[J.C.you]

you are probably loosing ignition, if it fires and when you get off the starter button it dies, if i read your post right.

[GTO Dan]

Originally Posted by Scott Roberts

That would be my guess...

X3 may not backfire if it is not running long enough.

[gata79]

Okay. It will be Thursday when I can work on it again. Thanks for the replies I'll let you know.

[Scott Roberts]

Not to insult your intelligence, but did you verify you are on the compression stroke by pulling the valve covers when installing the dist.?

[gata79]

You wouldn't be insulting my intelligence,just my engine knowledge. I know how to do what you're talking about, but no I haven't done it. The way it runs made me think it couldnt be that. In the past when I've had one 180 out it let me know as soon as it fired. This one has no miss or backfire. Though 10 or 15 seconds is the longest it has run. It just kind of peters out.

[aaronman]

Go back to the basics. Timing - ignition and cam, fuel, compression, air. Test these 1 at a time until you find the issue.

[johnta1]

1st take the #1 plug out, rotate the engine by hand, put your finger by the hole, when it puffs,pushes your finger out, stop and see where the rotor is pointing.
It should be pointing at the #1 post on the cap.

Go from there.

[russ467]

it wouldnt run 10-15 seconds if the timing were 180 out. I think either your timing is retarded too much, serious vacuum leak. Even though you have tried 2 carbs, I would borrow a KNOWN good carb off of a running vehicle and try it.

[7D9TA]

I had a very similar issue with the first Pontiac motor I assembled. I did not notice that the aftermarket valley pan I used wasn't letting the intake set correctly against the heads. I had a vac leak at the intake to head on all 4 runners on the driver side. I ordered a thicker intake gasket and problem was solved.

[archerytony]

Originally Posted by johnta1

1st take the #1 plug out, rotate the engine by hand, put your finger by the hole, when it puffs,pushes your finger out, stop and see where the rotor is pointing.
It should be pointing at the #1 post on the cap.

Go from there.

you can also run the timing light when you are turning it over and see where its at and if its firing all the time too

[Jim Scites]

When you have someone start the engine, put your hand over the primary side of the carb so you hand acts like a choke shutting off most of the air to the engine. If it keeps running then you have a vacuum leak. Plug all the vacuum ports of the engine and the carb and try it again. If you have to leave your hand on top of the carb to keep it running then you have either vacuum leak at the intake gaskets, an intake valve too tight or a leak at the carb.

[gata79]

John, that's the way I've always done it. And it's been reset that way at least 4 times. But I'm going to pull the valve cover Thursday to make sure. I have 2 dominators, both are rebuilt but neither is proven. I'm going to order an adapter and use a known 850 I have. Then if not fixed I'll start trying to track vacuum leaks.

[tininjun67]

if it's ran for 15 seconds, you're not 180 out. however, if you want to check, pull the pass side valve cover and put #6 into overlap. at this point the balancer should be close to zero, and #1 at tdc compression. check your dist to see where it's pointed.
I think it's fuel related, it shouldn't run for 15 seconds with a poor electrical connection.
what is your fuel pressure while it's running?

this sounds like a simple problem that you'll give yourself a face palm over once you find it.

[dmac]

check voltage to fuel pump when you have it running for a few seconds, or drizzle fuel into carb to determine if it electrical or fuel issue. If it stays running when fuel(or starting fluid) is being introduced, you can quit looking at electrical issues.

[blueghoast]

Originally Posted by J.C.you

you are probably loosing ignition, if it fires and when you get off the starter button it dies, if i read your post right.

This is what it sounds like to me too.

GT.

[77 TRASHCAN]

Originally Posted by blueghoast

This is what it sounds like to me too.

GT.

like no juice in the run position of the ignition swi...

[blueghoast]

Originally Posted by 77 TRASHCAN

like no juice in the run position of the ignition swi...

Yep; It almost sounds like when you let off the key it looses spark.

GT.

[R 70 Judge]

Originally Posted by gata79

Okay. It will be Thursday when I can work on it again. Thanks for the replies I'll let you know.

Did you change the firing order on your cam? (4-7 swap) Do the plug wires match the firing order. I know that sounds stupid but sometimes we can overlook the simplist things.

[David Holmberg]

Originally Posted by blueghoast

Yep; It almost sounds like when you let off the key it looses spark.

GT.

It sounds more like this to me as well.

If you're still using a key switch it could be just a bad switch.
I'd run a new wire to the ignition box/dist and try again.

I hope its something simple.

[77 TRASHCAN]

Originally Posted by David Holmberg

It sounds more like this to me as well.

If you're still using a key switch it could be just a bad switch.
I'd run a new wire to the ignition box/dist and try again.

I hope its something simple.

If the car has the lock cyl in the column, w/ the ign. swi. on the column.......... Have you fooled w/ the column lately??? The electrical part of the switch could be out of adjustment, a hair, and do this, I HATE working on those... I pull the drivers seat out so I can get to the switch easier, only way to work on it....