4.0 power loss

[H munster]

got a chance to buy a 93 explorer 4.0 auto for $1200. Only problem i can find is at 50 mph the thing falls on its face like its hitting a governor. Anyone ever hear of anything simular? Oh 160000 miles:

 

[vrruumm]

Sounds like your fuel filter is clogged. Although it should have the same symtom in any gear or speed, as long as you have your foot in throttle hard enough and the rpm is high enough.

Try dropping the shifter down to 2 and floor it. If it does the same thing, its the fuel filter.

 

[MAKG]

Well, it could be other things as well. For instance, a plugged cat or weak (or poorly powered or poorly grounded) fuel pump will do the same thing you describe.

I would suggest an hour of professional diagnosis by a competent technician.

This isn't a very good project to learn on. It has too many variables.

 

[vrruumm]

9/ 10 of these types of problems in my experience have been fuel filters. The fuel filter retails for $14.64 the special tool for changing these is in the 10 dollar range. It extemely easy and cheap to replace your fuel filter. Be carefull of spilled fuel, but take a trip to the auto parts store, grab some rags and give it a try. 25 bucks is alot less than you will spend at a shop, and even if it is not the problem, it probaly needed to be done and you saved some coin doing it yourself.

 

[H munster]

went ahead and bought it. After driving it i think the problem is in the transmission. At about 50 mph it seems to come out of gear. Thanks for the info. will try fuel filter first.

 

[eric17]

can you accelerate past 50 fine? is it only when your cruising along.

 

[H munster]

no cant accelerate past 50 mph normal driving

 

[eric17]

how about your check engine light? anything coming on? also special tool for the fuel filter? i just replaced mine and it took a floor jack and maybe, maybe 4 minutes.

 

[H munster]

No check engine light. I did get it up to 60 mph today on a long stretch and feathering the throttle.

 

[H munster]

Tested the fuel pressure at 30 lbs. Pressure went down immediately when i turned the key off.A good friend who is also a mechanic said to change the pump. He likes to see around 45 lbs. What do you think. I dont want to drop the tank and that not be it. Going to start with a new filter tomorrow.

 

['94RangerXLT420]

You don't have to drop the fuel tank to change the pump. Take the bed off or take the bolts out on the side with the tank and loosen the bolts on the other side and prop the bed up. That is how a friend did his in a parking lot where we was pouring concrete. And get some Mass air flow senser cleaner and clean the maf. I had some what of the same problem with my 4.0 and that fixed it haven't had another problem. Hope that helps and good luck

 

[eric17]

well the book says 30-45psi for fuel pressure, mine was about 34psi and when i found a small vac leak on the fuel pressure regulator, cut the hose and put it back on and it gained about 4psi more, i think the vac leak was just causing havok, i drove it shimming like that when id ease into the gas at like 50 for a month or more, i though it was my tranny about to go tits up, i was so surprised after givin it a little tune up how it ran, it was like a totally different truck.

 

[mjonesjr]

You don't have to drop the fuel tank to change the pump. Take the bed off or take the bolts out on the side with the tank and loosen the bolts on the other side and prop the bed up. That is how a friend did his in a parking lot where we was pouring concrete. And get some Mass air flow senser cleaner and clean the maf. I had some what of the same problem with my 4.0 and that fixed it haven't had another problem. Hope that helps and good luck

Since when did Explorers have removeable beds? You will have to drop the tank on an Explored.....


I think you should go have the codes pulled....even if it isn't showing a check engine light, there could still be codes....not all codes trigger a light.....

If you are dropping fuel pressure like that, it sounds like a bad fuel pressure regulator...

 

[eric17]

throw the ol compression gauge on it too, let us know what it reads.

 

['94RangerXLT420]

Since when did Explorers have removeable beds? You will have to drop the tank on an Explored.....


I think you should go have the codes pulled....even if it isn't showing a check engine light, there could still be codes....not all codes trigger a light.....

If you are dropping fuel pressure like that, it sounds like a bad fuel pressure regulator...

my bad thinking about a ranger