(Looking at a couple of posts here this morning tells me a few us were not having the best of days yesterday...)
While cruising around out in the country yesterday late afternoon to blow off a bit of steam, I suddenly was getting some intermittent, but severe loss of power. It first occurred at ~65 mph, at a steady cruising speed. Power loss was almost total, accompanied by a low volume 'boggy' sound. Any additional throttle was unresponsive. It was severe enough that I needed to pull off into the median of the highway. The engine never cut out completely. When it continued, I came to a complete stop and check under the hood for any obvious issues and all looked well. After a minute, throttle response was fine and I pulled back onto the road. A minute later, the same thing happened. This occurred several times over the course of the evening, at various speeds, at various intervals of 2-3 minutes apart, to 15-20 minutes apart.
I am at a loss. My only thoughts are a bad batch of gas (Yeah...BP!) or a partially clogged fuel filter.
Anyone?
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
1) add 1 bottle of gasline antifreeze to your gas tank - this will displace any water that could have entered the system. 2) replace gas line filter 3) tap the carburetor near the float to free a sticky float 4) lastly it could be you fuel pump starting to go. Sometimes you get a warning b4 it fails
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________
Possible fuel pump diaphram failure has started. Issues will be at higher speeds with lower RPM's OK and then it gets worse and worse.
You will find pieces of your diaphram in the downstream filter.
Today's ethanol will kill yesterday's fuel pumps.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
Possible fuel pump diaphram failure has started. Issues will be at higher speeds with lower RPM's OK and then it gets worse and worse.
You will find pieces of your diaphram in the downstream filter.
Today's ethanol will kill yesterday's fuel pumps.
Didn't think of the fuel pump.
It is a new fuel pump with less than 1.5k miles, but a vintage one. I try to avoid stations with Ethanol for the very reasons mentioned, but cannot be positive I have not run any through.
If it is a pending failure, I should see some evidence in the filter at the carb, correct?
And you are correct, it was at highway speeds at lower RPM's when it started.
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
Check the oil for a gas smell or dilution as well. Both signs of fuel pump failure. If the fuel system checks out and you still have the issue, start looking at the ignition system.
Check the oil for a gas smell or dilution as well. Both signs of fuel pump failure. If the fuel system checks out and you still have the issue, start looking at the ignition system.
LOL... I hope not! I just friggen' changed the oil! The stuff is not cheap anymore once you figure in a quality oil with ZDDP additive!
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
Yes, you will see a lot of debris in the downstream fuel filters.
And it will get progressively worse as the pump dies (if that's the issue).
Had one die quickly on the way to the beach (So Cal) in my old '70 Mustang. 1st I could not hold high freeways speeds, then low freeway speeds and finally I limped home hardly able to get over 40 mph. My in-line fuel filter was packed with crud.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
I wish I could get all the bugs out so I can drive the dam car... Car wants to run at 200 degrees water temp. It very slowly creeps up there takes about 15 minutes to get there. At cruising speed it slowly climbs... About ready to trade it for a mustang or camaro.... Yeah right. I'll walk first.
When I ran my Qjet, it would often act as you described. I had to limp home, then blew compressed air through the fuel inlet. Problem would be solved for about 250 miles or so...rebuilt the carb...same problem about 3 months later.
I'm a hobbyist. Not a professional. Don't be hatin'!
I will add that I have not changed the filter since the car was put back together. That includes a new gas tank, all new SS gas lines, pickup and fuel pump. Maybe it it's all just manufacturing debris?
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
Holy crap! That's a lot of, well, crap. How is the car running now with a new filter. I would have to think that this was your problem. Now just hope none of that made it through the filter. That's the thing with those filters, they are so small. Some people do run another inline prior to the fuel pump. The first couple of pics you posted don't look too bad, but that last one!
