Author Topic: Weak Spark please help  (Read 11177 times)

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Offline Silentstrike

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Re: Weak Spark please help
« Reply #30 on: February 24, 2009, 03:14:57 PM »
Its a strong turn over (we thought preservative of some kind so the seals don't dry out) it seems to back fire a bit but not much we were gonna try putting straight gas in tonight when we have the time.  The vapor isn't steam or gas it makes you cough and choke but its not exhaust either.  And no the plugs were dry when we pulled them

Offline Joker (§ir£Ğragon)

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Re: Weak Spark please help
« Reply #31 on: February 24, 2009, 03:21:49 PM »
With minor backfiring it could be something as simple as the timing being off now.
Larry


Offline Silentstrike

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Re: Weak Spark please help
« Reply #32 on: February 24, 2009, 03:37:54 PM »
It doesn't actually fire it only puts out a minior back fire but the engine doesn't run at all

Offline Rick

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Re: Weak Spark please help
« Reply #33 on: February 24, 2009, 04:36:26 PM »
It's common for them to spit a bit while they're cranking if the timing is off.  As you get closer they may also sound like they're barely turning over as the starter "grunts" to keep it going.  You pulled the distributor, which totally blew the timing as you are likely many degrees off from where it was originally.  Try twisting the distributor around to see if it will catch.  If not, and if everything is there (fuel and fire), then you may have to statically time the engine to get it in the ballpark.  Let's hope you don't have to go that far because it's kind of a hassle, though.

I'd start by turning the distributor so as to advance the timing because it sounds like it may be firing after top dead center.  If it's grunting (barely turning over) that's an indication that it's too far before top dead center, so you need to retard it a little at a time.

Once you get it running you'll need to put a timing light on it to get the fine tuning right.

Offline Silentstrike

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Re: Weak Spark please help
« Reply #34 on: February 24, 2009, 07:36:57 PM »
Thank you very much I'll try and see

Offline 78ta

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Re: Weak Spark please help
« Reply #35 on: February 25, 2009, 03:14:54 AM »
He could still have the dist 180 out. In the reading I've done on this thread, I read that they got the dist in but I haven't seen anything that would indicate that they have verified that the dist is in correctly and not 180 degrees out. And that's what it sounds like by it not firing and occasionally backfiring.
It's a simple check really. I think this is what Rick was talking about when he mentioned static timing. Take the dist cap off and the number one spark plug out. Also, with HEI, you might want to unplug the coil wire so you don't damage the coil pack if you're cranking it with the key. Someone check me on that. Crank the engine either by hand (with a wrench on the crank shaft) or by turning the key until you can see (with a flash light) the number one piston come up to the top in the cylinder. I think you also need to make sure that it is on the compression stroke when it is up. I just put a finger over the spark plug hole while cranking it. If it's on the compression stroke, the compressed air will push your finger off the hole. Once you get the number one piston at the top of it's travel on the compression stroke, the rotor contact should be pointing at the number one spark plug wire position. Then you're in the ball park.
The dist may still be a tooth or so off but you should be able to turn it enough to compensate for being off that little bit and get it started.
Good luck
« Last Edit: February 25, 2009, 03:25:40 AM by 78ta »
Randy

Offline Rick

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Re: Weak Spark please help
« Reply #36 on: February 25, 2009, 09:11:10 AM »
Yes, Randy is describing the static time method.  I don't like to have to do that, which is why I go to such great lengths to mark the location of the distributor and the rotor and AVOID "bumping" the engine at all when I have to remove a distributor.  But if it comes down to it, that's what you have to do to get the timing back in the ballpark if something does get messed up.

Offline Joker (§ir£Ğragon)

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Re: Weak Spark please help
« Reply #37 on: February 25, 2009, 11:30:33 AM »
Well, I'm going under the assumption that he put it back so that it's pointing in the same general direction that it was in before he pulled it and that he didn't try spinning the engine without the distributor in it.
Larry


Offline Silentstrike

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Re: Weak Spark please help
« Reply #38 on: February 25, 2009, 02:35:14 PM »
We pulled it and its pointing the same general direction

Offline Silentstrike

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Re: Weak Spark please help
« Reply #39 on: February 25, 2009, 04:28:41 PM »
Now it is wanting to start striong spark getting gas but it wont any ideas bad gas maybe it will almost kick but then it will stop

Offline stimpy

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Re: Weak Spark please help
« Reply #40 on: February 25, 2009, 05:22:24 PM »
pull your plugs and if they are wet/damp  ( i ussually place them on a pan over a heater to give them some warmth to help evaporate the gas )  let them dry then reinstall them , and if does the same thing very slowly turn the distributor ( with the bolt loosened slightly to prevent it from being pulled by the motor but enough to turn by hand ) as your cranking to see if your still retarded ( turning it clockwise). 

Offline jphillips3333

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Re: Weak Spark please help
« Reply #41 on: February 25, 2009, 07:34:55 PM »
Disconnect the fuel line from the carb and turn it over - does gas go into the bucket ... if yes;
When you work the throttle manually, are you seeing gas? ... if not;
Is the fuel filter old/clogged?
What about dumping gas into the carb directly?  You'd said you were going to try that - did you?  if so;

Pull the plugs per stimpy - they could be fuel fouled.
Ensure the distributor is on the compression stroke per 78ta
Make sure the rotor would align with the #1 cap/wire when you put the cap back on.
It would be @ 0 degrees timing at that point - do what Rick says about rotating the cap ~5 to 10 degrees
Is the HEI producing spark ...when you pull a wire and turn the engine over, holding it next to the heads, it should produce a spark.  (You might feel a slight shock at some point ...)

Firing order is 1-8-4-3-6-5-7-2 ... are you sure that's right?

John

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Offline Silentstrike

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Re: Weak Spark please help
« Reply #42 on: February 25, 2009, 08:04:01 PM »
Gas goes into bucket
fuel direct into carb won't fire
tested fuel filter its clear
cleaned fouled plugs
on compression stroke
HEI is producing spark

cheacking firing order is that for a 305? and does this car have an EGR on it, could that be a problem?

Offline jphillips3333

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Re: Weak Spark please help
« Reply #43 on: February 25, 2009, 08:21:07 PM »
#1 is the driver's front cylinder, #7 is driver's rear.
#2 is the passenger front, #8 is the pass rear.

Firing order is counter-clockwise looking down on the distributor.
John

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Offline jphillips3333

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Re: Weak Spark please help
« Reply #44 on: February 25, 2009, 08:24:47 PM »
What engine are you running? ...
John

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