Have a DUI dist and keep burning up control module truck starts and runs for about 30 min then shuts down/put in a fresh module and runs great for about 30 min...need some help, any ideas out there,thanks papajoe49
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Have a DUI dist and keep burning up control module truck starts and runs for about 30 min then shuts down/put in a fresh module and runs great for about 30 min...need some help, any ideas out there,thanks papajoe49
Welcome to CHR - Can you give us a bit more information? What engine is this? What brand distributor? What coil? Are you running a ballast resistor? My first thought would be that you're drawing too much current - this the question about a ballast resistor.
Best,
Glenn
Hello PapaJoe49, nice to see you here. Along with Glenn's questions. I'd ask if you have checked the ground circuits? Are they clean and tight? Is there a ground wire between the battery / frame / body / engine? What does the vehicle use for a regulator? is it grounded?
I know we're asking a bunch of questions.. but this is where we need to start. Do the basics first, then build upon them.
Have DUI dist am not using a ballast resistor when running at idle I have 12.35 volts at dist. Have engine to frame ground,cab to frame ground, separate grounf from dist to cab at about 200 deg it starts running rough then quits, next morning it will start up. running a alternator with enternal reg when runiing have 12.35 volts output and the same going to battery. Have put 6 new mods in dist from cheap to acell.
I'm assuming this is an HEI style replacement distributor? Are you using the DUI coil? What engine? GM can run hotter as the air circulation at the rear of the engine is not as good as the Fords up front.
Heat is usually the culprit. The DUI distributor does not recommend a ballast resistor, rather a direct battery lead - which is what you have. Did you put a blob of dielectric grease under the module(s)? Any brand will work and a small tube typically comes with the module. It's critical to use the grease and make sure the module seats tight to the distributor to transfer the heat away from the module.
Your voltage is too low.
Firebird77 beat me to the punch, you do not have enough voltage coming from your alternator to charge your battery. It is possible your regulator is spiking the voltage high at above idle speeds and burning up the module. Check your voltage using a known good quality volt meter (possible your meter is incorrect) at different speeds to determine if this is the problem.
I have a 55amp alternator can anyone tell me how much voltage it should be putting out ? I had it bench tested and they said it was a good alternator. Do I need an alternator with more amps to feed this ignition system? Thanks for the help guys!
Check your regulator you need 14 volts to charge a 12 volt battery.
checked alt output at idle and high rpm have 12.53 volts.. also have 12.53 volts at the dist..I have a delco 55 amp dist...do you think I need to go to a higher output alt...this is a bare bones rod no electrics other than motor and gages and lights...
I believe your alternator size is ok. I think either your regulator is bad or your meter is inaccurate. You need between 13.5 to 14.5 volts to charge the battery. Normally on a 12 volt battery system less than 13 volts usually will not keep the battery charged, more than 15 volts will usually cook the battery.
This minimum charging voltage is 13.8 volts across the battery terminals, or at the output of the alternator. A single lead-acid cell starts to charge at anything over 2.25 volts. Since a 12 volt battery has six cells, any 12 volt lead-acid battery needs at least 13.8 volts to start to charge. Check this web site: Testing battery and charging system
I think you have a bad alternator - pull it out and take it to your local parts store and they can test it on the spot.
Papajoe49, you haven't said what car this is for, but depending on your accessories 55amps may be small, especially if you're running an electric cooling fan or worse, a pair of fans? If it's a bare bones hot rod with just engine, head lights, tail lights and brake lights you're fine, but if you've got fans, audio, seat heat, power anything you could be short. Just saying that it's good to look at your loads, especially if you're replacing the alternator.
Quote:
Originally Posted by papajoe49
You must've missed it Mr. Spears.. he did mention it's "bare bones".. and 55 amps should be fine. Need to get 13.8 to 14.2 volts from the charging system. Alternator? or Regulator? take'em both to NAPA or a local shop for testing.. and I can't say it enough. check them grounds!Quote:
Originally Posted by rspears
:o:o Sorry, I guess I've lost the ability to read & comprehend. :o I totally missed the "bare bones" statement. Pretty obvious I'm not adding value here.....:HMMM:Quote:
Originally Posted by 34_40
No harm / No foul... adding value?? Your participation is value enough!
As the kids used to say, Chill Out! It's all good..
Ditto what 34-40 said rspears, you add more than you miss!
hey guys its papajoe again. Put a new alternator in and have 14.5 volts going to the battery.took it for a run and it ran great ran it for about a half hour volt meter said 14.5 volts. Started it uo tonight and it fired right off. Went for a drive about 15 minutes into it slowly shut down started coughing and quit don't know where to go put a brand new module in yesterday...Take any help I can get. its a 350sb mild cam bare bones..DUI dist. New everything..Cant seem to get a handle on it!!!!!
Joe, in the other thread that you posted on MikeP went through his HEI, and the problem he described sounds exactly like what you're experiencing with yours.Do you have a book on that distributor, so that you're confident pulling it apart and putting it back together? I'd say you're to that point, or else shopping for a replacement distributor for it. Then you can post mortem this one at your leisure, and have it as a shelf spare, or for the next build.Quote:
Originally Posted by MikeP
Do you have a electronic tach connected to the distributor? If so, disconnect the tach wire at the distributor and try it. A bad tach will cause all kinds of trouble with HEI.
