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Sputtering engine help


Crom Cruach

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You can hear it best at the start of the video:

So timing, compression, spark, fuel. Can anyone chime in on which of these it sounds like? it feels like not enough fuel getting pumped, but this was not an issue the last time I drove her (a month ago). 

Only change I made was I adjusted the choke rod so it sits in the notch when the rod is pushed down on the spring. The rod was previously too short to reach the notch. This was supposed to fix the running rich issue.

The sputtering  comes and goes. It could drive lovely for a few minutes, then start sputtering.  It seems worse on low throttle. It actually cut out on me at very low speed a couple of times. It was also extremely hard to start - took 10 or 15 goes to drag her to life. 

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Sounds like she's thirsty… Bad fuel or intermittent fuel pump…   Possible fouled plug or two.. I'd pull the plugs first.. 

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I'd definitely pull and clean the plugs while your at it since it was running rich before. I'd think a seriously fouled plug would be obvious at idle And just because this has happened to me, double check all you plugs wires are tight on the plugs and the dizzy. Tom made good suggestions, goes to the old saying go back to the last thing you changed before the new issue started. Keep us posted and good luck 

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Yep plugs are next. Just ordered a set of R44T AC Delco as per the Haynes manual. The standard fuel here is 95 octane unleaded, will these plugs work well with it? The old plugs were R45TS, hotter and extended, I wonder were they chosen to make up for modern fuel?

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Dirty/plugged fuel filter ??? 

It sounds like the fuel is coming and going...... Did you flush the fuel system yet ?

Could be the fuel pump too......... ???

As for 44 vs.45's, the hotter plugs were more for it town/stop and go driving, as opposed to open road driving. 

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Plug wire going bad? Mine did out of the blue for no reason, I had NOT touched them.

I had a big problem just after I washed my engine one time. Blew out the cap and let it dry and it was OK.

If you have all the plugs out some day, I would run a compression test. Remember to open the throttle some when cranking the engine for better airflow.

 

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I would like to do a compression test and check the timing. I don’t have any tools for this - would anyone recommend something from summit/ jegs or wherever? Any brand that is good value for a timing gun and compression gauge?

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For occasional use you don't really need anything to fancy. I wouldn't buy the cheapest thing out there but not the most expensive either. The timing light I have I think someone gave to me a bunch of years ago and works fine. The compression Guage you want something that screws in the spark plug hole not the rubber tip thing you hold against the plug hole. Remove all the plugs when you do the compression test. Good luck with it.

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7 hours ago, Crom Cruach said:

I would like to do a compression test and check the timing. I don’t have any tools for this - would anyone recommend something from summit/ jegs or wherever? Any brand that is good value for a timing gun and compression gauge?

I just ordered these on Amazon… Seemed to be a great product.. 

Screen Shot 2022-03-13 at 7.43.06 PM.jpg

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3 hours ago, Crom Cruach said:

Nice, thanks Ed, you must be on a similar mission!

I got tired of paying the mechanic to do simple things…  Thing's I used to do myself...

I think you'll like these two items …. Good luck, Paul…... 

Ed ...

BTW,,,,, this timing light will work on dwell for points ignition or the HEI style… It's doubtful how accurate it will be on the double fire MSD ….  I took the new MSD off of my Monte , went back to vacumn advance, and reset my timing…. The Car runs better, actually has more power,, and gets better fuel economy… 

IMG_0117.jpg

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Back to your fuel problem …. My first reaction to the sound of your car was the accelerator pump… Going back to the last thing you did… If you changed the choke , is it possible that you altered the pump stroke or movement ???  Just throwing the idea out there….

I no longer use the stock Quadrajets… Always a problem with the valve bodies and accelerator pumps… Great carb as long as they are working well…. I use Edelbrock carbs and intakes…. I stored the old stuff just incase the next owner wants it original .. I prefer driving the car… You may want to check the accelerator pump too.. It can do strange things thing  …. 

Ed

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