Explorer Won't Start, No Spark...

[runasoft]

Hey there,
I am having problems with my 1992 Ford Explorer 4WD.

My vehicle has 170,000 miles on it as of right now.

Now, my story. 2 days ago I was taking the wife to work. We were listening to the radio waiting to turn into the parking lot where I drop her off. While waiting, the explorer's engine just shutoff. There was no warning or chugging, it just shutoff. I put the vehicle in park and attempted to start it, it cranks hard but there is no sign of it wanting to kick over. It just cranks and cranks.

I pushed the explorer over to the side of the road and a passerby stopped to help. I thought the problem was that I was out of gas. Went to a nearby store, filled up a 5 gallon gas can and came back. Put the gas in, tried to start the X and it just didn't want to kick over.

The paserby informed me it was the fuel pump because no fuel was getting to the engine and we couldn't hear the fuel pump come on even after messing with the fuel pump relay.

I called a friend of mine, purchased a new fuel pump and fuel filter from autozone for 135 bucks. My friend installed it for free which required us to drop the tank and what not. Luckily there was about 1/4 of a tank of gas so it wasn't too heavy.

Anyhow, we installed everything within a couple of hours and then proceeded to check the inertia switch for safety measures. It had not been tripped.

I attempted to start the vehicle and it cranked and sounded exactly the same. I did not hear the fuel pump whine so I thought.. HMM It's the fuel pump relay. I replaced it with a new one from oreilys.. Still Nothing... I hear the ECC relay come on and the A/C Blower Motor relay but not the fuel pump relay.

I jumped the fuel pump relay connection and you can clearly hear the fuel pump come on and hear it spurting gas into the engine. I tried to jump the connection and start the vehicle but it did not start at all. It didn't even sputter or anything. It just cranked and cranked.

Ok, so with that out of the way, we checked the fuel rail nozzle. Fuel sprayed out as it's supposed to so the engine is getting fuel if we jump the connection.

Now, from here we checked for Spark.. Much to our surprise, no spark whatsoever is coming through to the spark plug wires. We do not see an arch on any of them. We have not yet checked the plugs at the actual power pack but I will do so after I post this. the plugs are in good condition tho so I don't see why a spark wouldn't come through if the power pack was good.

What all this boils down to is now I have a vehicle with a new fuel pump and fuel pump relay which doesn't activate the fuel pump but the fuel pump will activate if I jump the connection. I bought another relay (different brand) just to be sure with the same results.

Also, I have a vehicle which doesn't spark...

Can anybody offer up any suggestions as to what I should do next ? I have searched all over the forums but nobody has my exact problems and ones that are close simply stop and no further communication is made between the original poster and the community.

Also, I forgot to add. I attempted to pull codes and it just isn't happening. It may be that my battery is low from all the cranking and stuff so I will have it recharged and attempt to redo the code pulling. I did check the light bulb of the check engine light and it is fine. The CES is not on at all but the car won't start so I'm not sure what that's all about.

thanx,
Rudy

 

[Longjohn119]

I'm shootin' from the hip here but looking at the wiring schematic for a '92 I can see the EEC relay applies power to both the fuel pump relay coil and the Ignition Control Module which 'distributes' the spark to the different coils in the coil pack ...

I'd say you have a bad EEC relay ... just because you hear it click doesn't mean the contacts are still good .... if you still have the old fuel pump relay around it might fit the EEC plug for test purposes ....

 

[runasoft]

I'm shootin' from the hip here but looking at the wiring schematic for a '92 I can see the EEC relay applies power to both the fuel pump relay coil and the Ignition Control Module which 'distributes' the spark to the different coils in the coil pack ...

I'd say you have a bad EEC relay ... just because you hear it click doesn't mean the contacts are still good .... if you still have the old fuel pump relay around it might fit the EEC plug for test purposes ....

I already tried this unfortunately. I actually had purchased 2 relays, one from oreilys and one from autozone. I believe the part number as r647 but thats off the top of my head.

I plugged in both new relays.. One to the fuel pump relay and the ECC.. I still had the exact same results. The fuel pump relay and the ecc relay are the exact same thing and I read in the Cross Reference manual at oreily's that they are used for numerous other relays in the X with the ECC And Fuel Pump relay's being a couple.

Thanx for your response and just a bit of an update. I just got my battery recharged and I'm still unable to pull codes.. Very strange. I am very electrically inclined so I know I'm not doing anything wrong when it comes to grounding the connection to pull the codes.

I am going to see if I am getting any spark at the power pack.. Maybe my wires are bad. I will also attempt to see if I get any power from the actuall connector to the power pack..

- Rudy

 

[Glacier991]

Could also be one of the VERY rare cases in which the PCM is bad.

 

[monkeydude3]

I would agree.... seems like you have covered your bases. If you lived near me I would let you borrow my PCM... That is to my knowledge what would cause those two things to go bad. For humoring purposes you can always try a different ignition coil in it. But with no fuel or spark it definitely won't run.

