that point I was both ashamed of my stupid mistake and happy that I found my problem.

Now the blower is working properly I tried again. Same MS setup, won't even fire up that second that it did before... I was convinced it should work now, i've posted the setups and two logs one with the blower standing still and one with the working blower, which you can clearly see in the map readings.

The Gve readings are significantly different between the two logs, does somebody know what that is? or is there anyone that can find something unusual???
cranking RPM when it doesn'f fire is usually around 90-110 rpm, and yes i know that's low but should that be the problem?

Hope that someone can help me out here...Thanks for trying!!

Edd

and this is the ms setup when it almost fired up, with the blower standing still.

Edd,

You are running very old code (2.10, released several years ago - ~2005 if I recall correctly) for which a number of bugs have been fixed. You should upgrade to the latest code: http://www.megamanual.com/ms2/code.htm before doing anything else, the code is improved, and more people are likely to know what you need to do to get running.

Lance.

Lance,

Thanks for the tip, I'll give it a try this week.

Edd

Well,

I uploaded The new firmware v2.92 and gave it another try. And again I found a problem, voltage drops to 6.7 volts during cranking... You can see the rpm signal dropping to zero because of the low voltage. (Battery was not fully charged anymore but still should get a car starting...)

Anyone any suggestions on how to decrease the voltage drop when cranking? I've posted the log and msq below. Are there any other weird values or something in my setup?
Thanks for looking!!

Edd

By the way its a 75 Amp battery

voltage drops to 6.7 volts during cranking

Edd,

This could be a big problem, especially because megasquirt reports increasing higher voltage as the actual volts dip below 7.0, and the processor doesn't function properly, as you might imagine. That alone would make starting very difficult or impossible.

Anyone any suggestions on how to decrease the voltage drop when cranking?

Bigger and/or newer fully-charged battery? Or perhaps a more efficient starter (gear reduction, for example).

Lance.

Battery is brand new, and bigger then the original one. I'm going to try renewing or adding some ground wires to the engine and starter motor. Could be that because I added the blower and stronger valve springs that the starter motor is too weak..I hope not.

Are there any bad inputs in my setup? or weird values in the log. I'm not that experianced setting up a tune...want to be sure that this is a setup on which the car should fire up.

Edd

Well, with a few more/new grounds battery voltage is about 8 volts during cranking. Engine almost starts but doesn't seem to run on its own power.... Now that there is some descent cranking data is there anyone here that can find something weird in my data?

Edd

I checked almost everything except injection timing, is there a way to check this without disassembling all the injectors? other than that only the B pin of the HEI is disconnected, I dont suppose this causes the engine not to fire up?

Edd

Injector timing isn't nearly as important as the injected fuel amount. Try adjusting the cranking pulse width.

Also, is your MAP sensor line unplugged?

Matt,

the MAP sensor+line is plugged in, why do you think it is not?
Cranking pulsewidth is set from 11 msec to 3 msec at the highest temp, what do you recommend?
injection timing is the last thing i didn't check but i realise it is not that important.

Edd

I noticed the 320% cranking pulse width at minus 40 centigrate in the manual (http://www.msextra.com/doc/ms2extra/MS2 ... anual.html), mine is set in msec 11 to be exact, but 320% of my required fuel is no where near 11 msec right?? I'd think i'l seriously flood my engine if i put in 320%.... anyone ideas?

Edd

I'd recommend using a curve based cranking pulse width instead of two point; I tend to see better results with that.

Usually the MAP reading would drop while cranking.

map reading goes up slightly after it ignites a few bursts due to the blower, but after that it drops again.

I've got a setup now at which the engine ignites, but looks like its not powerful enough to get it running. I got dry spark plugs, if i increase the req_fuel or the pulse width curve a bit it ignites less and i get wet plugs. I can try to put in the HEI pin B which i still have disconnected, but it only adds another variable..Ignition