# 94 Ford Exploder, wont start!



## GR8ness (May 7, 2007)

OK, I bought a 1994 Explorer in Feb. Its been great until just recently. Out of nowhere, when the car has run for some time, like running to the store, we would shut it off, then it wouldnt start again until it cooled off. Well, during one of these fits, a mechanic suggested I replace the IAC(idle air control valve). First I looked it up on the web and found out you can clean it if its not too gummed up. I did so, and it worked great, for about a week. Then it started acting up again, so I just replaced the IAC. That worked great, until another week went by. Now, the car will turn over but will not fire up. Any suggestions before I shell out too much money to an overpriced mechanic?


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## qldit (Mar 26, 2007)

Good Afternoon GR8ness, it sounds like you have zeroed in on the problem, but as to why you are having the trouble sounds odd!

It is possible you may have picked up some contaminated fuel, I would be inclined to follow that cleaning procedure again and then possibly consider draining the fuel tank and and cleaning it, then adding some fuel injector cleaner and topping up with decent premium fuel.

But I am guessing somewhat, you shouldn't be having that problem.

The fuel filter may tell you something, but ensure the battery is disconnected and follow the maintenance procedure if you check that filter.

We are having a few odd problems with ethanol blended fuels here, they might be avoided.

Cheers, qldit.


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## GR8ness (May 7, 2007)

Thank you for your reply. I forgot to add, that after it quit firing, I(expecting the fuel or fuel pump to be the issue) tried spraying some starting fluid into the intake, and nothing. Still doesnt start or fire.


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## qldit (Mar 26, 2007)

Good Morning GR8ness, well that is interesting, have you tried disconnecting a spark plug lead and checking for spark?

Be careful if you do this, it is best to use an old spark plug and connect the disconnected lead to it (with the plug sitting in a suitable observable position touching the engine) so that you can watch what happens. Some sparks are pretty hot and if there is no relative easy path to jump, can reflect a problem back into the coil etc. etc.

If you confirm you have no spark evident, that complicates matters.

Actually it seems odd that such a vehicle won't kick, is there any possibility the original problem may have related to an ignition performance problem?
When it was running, was it operating perfectly or was there some sign of performance loss. (like only just running!)

Cheers, qldit.


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## qldit (Mar 26, 2007)

Good Morning Again GR8ness, I have been pondering over your original problem symptom, I seem to think that even if that "Idle Air" system did have a problem that the engine should at least kick when cranking, even if it didn't idle!
I would also expect the thing to accellerate if the throttle was opened during cranking, even though that may not be the proper starting routine.

So my thinking now, (in view of your original description) kind of leans toward the original problem actually involving ignition and you have been sidetracked somewhat with the other finding.

I think that machine has a solid state ignition sensor in the distributor that is possibly causing your problem, when it gets hot it complains.

If you have a small transistor portable radio you should be able to hold it in the engine bay area (on AM band and not on a station) and hear the ignition firing (if it is actually operating) as noise in the radio. (A constant clacking for ignition and a whine for an alternator)

This is a cheats method of troubleshooting alternators and ignition systems. (so keep the secret to your self)

I don't have a schematic diagram of that electrical system so I am guessing.

The other chaps here may have different ideas.

Sorry not much positive help.

Cheers, qldit.


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## kendallt (Feb 21, 2007)

Check the crank position sensor, lovated low on the front of the engine near the balancer, sometimes a pain to se, but easily seen and worked on after you find it. 

Remove wires and pull the unit, -should- have some resistance between terminals, not an open. hook the meter leads to the terminals and set the meter for lowest voltages, and wave a wrench or screwdriver close to the pointy end, should see some slight volt surges. if everything is good, use a hairdryer/heat gun and warm it up, then repeat the same tests.

your ignition module is behind the passenger headlight on the 94 I think, check it out for loose connections or corrosion. Most Napa stores have the equipment to test ignition modules, up here they do it free. 

Also, somehwere around 94/95 is when they started using the cam position sensor, top center of engine far back at the bell housing you'll see the place where the distributor is supposed to be, (awkward) if you don't have a cam position sensor, it will be just a plain cap, with the sensor there will be wires or a terminal block on it, check that the same way as the crank sensor. 

if they all check out good, start heating components with the hair dryer till you find one that produces the same symptoms.

The explorer computer has a failsafe mode, and when certain sensors go out it will normally switch to a default mode where it calculates timing and such, using the sensors it does have. normally takes up to a minute of cranking to hit.

Ken.


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## qldit (Mar 26, 2007)

Good Afternoon Gentlemen, I have just had a look at 94 Ford Explorer problems and the symptom of "cranking when hot and no start" appears to commonly be caused by the ignition control module.
It seems this module is located in the distributor in some models or on the side panel on others as kendallt suggests.

Interestingly if this problem involves the ignition, when the vehicle is in the actual cranking condition, the computer should not really be involved, but as soon as the engine starts for a short period, the computer then takes over and controls sparking refinement in conjunction with the distributor information.

