LUVTruck.com

Is there any reason to change jets on these carbs because of poor performance? At idle and in first gear it does fine. But any gear after that, I don't seem to either be getting enough fuel or it's something else. As I try to accelerate, the truck is O.K. at first but has problems the more I push the accelerator pedal. It gets worse the faster I have to go. Going on the highway is a pain as I can only get up to speed if I'm on a straightaway or going down a hill. I put the pedal to the floor and it acts like I'm asking for a miracle from it. What could be the problems?

Does it stay running almost normal just gutless or does it stumble/die/cut out at higher speeds. If it kind of cuts out, it might just be fuel delivery to the carb. Bad fuel pump, clogged filter, something like that. Low fuel flow to the carb can act like you describe, idle is fine because little fuel is needed and the flow can keep up and first gear is ok because the bowl on the carb is full of fuel and doesn't run dry until about your 1st to 2nd shift or so. To test this theory try going in first, get up to just about where you would normally shift and keep that speed without shifting it out of first. If it eventually starts to fall on its face then you'll want to check/change fuel filter and test out the pump.

Normally Webers from the kit designed for the LUV don't need much for jet changes. You can follow the adjustment procedure at http://www.redlineweber.com/html/Tech/c ... _best_.htm and that should tell you if you are very far off on jetting. I doubt that is the case though. It would have to be way off to be having a noticeable effect on performance.

Another thing to check is the points. When they are bad they can kind of act the same way, almost like a rev limit.

_________________
95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

Hmmmm....the fuel pump may very well be the problem as there is two fuel pumps on the vehicle right now. The stock one is not hooked up because it seems to be faulty and there is another that is hooked up pumping fuel bolted to the bottom of the frame which is inline from the other one. It may not be sufficient enough for the truck and/or their is a blockage between them or in the old one somewhere. I will look into this when I get back tonight to see if I can narrow it down in that area. If it does end up being a fuel pump, what is the recommended fuel pressure on the '79 Luv? Thanks for the ideas, 800! Very much appreciated!

From what I have seen here these carbs like a certain fuel pressure, I think it was 3 psi but please check that. Also like 800 said the delivery in volume sounds like a issue.

_________________
Certified pilots, looking down on people since 1903.

Yeah that sounds like your problem. The bad pump will act like a blockage most likely. I think luvrv8 is right on, 3-4 was the right number on pressure, but if there is a return line hooked up to the tank it will probably work ok with a small bit more.

_________________
95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

Well, I checked the pump out and it was acting like it was getting intermittent voltage. Under the hood, there was an inline fuse that was creating this problem. Bypassed the fuse and the pump no longer worked. Tested, retested, and tested again and it wouldn't budge. So, I went and got another 2.5-3 gpm pump and it works great. But, it still does the same thing as it did before. In each gear it's gutless when the accelerator is applied and almost cuts out completely with the pedal to the floor. First gear is o.k. until you get to the end of it, and then it does the same thing as the rest of the gears. Removing the fuel line from the carb and turning the key to the on position puts out plenty of fuel so I think the pump is no longer a factor in the diagnosis. Should there be problems with performance just idling in the driveway when you remove the vacuum lines in various places? The vac line coming off the distributor when removed does nothing to the idling and neither does covering the holes. I haven't checked out the points yet as you suggested 800, but when I get a chance to work on it again, that will be the first order of business. Thanks guys for the help so far. I know we can get this figured out.


Oh, I almost forgot:


Because it's been awhile since I purchased this carb, I can't remember if I bought it specific to the LUV or not. Are all 32/36 weber carbs the same, or are they all different and designed for specific purposes? I also dialed in the carb according to the directions in your link. Hmmmm.......does my truck know I'm more of a Ford guy and it's retaliating against me?