Help! Engine Won't Start...Sih

[JustLearnin]

Ok, I haven't worked on engines since my teens, when I did so out of necessity (no money means doing it yourself). I have a '72 Blazer with a 350 and an Edelbrock carb, both new; also new fuel pump and coil/distributor system. I've been driving it without issues for the past month, until now...

I drove it yesterday morning, and then parked it in the garage. When I went back to start it, it would turn over, but not fire. It almost did at one point. I could smell the gas so I left it alone for several hours thinking maybe I just flooded it. Went back out this morning and it still doesn't start. Can any of you give me some pointers as to where to start looking, what to check? Thanks!

[Rufton]

I'd try starting fluid next.

[IwantaK5]

Check the volts on the coil, Maybe a loose wire somewhere? I had a blazer that had a weird starting problem and it ended up being a loose wire at the ignition switch.

[IwantaK5]

pull a plug and check spark first.

[JustLearnin]

I'll grab some starter fluid. Need some around here anyway.

So, to check spark, just pull a plug wire and hold it to the exhaust manifold or something and see if it it sparks?

I will definitely check for loose wires; I didn't think about that one. That has been a bit of an issue with this rig (should have put in a new wiring harness).

Thanks guys; I'll go out this afternoon and start working through the suggestions.
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[jaros44sr]

Originally Posted by JustLearnin

I'll grab some starter fluid. Need some around here anyway.

So, to check spark, just pull a plug wire and hold it to the exhaust manifold or something and see if it it sparks?

I will definitely check for loose wires; I didn't think about that one. That has been a bit of an issue with this rig (should have put in a new wiring harness).

Thanks guys; I'll go out this afternoon and start working through the suggestions.
Posted via Mobile Device

I wouldnt recommend HOLDING the spark plug wire to the exhaust, just lay it there, so it makes contact to ground

[Rufton]

FYI: Spark can jump Knipex pliers insulation.

[JustLearnin]

Update:

So I tried the starter fluid; no change. Pulled the plug and had the better half crank it over for me; couldn't see a spark. So I hooked up the battery charger and set it on booster, and it fired right up! Why in the world would it start with the booster, but not without? I've got the battery charging now (it too is new).

Probably time for a little more history. I hate writing dissertations, especially if it's irrelevant; but in this case it probably isn't... When I got my blazer back from the bodyman, it would only seem to run for about 15 miles or so, and then start cutting out. The radio was barely working too. I had the alternator swapped out thinking it wasn't charging, and then had the distributor/coil replaced with the smaller style (I hated that the old distributor was so close to the fire wall, actually touching). Nothing seemed to fix it. Then my mechanic checked the voltage coming out of the fuse box (at least I assume that was where he checked it) and it was around 11 volts.

So my bodyman took it back and (again I assume) fixed the wiring (and a couple of other minor things). I've probably got 500-600 miles on it since then without issue, until now.

Any thoughts/suggestions on what to look at for a long-term fix? I'm thinking I might put a new wiring harness in this winter; maybe that'll take care of it?

Since I know that we all like pictures I thought I'd share one from our trip into the mountains last Sunday with the family to pick huckleberries...thanks everyone for your help!

[Joanne]

The voltage isn't right, that's for certain. I believe it should be be a bit over 14v when it is running. Symptoms sound like it's running on battery voltage until it gets too low to keep running. I would check the voltage regulator and its wiring. I would almost bet the issue is there.

Joanne

[1972_K5]

I second the voltage regulator. On mine everything seemed good until I tried to run with the headlights on. Battery died and wouldn't restart. Charged the battery and it fired right up. Thought the alternator was the issue. Had it tested and it was fine. Finally found that we had missed hooking up the ground wire on the voltage regulator. Grounded it out and all of my charging issues were fixed. Another thing I just thought of was if you switched to a HEI distributor make sure it is getting power from a 12v source. Not through the original wire, I believe it has a resistor in it and drops the voltage down. Good Luck!

[JustLearnin]

Forgive my ignorance, but isn't the voltage regulator inside the alternators nowadays? I believe that my original voltage regulator is still there, and has wires running to it, but I was under the impression that it is bypassed?

I took a photo of the wiring on my alternator, if that helps anything. My bodyman ran a loop wire from where the red wire connects up to another point on the alternator. Hopefully you can see it clearly. What is the purpose, any idea? And, based on what you see here, what would you consider my next step to be? Thank you all!!!

[Ol Blue K20]

You need to check voltage while it is running. The alt in the pic is internal reg but if your old reg isn't bypassed they may be fighting each other. There is a thread on here some where showing how to do away with the external reg and have every function

[JustLearnin]

Thank you Ol Blue. So where do I check the voltage at? I'm sure I've got a volt meter in my work shop, but what places would I check at? I will search for that topic that you mentioned. Thanks again!

[Ol Blue K20]

I would check it at the battery, fuse block and any where else you can to make sure it is all the same everywhere. Also check and clean all grounds too.