Dis

scbird1

Registered User
Has anyone had one go bad and what were the symptoms?
My 94 seems to have this funny little miss now and them like someone is turnning off the key . I say this because the tack just drops to -o- and back to what ever the rpms were for a split second. It only dose this about 2 to 3 times while im driving for about a hour. no lights on dash come on. no codes. Now I think I know what DIS stands for {dam it sucks} whan they go bad.
Intermitant problems are the worst. Car has new everything but DIS and crank sensor. anyone?
 
If your tach is dropping to zero, then it's probally the crank sensor. That is a classic symptom of it. A bad DIS will cuase it to run rough, and not idle very well at all. You will know for sure if the DIS fails.

Thomas
 
That's how my crank sensor started out, split second power loss. After while it will leave you stranded.

Aaron
 
I would inspect the area of the crank sensor carefully. It is mounted just above and behind the crankshaft pulley.

With the engine running you should look at the crank pulley and make sure it is running in a smooth plane and not wobbling.

Then inspect that the large bolt that retains the harmonic balancer (that the crank pulley is attached to) is still tight.

Then check the harness for the crank sensor and take it apart, blow it out with air to clean it, and reinstall with a dielectric grease to seal the contacts. See if the problem goes away.

If not, you'll need to replace the sensor.

The crank sensor is a key sensor used by the ECM to determine crankshaft position. Without this signal the ECM can not operate the engine. Thus if the signal stops, for even a moment, the engine will effectively shut down.

It only starts back up because the signal comes back, the ECM is powered and the stored energy from the spinning flywheel starts it back up. If you were sitting still at a light, you might have to restart it manually.
 
I second what is said above...I was told the other day that my DIS module was bad, but sure enough it was my harmonic balancer still in place but cracked in two!
 
Who told you your DIS module was bad Merc?
Your mechanic?:confused:
Surely you didnt have to keep a part that he told you that you needed but turns out you didnt?:confused:
 
MIKE 38sc said:
Who told you your DIS module was bad Merc?
Your mechanic?:confused:
Surely you didnt have to keep a part that he told you that you needed but turns out you didnt?:confused:

Yes the mechanic told me the module was bad, and NOW I have no intention of paying for the HB because he didnt listen to me about checking the HB to begin with!
The car broke down on me at 3am and I didnt have enough light at the time to feel around for bolts, so I had it towed to the shop and phoned them in the morning and informed them what to check for.
They said they wanted to run codes first, so I wouldn't have to blow money on parts I didnt need...HA
Afterwords, they said they couldn't get any spark and it was just the DIS gone.
After going out and hunting over the entire city, cause the shop couldnt find the right one, I managed to find a used DIS that I picked up with my own time and money...and then finding out it wasnt the problem!

I'm very pissed right now cause the mechanic I informed about the HB didnt pass on the info I gave him to the mechanic that actauly worked on my car.

I'm a student on a tight budget right now, and I'm thinking about getting my car towed home to do the job myself...like I should have done to begine with!!!
 
Ok heres the update. It dose it more when the temp outside is hotter than cooler. Keep in mind that this is a 94 with a updated crank sensor. No wobble or loose bolt. Car has 80k on the clock.
Do the 94 crank sensors go bad like the early versions did?
I would still like to here from the guys who had the dis go bad.
 
Late model sensors don't fail at a rate any greater or less than a early model sensor.

If you can have the car duplicate the problem in the driveway you should be able to test for the device failing.

But I would start with an inspection of the wiring. The crank sensor is hard to get at but you should check the connector. It's location makes it prone to collecting junk from coolant and oil and sc fluid leaks.
 
Your right on mike but this thing is very intermitant. I took it for a ride tonight and it was perfect, did not miss at all. This car has been disasembled and cleaned to the point of you could eat off of any part. I took the plug off of both ends and both were clean. I used the dialetic grease on the fittings and reconnected it . I also changed out the coil pack with my 91 which has a new coil a f5 # on it so we will see if that makes a diffference. I would still like to change the crank sensor. Should I buy a new or used one and what might be the price for one of these bad boys new or used?
 
Bad Idle

I had a problem where my t-bird would run fine and then start running rough. My mechanic ended up changing the crank sensor that had a slice cut into it by the balancer. This caused the DIS module to go bad and after having it replaced everything is fine.
 
After changing the crank sensor I still have this once in a while miss. Well next I will try the cam sensor. Its about 2 years old but I dont know what to do next as it has no stored codes and passes the koeo and koeo tests with a 111. after that the DIS or the plugs and tuneup crap are next but they are less than a year old but I will go over everything again. Still looking for anyone who has had the same problem. Thanks Mark J.
 
A few people have had that problem and not all have reported back. User Randy&Connie had a miss that was driving him insane. Someone helped him resolve it but I don't recall the fix.

One other user had such an issue and found it was a spark plug wire loose.

If you can find it missing sometimes in the driveway i'd throw a timing light on each plug wire trying to nail down what cylinder it is.
 
The only problem is it dose this once maybe every 2 hrs of driving. The strange part is when its hot out it dose it more and thats why I was looking at the DIS I guess I will just replace till I find the right part. Thanks
 
Drive it for two hours and then stop. If it's doing it, run under the hood and try.

you can certainly start swapping parts, but wouldn't it suck to find out it's the wires after $300 in parts have been swapped out?

Just keep thinking logically when working on it and don't forget to look into the simple things.
 
The wires are the new ford motor sport blue and had no problems
when I installed them last year. Only a few original parts still remain on this car anyway. I always use dialetic grease on all my connections to so I am still miffed.
 
That doesn't mean a wire can't rub up against something hot, or sharp. It also doesn't mean that you don't have a problem in one cylinder that could have damaged a spark plug.

Being simply at a miss that occurs only after driving a while, you haven't really eliminated anything other than it's not the bulb in the left rear turn signal causing the miss.

Thus the start with simple stuff. Like inspect the plug wires. Using a timing light you can verify that the spark signal is leaving the coil pack for the spark plug. If you don't get a spark signal from the coil pack.. well then we know it's not the wire or the spark plug. It's somewhere else. You have to pick these things apart one step at a time until you work your way towards the problem.
 
Oh no not the plugs again? I dont know if I have knuckes to do this again but I will check every thing like you say. These cars require a lot of TLC when It comes to Ignition systems. Thanks mike for keeping me on top of it. I feel like I live on top of my engine anyway. Mark J.
 
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