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1991 explorer cold starting problem


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February 19, 2006
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Have a 1991 Explorer and I am havong big problems with it not wanting to start when it is cold out side.Have changed computer, fuel pump, spark plugs,crankshft positions sensor,coil,and everything else I can dream of,had electric spark control tested and was told it was ok.Really at my wits end,it is a very good truck and would like to keep it ,but dont need a yard ornament,checked the spark by removing a spark plug and it would fire several times and then quit and then would fire a few more times and then quit again,then sometimes it starts and sometimes it doesnt,any suggestions short of pushing it off a cliff

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Welcome to the board.
Has the check engine light been coming on? Was it missing when it was running?You probably have the same misfire problem when it's warmer but it's harder to start without good fire when it's cold out.

Have you changed or checked your plugwires?I seen you had replaced the plugs.

Welcome to this forum! I once had a no start condition. It turned out to be related to the cap, rotor, plugs, and wires on my 88 Aerostar. I once had an 89 Sable that always had problems starting in all kinds of weather. The coolant temperature sensor, air charge temperature sensor, fuel pressure regulator, and fuel filter had to be replaced to fix this problem.

have changed fuel pressure regulator,sparkplug wires ,coil ,fuelpump, computer,map sensor mass airflow sensor crankshaft position sensor fuel pump relay. not sure what you mean by coolant temp sensor.Thing runs great after it starts,Only seems to not start when really cold I mean below 25 deg.Only thing I have really noticed is that when you remove a sparkplug and check for spark it will fire a few times and then stop and then will start firing again and the loses fire again and after a little bit of this then it starts

I would check the ICM(Ignician Control Module) like Brooklynbay said. Its mounted on the front clip just in front of the battery. Its black and the plug is perpendicular to the module. I wore out my starter until I found this thing. Go to a junkyard a get one. They are expensive new.

I think one of the first things I would do is pull codes from the computer.

MrShorty said:
I think one of the first things I would do is pull codes from the computer.
Well if he has replaced everything, which is what I did, then my money is on the ICM. There were 2 days when it was realy cold and my truck flat out would not start. I would come home in the afternoon when it was warmer and boom starts right up. After a while, it didnt matter what the temp was. Eventualy, the starter went. On the other hand you are right. That should be the first thing you do.

What Mrshorty said and then check for voltage drop between Batt. + and coil pack +, key on you can access this by disconnecting rf capacitor and hooking to the harness side. It shouldn't be much more than 0.5v. Check it also during cranking. My 91 did the same as yours and it was the ignition switch that had high resistance, new switch and bingo. If your car is dead now and fails this test run a wire from the Batt+ to the same harness end where you measured the Vd and see if she'll go, mine fired right up and it was music. Have a friend crank when you do this test for safety.

Plug it in when it is that cold!!!!! I live in Calgary,Alberta Canada and when it hits the -15's or colder, I plug in the truck or it will not start.

86caprirs said:
Plug it in when it is that cold!!!!! I live in Calgary,Alberta Canada and when it hits the -15's or colder, I plug in the truck or it will not start.
american versions don't have the block heaters...but you can install one easily enough.

I've never used it because I'm not sure what kind of wear and tear it causes but I keep a can of starting fluid in my ex just in case it decides it doesn't like the cold. Some vehicles just don't like cold weather, my parents used to have a 92 F-250 and it wouldn't start unless you plugged it in when it dropped below freezing. I believe they also make a battery blanket, not sure how well it would work for you though.

There is also something else that works in a similar fashion to a thermos bottle. I'm not sure who makes it, but I once saw it in a catalog. It has a coolant inlet, and outlet going into a themos style tank that holds a little antifreeze, and keeps it warm for an extended period of time. When you start your vehicle, it will push out some of this warm antifreeze, and mix it with the rest of your coolant to warm it up a little.

It would be interesting first off to see if in fact there was a stored code. failing that I too am suspect of an ICM going bad... but if all we do is throw parts at a problem, the fix, if one is to be found at all, can be VERY expensive.

I think it is safe to say that both the ignition system and the fuel system are candidates for close inspection. (I know... DUH)... but all too often we fail to go back to the basics in troubleshooting a no start... spark, fuel and then mechanical.

FORD used to provide its dealers with an "Intermittent Ignition Analyzer" for just these kinds of problems.

But, once again, the plain wisdom of Mr. Shorty (probably the most respected diagnostician on this board) comes through with the simple suggestion.... start by checking codes.

By the way +25F isn't all that cold so as to create a non-start. In fact with electronic ignition, so long as you can crank you ought to be able to get it to fire.... although I will bow to the notion of heat maybe being a necessary addition at about -15F and lower.... still, my 92 with 200,000 miles has started at -10F after just a few cranks...so it ain't out of the ordinary.

mine is a U.S. 94 XLT with a block warmer. I live in the hot desert so I don't use it, but it's there.