Motor Backfires Thru Exhaust When Trying To Start

[Gaz64]

Originally Posted by Jim Coleman

Here's what patrickt said to do using a piston stop:


1) Put a pointer, any pointer, aimed at an easily reached spot on your dampner.

2) Put a stick in your #1 spark plug hole and using your wrench on the crank bolt, rotate your engine until you are just past TDC (piston is heading back down the hole).

3) Remove your stick and insert your piston stop and screw the little screw part down until it touches the top of your piston and goes no further.

3) Put timing tape on your balancer with the zero degree mark aimed at your make shift pointer.

4) Rotate the engine in the normal direction all the way around until it stops again because of the piston stop. Note the degree that the pointer is aimed at (for instance, 24 degrees). Divide that number by two (12 degrees).

5) Remove your piston stop and rotate the engine a little bit farther to that number (in this example, 12 degrees).

6) You are now at TDC.

I followed this procedure and TDC shows to be within 1/2" of the 5 - 8 marker on the balancer. I hope I did it correctly as I am extremely not knowledgeable on all this stuff.

Thanks for all your help Gary, I know it must be exasperating to you that I'm having trouble grasping this, and it doesn't help that I injured L-3 in my spine and am taking large doses of pain killer...…….

Jim

Hi Jim,

So you are not using the ignition timing pointer on the timing case?

And if your positive stop was in No.1, where does the rotor point to in relation to the cap terminals?

Sorry to here of your L3, I have L5S1 for 4 years now.

Gary

[Jim Coleman]

Gary,

I did use the ignition pointer on the timing case.

I haven't checked where the rotor is, yet. Back pain got me yesterday, bending over installing the harmonic balancer.

Sorry to hear of your L5S1. I just developed the L3 in the past month and am waiting for an MRI so they can determine what to do next.

Thanks,

Jim

[Gaz64]

Jim,

I don't see how the balancer could be "within 1/2 inch of 8/5".

Can you some pics of what you are doing here?

Perhaps the wrong timing tab has been used.

Gary

[lnfletcher]

This is way too complicated! Like they have said before, pull out #1 plug, turn the engine over by hand until air squirts out and put a soft prob in the hole to feel the piston at top dead center. Then you can make a mark on the balancer for your 0.

[Jim Coleman]

https://photos.google.com/photo/AF1Q...WhSR2jJULr9-kZ









Dropped Photobucket, click on link to see.

[blykins]

I've picked up way too many engine blocks off the floor.

In June I managed a 12mm herniation in my L5S1. Had to take a few months off. Everyone I knew was screaming I needed surgery, but there's a physical therapist in town that specializes in spine care. If it weren't for them, I'd be in bad shape right now. Currently zero pain.

If your MRI shows a herniation, head to PT, don't do anything else yet.

[patrickt]

That photobucket image is so blurry it looks more like an AC compressor than it does a balancer.

[Jim Coleman]

Added Google photos. Couldn't get it to auto load, click on link to see.

[patrickt]

OK, since you now know where on your balancer TDC is located, let's just do a "double check" to be absolutely sure. Pull the spark plug out of the #1 cylinder hole and put your stick back in its place. Place a little piece of duct tape on the side of your distributor directly under the location of the #1 plug wire. Now remove the distributor cap, leave the rotor in place, and rotate the engine via the crank bolt. You should see the stick coming up out of the #1 cylinder as the piston is pushing it up. At the same time, you should also see the balancer begin to get closer to the TDC location. Also at the same time you should see the rotor begin to get closer to the duct tape that marks the #1 plug wire. When the stick is at it's highest point out of the hole, and your balancer says you're at TDC, then the rotor should be pretty darn close to the duct tape. It doesn't have to be perfect, we're just checking to make sure it's not way, way way off. If the rotor is pointing to the other side of the distributor, away from the duct tape, then you've found your problem.

[Jim Coleman]

Originally Posted by Gaz64

Jim,

I don't see how the balancer could be "within 1/2 inch of 8/5".

Can you some pics of what you are doing here?

Perhaps the wrong timing tab has been used.

Gary

Gary,

Finally got a decent photo pasted with Google.

The timing tab came with the chrome timing cover, I assumed it was correct.

I did pull the distributor cap and the rotor is pointed at about # 7, not #1.

Patrickt posted a follow up procedure and I'll give it a shot tomorrow.

Thanks,

Jim

[Jim Coleman]

Originally Posted by blykins

I've picked up way too many engine blocks off the floor.

