Won't rev...

[hayesbd]

Need some advice, here.

I was cruising along the freeway at around 70 mph the other night and the car momentarily bogged down with no throttle response for a few seconds and then picked right back up with no apparent problem. 50 miles later, it repeated the problem, but would not maintain speed. I pulled to the side and noticed that it would idle just fine, but would not rev steadily above 2000 rpm at all. Full throttle with the car in neutral would cause it to rev, drop down, rev, drop down, and so on. I managed to limp into a gas station with the car going 10 mph in first gear and topped up the tank, but no change. I swapped out the ignition condensor, cleaned the points, removed the fuel drainback valve, but it still would not behave. The next morning, I put in a new coil and still no joy. Had to get it towed.

Today, I managed to check things out more thoroughly and find that the timing belt (fairly new) had not jumped, the coil checks fine and it runs much the same. Even in the driveway, it will pop and backfire above 2500 to 3000 rpm but idles fine. A disconnected fuel line at the carb pumps fuel, so it is getting at least to the carb. The ignition timing is good and even moving it around a bit does not change the behavior, so I have concluded that it is probably a problem with fuel delivery inside the carb, but I am at a loss as to what to look for. Has anyone had a similar experience and know what might be the issue? The car is pretty much a stock 1592 with the DHSA carb.

Thanks,
Brian

[MIGHTY 8]

Hi
I had a similar issue awhile back. Maybe this helps, but it could be fuel pressure related (ie something clogging up in the system.) works ok at idle, but when the pressure is required to accelerate put a load you get the issue you’re describing.

It turned out in my case it was a faulty check valve in the fuel system that was causing the problem. On my 1980 it’s located underneath the car forward of the rear axle.

Maybe this helps.

(I also recall with the car running, opening the gas cap and it was horrendously tough due to the high pressure being caused by the clog!)

[hayesbd]

Thanks! I will try loosening the fuel cap. I did remove the check valve to see if that helped, but it didn't.

Brian