Engine not starting - HEI8

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dart73
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Engine not starting - HEI8

Post by dart73 »

Hello all,

kindly need your help to start my engine. This engine worked a long time ago... changed harmness and using a relay board.
Rebuilt the engine.

- Mopar 318 V8 MS Extra with HEI8;
- Fuel pulsing in both fuel banchs;
- tested VR sensor running distributor in my hands and MS is detecting RPM rotation;
- new MSD blaster coil... fires.. but looks like a weak spark... but sparking;
- trigger angle set to 10º. This engine runned before with 36º. Can this degree be influenced by a bad engine mounting? Tryed with 36º and 10º but dodn't work with anyone;
- Running on ethanol now. Should I try to start the engine on gasoline? Should it be easier?
- Starting dwell 6.0ms and running dwell 3.6ms;

No datalogs, will save on next try and post here.

Can you give your opinion?

Thanks,
Fernando
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
billr
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Re: Engine not starting - HEI8

Post by billr »

Is your "crank wheel" in the dizzy? If so, can't that be installed into the block with the shaft/wheel in just about any position; and the dizzy base can be rotated to further affect where the trigger point is relative to the crank TDC? Point is, neither 10 or 36 degrees may be correct, you need to check it with a timing light. Use a quick blast of starting-fluid if you have any doubts about the fueling being to far off to let it fire.
dart73
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Re: Engine not starting - HEI8

Post by dart73 »

I have set the engine to TDC and aligned dizzy rotor to #1 cylinder.

You said check it with timing light. How it's the triggering angle related to spark advance that I can see with timing light?

Isn' t triggering angle the timing between the VR sensor detected and firing the oil.. Like a delay?

Regards,
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
dart73
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Joined: Tue Sep 21, 2004 11:12 am
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Re: Engine not starting - HEI8

Post by dart73 »

Is the trigger angle the angle befor tdc?

I.e. If I set it to 20 .. Then i put engine to TDC.. I have to rotate the body of distributor until the vr trigger stays at 20* before #1 cylinder? Is this correct?
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
billr
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Re: Engine not starting - HEI8

Post by billr »

Your reasoning about what those numbers mean may be correct, I don't know. But why bother to figure it out? It is so easy to just use a timing light and see what is going on! Just change the number until the light and a "fixed" timing set in TS agree. After you can get it running, verify that the setting is still correct and doesn't drift as rpm is increased. Most folks find this is easiest to do with a "simple" (non dial-back) type of light. You may have to put temporary "timing marks" around the whole 360 degree circumference of the harmonic dampener or crank trigger wheel until you get the offset number close enough to use normal timing marks. That doesn't have to be at all accurate, you just need a guide as to which way to move the number. A few tries and you can get it right-on.
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Re: Engine not starting - HEI8

Post by jsmcortina »

Have you read the manual that applies to your Megasquirt version ? (which one is it?) HEI8 is covered for MS1/2/3

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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dart73
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Re: Engine not starting - HEI8

Post by dart73 »

Hello James,

yes I have read the msextra manual several times and checked all mods.


Regards,
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
dart73
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Posts: 124
Joined: Tue Sep 21, 2004 11:12 am
Location: Brazil

Re: Engine not starting - HEI8

Post by dart73 »

Hello guys, kindly find attached a datalog. Could you please go around it and try to see if missing something?

Did the following:

- Set the engine at TDC;
- Checked firing order and distributor #1 aligned with rotor;
- put the engine in 10º btdc and aligned distributor pickup lip;
- set trigger angle to 10;
- engine didn't start. Saw some backfires sometimes and fuel smell.... but nothing.
- increased dwell from 6 to 9ms and hei module still cold after a lot of tries (could be a burned module?);
- looks like the spark is weak but I had nodoby do help me here today so I couldn't see it;
- MS Blaster SS Coil;
- changed triggger angle from 0-45 in 5º steps and nothing.

Can you give me you opinion?


Regards,
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
Matt Cramer
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Re: Engine not starting - HEI8

Post by Matt Cramer »

What's the timing look like if you check it with a timing light?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
dart73
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Re: Engine not starting - HEI8

Post by dart73 »

Hello Matt,

did a test here with a spark testing device like this http://continuouswave.com/whaler/refere ... 00x191.jpg and I could see the spark... gap was up to 0.40" and still sparking.

