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timinclyde

GM 454 Backfires

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Is that a hairline crack I see in picture number 3 ? You might want to get rid off all the dust, dirt and rust ! :D

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Update but still not resolved.  Removed the ignition module from the distributor and had it tested at local auto parts store.  Tested good.  Purchased a new coil and installed.  Used phillips screwdriver in coil wire atop of distributor and cranked engine... nice strong spark.  Tried to start but no go.  Sprayed some starter fluid into the carb and attempted to restart.  Did not start nor even fire a single time.  So, it's got fuel, got spark and then just spins with no firing.  To me is sound like when a smaller car's timing belt breaks and it just spins and refuses to fire.  I didn't have time this afternoon to pull the oil filler tube to see if the valves were moving in case the timing chain is an issue.

Any suggestions?

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7 minutes ago, WILDEBILL308 said:

Have you replaced the distributer cap and roater? Plug wiers. You tested spark from coil but have you tested spark at the plugs?

Bill

I replaced the cap and rotor when I first starting having the misfire issue and it helped for a while.  I didn't check through to the plugs as I didn't have a spark plug wrench with me at the time. I am going to try that today.

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Pulling a spark plug is a good diagnostic tool. See if the plugs are wet and if not what do they look like. You can allso just use a extra spark plug to see if you have spark. 

While the first thought is no spark, I still have this naging though about no fuel. Let us know what you find.

Bill

 

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If you tighten the air cleaner wing nut too much you distort the carb housing so the choke sticks. Try giving the stud sticking thru the loosened wing nut a healthy whack with a hammer to restore the carb top to its original round shape.

Had it happen to me and a friend. After friend did a tuneup his chev wouldn't run. Wife said to give her a hammer. She whacked the stud and engine went to purring.

Friend almost filled his pants when she started to hit the stud--let out a scream.

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Since I was getting spark at the coil wire, I grabbed my spark plug socket and few other tools and when back to the storage unit to see if I got spark at the plugs. Before I pulled  plug, I put my screw driver in one of the plug wires at the distributor and gave her spin.  No spark.  Wow... okay... so a quick trip to Autozone and got a new rotor and put it in.  Cranked up.  Hmm... road test.... ran lots better but still mis-fires under load... just not a bad.   I'm thinking I need to get the timing set.  Need to find a local mechanic that is familiar with these big blocks here in the Spring/Houston area.

Getting closer.  Thanks to everyone for their help thus far.  Haven't resolved the original issue but at least she is running now.

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Got full lobes on the distributor? Or not used on that model? Had a Chev 6 cyl with worn out lobes--distributor shaft was perfectly round--on an uncle's truck and it backfired under load. Swapped the entire distributor out of another of his trucks and it then ran fine.

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Well....I still have my old timing light and dwell meter if you want to borrow or need help. I've had several 454's, and have built a few, but that was a long time ago.

I'm at I45 and Research/Tamina area.

If you'd like to turn it over to a mechanic, Ross at Town Center Automotive and his crew are really good.  He has an old timer mechanic (Lonnie) that knows his way around engines.

Blake

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New rotor cap, plug wires, plugs wouldn't hurt. I would look at all the vacuum lines. Make sure it is getting spark advance. I would change all the fuel filters and check fuel pressure.

I would recommend you get with Blake.B)

Let us know what you find. 

Bill

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On 4/11/2017 at 7:28 PM, wrkey said:

Update but still not resolved.  Removed the ignition module from the distributor and had it tested at local auto parts store.  Tested good.  Purchased a new coil and installed.  Used phillips screwdriver in coil wire atop of distributor and cranked engine... nice strong spark.  Tried to start but no go.  Sprayed some starter fluid into the carb and attempted to restart.  Did not start nor even fire a single time.  So, it's got fuel, got spark and then just spins with no firing.  To me is sound like when a smaller car's timing belt breaks and it just spins and refuses to fire.  I didn't have time this afternoon to pull the oil filler tube to see if the valves were moving in case the timing chain is an issue.

Any suggestions?

Do you get spark at the plugs? If you do - has the distributor been removed at some time ? Good Spark and fuel should make fire unless the timing is off or the plug wires are not connected to the proper plugs. Any of the listed items would cause starting problems if there is no spark on the compression cycle.

Rich.

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On 3/30/2017 at 2:01 PM, wrkey said:

Well whatever it is, it decided to get worse.  Thankfully I was in the storage lot where I keep her when she died and now won't start.  A quick look re sales she is getting fuel so it is an ignition problem.   I don't have the tools with me to dig farther right now.   But here are the photos of what she has.  First photo is the distributor with out the. So in place e, the second is a shot across the top of the motor and the third is under the distributor where a vacuum advance normally is.

KIMG1185.jpg

KIMG1188.jpg

KIMG1187.jpg

wrkey, From the pictures, it looks like your engine has a Hall effect style distributor like the one in this link. Does it look like this?

http://www.ebay.com/itm/CHEVY-SBC-305-350-BBC-454-DISTRIBUTOR-LATE-EFI-TBI-THROTTLE-BODY-350-6652-R-/371370136642

Rich.

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10 hours ago, manholt said:

Bill.  Don't sugar coat it ! :lol:

Carl, that was the sugar coated version. He has a GM guy with tools and knowledge just minutes away. I would be on the phone/road.:D

Bill  

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Update - RESOLVED!  At least for now!   

Okay, so it took a while to get back over to work on her but.  First let me say I appreciate all the advice and suggestions!  This is a great forum and the folks here have a genuine interest in helping.

Well, as suggested (several times... I am a bit thick at times), I bought a set of high quality silicone plug wires and new platinum spark plugs.  In the process of installing them at least half of the plug wires came off by leaving the 'plug clip' on the end of the spark plug itself.  Obviously the wires were in worse shape than they appeared to be.  But, as I was told, they may look good but they are still 20 plus years old!  With the new wires she seems to run better even under load.  I haven't had the time to go long distance but I've been up on the freeway and she got there as quick as can be expected.

The real test will be next weekend when I take her to Bastrop State Park for the weekend as my daughter graduates from UT with a BS in Public Health.  The run there in and back should shake out any issues that remain.  (Ya'll like the 'backdoor brag' I threw in there!)

So what did I do to resolve my initial problem?  Well, everything I did fixed it a little, but the wires and plugs did the most.  So, if you are reading this have the same kind of issue... get a good clean ignition foundation with 1)New plugs, 2)New wires, 3)New Rotor, 4)New Distributor Cap and 5)New coil.... in that order.  Do this before looking to the ignition modules and save yourself a lot of time.

Thanks again to all that provided assistance!  See ya'll on the road!

Rusty

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Rusty.

Thank you for the feedback!  That's always appreciated.:)

Congratulations on your daughters graduation!  Unless you have another in College, you should now, have more to play and travel with.:lol:

Carl

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