Won't start, I am throwing in the towel

hi guys, need some serious help here.

1967 plymouth fury III 383.

one day driving down the road, a loud backfire then engine died, wouldn't start. so I had it towed home and have replaced the following since:

new distributor, new ignition coil, new fuel pump, new fuel filter.

still wont start. but I can feel it really WANT TO start, so close..... yet.....

I used the spark tester, has sparks to the plugs.

what am I missing? what else should I try?

please help.

If the motor has a lot of miles on it I would guess the timing chain skipped a tooth.

That was my first thought as well.

Mine too, happened to me with a '68 440.

thanks guys.

is it a difficult job to adjust timing?
is there a link for the procedure?

thanks

skipped a tooth means time for a new timing chain and gears

If you are lucky, if not it means bent valves.

please tell me what I should do first, second.....

thanks

Find someone locally that can help. This is not a job for a brand new car guy. You can fumble through it and maybe figure it out but this isn't as simple as changing a few external parts.

Remove your distributor cap so you can see the rotor.

Get a breaker bar & find a socket the right size for the harmonic balancer bolt inside the crank pulley.

Rotate engine just until you see the rotor end move.

Then change directions, if you can turn the engine several degrees before the rotor starts to swing back, your timing chain and / or pulleys have worn to excess.

thanks, exactly the kind of help I am looking for.

I will do it tomorrow and report back.

Another way to check for a skipped timing chain is to pull out the coil wire, take off the air filter, and have a helper crank the engine. Hold your hand over the carburetor throat while cranking. You should feel only suction at the carb. if you get puffs of air pushing up out of the carb it's a timing chain issue.

You might do a compression test, easy & non invasive. The socket for the crank priorly mentioned is 1&1/4". As said I would ask for some help. Holler how it turns out.

If your timing chain jumped, you may start losing teeth on your torque converter/flywheel (if you have an automatic transmission) when your engine backfires. If this starts to happen don't waste your time and assume that it is a starter issue. Unfortunately, I'm speaking from experience...
Good luck.

Even a low compression 383 is an interference engine. Found that out the hard way (my brother was driving the car at the time). I was in a back brace following a broken back, BUT I replaced the timing set AND the bent pushrods (15 of 16 were bent, but all were replaced). Valves were clearly bent, but we never dug further into it. Dad traded it in later that summer (1980).

Best 1st move to make IF you KNOW that motor has many miles on it, OR even if you don't.
A true roller chain/gear would have to wear alot before skipping. Those plastic coated teeth gears, not so much.
When those plastic pcs. break off the gears, they usually fall into the oil pan.
Drain some oil & see what's there.

Skipping one tooth will not make it not run! I would say it has jumped timing but not just one tooth.

One tooth, two teeth, ten teeth, point is it needs to be checked and fixed regardless of the number of teeth it may have jumped.

Find yourself a Chiltons manual for that year and follow the diagnostic guide. Here’s one that I found on the net.


https://www.ifitjams.com/starting.htm

If the timing chain is OK check the carburetor for fuel problems.

Backfires can bust power valves and bend plates that may prevent starting. Most backfires do not cause problems, some do.

Additionally if it isn't the timing chain you need to find the source of the backfire. Probably a misfiring plug cause by bad wires, cap, or plug.

I just had a 318 skip 1 notch and it would run, when I did try starting it turned over way to easy with the starter winding up way high which was an clear indicator since I lost compression and I put a new one in and got lucky w/mo burnt valves

Back to basics...compression test 1st,spark plug condition check , firing order, distributor cap,rotor check,spark plug wire check for ohms,check for spark at each plug..not just 1..gas flow and volume..

This^ Plus check the relationship of the harmonic balancer timing mark relative to #1 cylinder tower on the firing stroke.It should be close to the tower,if not the chain jumped or is severely worn at minimum.

