Annoying Problem with Accel 300+ Ignition Box - Third Generation F-Body Message Boards

S!MON · 08-01-2009, 07:30 PM

Hello everybody,

my lovely 350 got a new Accel 300+ ignition box with coil at the last swap.
At the beginning everything went fine but when I drove home the first time it happened:

I was driving on the Autobahn (I'm living in Germany) and accelerated hard to 120mph or a little bit more...everything ok...then I removed my foot from the gas and let it deaccelerate by its own...then it happened, engine failed and I saw some glowing parts falling from my back

.

I drove to the right and thougt: Ok, that's it...if I now look under my car I will find fire, parts and tons of oil, but...everything was fine *puh*
So I started to search under the hood..Holley sprays fuel but no ignition spark.

Finally I found out it was the 10A fuse on the ignition box that was blown!

Found another 10A fuse in the fuse block (from the radio), started the car and drove home for the next 100mls.
I never had the problem in our test, adjustment and cruising drives before!

I've bought some fuses to be on the safe side and had some 100mls since then on it witout any problems...until yesterday!

I've changed the primary power valve and jets on my Holley and made a test drive with some hard accelerations without any problems. After that I took some time to set the 4-corner idle and made a test drive after that...the same problem occurs...no ignition spark after an medium accelerating phase...changed the fuse...started again...accelerated (another car came up behind me) and blown the fuse again. Replaced it and never accelerated over 2000rpm and came home.

So what is the problem here? I have absolutely no clue and I'm pretty much frustrated as I can't accelerate with confidence at the moment.

I have two more eletrical issues but I'm not sure if they count here:

-some problems with my windshield wipers. If I turn them on on interval or the first speed they won't work at all or will start after a few minutes if they like to. The highest speed normally works.

-I have a Summit Electric Fan Switch which won't work right. After the installation the 10A fuse box switched from on and off all the time. I decided to bridge the fuse...worked out fine for a while. But then one time the fan won't stop running so it seems that the switch now is dead. I have now installed a manual switch for the fan which is not really comfortable. So I've orderes a new switch and a new fuse box with 20A or 30A.

So do you think that could have a connection to the ignition box...I'm not that sure!
I can temporaily live with the two small problems but I have to solve the 300+ fuse issue or I have to remove the box. In the past I never had such a problem with that engine.

So does anybody have an idea...or could maybe describe why the fuse from the ignition box can blow?
Greetings and many thanks in advance.

Simon

P.S. I think the glowing parts from the beginning were some catalytic converter parts as there was maybe too much unburned fuel in the hot cats...I have no other theory.

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S!MON · 08-03-2009, 02:05 AM

Do you think it is more a General Engine topic? I would move it then to another section.
Greetings,

Simon

V10Mike · 10-17-2009, 11:24 AM

I'm sorry this reply is a little late, but I picked up your problem on a google search as I am having exactly the same symptoms. I believe I have found the cause. My 300+ box was mounted with the access plate for the rev limiter facing upwards. I found that water had entered the box through the cable grommet, and when I accelerated the puddle moved backwards and shorted the power transistor to its heatsink, blowing the fuse. The potting compound does not completely cover the edge of the transistor, and you can see where it has been shorting. I dried it out and used some silicone RTV to repair the insulation. All now seems OK.

I suggest you take the end plate off and check for water -please let me know if you have the same problem as me.

S!MON · 10-30-2009, 12:41 PM

Hi Mike,

I've solved it the other way. First of all I've separated the cables from the coil and the distributor, so now each of them are in a seperate wiring harness now. I've read in an offraod forum from a similar problem where they described it:

______________________________________________________

More than likely, what you are hearing isn't the module it's self (although it might be)...
What you are probably hearing is the INDUCTION noise being made by the modules' wires running too close to radio/antenna wiring.

And with INDUCTION, the radio doesn't even have to be turned on to make noise from the speakers...
You should probably disconnect the speaker(s) and see if you can still hear the noise when the engine is running...

Accel usually makes pretty cheap crap, so I'm sure it's leaking like crazy!

If it's the module (proper) making the noise,
the ONLY way a CDI module can make a buzzing noise is for there to be false fires from induction problems.

That means you are running the distributor trigger wires along with the coil feed wires, and probably the module's heavy wires to supply current to the module.

For every 'Fire' signal produce at the distributor,
(or by electromagnetic induction in the trigger wires)
The module will fire the coil 5 or 6 times.

Each one of those coil discharges will create another trigger signal, so for every single PROPER trigger signal,
You module is getting 5 more trigger signals from induction,
And each of those is creating 5 more trigger signals...

And pretty soon, your module can't keep up, and you will then hear the capacitors trying to charge/discharge without enough time...
That will make a 'Buzzing' sound in the module box...
Shortly before the module fails.
-----------------------------------------------

NOW!
What you SHOULD do, and what you WILL DO are probably two different things...

You *SHOULD* separate the distributor trigger wires from the rest of the batch,
And SHIELD THEM from the EM 'Noise' that can case false fires...

______________________________________

Made sense for me and after sepearating the cables it ran fine. A few days later I also realized that my alternator was gone. So if there could've been variations in current, that could also come into play.
So, after doing the cables and replacing the alternator I can again rev to over 6000rpm and everything is fine.
Greetings,

Simon