If the fuel filter does not make a big improvement, check coil primary wires for tightness, check rotor for slop, check distributor cap for a loose clip.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
Thought for sure I had it licked. Drove for 100+ miles today without issue. Than it occurred again. Only one time. Pulled off into the berm and waited for a minute, than started on my way gain. I was very close to my exit at that point, so I was not running at freeway speeds for more than a few minutes.
I stopped to visit my father for a few minutes and his suggestion was that the rear butterfly on the carb may be opening for some reason.
The sound that the car was making does sound like bog, just not sure how it could happen.
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
90% of no-run and performance problems are electrical, not fuel, at least on old school engines. Don't belived me? Look at any quality technical texbook in troubelshooting. It's ususaly the opening f/ing sentence in the introduction.
I'm not big on throwing parts at a problem as a way to troubleshoot, but based on your description, this would be an exception to the rule.
If it were my car, I would throw a coil at it. This is one component that cannot be tested because--duh--it will always work when testing it. Also, it's a textbook coil failure.
But it's your car, so use whatever other approach makes you happy.
But it's your car, so use whatever other approach makes you happy.
Why are you grumping at me? I appreciate your input into my issue.
Just a note, the coil is ~1 year old Flamethrower from Pertronix. I will shoot them an email and see what they think as well before I order a new coil.
Thanks for the help.
Tim
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
Late comer to the tread... Tim it does sound like like a bad coil. Had the same issue with my boat. It would run for an hour or so then loose power and stop. Wait 10-15 minutes and it would fire right up and run for another hour. Ran the gambit of troubleshooting for about a month.
Finally gave up and called the Island marine mechanic and explained the symptoms. He called me back about 20 minutes later and said "it's fixed". Just a bad coil as he expected. He said it is the most common cause for sudden loss of power. Boat has run great ever since.
So far, so good with the new coil. No problems with about 40 miles on it. This weekend will tell for sure...
Originally Posted By Dr. Drivability
Check the oil for a gas smell or dilution as well. Both signs of fuel pump failure. If the fuel system checks out and you still have the issue, start looking at the ignition system.
In a strange turn of events, the fuel pump went on the wife's 65 T-bird on Monday. Discovered it yesterday while trying to diagnose an engine tick. Thought maybe their was some sludge knocked loose after an oil change gumming up a lifter or two from the car sitting for so long. I was going to add a quart of tranny fluid and let it run to clean things out. Before I did, I went to pull a little fluid out of the pan only to discover it was VERY thinned out. Looked like about half a quarts worth of gas was in with it. New pump, oil and filter and runs nice again. I will need to re-adjust the carb again as it was adjusted on a fuel system with low pressure.
Been going through lots of oil lately!
68' Firebird 400 convertible, numbers matching, solar red w/ deluxe parchment interior. 66' Pontiac Ventura Hardtop 66' Pontiac Catalina Convertible
90% of no-run and performance problems are electrical, not fuel, at least on old school engines...
I'm not big on throwing parts at a problem as a way to troubleshoot, but based on your description, this would be an exception to the rule.
If it were my car, I would throw a coil at it. This is one component that cannot be tested because--duh--it will always work when testing it. Also, it's a textbook coil failure...
Good call Merv!!!
I'm a hobbyist. Not a professional. Don't be hatin'!
I will keep this fix in the back of mine as I still have the original coil in my car. I will assume it's days are numbered. I have changed the fuel pump 3 times though.
Merv is the man!
Engine Test Stand Playlist: https://www.youtube.com/playlist?list=PLwoxyUwptUcdqEb-o2ArqyiUaHW0G_C88 restoring my 1968 Firebird 400 HO convertible (Firedawg) 1965 Pontiac Catalina Safari Wagon 389 TriPower (Catwagon) 1999 JD AWS LX Lawn tractor 17hp (my daily driver) 2006 Sequoia 2017 Murano (wife's car) 202? Electric car 203? 68 Firebird /w electric engine 2007 Bayliner 175 runabout /w 3.0L Mercuiser__________________________________________________________