[CDN OpelNut]

Need some sage advice on this – I’m at wits end.

Some Background…

Last year my 71 GT was suddenly afflicted with really bad hesitation. I’ve owned the car for 17 years and have changed nothing in the engine for the past few. I was driving home when the car suddenly had hesitation. Within a few blocks it was virtually un-drivable. The hesitation was so bad it was violent and lurching – almost like your first day with a clutch. I managed to limp home by keeping the gas floored.

I cleaned the carb with some spray and had it idling fine. It started all winter and seemed smooth. When I got the car on the road this summer, I drove maybe a mile and it did it again. Violent lurching hesitation with the car ultimately stalling – limped home again.

Since then, I have:
- Put in a new fuel pump
- Changed the fuel filter, plugs, and spark plug wires
- Took out my Accel coil and put the original back in
- Replaced the points with a Pertronix
- Rebuilt the 32/36 DGV including new jets from Top-End Perfromance

The car will start and idle fine and will travel at slower speeds, but under load still hesitates badly, but hasn’t stalled yet.

The car pushes a lot of blue owing mostly to a scored cylinder from a broken ring. I replaced the rings about 5 years ago. Compression is likely poor. The engine is tired and the plugs oily and pressure really low. Not sure if this is contributing or not but it’s not a new problem.

I could really use a list of things to check………………….

 

[N61WP]

Sure sounds like a fuel delivery problem. You said you changed the fuel filter, but did you check or remove the sock in the fuel tank? Do a search, that seems to be a common problem.Bestus,
James

 

[garrymc]

- Rebuilt the 32/36 DGV including new jets from Top-End Perfromance

I'm sure you cleaned the filter screen inside the weber.

Garry

 

[Jeff Pozorski]

Make sure to check all the linkage is tight and that nothing has loosened up that may account for the sudden poor carb response. You said you just rebuilt the carb so hopefully the linkage was checked at that time.

 

[oldopelguy]

vacuum?

If you're confident apout the fuel end of the fuel/air equation, next to check would be the air.

A significant leak would cause an overly lean condition that might run, but wouldn't accelerate worth a [email protected] Also, if there was a leak associated with the distributer vacuum signals, guarenteed the timing part-throttle response would be terrible.

Besides, vacuum stuff is leak prone after 30+ years and cheap to try.

 

[Gary]

The car will start and idle fine and will travel at slower speeds, but under load still hesitates badly, but hasn’t stalled yet.

Like N61WP said have you checked the sock? There is a "Sock" filter in the tank at the fuel line outlet. Sediment can build up aound it and it will restrict the fuel delivery. It may be fine at an idle but put some demand on the fuel like high speed or acceleration and it will starve the carb causing some of the symptoms you describe.

There is an article by Otto(?) floating around that describes an easy method to remove it.

 

[CDN OpelNut]

Thanks for the help so far....

I got around to inspecting the vent lines at the tank. None of the hoses are rotten and all are attached as they should be. When I went inside the car to look at the line that attached to the front of the tank below the spare tire, I noticed that it is full of fluid - up to about an inch from the tank connection. I'm guessing that being full of gas would prevent it from doing much venting....

Could this be the cause of my trouble?

 

[Gary]

Thanks for the help so far....

I got around to inspecting the vent lines at the tank. None of the hoses are rotten and all are attached as they should be. When I went inside the car to look at the line that attached to the front of the tank below the spare tire, I noticed that it is full of fluid - up to about an inch from the tank connection. I'm guessing that being full of gas would prevent it from doing much venting....

Could this be the cause of my trouble?

Easy way to tell is to remove the gas cap when it's hesitating and see if it is under a vacuum. If it is and the problem clears, then the vent line on the filler neck is plugged.

Did you tap on the old fuel filter to see if a lot of crap came out?