Cranking Settings

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CBDZ
Posts: 183
Joined: Mon Jun 01, 2009 9:22 am

Cranking Settings

Post by CBDZ »

I can't seem to get a good start. I crank for a long time before I get it to pop. It will pop and die, and then gradually get better with each attempt, and then finally run.

I don't know if my cranking pulse width is too high or too low. I've tried all kids of combos, but don't have much success.

Timing is set at 12*. Is there a way to have a different timing value while cranking, instead of using the RPM and vacuum values in the base spark table?

This link will take you to a google drive with MSQ and Config files...

https://drive.google.com/folderview?id= ... sp=sharing
My Car Details:
Fiberglass Buggy on 1973 Chassis.
1904 cc
Megasquirt (MS1 with 3.57 board) Fuel Injection: German Intake Plenum, CB Performance End-Castings, Ford Escort Throttle Body with custom Adapter, MS controls Wasted Spark Coil Pack
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Piledriver
Moderator
Posts: 22760
Joined: Sat Feb 16, 2002 12:01 am

Re: Cranking Settings

Post by Piledriver »

With MS1 you live with the first column of the fuel and ign tables for cranking fuel and spark values, much like the idle area.

MS2E/MS3 have a separate cranking timing, afterstart enrichment and decay rate for same, idle VE table, idle vs load table (to help stabilize idle speed) , closed loop idle speed and all sorts of idle goodies that can make it run like a modern car with some effort.

I always found that when it didn't hit instantly I was feeding it too much fuel.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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markvwguy
Posts: 66
Joined: Wed Sep 09, 2009 8:36 pm

Re: Cranking Settings

Post by markvwguy »

I'm having the same problem.
I got the engine to run. Throughout the day I clocked 30 mile( fresh engine) three sents of 10 mile runs for breakin. Started fine hot all day.

Next morning initial start cold start it wont run, but right off initial crank it will back fire BOOM. Than crank crank almost start crank crank BOOM .... pop pop pop.

My REQ fuel went from 14.1 (1600cc) same tables to 19.0 with the 1956cc to get my VE back in place.

It did catch and run for about 7 seconds and died right out. I was thinking next time warm the CLT to reduce fuel. trick the ECU to show a hotter engine/ less fuel and see what happens.

I was almost thinking timming, but this MS1 v3.0 combo FI has almost 10,000 miles, went from 1600cc build to 1956cc now I have this start condition.

I would attach my MSQ, don't have it with me, haven't attached one yet. I'll try
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markvwguy
Posts: 66
Joined: Wed Sep 09, 2009 8:36 pm

Re: Cranking Settings

Post by markvwguy »

The MSQs are set up for

MS1 v3.0 board
generic whl 36-1
direct dual coil drive (not EDIS)
German TB, plenum, end castings
Vanagon 2.1 injectors with T1 pintle caps
andy198712
Posts: 2433
Joined: Wed Apr 13, 2011 1:01 pm

Re: Cranking Settings

Post by andy198712 »

I'm on MS1 2.2 and with my cold cranking, i had to add cranking pulse width, so more fuel, and it helped a lot, when i add a CLT it will let me fine tune that better, but thats what worked for me...

you could try it both ways. you can set the cranking settings, then the after start enrichment to keep it going once its fired.... :)
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markvwguy
Posts: 66
Joined: Wed Sep 09, 2009 8:36 pm

Re: Cranking Settings

Post by markvwguy »

Made some changes, now it starts just turn key at 60°F,

What I did was increase crank pulse width to 125%, the reason was at crank 60°F I saw the clod crank PW at 2milli seconds. Also at 130°F the PW was 2mS. A cold engine needs more fuel. At 100% no backfire and caught pretty quickly.

Next I reduced the crank RPM to 200. The reason is; you satisfy the 200RPM and the ECU goes to the running tables. It does not wait to satisfy 300RPM and cranking cranking cranking. Larger engines higher comps, and cams will make cranking harder( IMI starters are great ).

Also, increased the ASE for smoother after start performance.

Hope the info helps someone.
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