'88 Hardbody low-to-high fuel combustion chokes

[luiguiv]

Hello everyone, I'm new to the forum and I hope you guys can guide me on finding the solution for my truck's problem.

Ok, here i go. My truck is a 1988 hardbody single cab 4x2 Z24 engine one, and from a few years ago it started working in a wrong way; the problem description is a little messy so i hope you can understand me. If i'm in the city, which has a high traffic almost all day long you have to cruise at a low speed lets say 30kph to 50kph so techically truck works well but the problem comes when i'm on the road on frecuently work trips. Problem: when you speed up carburators change from low to high right?( i've heard mechanics call it that way is it right? ) so my truck chokes when it tries to make that change and i can´t get the full power of the engine it used to have when i bought the truck about 10 years ago.

The complement to this problem is this: truck chokes only at certain altitudes ; for example this city es over sea level so here truck works aparently well. When i go to cities near sea level or at sea level truck chokes and chokes when i try to speed up; i can only cruise at low speed but if i need to step up the pedal to get power to pass another vehicle i have to change gears when it is about to choke to compensate that power loss.

I took the truck to many mechanics around my country but the don´t know nothing the always say things like "oh change that engine" or "is the carburator, i can sell you another engine with a good one" but the never seem to know what the problem really is, they take the easiest way possible saying "change the engine". I can tell you the main engine is in great condition you can even tell that by examining the exhaust pipe residuals i mean i've taken care of that engine, so it is not in bad shape

A mechanic told me sensors could be dead, other said maybe the car computer is not sending the low-to-high switch signal to the fuel system which i guess it is sending because truck chockes at that change. Stupid question but, does this trucks have an "altitude" sensor that could be wrong?

Do you guys think this could be a sensors problem ? if thats the case, what sensors should i check and where to find them?

Could it be a dead carburator ?

See i have a 1987 nissan pathfinder and man, that engine rocks!!!!! i'd really love to get my truck like that pathy's engine again.

If you need any further data to get the idea for the problem just let mi know.

Thanks a lot for reading this extensive thread :

[NM50]

Carbureted z24 engines in the states had an option for altitude compensators.If your engine has a carburetor as many south american trucks do you may be able to find one in a U.S salvage yard locater.

[luiguiv]

Hey man, thanks for that info. By the way, this truck was bought in the US and i took it way down here to guatemala about 10 years ago. So, if this truck could be one of those with altitude compensators, where in the engine could i find those compensators?

thanks in advance.

[NM50]

It has a bracket screwed to the firewall behind the filter housing.