Hi all,

I have a '94 Explorer XLT that has always been good to me. Recently my "Check Engine" light has been coming on when I'm on the freeway. It mostly happens after about 20 minutes and when I'm going above 65 mph. Lately it has been coming on sooner and staying on longer, even at slower speeds. My mechanic wants almost $200 just to diagnose the problem. Is that reasonable?? It seems to be running fine, but I've been avoiding driving it long distances. Now I want to take a road trip but I'm afraid it will leave me stranded.

Any suggestions would be greatly appreciated!
Thanks,
Sue

 

Sue , $200 is very excessive just to check the Ecu for a trouble code . If all you have wrong is the check engine light coming on accessing & retieving the diagnosic trouble code is a minor thing . Any descent mechanic would do this for free & tell you what would be involved as far as labor goes in diagnosing what code(s) were found , Even a minimun labor charge isnt going to be $200 . Once you have an idea of the cost you can either OK the repair or say no . Id suggest you find a mechanic / shop that is more willing to repair the problem than charge you a lot for something that really isnt that labor intensive .

 

The codes can be read quickly--about 5 minutes worth of work. I have had the same thing going on with my 94 Explorer and have successfully fixed it based on symptoms and codes. If you can describe some of the symptoms, other than the check engine light coming on, I may be able to steer you in the proper direction if it sounds like my experiences.

 

Hey, thanks for the tip! I'm glad I didn't pay the $200...

I don't know what to tell you though, there really aren't any other symptoms. However, and I thought this was unrelated but maybe not...there's a rattling or pinging(??) when I accelerate, especially uphill. That started a couple years ago, and of course it doesn't do it when the mechanic drives it. I tried higher octane as he suggested, but no luck. The noise is very faint by the way. So other than that, it runs fine. I seem to have plenty of power, the gas mileage is the same, no other lights come on, and the gauges haven't moved either. The engine light usually only comes on for a few seconds and goes off when I slow down. The last time it stayed on for a few minutes even when I did slow down to 60. (It likes to go 76!) I've got just under 78,000 miles on it and it had a full tune-up just a few months ago.

Thanks again,

:-)

Sue

 

Sue , Mass Air Flow Sensor contamination is a very common problem with the Explorer engines & will cause the pinging / rattling noise . It may be the MAF Sensor is the problem . Have a mechanic that knows Ford engines have a look . Tell him about the pinging & the check engine light . The wires inside the MAF can be cleaned if they have accumulated dirt etc . The dirt keeps the MAF from delivery the proper signal to the vehicles computer , The Ecu senses a lower volume of air entering the engine & thus reduces the fuel / air mixture to the point where the engine pings .

 

I had an almost constant Check Engine light when my Mass Air Flow sensor was problematic. Cleaning did not work, had to break down and get another one.

A dirty air filter can also cause a check engine light.

The EGR Sensor is another common culprit.

The EGR valve too.

Oxygen sensors in the exhaust areas (have not worked with those though).

Basically anything having to do with air/fuel mixture and emmissions.

 

Most Auto Zones have a loan-a-tool program. They have the tester, you may have to pay a deposit but will get it back when you return the tester. it also comes with a book to tell you where to hook it up and how to read the codes.

 

You say you have engine ping, well, I have the same problem with my 92 4.o litre. I have done it once, and now once again. The intake lower intake manifold bolts become loose and this allows a vacuum leak into one of the cylinders. From what i have read on the internet, people are saying that it is cylinder No. 5 that leaks. This would be the centre cylinder on the drivers side of the engine. I think that they have the cylinder numbering confused and it is actually cylinder No. 3. The aft cylinder on the passenger side that leaks. I am rebuilding a 4.0 litre for my 92 as we speak and No. 3 cylinder is the one that was definately leaking. It was the only cylinder with lots and lots of carbon and oil soakage. Before you do anything I would tighten your Intake. It is tough to get to, but it worked for me and i am sure that this will more than likely cure your ping problem as well. I am not ruling out the Mass Air sensor though. Clean that while you are at it.

 

Hi everyone,
I've had a heck of a time getting thru here.
Anyway, here's an update...

A few days ago, I went for a drive up in hills not far from my house, and the engine light came on, and STAYED on. Not only that, the temp gauge was all the way below cold.

I've been calling around, and everyone wants almost $200 to diagnose my car. I found one guy that works on Fords, ($180) and he thinks it could be the catalytic converter, if not the O2 sensor. He also told me that the engine light has to be on for them to figure out what's wrong. If that's true, I may never figure this out. Someone else said there's a "log" in the car's computer that tells when the light came on. Is this true?