The actual speed controlling and make and break for the coil appears to be soley controlled by the actual distributor hall effect magnetic sensor in conjunction with the ignition control module which does the "grunt".

The interesting thing with this is that ignition should be present initially, so quite obviously the computer should not be involved with that problem.

This kind of points to the ignition contol module as a likely cause.
(assuming it is an ignition problem)

I understand you have no lights showing on the dash?

Cheers, qldit.


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## qldit (Mar 26, 2007)

Oh, Good Afternoon Again, I neglected to mention that on some vehicles Toyotas especially I have noted that the "igniter" similar to your "ignition control module" which does the controlling of the coil, can be damaged by defective leads or allowing an excessive high tension voltage to exist without a relatively short gap for it to "jump", this is why I suggested using a spark plug to test with. 

The reflected effect of an open circuit lead with a high voltage present obviously affects the system driving the main ignition coil, so it may be worth examining and measuring your spark plug high tension leads and ensuring they are all good also.

Once you know about this possible problem and it's implications it can be very helpful.

Checking presence of spark these days is a bit different to the old days!! LOL!!

Cheers, qldit.


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## kendallt (Feb 21, 2007)

I'm leaning towards either the ignition module, or the crank sensor.

There is a fuse that runs the ignition itself, located in the power distribution box on the fender, I assume you've checked that though!

Not sure, but I think they went distributerless when they built the 4.0, ignition runs off the crank position sensor, the ignition module, and coil block, certain years use the cam sensor as part of the ignition timing sequence.
I thing the cam sensor was used when they switched to sequential injection, instead of 'bank' fire.

Have never seen one with a distributor, but it still has the opening for the distributor, it has a 'dummy' that's used to drive the oil pump. 

ken.


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## qldit (Mar 26, 2007)

Good Morning Ken, yes that makes a lot of sense, I have only seen a couple of these machines and they were 6 cylinders and I haven't seen any computer or ignition problems on them, my info was from another tech.

Quite obviously I would expect a vehicle in that age range to have coil banks and be distributorless as you mention.

The mentioned problem in that case would confirm your suggestion ideology.

So GR8ness, you might check and see what that vehicle actually is, does it have separate leads going to the spark plugs from separate coil packs?
If so disregard my suggestions.

I rarely touch these things these days and we don't have many of them here.
(thankfully!! LOL!!)

Cheers, qldit.


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## GR8ness (May 7, 2007)

First off, thank you all for your suggestions and input. And let me tell you one of the oddest things ive ever seen. After reading more on the web, and of course, youre suggestions, I decided I needed to see if I had spark at all. So, I took off one of the plug wires, put a screwdriver in it and gave it a crank. I couldnt tell one way or the other, so I moved the screwdriver, accidentally laying it on the windshield wiper. Gave it a crank and a small puff of smoke came out of a wire cluster. So, Im thinking oh great, i just fried it! Didnt find any fried wires, so I put the plug cap on to see if it would even turn over anymore, and, to my surprise, it now starts and runs fine?!?!?!?! Makes no sense whatsoever, and Im going to go and get a diagnostic scope today to see if I actually fried anything, and to try and find out why this would happen and why it now works. Anyone else hear of anything this bizarre????


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## qldit (Mar 26, 2007)

Good Evening GR8ness, do be very careful with windscreen wipers and earthing, the windscreen wiper system is usually mounted on rubber insulators with a small earth lead attached and it is not hard for a backfeed to affect the variable controller.

I can't explain what might have happened to fix the problem, is that a single coil and distributor or separate coil packs on that machine as Ken suggests? 

I hate problems that disappear, murphies law usually applies after that!!

I am interested to see what you might find, chances are there will be a load of useless stored codes.

Cheers, qldit.


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## GR8ness (May 7, 2007)

It is a distributorless system, as Ken suggested. I will let you all know what the diagnostic comes up with.


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## Brandon35holl (May 12, 2007)

We also bought a 93 explorer with almost the same problem. It turned out to be a relay related problem. Under the hood on the left side there are relays for the fuel pump and also for e.f.i. and some other misc. engine controls. You will also see some big plastic fuses that look just like your normal color coded fuses. A couple of these had popped and 3/4 of the entire fuse block was completely dead. This problem caused the fuel system and the ignition system to shut down. We ended up replacing a couple relays a couple of giant fuses and i believe 1 or 2 of the little bity fuses you will see. Anyways the truck fired up and we have not had a problem since. Good luck.


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## GR8ness (May 7, 2007)

I took it to the auto shop, to get it diagnosed, but no problems! It was suggested that maybe by pulling the starter relay and putting it back in I somehow "reset" the system. Still unsure of what happened but runs fine now.


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## qldit (Mar 26, 2007)

Good Morning Chaps, given the information, it kind of leans toward the actual EFI Control relay possibly being intermittent, Brandons problem seems similar, it may be worth your while identifying it, and if you have any further problem maybe tapping it and recalling Brandon's experience may determine the source positively.

I suspect you may have had 2 problems (not associated) and they are both cleared, but I am usually wrong, so take it at guess value! LOL!!

Thanks for the info, best of luck.

Cheers, qldit.


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