1993 Ignition Problems

I am having a problem with Standard 351 PCM engine. When engine is run under load for 10-15 minutes, it starts to miss. I have replaced the Carb for another problem and it starts, runs, accelerates, idles, etc as it should. After running under load (cruising @2200 RPM) it starts to miss, and last time out finally dropped down to 1000RPM@ WOT. Just before last outing, I did research here and decided it was probably coil. The resistor had been by-passed by a previous owner, so I replaced it with an standard Ford oil filled, internal resistor coil. I am not sure what Distributor I have. I think it is a points Prestolite which has been converted to EI. Please look at pictures and see if that is correct. It has 2 wires to Distributor. 1 to 12 volts and the other to the - side of the coil. I also fabbed up a bracket to stand coil up. I have read a lot (probably not all) of the previous posts having to do with Coils and Distributors, but most do not fail only when hot. The coil was extremely hot after the last run. The engine operating temp is about 145°-155°. Would this be a characteristic of a failing ignition module in the Distributor.
Any suggestions are appreciated.

Correction- thats a Prestolite dizzy with a PCM (Prestolite) EI kit installed.

Also check your pick up to trigger gap on the EI.

Is it .100?? It's been a while. You could confirm that with a google search. Those ever-so-helpful MasterCraft forums might also have the answer.

I have a Prestolite kit in my boat as well but a MSD Blaster coil. I know the ballast resistor is still in play but not sure if its only online for the coil and bypassed for the distributor or is still serving both. I want to say both. I have been meaning to take a closer look at it and measure the resistances, will hopefully get to it over the weekend and report back.

You can't expect to bypass your stock coil with any of these kits and not expect it to fail.

I think that the person who installed the conversion on my engine did as you suggested, but he fed the distributor off the coil, therefore he put 12 volts on a coil clearly marked for an external resistor. I think that is what burned up my original coil. That is why I replaced it with an internal resistor coil.

Sorry to Jump in mid thread, but this seems to be dancing around an issue I have with the same setup. Let me know if it is best to start a new discussion but if all the right people are here...

My 99 Sport (351 HO) has the same prestolite dist w/ mag pickup and non-ballasted coil. The boat runs fine, but the whole circuit (incl. panel power, alternaor exciter, coil, dist) are stuck at ~9V. The battery is pushing a solid 12V everwhere else. My biggest concern is insufficient exiter wire voltage to the alternator.

I disconnected each wire in the circuit till it went from ~9V to the proper 12V. The offending part is the mag pickup in the dist. Further, I left the mag pickup wired and pulled it less than a inch up from the dist and whamo - 12V on the circuit. Then I grounded to the block and the 12V held. It seems its only when the mag pickup is in place does the voltage reduce from 12V to 9V.

Questions: Will my alternator work with only 9V exiter supply? how is the mag pick-up draining 3V when in posision, and why not when grounded elswhere.

Thanks in Advance

While trying to set gap for the pickup in the dizzy, I found that the dizzy had .006 side to side play in the shaft. After finding that and talking to Vince at skidim.com, I decided to replace dizzy, coil and resistor. Just ran boat for 30 minutes at 2500 rpm and I was able to hold my hand on the coil. Last time out, I got a blister from touching coil. Before I changed dizzy, timing was retarded from the shaft play. After replacing dizzy and setting timing, the boat has much better power. Out of the hole is probably 2 times faster. After a new carb and all new ignition, it runs better than it has since I have owned it.
Thanks for all the input and advice. I especially appreciate Vince at skidim.com. He tried to help me with the most cost effective solution, but when I decided to replace everything , he worked his magic to get it shipped late Wednesday so I could have it today.

It is very important. Follow the directions exactly.

Check your instructions carefully--they should clarify if they are diagrammed for an externally resisted coil (ballast resistor) or for an internally resisted coil. And then confirm which type of coil you have.

Externally resisted coils can also have a loom resistance wire instead of a ballast resistor. My Mercruiser had one of those and it got old and caused all kinds of grief, so I bypassed it and added a ballast resistor. Chris, did PCM ever use a resistance wire in the harness instead of a ballast resistor?

There was an old resister bolted to the coil but not in use.
I have now put a new coil in. It is a Bosch Blue part number 0 221 119 027. Doesn't say on it about a resister

From Hot-spark.com
Compatible Coils

The HotSpark® HS17HEC high-energy coil (epoxy-filled) has 1.7 Ω primary resistance and 10K Ω secondary resistance.

The HotSpark® HS34HEC high-energy coil (epoxy-filled) has 3.4 Ω primary resistance and 10K Ω secondary resistance.

The following 12-volt replacement Bosch® coils should be compatible with the Hot-Spark electronic ignition module:

00 015
0 221 119 021 (Bosch Black coil)
0 221 119 020 (Bosch Black coil) (VW 022 905 115C)
0 221 119 027 (Bosch Blue coil) (VW 043 905 115C)
9 220 081 039 (Brazil)
9 220 081 054 (Brazil)
9 220 081 083 (00 012) (Bosch Blue coil)

The Bosch coils above should have a primary winding with 3.0 to 3.3 Ω resistance. Bosch coils are made in a number of countries, with varying amounts of primary and secondary resistance. It's best to check the coil's primary resistance with an Ohmmeter (a digital multi meter in the 200 Ω mode). Install a 1.4 Ω or so external ballast resistor (HS14BR) between the ignition switch (+12-Volt power source) and the coil's + terminal, if the coil's primary resistance is questionable or borderline.

Bosch 0 221 119 030 (Bosch Red Coil, Brazil) 1.6 Ω to 1.8 Ω primary resistance (OK for 6- or 8-cylinder ignition kits, not enough primary resistance for 4-cylinder ignition kits).


And from http://advanceddistributors.mybisi.com/product/bosch-blue-coil

This Bosch Blue Coil has been one of the leading coils on the market for over 20 years! Its an Epoxy filled coil, which means a very stable construction. Oil filled coils have a greater rate of expansion and contraction, allowing the windings to break over time, leaving you stranded. I've NEVER heard of a single Bosch Blue Coil failure, and in my book, that makes it worth every penny!

This coil has 3.4 Ohms of internal ballast resistance. That means its safe to use on most all 4 and 6 cylinder cars running points or electronic ignition systems (including Pertronix and the Crane XR-700.) Always check the instructions that come with your aftermarket ignition, or just call and ask!

I have been messing around this week and the coil is getting hot electrically rather than from engine heat. The 'new' bosch gets to 77 deg C (170 F) after about 35 minutes and then starts to misbehave.
When the ignition is off the voltage to the coil is battery voltage. With engine running the alternator at idle is giving about 13.5-14v as expected, but the voltage across the coil varies between 9 and 18v.

Any ideas what causes this?

must_dash wrote: ... When the ignition is off the voltage to the coil is battery voltage. ...

Do you mean when the engine is not running, but the ignition is ON?

If you're seeing voltage at the coil with the ignition OFF, then something is wired funny.

must_dash wrote: The voltage is with the ignition on and measured across the terminals of a ballasted resistor.

Wait, you're grounding your black meter wire to the block when you take your measurement, right?

This thread talks about a module replacement for the setup you have:
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=31242

Of course, I doubt anyone can argue with your DUI idea.

Bri892001 wrote: This thread talks about a module replacement for the setup you have: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=31242 Of course, I doubt anyone can argue with your DUI idea.

Looks like a duff link, do you know the thread title, I get a page not available.

Tom

Thanks.

Are there any other distributors worth considering other than the performance distributors DUI?

If I'm spending the money, whats the best way to go...