George

 

[runasoft]

Could also be one of the VERY rare cases in which the PCM is bad.

yes, this is what i was thinking.. is there anything i can do to rule this out? Something simple ? I'm guessing not because I have heard this is very hard to diagnose.. I can remove the PCM and check it but I doubt I'll be able to find anything wrong with because as a PC Technician, I have had parts go bad (PCI cards etc) and do not notice anything burned, they just seize to work. anyways, thanx for your input and its definetly something I will look into.. If anyone has anymore suggestion, by all means let me know.

I do have a friend with a 94 Ford Explorer 4WD.. do the 92 and 94 share the same PCM Model ?

- Rudy

 

[Longjohn119]

Well like Glacier said, it could very well be a bad PCM, it's about the only other thing common to both fuel and spark .... unless you know sopmeone with a spare you can swap to test, I'd go over your wiring real good first looking for corroded plugs and connections, and for burnt or broken wires before I shelled out the bucks for another PCM ...

Also just because you have fuel at the rail doesn't mean the injectors are firing ... if they are and you have no spark, you should have wet plugs if you pull them after trying to start it for awhile ...

Another thing, if you do believe it has been getting fuel into the cylinders and you have flooded the engine quite a bit, you'll want to change your oil .... oil contaminated by raw fuel will ruin an engine about as bad as running it with no oil for a short period ... even the cheapest oil on the shelf will be better than the fuel contaminated oil ... anytime I flood an engine real bad or have an overheat problem, I change the oil immediately ....

 

[runasoft]

Well like Glacier said, it could very well be a bad PCM, it's about the only other thing common to both fuel and spark .... unless you know sopmeone with a spare you can swap to test, I'd go over your wiring real good first looking for corroded plugs and connections, and for burnt or broken wires before I shelled out the bucks for another PCM ...

Also just because you have fuel at the rail doesn't mean the injectors are firing ... if they are and you have no spark, you should have wet plugs if you pull them after trying to start it for awhile ...

Another thing, if you do believe it has been getting fuel into the cylinders and you have flooded the engine quite a bit, you'll want to change your oil .... oil contaminated by raw fuel will ruin an engine about as bad as running it with no oil for a short period ... even the cheapest oil on the shelf will be better than the fuel contaminated oil ... anytime I flood an engine real bad or have an overheat problem, I change the oil immediately ....

Ok, I'm going to see if my friend will let me use his PCM off his 94 explorer. I first have to see if thier models match but I'm pretty sure they will. They are both automatic's and 4x4's as well as xlt's and the engines are exactly the same.

Anyhow, I am a bit confused as to what I'm supposed to buy if my PCM is bad. I hear the abbreviations (PCM, ECU and ECM) all used. Are they all the same thing? I'm guessing they are as I'm replacing the "BRAIN" and they all seem to follow that category.

- Rudy

 

[monkeydude3]

yeah they are all the same name. Yeah the 'brain' is a good term for it. ECU (electronic control unit) , PCM (powertrain control module) ECM (electronic control module) , EEC, (electronic engine control)
all for thesame thing. The computer that controls everything that should be adjustable... I miss my old carbureted pickup, if it ran lean I just richened the carb.


George

 

[MrShorty]

If I suspected a bad computer, the first thing I would do is attempt to pull codes from the computer (see www.troublecodes.net/Ford).

If I couldn't get the computer to respond, then check for power to the PCM and check the PCM's ground. It's not unheard of for the little pigtail on the neg battery cable that goes to the computer to corrode through.

If I got any trouble codes, then diagnose those accordingly.

I don't expect you'd get all pass codes, but, if you do, cross that bridge if you come to it.

Diagnosing a bad PCM is usually a matter of eliminating all other possibilities. If everything else is working, then the computer must be at fault. Trouble here is it is difficult to say with certainty that everything else is good.

 

[runasoft]

If I suspected a bad computer, the first thing I would do is attempt to pull codes from the computer (see www.troublecodes.net/Ford).

If I couldn't get the computer to respond, then check for power to the PCM and check the PCM's ground. It's not unheard of for the little pigtail on the neg battery cable that goes to the computer to corrode through.

If I got any trouble codes, then diagnose those accordingly.

I don't expect you'd get all pass codes, but, if you do, cross that bridge if you come to it.

Diagnosing a bad PCM is usually a matter of eliminating all other possibilities. If everything else is working, then the computer must be at fault. Trouble here is it is difficult to say with certainty that everything else is good.

ok, well I have tried to pull codes and followed the information here..

http://fordfuelinjection.com/index.php?p=13

I cannot pull codes at all. I have taken apart my dash just to check the little light bulb to the Check Engine and it is fine. I took it out and put it in the blinkers socket and it worked just fine. So I know it's not the actual light bulb.

I will check the ground to the actual PCM.. Right now I am prepared to buy a new PCM and a new Coil Pack but what good will they do me if the PCM is not getting any power.. hehe

- Rudy

 

[runasoft]

Anotheer EDIT: I had asked for the PCM Schematic but I found one as well on Autozone...