When trying to see timing during cranking I couldn't see anything. Changed the timing light and the same.... couldn't see anything.... any guess?
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
billr
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Re: Engine not starting - HEI8

Post by billr »

Are you saying you can see a spark at a plug laying loose, out in the open, but the timing light won't flash at all?
dart73
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Re: Engine not starting - HEI8

Post by dart73 »

Yes Bill,
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
billr
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Joined: Sun May 15, 2011 11:41 am
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Re: Engine not starting - HEI8

Post by billr »

"- new MSD blaster coil... fires.. but looks like a weak spark... but sparking;"

I guess we need to go back to that part of the OP. It seems like it is too weak to even trigger the light. What kind of coil driver are you using? You have confirmed there is a good 12V supply to the coil, no dropping ("ballast") resistors were left in that circuit? Do you have a Stim, do you get a weak spark and no light triggering with the Stim?
dart73
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Re: Engine not starting - HEI8

Post by dart73 »

No ballast resistor and good 12v direct from battery.

I didn´t test ignition with stimulator. Just MS board and was working fine.

HEI is driving the coil like the scheme found here:
http://www.msextra.com/doc/ms1extra/MS_ ... htm#gm7hei

How Can I test ignition with stim? There's a RPM potentiometer, How can I test VR input with this? or just ignore VR sensor and test just coil and HEI module?

I think I´ll have to remove everything to do this...

Thanks,
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
billr
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Joined: Sun May 15, 2011 11:41 am
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Re: Engine not starting - HEI8

Post by billr »

I made a mistake, I meant to ask if spark is weak and timing light not flashing using "Test Mode" in Tuner Studio. I don't have a Stim, so can't really tell you anything about whether it can be used to test spark, although I expect it can. Likewise, I have no experience with the HEI8, so can't help much with that. You will have to wait for someone else to chime in, but I'm pretty confident there is no point in trying to get it started until you can verify with a timing light that the timing base is correct; and if you can't get a light to operate on your spark well enough to do that, then you have to solve the weak spark issue first. Do you have access to an oscilloscope?
dart73
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Re: Engine not starting - HEI8

Post by dart73 »

No ociloscope. What can I see with the osciloscope?
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
dart73
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Re: Engine not starting - HEI8

Post by dart73 »

I think test mode just available for MS2. This is MS1 v2.2 board Extra.
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
billr
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Joined: Sun May 15, 2011 11:41 am
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Re: Engine not starting - HEI8

Post by billr »

The scope would be to look at the voltage/current in the coil primary. That is a very brief event, only lasting approximately the "dwell" time *, which is 6 milliseconds for you while cranking. And the turn-off time for coil current, which is important for maximizing spark voltage, is just a short part of what dwell time is. Because these times are so short, you can't really tell if the coil is being turned on-and-off properly without a scope; a voltmeter is too slow. I recall that you said the coil is new, but perhaps you might try another one anyway. This being MS1, we really need somebody else to chime in, my experience is all with MS3.

* Strictly speaking, the "dwell" period is only when power is applied to the coil primary, the actual spark period is separate from that; but both appear as kind of one wave-form on the scope. I was trying to keep my explanation as simple as possible... but don't think that worked! It's late, that's my excuse.
dart73
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Re: Engine not starting - HEI8

Post by dart73 »

Hello all,

long time passed... continuing with that....


So, now I have a good spark and correct trigger angle. My cranking advance angle set to 15º and fixed angle to 15º (not using spark table by now).
No signal of the engine trying to start.

I realized looking into the msq that my V8 engine is set to 2 squirts / cycle and in some V8 examples as 4 squirts / cycle.

Could this be preventing my engine to start or this is just taken in consideration when calculating the injector pulse time?



Regards,
Fernando
MOPAR or NO CAR!!
1973 Brasilian Dart
megasquirted
Matt Cramer
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Re: Engine not starting - HEI8

Post by Matt Cramer »

A V8 can run either way; you're generally best trying both and seeing which way it runs best on once it's up and running.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
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