my 84 pickup has problems! once i get her up to about 50mph she just starts surging and going flat. I havnt been able to get it to go over 60mph. <img src="/forums/images/graemlins/confused.gif" alt="" />0 to 40 mph is good to go. i thought it was the EGR valve because it had a vacuum leak but i replaced it yesterday. the vacuum leak is gone and it idles smoother but still wont go at high speed. i also noticed if i hold the throttle at about 1900-2000 rpm in nuetral, it will surge (about 100-200 drop)on its own, almost as regular as clock work(about every other second). my book says either fuel pump or air leaks. the fuel pump is a week old and i replaced the fuel filter yesterday, i cant hear any air leaks and it has all new gaskets. any ideas? thanks

Did you replace the carb recently? I have an idea on what is happening...


Josh

no i havnt replaced it yet, the carb is from an 87. its pretty dirty and is my next guess. i just found a carb from an 84 thats in good shape so hopefully it works. i should get it in a few days. my plan was to throw the 84 carb on while i rebuild the 87 carb. then once i sell my other truck, buy a remanfactured engine to throw in with the fresh carb. anyway, what do you think the problem might be? maybe the choke? i dont know a whole about these carbs yet, thats why my last post asked if i could put a manual choke on it. thanks for the help <img src="/forums/images/graemlins/kewl.gif" alt="" />, dave

Carb might just need a new needle/seat. Cheap, but not that easy.
Also, your distributer's centrifical advance
might be non-functioning.
Do you have an aftermarket fuel regulator ? If so, it could be getting fouled .

no aftermarket regulator. what is the distributer's centrifical advance. thanks

I once put a 2wd (possibly celica) carb on my truck once to test. I used to rebuild carbs and sell them on ebay. I tested each one to make sure they worked.

I could not get that carb to work. At 45-50 mph it would just die. I it had good acell up to there but no more.

The problem (I think) was in the fact that it only had linkage on the passenger side choke plate. The driver side just had a hole in the plate and didn't more much. I wired the driver side plate open and it semmed to help but not really.

Try a different carb and see what happens. They aren't that hard to rebuild, just leave the throttle linkage alone. just take off the top and bottom, clean well, add new parts and put it back together. Its pretty easy really.

Josh

thats what im gonna have to do. i lost the other carb i was talking about so i might buy an aisan to put on incase i screw up this carb when i rebuild it. thanks for the help!

DDog, FWIW, there are carbs out on ebay all the time if you don't want to pay thru the nose for 'em, and are willing to rebuild. Just make sure you ask if they're off a Celica or a truck/Runner.

Josh, can you tell us what, if any difference there is between the Celica and truck carbs? Jets maybe?????

I have one in phoenix I may get some pictures of when I come down. I've seen it on many different veh that are having problems. I don't like the design and the reason I say that its a celica carb is they were early model 22r carbs.


The carb has a hole in the driver side choke plate instead of a full linkage. It was kinda a shortcut method that I don't think worked. It was only opened by vaccumm and is more of a restriction than anything.

That is one nice thing about a weber, both choke plates open together to form a much more clean opening and more power.

The CFM rating on a 22r carb is higher by about 15 than the 32/36 but the 32/36 performs much much better IMO.

Josh

try running the truck with the gas cap off,
if it runs ok then, you have ventilation/evaporation
system blockage. The charcoal canister or related lines could be blocked up. It just may be the carb is ok.
I have lived this problem, I can tell you the sight glass
was always perfect as well. <img src="/forums/images/graemlins/oink.gif" alt="" />