caliboy16

INTRO:
'81-4wd-22r-carbed- Bucking like a bronco! I could be dillusional and think of myself as a cowboy riding a bronco down the street....But i Dont care for Ford Broncos, and wouldnt really want to refer to my Yota as one..lol...Anyways, I did a forum search on "surging" and found nothing but info about cleaning injectors and what not. But Im carbed....So?

PROBLEM:
It starts and runs fine cold....Runs fine hot (With a slight fluctuation when cruising...Very-mild surge "barely noticable")...But once its warmed up and turned off....I restart it, take off, and ride my buckin' bronco to my next destination...Of course it stops bucking once i get up to my shift point...But once in my next gear it surges some more until i get back up into the rpms. Anyways, once its "re-warmed up" It does'nt really buck....But its still got a surging rythm to it whether im crusing at 25 or 60...(Like mentioned above when first warmed up).

POSSIBLE FIX?:
Thinking I need to go through and rebuild the carb.....I have about 5 of em including the one on my truck...So those are my plans. Just going to Build up one carb and make sure its up with specs...If that doesnt do it, ill be back on here...If you guys have any suggestions, or alternate paths i should look into let me know.....just want and need my truck to start running right (it would be a first) I happend to fix a few issues this week so far....So, crossing my fingers.

Any suggestions appreciated.

NathanBERG

Also check into the fuel pump. I had a jeep M715 that did that same thing.
Turned out to be the fuel pump. Just a thought. Hope you get that thing running good!! Let us know what you find out.!

epic37311

Hey let me know how this worked out mines doing the exact same thing and I aready replaced the fuel pump

epic37311

But mine doese it after I am on the road for about 15 minutes. Sounds like its cutting out when not bucking. New plugs and wires so ..... hell if I know

caliboy16

Well, when i first got the truck i was having some other "issues".....I ended up taking of the "rebuilt" carb off and replacing it with 1 of 4 other carbs cus i thought that was the issue. (Was'nt the issue).....But after i got the other problems fixed it started with this surging thing, and i never tried the "rebuilt" again. So, after reading my own post, about rebuilding a carb and swapping the other one out....I remembered the "rebuilt" i already had. I put it on the other day, and the truck runs a lot better, but the surge is still there, just slightly though (when compared to before). Im pretty sure my fuel pump is new, so im out of ideas....Unless its in the distributor? Maybe its some solenoid on the carb? Any other ideas?
Yah, Epic, mine does the same thing...Its either "just" bucking, choking on itself and surging in the lower rpms or mildly surging while cruise at a consistant speed.....Although....When i have it in the garage in neutral...I hold the throttle down untill about 3000rpm (*guess*....No tach) and then it sounds like it starts to miss really bad and bog down but it stays up in the 3000rpm range...Dont know what to say...? ?

caliboy16

I fixed the surging problem! I can barely type with all the excitement of driving my beautifully running truck! Three words Auxiliary Accelerator Pump! I discovered it was the AAP valve, after finding that the vacuum line on it was full of gas. Turns out the diaphragm in it was bad. The main accelerator pump and the auxiliary accelerator pump work off of the same fuel circuit, so when my accelerator pump was actuated, all it did was force fuel through the diaphragm in the AAP and into my vacuum lines...which all go to the intake manifold, creating the surging. So, there ya have it! Now, i can focus on other problems! Yay! Good Luck.

Gadget

I had a Mazda B-2600 that did pretty much the same thing. Turned out to be a plugged up fuel filter. I would replace the fuel filter and the same thing would happen about once a week.

What it turned out to be was contamination getting into the fuel tank constantly. I finally traced it down to the filler hose that connects the gas cap to the tank. It ran through the rear wheel well and it had a slight split in it. When I drove it, especially in the rain crud would get slung off the tire and pushed throught this slit and into the tank and that is what was causing all the problems. It was not an easy find and took a while and I was very frustrated until I found it.

You just never know what the problem will end up being, but from the sound of it, it clearly indicates a lean condition, now you just have to find out why.

Gadget

epic37311

Sweet. Thanks I will look into that