With a 1&1/4" socket/breaker bar slowly bump/hand turn the crank so the timing mark slit on the dampener is coming up to the TDC (zero) mark on the timing tab & stop when the points "just" open (use your test light) & note the dampener reading at that point. EDIT Say your initial was "15" so that is what you would get (or very close to 15) if no damage (that'd be your normal timing). If it has jumped a tooth you will be way off from 15. You could divide the # of teeth on the crank sprocket into 360 to get the # of crank degrees it would off from 15 if it has jumped a tooth (& the wear as mentioned would exacerbate that # even further). Holler how it turns out.

over the weekend, I rented a compression tester from Oreily's.

got the following results (partial):

cylinder 1: 100 psi
cylinder 2: 50 psi
cylinder 3: 95 psi
cylinder 4: 105 psi
cylinder 5: 120 psi
cylinder 6: 100 psi
cylinder 7: unknown, can't get to it.
cylinder 8: 110 psi.

when i removed plugs, both spark plugs on cylinder 7 and 8 are soaked with gasoline. I probably flooded them when I was trying to start by keeping on tapping on the gas paddle.

so, based on the above information, what you guys think?

thanks so much for voicing your opinions, all appreciated.

If you are sure you got accurate readings on 3 & 5, you've got a problem. Next step could be a leak down test to see if it's leaking compression pat the valves or rings, but either way, it's time to break out the tools and start taking the engine down.

Could be blown head gasket since you have low compression on two adjacent cylinders.

taking the heads out would be my absolutely last resort.

anything else I can do/try before embarking on such a big project?

you could try pulling plugs on those and squirting oil down the cylinder then cycling by hand slowly.
if what you say is accurate, you could have washed out the cylinders with too much gas pumping.

but that also means you should probably consider replacing the oil in the engine as well.
check the level and smell it. if it smells like gas, replace it as well.

Redo the compression test, but if cylinders 3 & 5 don't come way up, you have a problem.

I'd be more worried about cylinder 2 and not 3.

He doesn't have low compression on two adjacent cylinders. 3 is a touch low but within guide lines. Cylinder 2 and 5 are the issues and they are not adjacent.

There may be an issue with #2 and #5 "but" ,it still should run,pull two wires on a running engine,it will miss but still run !

My bad. Old eyes saw it as 3 not 2. So ignore the comments about adjacent cylinders. Still a big problem though. Other poster is correct: it should start but it will not run good at all.

sorry, my bad. I re-tested #5, compression is 120.

So here is result of the new test (sober test, didn't drink any beer this time).

cylinder 1: 100 psi
cylinder 2: 50 psi
cylinder 3: 95 psi
cylinder 4: 105 psi
cylinder 5: 120 psi
cylinder 6: 100 psi
cylinder 7: unknown, can't get to it.
cylinder 8: 110 psi.

A pop out the exhaust would tell me the exhaust valve on the cylinder with 50 PSI is the problem.

1st thing I would do is verify all the rocker arms are moving and the valves opening. It could be a wiped cam or collapsed lifter....If that is good then check your timing relationship between the distributor and the balancer.

1 way to verify crank/cam timing is to find TDC on Compression Stroke. Line up balancer line and zero on the water pump tag. Then see if the rotor tip is pointed at #1, if so, it is not timing chain.

even compression is as low as 50, it still should start, right?

Yes





Agreed, 1000%

Always, ALWAYS start with the basics.

Do you have spark? if so,,,Good, If not, why not ?
Pull the air cleaner and pump the throttle while looking down the carb, See fuel spraying? if so, Good, If not, why not?

But based on your initial post.
My gut says the timing chain jumped

Not if the timing chain has jumped a tooth or two
I had that happen on a early (1959) poly 318 truck motor, I started it up in the winter, went to back up and it tried to stall and backfired through the carb. It restarted but didn't have any power after that due to the timing chain being worn out and it had jump a tooth retarding the cam timing
The fix was to replace the timing chain and gears with new ones, which it sounds like you need to do also
Get some good help or take it to a good shop to have it tested and fixed properly

Timing chain jumping should affect all cylinders, not one or two, unless it put a valve into a piston then you'd have zero.

