My 1990 Montero (3.0l V6) is not running the fuel pump with the ignition in the "on" position. I have checked the control/start relay and have replaced the ECM/computer. I have another ECM that does not have any spark, but the fuel pump runs fine. I replaced the ECM again and still have no power to the fuel pump when key is "on". None of the computers have anything burned on them. I assume, because the fuel pump runs fine with one of the ECMs, that the fuel pump circuit is fine. Could I have another bad ECM? It is about to drive me crazy. Any suggestions?

 

I've got the same issue, 90 montero, wont start, figured it was a low fuel pressure thing, because after 5-6 turn overs it starts. then runs fine, till i park it for 4+ hrs. then its the same thing over again. Ecu isnt burnt, so I dont know.
let me know what you find out.
Thanks , Rob

 

I'm sure you guys checked the obvious - fuses, etc?
Not sure if this relates to the 90th models of Montero, but can a faulty crankshaft position sensor or something like this be responsible? I had similar issue on a different late 80th model vehicle - the fuel pump was not getting any voltage unless ECU was getting a signal from the crankshaft position sensor that the engine was turning. All other systems were OK at that point, but no voltage at fuel pump. Once I replaced the faulty sensor, the fuel pump got energized.

 

Gec2 so with one of the pcm's you have a running pump? That would indicate all other pcm's bad. If the pump always comes on with that PCM you know ignition switch, relays, wiring and pump is all good. Rob.allee it sounds like your fuel pressure is bleeding off over time. Three causes if you have no fuel leak. It's either the check valve in the pump assembly, an injector bleeding the fuel into the engine (usually runs rough and black smoke at first startup) or the fuel pressure regulator

 

Hon450, thanks for the info. I already replaced the injector seals (some broke apart when I was taking them off) so I'll try the fuel pressure reg, and check the pump, although it's less than 1 week old.

 

[QUOTE=I already replaced the injector seals (some broke apart when I was taking them off) [/QUOTE]

Injector seals will have no effect on the leaky injector. They just seal the body of injector against the intake manifold and the fuel rail. Injector leak comes from the business end of the injector and will leak fuel into the engine when the engine is off. By any chance did you have injectors checked when you had them off?

 

When you replaced the pump was it just the pump itself or the assembly? There is usually a check valve somewhere that keeps the fuel pressure up in the lines/ rail if its bad the fuel will drain back into the tank. Causing a long crank. I'm not sure where it is located on that certain vehicle but I can look it up at work on Monday.

 

hunterD- Their not leaking gas, I was thinking they were letting air in through the bad seals, causing the gas to travel backward.
Hon450- the fuel pump was just a pump with new positive wire + hose , I wonder if the check valve is in the pump housing. The last pump I bought was less than 3 yrs ago, and I bought a new one just to make sure the pump wasn't the problem, now if the check valve is in the pump housing that might make sense. I'm installing a new fuel pressure reg sunday.

 

Yeah the check valve is gonna be in the housing most likely. Cuz that pump you put in is just a pump. I'm not sure if the check valve is available separately usually isn't

 

So I checked with an auto part store (Costless Auto) and they looked up the specs and told my there is no check valve, that the low\no fuel pressure is either a bad fuel pump, fuel filter (just replaced both) or fuel pressure regulator. So I'm going with the fuel pressure reg. I'll let you know what happens
R.