I found it here.. Dead Link Removed

Anyways, I see for my explorer model.. the 92 ford explorer that pin 50 and 20 are grounds which are the Black/White and Black/LightGreen wires.. I guess from here I can check to see that I'm getting power..


EDIT: I had asked what PCM I should buy but i found my exact PCM on ebay for 28 bucks with shipping so I bought that just in case. It's always good to have a backup anyhow..

- Rudy

 

[runasoft]

ok, well here is some new information that I have found while using a multimeter to check the grounds and for voltage to the actual PCM connector.

I have checked the ground pins 60, 40 and 20.

60 = Black/White
40 = Black/White
20 = Black - Schematic say B/W but its all Black on my connector

I tested each of these against each pin on the connector and the ONLY pin which I get 12 Volts from is pin 17 (Pink/LightGreen).

Pin 17 for those that don't know is the Tester Pin for the VP Data Link Connector.

Is this right ? Should I only be getting voltage from pin 17?

Also, I tried pulling codes using the Multi-Meter method and although i get 12 volts when the car is in the off position, when i set the car to on, the voltage drops to nothing and the meter does not move at all even after watching it for more than 30 sec...

Does this all boil down to a bad PCM ??

Thanx,
Rudy

 

[runasoft]

does anybody know the answer to my last question?

Thanx,
Rudy

 

[runasoft]

^bump^

 

[MrShorty]

Sorry for the lateness of my reply; I was going to reply Saturday, but everyone wanted to celebrate my birthday (I'm too old for birthdays, aren't I??

To verify that I understand what you are doing: You have your negative lead attached to pin 40 or 60 and you're probing the other connections in the 60 pin connector with the positive lead. Assuming there isn't a break between pins 40/60 and the negative battery post, I would expect you to see + 12 V (with the key on) at pins (and I'm not going to make this exhaustive):
37, 57 (main computer power)
58, 59 (fuel injectors)
52, 53 (transmission solenoids)
22, 8 (fuel pump relay)
31 (CANP solenoid)
21 (IAC valve)
and so on. (Controls are almost always ground side switched, which is why you will see power at the computer for each of the solenoids.)

You should see + 5V at pins 46 and 49 (Vref) and various voltages between 0 and 5 V for each of the sensors that feed off of Vref.

All of this suggests to me one of two possible conditions:
1) A bad ground (note assumption at beginning). Put your positive lead on the negative battery post with your negative lead still attached to 40/60. If you read -12 V, you have a bad ground connection. If you read something near 0 V, then...
2) No power to EEC-IV system. Check for power to EEC relay, check EEC 30 A fuse, check that EEC relay is closing with the key on, and so on. You have an adequate wiring diagram and at least a basic understanding of DC electricity. This shouldn't be too hard for you to find.

 

[runasoft]

ok, well my battery died again from all the cranking I was doing. I am having it charged now but the tester said it was 80% so I'm going to check my wires for corrosion and what not.

I will then do some more testing to further rule out that it's an actual ground/power issue.

I do have a question tho.

If grounds are my problem can I simply create new grounds somewhere in the engine bay or even on the firewall and use them as grounds for pins 20, 40 and 60?? This way I won't have to trace the grounds and find out where they are actually broken or frayed..

- Rudy

 

[MrShorty]

I don't see why you couldn't make new ground wires. I'm not sure which ones, but at least one, if not all three grounds, is usually wired straight to B- (you know those little "pigtails" that come off of the battery cables?). If it were me, I would string the ground wire(s) somewhere to where they can attach directly to the negative battery cable rather than grounding the computer through the body.

 

[runasoft]

ok, I have finally elimanted quite a few problems.

It's not my fuel pump
It's not my fuel pump relay
It's not my EEC Relay
It's not my EEC (aka PCM, Brain, Computer)
It's not my Ignition Coil Pack
It's not my Spark Plug Wires


What I have narrowed it down to is a short right before Power enters the Distribution Box under the hood. The EEC Relay FUSE keeps being blown everytime I attempt to start the vehicle. If I put a new 30AMP fuse in there and just turn the key to the ON position, I will hear the EEC Relay and Fuel Pump Relay as well as the actual fuel pump whirring sound..

If I attempt to start the vehicle, it sometimes will start and stay on for 3 seconds and then blow the EEC Relay Fuse or It will just crank and blow the EEC Relay Fuse..

No Other fuses are being blown except for the EEC Relay Fuse..

To rule out the distribution box and the fuse connection I clipped the Yellow wire that goes into the distribution box and connected an inline Heavy Duty 30AMP fuse and it still got blown...

I am attempting to track down the short but have not had any luck... I have undone any and all changes I have made to the truck as far as electrical wiring goes except for the alarm which was professionaly installed.

I have traced the Yellow power wire and have not found any cuts or anything like that. I think the problem lies in the actual ignition wiring but I am in the process of taking apart the dash...

Please give me input on this problem..

- Rudy

 

[cainfan4u]

is the small wire on the battery cable corroded and or grounding out somewhere?