I had a timing chain jump on me when turning the engine by hand while priming. I heard it and couldn't understand at the time what really happened. That engine would not stay running until I resolved the problem.

has spark, has fuel.

new timing chain.
when I installed it, I made sure dots on gears are lined up: top gear at 6 o'clock, bottom gear at 12 o'clock.
also, right now, rotor points at #1 cylinder when 1st cylinder is TDC on compression stroke.

With the dots pointing at each other (crank at 12 and cam at 6) you are on #6 firing NOT #1...

When the dots align like you had them the motor is starting on the first stroke which is the overlap stroke when the exhaust valve is closing and the intake valve is opening, the distributor rotor will be, and should be, pointing at #6 spark plug wire

If that is what's happening just lift the distributor up enough to allow you to turn the rotor 180* so it points to the #1 terminal and set it back down. After you tighten the distributor down try and start the engine.

Copy and paste from above..... The person that started this help string has said several times

I quote " also, right now, rotor points at #1 cylinder when 1st cylinder is TDC on compression stroke".

no where did he say when he had the dots aligned the rotor was at number 1......

A lot of people saying a lot of stuff is most likely confusing this guy and he is already asking for assistance....

What we know is 1 cylinder has 50 lbs of compression and the engine will not start.
We do not know if his #2 cylinder is on the same bank as #1 or not, so we are not even sure what cylinder is what, do we?

We also know he says he has spark and fuel. From the latest few posts we have a new timing chain assembly and the Distributor is correctly installed.

I asked if all the rockers were moving to see if he has a wiped cam or lifter before he removes the heads. His problem is heads or cam/lifters/pushrods for the low compression.

As far as the no start I am beginning to think the plugs are fuel fouled and the time is low, or his cylinder arrangement is 1234 on 1 side and 5678 on the other...if so he has a blown head gasket?


MOFWIW

Allen

this is getting me confused, compression test on #7 states cant get to it but then you state #7 plug soaked..so you got the plug out but not the tester in?did you try with new dry plugs?

What did the old chain look like? Had it jumped? How far? Check compression with new chain installed? Pull valve covers and check for loose rockers?

IF the compression tests are right (need to leak it) it likely lost the chain and bent pushrods if your lucky. Valves if your not.

Leak it. If it leaks, get the valve covers off and find out why. Wouldn't worry about trying to make it run until I knew the engine was 100%.

thanks guys for offering help. all advice appreciated.

the old chain was VERY loose. I didn't check if it jumped tooth, I just went ahead and replaced it.

It had had back fire problems before when car was cold, but after it warmed up, it was running fine. Until one day, when it was still cold, a loud backfire, then died.

Was able to remove #7 spark plug, but couldn't insert the compression tube, so I didn't check it and just put new plug in.

Cylinder Order:
Bank One: 1357
Bank Two: 2468

Firing order: 18436572


I haven't got the chance to pull valve covers yet, but I will.

I hope some of this info is usable.
I know think you have bent pushrds on the 1 cylinder. For your sake anyway...
Good luck

I finally went under the car, after some wrestling, was able to test the compress on #7.

Compression is 90 psi.

But here is interesting part:

at first few cranks, the compression is 90, then it shot up to 150, when I press the "release" button to release the air from the compression tester, the gasoline was spewing out from it. so it is flooded with gas.

dump questions: 1. could this be the SOLE cause of the starting problem? 2. what the cause of this flooding issue? (only on this cylinder).

thanks

IF the compression is actually that bad, it's not the only problem. Fuel issue could be a faulty carb/float/needle & seat etc - or you just been pumping the pi$$ out of the gas pedal.

Pull all of the plugs and get the fuel out of it. Disable the ignition so there are NO sparks and bump the engine around, preferably by jumping the starter relay so the ignition is not on. Try to pinch a fuel line or stop the fuel from getting to the carb until you verify that is not where the issue is. Allow it to dry out. Get some oil in the cylinders, either in the plug holes or fog some JB80 or something down the carb. Throw the plugs in the trash, they're done.

Still need to get the valve covers off. Bar or bump the engine around as if you were adjusting valves and look for loose rockers.

Be careful - with all that fuel there is a fire hazard.

