MFI, points question

[47silver]

hi:
i do not have mfi but i had problems about 2 years ago...my points were ok but the black wire on the points was rubbing on the distributor cam and shorting out (just occassionally and especially when wet). After i found this out,,,took longer than it should have, i installed a pertonix breakerless point setup that i bought from pelican and it works great....some have had problems but i have not had any...

gary

[mjshira]

thanks. I want to get one of those but I dont know what specific type of distributer I have. Is there an easy way to ID it?

[mjshira]

BTW what should I gap the new plugs at?

[Shuie]

Grady is the man on the MFI stuff. Milt is real good also. Both of them have helped me a lot troubleshooting my MFI

Im using the BPR8ES or BP8ES plugs in my car now and they have been great. Ive used the 6ES plugs before and wound up with detonation issues in the summer heat down here so I think they are a little too hot. I think the gap is around ~3mm, but I just make sure they are all consistent out of the box.

FWIW, ditching the points on my car and going to a Crane optical trigger was one of the better upgrades Ive done so far.

[mjshira]

sherman, what was the specific crane part number? did you ditch the CD box with that upgrade?

[Shuie]

I bought the two bottom parts and kept the Bosch 3 pin CD box.

Dumb simple install

Black wire -> ground
White wire -> black/purple wire that used to connect to the points
Red wire -> switched 12V from the bottom fuse on the fuse panel

[mjshira]

thanks Shuie, I really appreciate it.

[mjshira]

OK. This morning, the sun is out and so I went out to the car. I pulled the black wire at the side of the distributer, attached a jumper wire, pulled the center plug wire from the rotor and placed it near where it could go to ground. I then turned the key into the start position and put the jumper to ground. NO SPARK!

So, what should I do fellas?

[Shuie]

Is your CD box smoked? Does it whine with the ignition on? Ive got a good spare 3 pin Bosch box if you need one.

[Early_S_Man]

James,

To test the CDI unit and coil for good spark ...

1. Use a new spark plug with the body of the spark plug either laying on a good ground location or securely attached to a grounded clip ... attached to a known good spark plug lead inserted directly into the coil output terminal.

2. With the ignition switch on and CDI whining/whistling ... take the black wire from the side of the distributor and use it like a telegraph key ... repeatedly making and breaking contact with any nearby clean, bare ground locaction. You should see and hear a spark at the test spark plug each time the distributor lead is ungrounded.

For more information about the theory of operation of the CDI unit and how to test it ... see the Bosch test document posted in the following thread. It takes a long time to load all of the graphics, and hit the refresh button if any 'empty square' markers show up ... all of the links are good, but just slow loading at times, and Internet Explorer will sometimes time out before all are loaded!

Perma-tune CD or Bosch CD?

[mjshira]

thanks Warren and Sherman. The CD box is working. It makes that humming noise. I don't have a spark. I did the test and no spark. I pulled the rotor and cap and bumped the car over by turning the engine over. I can't see that the points ever make a gap between that little block and the cam in the distributer. I wanna be sure that its not my eyes lying to me so I am going to find a match or piece of paper to make sure but at this point I think the points are not opening.

[mjshira]

I have proper point gap. still no spark... I am at a loss here fellas. Any advice out there? I really need my wheels back.

[mjshira]

thanks Shuie, it seems to be working and Tyson sent me on my way from LA with a spare. I guess it has to be the coil. But its brand new??

[jpnovak]

ARe you sure there is no break in the blak wire to the CD? have you tried cleaning the 3pin connector at the CD unit?

[mjshira]

I dont think there is a break. I checked all connections and tighten/cleaned as appropriate. There doesnt seem to be any power to the coil (I know this is different than a normal system) SHould the green wire on the positive side of the coil be "hot"? I checked the ground behind the fuel filter, checked the wire from the CD unit to the coil for connectivity. I have used two different CD units to make sure that is not the issue. When I turn the car over it just cranks and cranks. I have checked and the fuel pump is working and fuel is reaching the engine.

[jpnovak]

There should only be power to the coil when the CDI sends a signal to collapse the field. You can test the coil. Remove the connections and measure resistance across the terminals. Here is an excerpt from Warren's coil tests.

>>>
The definitive test result for a bad coil is finding a secondary resistance lower than the limits ... meaning that part of the secondary winding is shorted out! Also, leaking oil is a sign that shorting out, even intermittent, had occured and resulting overheating caused the oil leak!

Coils for CDI-systems can be marked three ways:

Ealiest -- black finish
1 - 15 is primary ... 0.4 - 0.6 Ohms, 1 is ground, 15 is +
1 - 4 is secondary ... 650 - 790 Ohms

Mid years -- Bosch 0.221.121.001 ...

German-made are black; late Brazilian-made Bosch have a natural-finish aluminum case. Universal replacement for all CDI, including Turbo.

1 - A is primary ... 0.4 - 0.6 Ohms, 1 is ground ... marked '-', A is + ... not marked, though
1 - 4 is secondary ... 650 - 790 Ohms

Late -- Bosch 0.221.121.006 ... black finish
A - B is primary ... 0.4 - 0.6 Ohms, B is ground, A is +
B - 4 is secondary ... 650 - 790 Ohms
A & B terminals close together ... about 1" ... neither is polarity marked
<<<

You will need to determine which coil you have and measure the proper resistance measurements.

Things to check: continuity (zero resistance) between the coil + side and the output from the CDI. Good ground from coil to fan housing.

I can't imagine that both CD units are bad. Usually they are pretty reliable. I must admit that I had a 6pin CDI that had no output even with an electrical whine.

Don't worry, we will find the problem.

[mjshira]

thanks for that info Jamie. I will check all that. At this point, with each day costing me no car, I am going to order a coil (spare if the one I have turns out ok) and breakerless points. With those installed and verification once again that the CD unit is plugged in correctly, etc. I can't imagine why it wont run. Problem for me is that I am a novice and I dont know anyone around here who I can get some help from. Thanks to you fine people I'll have a fighting chance!

James

[mjshira]

anyone have any opinion on one of those CD/COIL combined boxes?

[RoninLB]

Originally posted by mjshira
anyone have any opinion on one of those CD/COIL combined boxes?

it would one less back-up part I'd have to keep around. I'd be very serious about the installed cooling ventlation and wiring.

[mjshira]

Hey Ron, What do you mean about the wiring? Are you in favor of this option?