87 mits mighty max 4x4 p/u


#1

my 87 mitsubishi (dodge) mighty max, manual 5 speed has a problem, well it has more than one problem but this one is major. I can drive it for a couple hundred highway miles(non-stop) but when i start it back up, and leave the fuel station it runs for about 500 ft. and then the motor dies. It acts like it is running out of gas. i then have to pull over and wait till the engine cools off before it will start again. i have only had the truck for 2 months. When it runs, it runs great. i have changed out the fuel filter to no avail. i live in Arizona, but the truck came from California and has vacuum hoses that run back and forth from everywhere,lol. Could it be some kind of vacuum leak? Maybe the float in the carb? Please help.
Thank You Kindly
Westie.


#2

This may be related to vapor lock. Vapor lock situations are usually brought on by summer heat and being in AZ I would assume the temps there are very high.


#3

I’m wondering if the tank vent system is working correctly. Next time this happens, take the gas cap off and see if it starts up and runs. If it does, there is a problem with the tank’s venting that will make the pump struggle to draw fuel.


#4

ty kindly for the response,
i have bought a new gas cap and vent filter and had tried what you suspected about a month ago but still have the problem, :frowning:
westie


#5

There is a large black cylinder near the radiator that has 3 vent hoses, think i will try seeing if it has some type of filter in it, maybe it needs cleaning or replacing?


#6

That might be the charcoal canister . . .


#7

ty so much for your comment,
i believe you are right, i’ll take the canister apart tomorrow.
I was told that people used to clip wooden cloths pins to the vacuum hoses to help transfer some of the heat?
Thx again,
westie


#8

These canisters can’t be opened and must be replaced, :frowning:
any ideas anyone?
ty kindly,
westie


#9

any ideas anyone< i’m at my wits end. :frowning:
westie


#10

I posed the vapor lock scenario earlier.


#11

And I posted a solution to tank venting. How fid that work out?


#12

“It acts like it is running out of gas.”

Throw a new fuel pump on it.


#13

First of all, the next time it acts up (stalls) pull the air filter off the engine, point a flashlight into the carburetor, open the throttle plate, and try activating the accelerator linkage. You should see fuel spraying from the accelerator pump. If there’s none, that means that the float bowl is empty, pointing to a possible vapor lock problem. Vapor lock can occur after a long drive because of heat buildup under the hood. Once the coolant stops flowing and the fan stops (when you shut the car off after a long drive) there’s a lot of internal engine heat that’s no longer being dissipated. It radiates out from the engine and the underhood temperature rises significantly. The heat can be sufficient to cause fuel to vaporize in the carburetor “circuits” (the passages through which the fuel passes) blocking passage of any more gasoline to the float bowl. Then, once the float bowl drains, the car stops.

If there is fuel, that means something in the ignition system has become heat sensitive. Check for spark. The #1 suspect is generally the coil/coil pack, as the coil windings’ varnish like insulation can break down over time and the cracks open up when heat expands the copper sires, shorting out and rendering the coil unable to induce a sufficient spark pulse into the coil secondary (the core).

Post back with the results.


#14

I worked a lot with vapor lock on EEC carburetors back in the 80s and 90s so that’s why the suggestion was made about this condition; especially considering summertime in Arizona.

Many of the Asian cars (Nissan and Subaru most notably) have sight glasses on the sides of the carburetors. It was common to shut one off on a hot day, wait 5 minutes, and the gasoline could be seen percolating in the float chamber just like coffee in a pot due to the heat spike soaking through the carburetor and the now inert gasoline.


#15

To Mountainbike and ok4450,
THX so much for your knowledge, i’ve been a bit under the weather latey (prostate cancer)
but will try your sugestions as soon as i’m up and about again.
ty kindly,
westie


#16

Whatever happens with the carburetor, sincere best with the prostrate cancer.