What carb do you have on the engine? If it is a holley, with all that back firing, you blew out the power valve. I am not sure about the other brands but I've had some holleys that this has happened to. It sounds like your issue is the carb flooding the engine. Again, if holley, will need a new power valve and probably needs rebuilding, since it backfires when cold. There are options for power valves that won't blow out if you get a backfire, look for them.

In the meantime, take all the plugs out and let the cylinders dry out. How is the oil? Does it smell like gas? If so, that will need changing before you do anything else. You can run the risk of destroying bearings and everything they touch. Once you've got the gas out of it, do you have a different carb you can try?

CM beat me to the bunch about the carb....

you're not gonna have consistent compression readings if fuel has washed down the cylinders either, it takes away from the sealing of your rings.

today, removed valve covers, everything looks PERFECT.

new discovery, Edelbrock 1406 carburetor chock plate is jam closed. probably this is the reason for the backfiring and won't start? How do I free it?

Thanks

More likely it was caused by the backfiring. Backfiring through the carb indicates the timing is off and you are firing cylinders with the intake valve open...Don't ask me how I know...

Very carefully, the shaft may be bent
try tapping gently on the choke plate between the primary and secondary divider, GENTLY

I know it is hard to tell by the naked eyes, but so far, it seems pushrods are straight, valves are opening and closing property. I know, only way to be sure is to take each rod out, I know, I know.

i tried to "gently" tap" on the plate, this thing does move one bit.

how can I free this damn thing?

did you hold the throttle open a bit when you tapped on the choke plate?

Try squirting some rust buster in between the shaft and the upper body and then try using a small crescent wrench on the tab on the end of the shaft that the choke linkage hooks to move the shaft gently, don't break it off
You may need to remove the carb. from the motor and try working on it on a bench, you may end up needing to heat the carb body around the shafts if it is corroded inside between the shaft and the aluminum top

Stephen, worse case just remove the choke plate screws and run with no choke...

hi guys,

Today I have something good to report. I was able to free the jammed choke plate. HOORAY!!!!

Then I tried to start.... it was sooooo.... close, it wants to start, sooooo close.


I think we are onto something here.

If the choke was jammed shut the whole time, the gas is now in the oil and plenty of it. A stuck open choke is less headaches than stuck shut, big time.

I can't imagine a stuck choke on an otherwise properly working carb causing THAT much fuel to get into the engine that it was squirting out the plug hole. It would be going out the exhaust as the engine turned over.

Are you running either a high performance fuel pump or an electric one? If so maybe you have too much pressure and you are flooding the cylinders.

You may want to clean the spark plugs too. I am sure they are fuel fouled. Burn the tips with a lighter and clean them with brake clean. That may get it to fire up....

hi guys,

yesterday I pulled #1 and #3 plugs, they are bone dry. I didn't pull out others.

mechanical fuel pump, not electric.

I am charging the battery, will let it sit for a day or two, then try to start it again.

thanks,

Well, You got me hooked!!!

Please let us know the outcome, as I am sure that others are waiting for the first fire-up!!!

Mark

X2!

make that x3 !

The poster needs to hire a good mechanic for one hour and the car would be running.

I disagree. This guy is in a steep learning curve and honest in his descriptions. When he has fixed the issue, he will be wiser and more talented, than if a mechanic fixes it and takes his money. Cudos to everybody who steps in to help him.

Ragnar in Iceland

the best lessons learned are the tough ones learned by yourself.

Anything yet?

Make that x4! I am looking forward to hearing you got it running! Keep us posted.

What happened? Did you get it running?

hi guys,

finally got some time this weekend, worked on the car a little bit.

was able to pry open the plate, it works fine now.

interesting new discovery: when throttling, the gas is not spraying from the jet, instead it is flowing like a facet. way too much gas. it wanted to start, but then always have big loud backfire.

it is a eldelbrok 4 barrel, there are two screws in the front to adjust air mixer, no matter what I do with them, still too much gas.

please help.

bad needle/seat or float or float linkage & eddys dont like more than 5&1/2 lbs fuel psi & alot of OE pumps put out way more than that.