Running Symptoms of a bad DIS?

Tim Groth

SCCoA Member
Alright when I purchased my '94 the tach has been dead or sometimes doing it's own thing...I replaced the Cam Sensor with a known good one and still the same deal, so pretty darn sure it's the DIS.

Now my car also has a slight miss, which for good measure, even though the motor only has 40K on it I will be replacing the Plugs and Wires. Is this something that could also be associated with a bad DIS Module?

Car starts hard too however I'm pretty darn sure that is the DIS Module without a doubt.

Anyways a list of the "Common Problems" associated with a DIS Module failure would be great.

-Tim
 
Can you rev fully in neutral? Mine backfired and missed real hard when at idle when the crankshaft position sensor's conenctor was loose and got water in it...part throttle no problem, anything past 70% throttle POW!

When the wires were bad, it just kind of missed at WOT, nothing near what the CPS caused [note: BUCK].

If it's bucking, try testing out the DIS at Advanced Auto, check fuel pressure as well.

If it's missing, try new wires/plugs [good ones, not cheapos], try gapping plugs to 48.
 
When my DIS failed, it was basically fine until it warmed up, then it would start to run badly - idle was up and down, and progressively worse. Tach would cut out randomly. Then the car would sometimes just die and not restart. One time, it wouldn't restart for maybe twenty minutes, then it ran fine all the way home. I had codes indicating a failure in one of the coil pack circuits, but they were false codes caused by the failing DIS.
 
When my DIS failed, it was basically fine until it warmed up, then it would start to run badly - idle was up and down, and progressively worse. Tach would cut out randomly. Then the car would sometimes just die and not restart. One time, it wouldn't restart for maybe twenty minutes, then it ran fine all the way home. I had codes indicating a failure in one of the coil pack circuits, but they were false codes caused by the failing DIS.

Good to know. I have a random check engine light and a miss, which at this point I'm darn certain is the DIS. Can't seem to find a DIS in the yards any time I go.. I also have the random hard starts and then Lazy Tach.

Thanks again.

-Tim
 
I think im having a similar issue as you, my tach will just randomly go to zero and the car will studder for a second then go back to what it was doing. Same with the occasional rough start. If you think yours is the DIS i might as well have the one in mine checked as well as the spare one the car came with.

J
 
well once again i will chime in with a question.....mine runs fine starts fine idles fine no misses....BUT the tach is always dead until it would be around 2500 3000RPM's it goes to idk 2500RPM's and isnt accurate but if you punch it it goes to redline and buries....hmmmm just overall goofy i dont know what else to do i changed the CMP and the DIS still nothing.....any help please!!! and the fuel gauge is STILL pegged at full never moves
 
I think im having a similar issue as you, my tach will just randomly go to zero and the car will studder for a second then go back to what it was doing. Same with the occasional rough start. If you think yours is the DIS i might as well have the one in mine checked as well as the spare one the car came with.

J

What year SC do you have - I have a good working 89-93 DIS Module I need to move if you're interested. I wish my 94 had the same!

Guess i'll buy a DIS and see what happens.

-Tim
 
How is the best way to test a DIS? I hear you can do it at autozone or advanced or whatever, but can you just take it in? (I took mine off my car) is there a way to test it off the car at home with a multimeter (by putting a certain voltage on certain pins)? My dad is an electrical engineer, so I have access to a great any things...
 
I'm not exactly sure, but I think there is a series of tests that they run at the places you mentioned. Like applying various loads, etc. I don't know if you can replicate it at home.
 
Just to update here:

Just received my new/used DIS module from ebay - it was a tested good part prior to install. I have nothing improved tach still does it's own thing when it wants.

Next thing I'm going to do now that the car has had both the cam sensor and DIS module replaced is the Tach.

Also this car had a new motor swapped at one point. Is there any sort of ground or lead that could cause this if not hooked back up?

Thanks again for the help!

-Tim
 
under the Air box there is a little ground strap connected to the frame, try taking off that and cleaning it and the frame.....Mine was acting the same way, it would be dead then peg and just go nuts......If that doesnt help or intermittently helps trace the rest of the strap down and clean the other end and in theory if the tach is good it will work....keep me and us posted i can get you a pic of it if you would like :D
 
check it out

Napa will test your DIS, make sure you put (heat sink compound Radio shack) under the DIS when you put it back on new or old. My car did the same thing it was the cam sensor cheaper than the DIS $40.:rolleyes: spider:cool:
 
Last edited:
Well the hunt is over - replaced the Tach with a good spare and there you go! Hahaha :D

I guess atleast I have a spare Cam Sensor and DIS Module - can never have enough extra SC parts laying around.

-Tim
 
Ha ha thats true tim can never have enough spares.

Just recapping on your fixd issue, it would drive fine but then the tach would plumit to nothing and stutter like it was going to stall correct?

J
 
Back
Top