Mechanics

ACCELERATION PROBLEM

Chevrolet Astro

I have a 1991 Chevy Astro Van, RWD, 4.3 V6, Carburated Fuel Injection, with 199,289 miles on it. I've kept up all the services, run it through every diagnostic problem it's ever had, for the first time two weeks ago the power belt broke on me while driving. I've always had it replaced once a year (I'm not fond of a single belt for the entire engine), after the power belt broke I had it immediatly replaced, and right off from the time I started the van and left the repair shop (not the one I usually go to) I've had an issue accelerating, as soon as I step on the pedal to gain speed the entire engine acts like it's choking out or bogs down dramatically. I've just run the van through it's annual service/diagnostics, all systems read normal in the testing phase, transmission service showed no problems, no shavings, clutch materials or any other bits and pieces in the old fluid, and the test drive (low speed) showed no problems. I did pull the air cleaner off and found the carburator/injectors loaded with heavy carbon/varnish deposits, spent two hours cleaning what I could see. I and my regular shop mechanics are at a loss (admittedly the shop is primarily a " Ford" repair shop but they've taken care of all my vehicles over the decades without fail). I know that's a lot of information, but I tried to get all that has been done in the past two weeks to try to figure it out. In case you were lost in the history, the main problem is the bogging down of the engine as I attempt to accelerate, this started after the power belt was replaced, help please?
Avatar
Billishere_100
July 9, 2007.



Techman 1,
Concerning the acceleration problem, I had already removed the belt and attempted the test, sitting still the accelerator would go to the floor but the carburation would still bog down, act like it was choking out, so I replaced the belt, dropped and drained the fuel tank, pulled and tested the fuel pump, tested out to book spec's, since it was relatively new (last year, 9 months ago), I didn't expect any different. After reinstalling the tank, instead of putting the screen filtered fuel in my tank again I put it in my sons 96 s-10 chevy blazer, his car started to bog down on him on his way to work that evening. I of course filled my tank with new fuel, and in two days driving now the problem is going away steadily, each time I drive the van now it's horse power and acceleration improve. My thought is I got some bad gasoline on the last fill up since the same fuel affected my sons vehicle as well, As a side note we did the same to his vehicle this morning, that tank was a monster to remove unlike the one in my van, and he just called me from work to inform me that his vehicle is running much better now as well. So trial and error may have proved the fix?

Tiny
Billishere_100
Jul 11, 2007.
Techman 1,
I do appreciate the information, and considering the issues that just occured with the fuel system, the " TBI" (note no use of the word carburatoir) acceleration issue. I too have the fuel filters (I had installed an additional inline filter as well) changed once each year along with the major service schedule, but had just been reminded about the fuel system cleaner I put in just about the sametime as the replacement of the power belt, and had not thought of the issues that might cause cleaning the gunk off the inside of the fuel cell as well, that may have been the cause of the issue to begin with and when I'd pulled the tank to check the fuel pump and replaced the filter as a matter of course in the process does explain why the system improved shortly afterwards, live and learn. Thank you again for the help.
Bill

Tiny
Billishere_100
Jul 18, 2007.