Author Topic: GT 500 - need your help with ideas on what could be wrong  (Read 7445 times)

csheff

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GT 500 - need your help with ideas on what could be wrong
« on: August 14, 2020, 05:12:13 PM »
Need more ideas on what to check. My 67 Gt-500 was running great on the freeway going 70 coming home the other day when it just sputtered,  spit almost like out of gas then a pop and died.
Everything under the hood looked ok, dry I ck'ed if I was getting gas, was. After I let it sit a while I tried to start seemed like it wanted to but nothing. Had it flatbed home.
Since I have ck'ed the condenser ck'ed good but replaced it anyway. Coil seemed to ck ok, I get spark. I tried starting again and it feels like it wants to start but just won't.
Help guys what am I missing? I'm assuming it's electrical.
« Last Edit: September 08, 2020, 02:13:47 PM by Forum Guide »

shelbydoug

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Re: need your help with ideas on what could be wrong
« Reply #1 on: August 14, 2020, 05:18:04 PM »
Check it with a timing light to see if it is firing on time. The results will tell you a lot.
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trotrof1

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Re: need your help with ideas on what could be wrong
« Reply #2 on: August 14, 2020, 05:57:39 PM »
Its either fuel, spark , or compression. I assume your fuel is OK , not degraded. you should have a good strong spark at the plug. If that checks out good pull out # 1 spark plug and rotate the crankshaft with a ratchet on the dampener crank bolt to # 1 TDC marked on the dampener. check to see if #1 piston is at the top of its travel the moment the mark on the dampener touches TDC. Take a maker pen and mark the dist housing where the #1 tower is on the dist cap. \ Pull off the dist cap and see if the rotor is pointing exactly at # 1. IF the timing marks, the distributor and # 1 piston dont line up exactly the timing chain might have jumped . If they do line up ok then go back and check fuel and spark again. This is just a basic check you would normally do on any engine. All my cars are small blocks so somene else here might be more familiar with 428 issues.

Greg

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Re: need your help with ideas on what could be wrong
« Reply #3 on: August 14, 2020, 06:18:56 PM »
You probably have a gas issue.  It is the fuel pump or filter.

If you have spark, pour gas in the bowls through the horns and see what happens. 
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Coralsnake

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Re: need your help with ideas on what could be wrong
« Reply #4 on: August 14, 2020, 06:32:47 PM »
Boiling ethanol comes to mind if it was warm out
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557

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Re: need your help with ideas on what could be wrong
« Reply #5 on: August 14, 2020, 06:36:28 PM »
You probably have a gas issue.  It is the fuel pump or filter.

If you have spark, pour gas in the bowls through the horns and see what happens.
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trotrof1

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Re: need your help with ideas on what could be wrong
« Reply #6 on: August 14, 2020, 06:42:00 PM »
I had to drain my tank out last year because of a fill up of bad gas. It does happen.

csheff

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Re: need your help with ideas on what could be wrong
« Reply #7 on: August 14, 2020, 06:47:37 PM »
I'm getting fuel, bad gas was a thought as I did fill up shortly after leaving but drove 30 miles before this happened.

trotrof1

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Re: need your help with ideas on what could be wrong
« Reply #8 on: August 14, 2020, 07:02:05 PM »
Pull out a plug and see if its wet possibly indicating a spark issue. You could put a breaker bar on the crank to see how much play there is in the chain . Roll it both directions to see how much travel before dist rotor moves.

Greg

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Re: need your help with ideas on what could be wrong
« Reply #9 on: August 14, 2020, 07:04:28 PM »
If you have fuel squirting (it can't be a dribble) in the venturi's then you have spark issue. 
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KR500

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Re: need your help with ideas on what could be wrong
« Reply #10 on: August 14, 2020, 07:14:51 PM »
I'm getting fuel, bad gas was a thought as I did fill up shortly after leaving but drove 30 miles before this happened.
Check for spark, use spark tester or a spare spark plug. Make sure you have a strong spark. If not check coil resistance, points, rotor, cap, wires, ect. Check the timing! Once in awhile the distributor drive gear pin will shear off. Seen valve stem pieces break off and get by the oil sump bypass and lock up the oil pump, shears the distributor drive gear pin off. Remove dist. cap , crank the engine, see if the rotor is rotating. No = drive gear pin sheared or timing chain /gear problem Timing gear/chain can jump if worn badly. Check compression. Timing chain/ gear out of time= low compression. Make sure you have good fuel and pressure. Good luck
« Last Edit: August 14, 2020, 07:18:31 PM by KR500 »
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trotrof1

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Re: need your help with ideas on what could be wrong
« Reply #11 on: August 14, 2020, 07:22:31 PM »
Eric the car guy on youtube has a straight forward video on checking timing chain slack. 7 degrees of movement would be max limit.

JWH

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Re: need your help with ideas on what could be wrong
« Reply #12 on: August 14, 2020, 07:26:53 PM »
Sheff, I had this exact same thing happen under exact same circumstances. Turns out it was the coil. My car died in the middle lane of the highway at rush hour. Thankfully it started one more time and if I kept the revs up (3,000 rpm) it would not die. I managed to make it home and then pffft, that was it. I installed a new coil and everything was good. I think you can get a decent coil at the parts store for $20-$30 so you are not out a lot if it is something else.
      I also like the thought of checking the fuel filters in your carbs for junk. Good luck and let us know what fixes things.
Jeff
« Last Edit: August 14, 2020, 07:29:07 PM by JWH »

s2ms

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Re: need your help with ideas on what could be wrong
« Reply #13 on: August 14, 2020, 07:40:54 PM »
+1 on suspecting the coil, especially if it's a repop yellow top. I've had the exact same issue a couple times.
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propayne

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Re: need your help with ideas on what could be wrong
« Reply #14 on: August 14, 2020, 08:12:21 PM »
Suck, bang, blow...
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