(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?

Start with the fuel filter(s), Q-jet?, may have got some junk interferring with the needle and seat. Definitely sounds fuel related though.

Yes, my car is now 99% factory duplicate.(it has a Pertronix III system)

First thing I would do is change the fuel filter and go from there...

Some things you can try:

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

slippery pedal, foot slid off? lol

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.

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!

no kidding, I just "Royal Purpled" Mine again...dam near $50 for the oil alone!.....

Good luck

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.

Speaking of oil changes, how often do you guys change the oil, I've been going about once a year and that's only about 1000 miles or so.

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.

Have a look at what these guys did foe heat issues.

http://www.highperformancepontiac.com/tech/hppp_0712_small_bore_pontiac_engine_build/photo_30.html

Floats do not normally come with the kit. Did you change the float? They get sticky and saturated.

Oil is nice and clean with no gas smell. Phew!

Pulled and cut the filter and this is what I got:







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?

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!

Keep in mind the last photo is actually only about 1/4" x 1/4". It did not look nearly as bad with the naked eye. The macro shot shocked me too.

The car fires right up, but it did before too. I have not run it any real distance yet. Dinner, kids, showers, etc., etc...

There is a car show tonight at the local Quaker Steak too

I think it was bad enough that I should probably re-set the air/fuel mixture.

edit: I think I will try and sneak out of here for a few...

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.

I should know better tomorrow or Friday, depending on the weather. If it is nice, I will take it to work and put a good number of miles on it.

Checked cap, rotor and wires on the side of the road...

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.

What do you change or fix since your last test?

Just the nice free flowing fuel filter. The test I did after the change was just a couple of laps locally. Not long runs at highway speeds like today.

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.

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

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.

Hope you track it down quickly!

Mike

Thanks for the input. I'll go grab a new coil and give it a shot.

So far, so good with the new coil. No problems with about 40 miles on it. This weekend will tell for sure...





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!

Cool, glad you got it sorted out!

Good call Merv!!!

well, my take on car problems is it can be one of two kinds...its either electrical or mechanical....LOL

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!

The weather here is just too d@mn beautiful for me not to put miles on her. Just got back from another 60-70 mile run and still no issues.

I think you nailed it Amervo!

Thanks for the input.

Tim

Few things i learned about old Pontiacs when i was a kid.
Keep on the self;

A good known stock carb.
New fuel pump.
Coil and set of points.
Cap, rotor, and wires.
Pole piece and module if using HEI.