In June I managed a 12mm herniation in my L5S1. Had to take a few months off. Everyone I knew was screaming I needed surgery, but there's a physical therapist in town that specializes in spine care. If it weren't for them, I'd be in bad shape right now. Currently zero pain.

If your MRI shows a herniation, head to PT, don't do anything else yet.

I don't know how or why this happened. I woke up with a pain in my lower back, sat down on a low wooden stool and almost wasn't able to stand up. I have a history of kidney stones and was sure I had another one. After a couple days went to the VA ER. (I am a disabled Veteran). They ran me thru a CAT Scan, and said it was L-3 in my spine, no kidney stones found. I was scheduled for a MRI last week, but was too sick in bed to have it done, they rescheduled the MRI to October 25th.

[Jim Coleman]

Originally Posted by patrickt

OK, since you now know where on your balancer TDC is located, let's just do a "double check" to be absolutely sure. Pull the spark plug out of the #1 cylinder hole and put your stick back in its place. Place a little piece of duct tape on the side of your distributor directly under the location of the #1 plug wire. Now remove the distributor cap, leave the rotor in place, and rotate the engine via the crank bolt. You should see the stick coming up out of the #1 cylinder as the piston is pushing it up. At the same time, you should also see the balancer begin to get closer to the TDC location. Also at the same time you should see the rotor begin to get closer to the duct tape that marks the #1 plug wire. When the stick is at it's highest point out of the hole, and your balancer says you're at TDC, then the rotor should be pretty darn close to the duct tape. It doesn't have to be perfect, we're just checking to make sure it's not way, way way off. If the rotor is pointing to the other side of the distributor, away from the duct tape, then you've found your problem.

Patrickt:


It appears that the balancer is at 2 degrees after tdc (The line marked 5-8 on the balancer if the stick is all the way up), and the rotor is pointing at cylinder#3 instead of #1.

Do I need to start over?

Thanks,

Jim

[patrickt]

Originally Posted by Jim Coleman

Do I need to start over?

Thanks,

Jim

I'm not sure. If you have marked TDC properly on your balancer, then it should be easy to get the engine to start and run without having to pull the distributor out again. Even if it's in wrong, we'll just rotate the wires around to match where they "should be." Let's assume you followed my instructions correctly and have marked TDC accurately.

First, follow these instructions from blykins:

Pull the driver's side valve cover off. Roll the engine over by hand and watch the rocker arms on #1. Roll the engine over until you see the exhaust valve on #1 open then close. At this time the intake valve should be opening as well. Keep rolling the engine over until the intake valve opens, then starts to close. At this time, keep rolling the engine over and be watching the timing pointer and the balancer. When you get to 30° BTDC, stop.

When you do this, where is your rotor pointing?

[Jim Coleman]

Pain pills...…...will try tomorrow.

Thanks,

Jim

[Gaz64]

Originally Posted by Jim Coleman

Patrickt:


It appears that the balancer is at 2 degrees after tdc (The line marked 5-8 on the balancer if the stick is all the way up), and the rotor is pointing at cylinder#3 instead of #1.

Do I need to start over?

Thanks,

Jim

Jim,

The 5-8 mark would be 90 degrees after the 1-6 mark.

The 1-6 mark is the one that should line up when finding TDC on cylinder 1, (or 6).

So the balancer outer ring has shifted, or some other abnormality.

And if you are on TDC 1, then the rotor pointing at 3, is why it won't start.

I am more concerned at why the balancer does not line up.

Gary

[Jim Coleman]

Gary,

I'm not sure what's happening with the balancer.

I just got off the phone with a motor rebuilder that says 6/1 is top dead center on #1.

I think he was guessing, because he said "the one with the number one in it" He said the sections were there to adjust the valves.

Patrickt,

I rolled the motor over as instructed, and the balancer is almost on the 2/3 mark.

My timing tab only goes to the 16 BTC mark. The rotor is almost pointing straight to the back of the distributor.

Thanks,

Jim

[patrickt]

Originally Posted by Jim Coleman

The rotor is almost pointing straight to the back of the distributor.

Thanks,

Jim

Is that anywhere near the #1 plug terminal?

[Jim Coleman]

Patrickt,

No, number one is at the front of the distributor.

Thanks,

Jim

[patrickt]

Originally Posted by Jim Coleman

Patrickt,

No, number one is at the front of the distributor.

Thanks,

Jim

OK, do you feel like rotating all of your plug wires around so that the #1 plug wire is under the rotor? Then see if it will start up.

[Jim Coleman]

Packtrickt,

I have to get the motor back together first, the water pump, alternator and oil pan are off the car no oil or coolant in the motor.

This will take a couple of days.

Thanks,

Jim