1994 Explorer wont start

[jhall68w]

I have a 1994 Explorer Sport 4.0 with almost 200k miles(I know a lot).

I am the 2nd owner of this vehicle and never had any isses except over the past month where it has got harder and harder to start. It will turn over, but it will not start.

What I have done and know:
-Fuel pressure is at 40 (standard is 35-45)
-Spark plugs have spark
-All fuses are good
-Mechanics said FPR is working
-New fuel filter has been installed

When hooking it to see if there is a code, there is nothing that comes up. A friend of mine that is the mechanic that I always take my car to say that it could be the PCM, which could explain why well spraying gas into the intake that the injectors never kick on and the spark plugs are bone dry.

Can anyone let me know where the PCM is? And where the FPR is?

 

[MrShorty]

PCM is behind the kick panel, in front of the passenger door, just below the glove box.

FPR is at the forward end of the fuel rail, just behind the thermostat housing/upper radiator hose connection, below the throttle body.

PCM is a possibility, I'd be inclined to look at PCM power and ground circuits first though. Make sure the PCM has power, make sure fuel injectors are getting power, make sure the PCM has good ground connections, and so on.

 

[cecilburt]

Don't know if your 94 has a "inertia" switch or not. It is a cut off for the fuel pump in case of a head on bump. Located on passinger side kick wall. Check and reset. Also alarm system can cause system not to start. Computer has to be reset.

 

[jhall68w]

I have installed a new pcm, and it did nothing different. My explorer does have an inertia switch, and it is working properly and does not need to be reset. We have come down to know that the injectors are not opening up. We think that it could be a possible ground wire or a short somewhere that is still causing it not to start.

Any ideas?

 

[budwich]

while its probably not a short as that would have blown a fuse... all of which should be checked. One can check for voltage going to the injector(s) to see if there is some there.... that will tell you a bit more. Injectors get their "command" from the PCM (which switches grounds) based on cam position sensor input.

 

[fixxxer]

Check the PCM power relay, main power dist. box under the hood, behind the battery.

 

[cecilburt]

I agree with "fixxxer" you have more than likely jarred a fuse or relay lose. One other thing you can check and that is the alarm system. May have to be reset. I know , sound crazy but check it out .Happened to a friend of mine.

 

[jhall68w]

update

so, we have checked the relays and all fuses. We also got a replacement for the crank shaft sensor. Nothing has fixed it. The injectors are still not kicknig on. This is a true mystery.

 

[MrShorty]

Are the injectors getting power (should have a constant +12 V with the key on)?

 

[jhall68w]

yes they do. They just never actually kick on.

 

[fixxxer]

so, we have checked the relays and all fuses. We also got a replacement for the crank shaft sensor. Nothing has fixed it. The injectors are still not kicknig on. This is a true mystery.

How did you check the relays? Did you check for correct voltage at the coil and at the switched contacts? Did you hear the relays energize and hear the contacts close?

 

[MrShorty]

Is the PCM getting power (you've checked the relay, now verify that the power is actually reaching the computer)? The PCM gets power at two or three pins, make sure all power pins have +12 V. While you're at it, make sure the computer's three grounds are good.

 

[CBKBAMF]

I'm having the same exact problem as you as far as I can tell in my 95. The Idle Control was going out before it just quit, so I replaced that thinking that it was the issue. Unfortunately (and $180 later), it wasn't the cause of the truck not starting.

Fuel rail is getting fuel, plugs are getting spark.

Truck starts when it wants to, which is more and more rare over the last week. Now it will go days without starting, start once, and then not start again for another few days. I haven't replaced the crank angle sensor yet, but was thinking that would be my next course of action.

 

[nukchew]

Same problem

PLEASE HELP US

I am having the same problem too. A auto repair tech. worked on the problem for 2 weeks for me and came to no conclusion. Just for laughs check out all the stuff I have tried

- 3 (thats right 3) PCM's from running Explorers
- 2 ign. modules
- Fuel pump
- fuel filter
- plugs and wires
- distributor
- crank position sensor
- coolant temp sensor
- ALL fuses
and a few more usless things.

Garage says the injectors are not firing. I have spark and good fuel pressure.

So I was thinking it must be wiring or camshaft position sensor. But is there even a camshaft postion sensor on a 4.0 liter engine? If so where is it. I have pulled the entire intake off my spare Explorer to try and locate it at the back of the engine but cannot find one.

Lots of good info in this thread. I will try all the voltage checks next.

Cheers

 

[nukchew]

Truck starts when it wants to, which is more and more rare over the last week. Now it will go days without starting, start once, and then not start again for another few days. I haven't replaced the crank angle sensor yet, but was thinking that would be my next course of action.

Intermitant problems are the hardest to troubleshoot. How many Tow bills do u have. I have been Towed 7 times now. My 94 is doing the exact same thing.

 

[MrShorty]

Fuel rail is getting fuel, plugs are getting spark.

Truck starts when it wants to, which is more and more rare over the last week. Now it will go days without starting, start once, and then not start again for another few days. I haven't replaced the crank angle sensor yet, but was thinking that would be my next course of action.

When you say the fuel rail is getting fuel, is that verified with a pressure gauge? I have had problems with mine getting fuel but not enough (20 psi, which is well below the spec of 40 psi). It is possible for the pump to generate some pressure, but not enough to start the engine.

Also check that the fuel injectors are firing. Make sure the injectors are getting a constant +12 V with the key on. Make sure the PCM is getting power and has good grounds.

Garage says the injectors are not firing. I have spark and good fuel pressure.

PCM is responsible for firing the injectors. Make sure the PCM (and the injectors) have power. Make sure the PCM has good grounds.

But is there even a camshaft postion sensor on a 4.0 liter engine? If so where is it. I have pulled the entire intake off my spare Explorer to try and locate it at the back of the engine but cannot find one.

Your '94 almost certainly has a CMP. '94 was the first year they put a CMP on all 4.0's. '91 and '92 didn't have CMP's (so if your spare Explorer is one of these older ones, then that would be why you can't find it there). '93 was kind of the transition year in this respect, so some '93 did and some didn't have CMP's

 

[timgalo]

94 Explorer Won't Crank

My 94 is having the Same problem It starts when it want to. I suspected the Fuel pump so I replaced it and it has only cranked a couple of times since then. So I came here to the Forums. When I turn the Key on with a pressure Gauge Connected I only get 34 to 35 PSI is this considered to low?? If I keep cycling the switch it might get to 40 psi but it still wont crank? I'm going to check these other suggestions and hopefully will have some more info Later. Thanks Guys any help will be appreciated.

 

[nukchew]

I havent checked the actual pressure at the fuel manifold. 35 - 40 psi sounds good though. I still havent found the prob. with my Explorer.

 

[nukchew]

My 94 is having the Same problem It starts when it want to. I suspected the Fuel pump so I replaced it and it has only cranked a couple of times since then. So I came here to the Forums. When I turn the Key on with a pressure Gauge Connected I only get 34 to 35 PSI is this considered to low?? If I keep cycling the switch it might get to 40 psi but it still wont crank? I'm going to check these other suggestions and hopefully will have some more info Later. Thanks Guys any help will be appreciated.

If your truck will not crank, then it is a different problem. If it cranks but wont fire and you have fuel pressure, try checking for spark then go from there.

 

[YBCold]

im not sure if this has too much of an effect but maybe check the IAC valve? or could it be an electrical isssue? maybe bad battery. my haynes manual says to check the timing chain.