You have a situation where the higher degree of spark is IONizing the air inside the dist cap-------was a common (well not too common) problem when the MSD 7 units came out and were run on engines up around 10000rpm. With the air ionized the spark just went all over causing some of what your discussing--------
On a race engine it was easy fix to just drill 8 1/2 inch holes between all the terminals however on a street engine this isn't a very good fix because of everyday street conditions----
Had a similar thing happen on several cars back in the 80's that had HEI. Would run great and then run crappy. I would take the cap and rotor off to look at the module or change the module. All would be great for a while then it repeated. Eventually every car that did this died. On one, I started looking at the rotor....under the contact for the center, there was a tiny hole eroded. There was some faint carbon tracking thru the hole that grounded the rotor to the distributor shaft thru this hole.....it seemed to be heat related to the conductivity... and related to me removing the rotor to change the module....I would destroy the carbon path and it took a drive to re-establish it. I also found that cheap crap rotors were the worst, real Delco rotors (the whitish ones) were the least susceptible to the problem. I talked to a couple of shops who admitted to making quite a profit by changing rotors but charging for a module. Also, look at the cap inside for tracking....it is really faint.
Mike in Tucson
An absolute must is a cap and rotor of high dielectric strength. For those of you who aren't familiar with that term it merely means components that are constructed of material that has a high opposition to current flow. MSD and other quality manufacturers, I assume, are you sort sort of bakelite material for their caps and rotors.
This will explain it much better than I can.
https://en.wikipedia.org/wiki/Bakelite
And I'll keep beating this old problem, make certain you have good grounds, engine to chassis, chassis to body, body to battery, battery to chassis, battery to engine. There is no such thing as too many grounds on a car or truck.
.
Roger that, Tech - I have a #6 directly from the negative post on the battery to a ground bar under the dash where I make all ground connections. This is in addition to a pair of straps between the body and frame, and two from engine to frame. Need to attach to bright shiney metal as well - paint (especially powder coat) is a great insulator.
By the way, ACCEL components are in the "worst" category for dielectric longevity. I am surprised that Accel stuff makes it home from the store before dying.
thanks for the input guys..i have tried all the suggestions, even made a list put a new summit mod in last night and it quit in about 15 min then would not start at all pulled it out and had it tested, it was bad this was mod 6 cant afford to keep throwing mods at it..uhave checked everything you guys have suggested, disconnected the tack today and will see what happens tonight ...again many thanks papajoe
Joe, what type of compound are you using between the module and the mounting surface on the distributor?
Have you contacted DUI products about this?
Have contacted DUI company about moduels...As you would expect they have never had any proplems with their distributors..go figure..
This is right from their site;
Topic 3: Distributor Will Not Fire
If you are experiencing a no spark problem with your new DUI Distributor, the following information will help you check and test the installation, connections and components of the unit so that you can get your engine running and start Driving Under the Influence of more power!1. First and foremost, check the 12 volt wire that you are using for power to the distributor. This wire should be a minimum of 12 gauge and have no resistors in line. Make sure your 12 volt wire is fully connected to the “BAT” terminal, which is the terminal located on the front right of the cap. Also, make sure the three wire harness is fully connected to the three terminals behind the BAT and TACH connections. WARNING: If the hot wire is connected to the “TACH” terminal, damage to the module and/or coil can occur.
2. If all of your connections check out good, then check your battery voltage as you are cranking the engine. Since the DUI is a high performance ignition system it requires more voltage than a standard ignition system. If your battery voltage drops below 10.5 volts, this is not enough power to get the distributor to fire. This condition can be due to a weak or old battery or you are using a hot wire that has a resistor in line. Use a volt meter to test the hot wire while someone else cranks the engine over. If the voltage drops below 10.5, check your battery. To make sure it is not the hot wire, run a temporary jumper wire directly from the positive side of the battery to the distributor. If the distributor fires using the jumper wire, run a new hot wire from your switched 12 volt source to the distributor.
3. A bad ground can keep the distributor from firing as well. The distributor grounds itself to the engine when installed. Make sure your ground to the engine block is secure. If the intake and/or the hold down clamp has been painted, remove any paint from the surface where contact with the distributor is made. To ensure a good ground, a secondary ground wire can be attached to the distributor by connecting a wire anywhere on the housing and running it to the chassis, body or negative side of the battery.
I just went though this..I changed the module 4 times on a speed shop dizzy..had the alt. tested checked ground staps and voltage..still could not figure it out...replaced the dizzy and have had no problems since..soma aftermarket parts are not built for the long hual.. I think it was shorting out on the pickup assembly under the rotor..
Papajoe logged off two minutes after he advised that he'd contacted the MFR about modules (Post #30) almost 14 months ago, before 36 sedan posted his good info, and hasn't been logged on again since. Hopefully he figured out his problem a long time ago ;)