I took it to my old mechanic a few days ago, because he said he'd only charge me $40 to check it out. He tried all day to get the damn light to come on, but of course it wouldn't. He ran te codes and found nothing. He said he checked the sensors and they seemed ok. (he said the same thing about my brakes once...and they WEREN'T ok). As far as the temp gauge goes, he thinks it's just a bad gauge. He's a nice guy and his prices are right, (He didn't charge me since he couldn't figure it out) but he doesn't seem to know what the hell he's doing. That's why I don't go to him anymore.

I don't know what to do here guys. I can't see paying $180-$200 to find out I just need a $20 part! That's ridiculous. You guys say it should only take 5 minutes, then why do these people want to charge me so much??? I'd do it myself as someone here suggested, but I don't know what the hell I'm doing either. Here's a brief recap: The car runs fine, I drive it to and from work everyday (45 min. RT)...but as soon as I go over 65-70 mph, or take it uphill, engine light comes on, temp gauge below cold.



Sue

 

Sue , Id like to have your Explorer in my shop simply because what you post seems to be more of an electrical problem than anything . Your Explorer has whats called a Continuous Memory within the engines computer , If the check engine light is on or has been on , it will store the code . Sue , Let me ask you this , have you had any other electical problems ? It doesnt matter how unrelated you think it is , let us know if you have . Are you sure that when the check engine light comes on that the temp gauge goes to cold , Is it simutanuous ? When was the last time the coolant was replaced or the cooling system serviced ? Im kind of leaning toward maybe a engine, Ecm , vehicle ground problem because the Ecm should retain any codes stored in the Continuous Memory except if for some reason the Ecm is losing its power , Once that happens anyone checking the Ecm for codes will come up with nothing . Also , How old is the battery ?

 

Hi,

I've never had any electrical problems that I'm aware of, and the battery is about 2 years old. As far as the cooling system goes, my records show it was flushed about a year ago and "checked" a couple times since. How often should that be done anyway?

Here's the thing about the temp gauge. When I first get in the car, the needle is on "C". As soon as I turn the key on w/o even starting it up, it drops all the way to the left, below C, and stays there, no matter how long I'm driving. I honestly don't know how long this has been going on. I only noticed it the other day when the engine light came on while I was driving around in the hills for half an hour. Normally the needle should always be on or slightly above cold, right?

So what now?

Sue

 

The gauge is working fine to the point where it doesnt indicate the engine is getting any warmer , Yes , Once the thermostat opens the temp gauge should remain fairly constant while you are driving . Coolant flush & replacement every 30K miles is fine . I assume the heater is working correctly ? You have lots of heat , right ?

 

>The gauge is working fine to the point where it doesnt
>indicate the engine is getting any warmer , Yes , Once the
>thermostat opens the temp gauge should remain fairly
>constant while you are driving .

So are you saying there's nothing wrong with it? I seem to remember the needle was usually on, or a tad above C, within the "normal" range on the gauge. Now the needle is all the way to the left, below normal, to where it can't go anymore. And why would the needle be on C and then drop when I start the car?

My heater works fine, by the way.

 

Sue , Sorry , I should have been more clear . When the engine is cold & you start the engine the temp gauge needle should swing to the cold position . My theory was you had a faulty thermostat , But since you say you have sufficient heat that rules that out . Ive reread all of what you have posted & I still think you have some electrical problem thats causing all of the problems . I wish I could narrow this down for you , But making a guess isnt going to solve much . This needs a hands on touch . Unless someone else has a definitive answer or knows where to procede with this , I suggest you find a competent Ford Mechanic that isnt going to charge you crazy labor rates to diagnose the problem .

 

Sue,

After reading your posting on 'check engine light' it sounded like you were describing my truck! The only difference is that my battery indicator gauge intermittently loses power and becomes non-functional. I also don't know when this started, however I am pretty sure it is unrelated to the check engine light.

Regarding the check engine light, at least the '94 fords are consistent?!? My truck seems to behave exactly as you described the issue with your truck. I am interested to know if you were able to get it fixed and if so what was the outcome? I have scheduled a service for my truck early next week (Mar 12th) to have this looked at and I hoping to hear some positive news from you on your plight. If you have not had any luck to date I would be happy to share my outcome with you next week.

Thanks and I hope to hear back from you.

Richard