Help: weird hesitation/jerking of engine w/o stalling

[lionel]

Hello everybody,

88 accord 3D DX (orig carb), 220kmi....

I am experiencing weird things:

It all started about 2 months ago, when the engine would, very occasionnaly, and for about 5/10 sec hesitate
while beeing in the 2,000-3,000 rpm range. Fully depressing the accelerator would then solve the problem.

Since then I've driven about 1500 mi, including a long higwau trip. No pb on the highway (engine running a 3,500-4000 rpm), and since my return the pb has developped a lot and comes on very often on a much wider range.

The engine would (always when hot) jerk/hesitate, with absolutely no power (car undrivable), even with no load, but would not stall. I can now barely get it back by fully depressing the accelerator.

The pb could be heat related, it never goes on when the engine is cold or warming up.

Before I start checking everything, do you have any hints?

I am suspecting evaporative fuel emission system or EGR.

Thanks a lot,

--Lionel

[A20A1]

It's probably fuel related... since the choke closed would richen the mixture when cold.

I suggest you check your BOOSTER VENTURIES they tend to come loose now and then... follow the how-to in the thread liked below to check the venturies. Sometimes they may be stuck in a loose position so do give some effort when testing to see if the boosters are loose in their spot.

https://www.3geez.com/showthread.php?t=8972

it also could be a vacuum leak,

[Michael Cote]

I would suggest carb heat too much. Unhook vacuum(and plug line) to snorkle flapper to see if better and also run power to low speed solenoid behind carb using quick connect.

[A20A1]

Snorkel flapper? You mean the hot air door?

"and since my return the pb has developped a lot and comes on very often on a much wider range.

The engine would (always when hot) jerk/hesitate, with absolutely no power (car undrivable), even with no load, but would not stall. I can now barely get it back by fully depressing the accelerator."

Thats what got me thinking loose booster, the heat might just be from running lean, and not actually the cause. But I like your suggestion, it helps a lot especially since I haven't delt with the keihin in stock trim for a long time.

I also have to disagree with my original diagnosis because usually a loost booster would mess things up even with cold... it would be nice to see if the problem occurs after the choke opens.

[Wipeout]

My Accord was experiencing similar problems. If you let it idle while it's doing it and you bring the revs up slowly, does it all of a sudden die? My #14 vacuum line had a hole in it.