Alright fellow Ford drivers.. this is my truck
1984 f150 w/ 4.9l motor

• 4wd 4 spd tranny
• offy dual plain intake
• holley 390 cfm with vacuum secondaries
• efi exhaust manifolds with two into one pipe straight to crusty (original?) muffler
• MSD 5520 Ignition Module with an MSD blaster Coil

I want to compliment my non feedback carburetor as so many have done before me with duraspark ignition. i purchased a distributor on ebay from a 1980 bronco 4.9l, and was going to take a trip to the junkyard for the module and wiring harness when i stumbled across someone talking about going with the MSD module instead. I cannot for the life of me find that thread, but im not sure if it would even help me with my problem. I purchased the MSD 5520 and the blaster coil and did the conversion over this past holiday weekend and ran into some frustrating issues. I installed the new distributor after pulling the old one without making any type of markings or references as to where the rotor was pointing. that hastiness cost me some time as i found TDC compression and got the rotor pointing in the right direction. I mounted the module on the fender on the passenger side. I pulled the TFI coil and modified the bracket to accept the blaster coil. I then wired it following the diagram for wiring a duraspark set up. When i went to crank it it would turn over but i wasnt getting any spark to the plugs. I tested it with a timing light and could only get spark from the coil wire to the distributor by jumping the magnetic trigger wires. It seemed like when fully assembled i wasnt getting a spark trigger from the magnetic pickup in the bottom of the distributor, so i went to napa and bought a new trigger assembly and swapped it into my ebay distributor only to get the same result. I spent hours and hours checking my plug firing order, ground connections, and overall wiring with no positive results. The truck was parked inside the garage at my shop, and i had promised my boss that i would have it out of there come monday so sunday night i went back up there and tossed the old tfi dizzy in and hooked up the MSD to it and after some tinkering got it sort of running enough to get it home. It ran like total crud the whole way back though. At this point I have a few ideas as to what to do, and have been trying to search and find someone with a similiar issue, but havent had any luck, and so i figured it was time for my first post. Im by no means a mechanic, but i do have about three years of solid experience with my motorcycles and now about a year and a half with my truck. I bought this truck to expand my mechanical horizons, and so some concepts im still trying to grasp completely so bare with me. I wouldnt have thought it would matter but is the issue im having related to the fact that i didnt have a duraspark module in my truck in the first place? I wouldnt think so but the whole issue with no spark trigger just baffles me. how does the msd module work together with the TFI module in my computer controlled distributor? Is it going to benefit me at all to have the MSD box plugged in? Any thoughts would be very well appreciated and thank you for reading my incredibly long opening post. I intend to take pictures of my entire installation in order to help answer questions or paint a better picture for the truck gods. Thanks

 

The colors don't cross over.
Have a look at this diagram, maybe it will help.
I'm looking at the diagram on the top of page 7 of the instruction manual, it looks like the 8860 harness is connected orange to violet and violet to green.

 

That is the diagram I initially followed. The only difference being that I connected the small red wire to a switched 12v source because I didn't have the existing duraspark harness to tie into

 

If you don't have the DSII coil connector, where do you have the small white wire connected?
Or is it capped like the instructions say?
There was no feed for your prior TFI coil?

 

Yeah I capped the white wire. According to the instructions, you use either the white wire or the violet and orange but not both of them.

 

Also I used a msd blaster style coil and got rid of the tfi coil

 

I don't understand why you get a spark when shorting the pickup coil.
The pickup should read 400-900 ohms across orange and violet.
When the reluctor wheel sweeps the pickup it provides a pulse that triggers a transistor in the stock ignition module.

Is the air gap of the new pickup set between .015-.025"?

 

I'll grab a feeler gauge and check that gap, but it seemed to be normal. In the msd instructions it tells ya in order to test that your ignition module and coil are performing correctly to place the coil wire near ground and to short the two magnetic trigger wires. If using the white trigger than you short it to ground.

 

I've never really done the MSD diagnostics, but it seems your coil and module are functioning correctly.
The only thing left is the distributor.
If it is turning with the engine and the gap is correct there is little else to fail.

Sorry that I don't have much experience working with these things.
I have installed a couple and removed a few problematic ones.
But the new installations always worked as they should.

 

It is VERY important to connect the wires in the manner Jim detailed [ask me how I know? ]. If the violet wire is connected to the violet wire and the orange wire to the green wire [backwards], then the timing will be retarded [electronically within the MSD box] by something like 20+ degrees. The engine can be made to run by advancing the timing, but the timing will never be correct. The MSD box gets its trigger signal off what looks like a wave. With the wires swapped, the trigger point will not be correct. This can cause all kinds of problems with ignition timing to the point that the vacuum advance cannot be used [again, ask me how I know?].

This may not be your problem, but I can assure you that the MSD system can work well as a stand alone system [no Duraspark box] when triggered by a Duraspark distributor.

 

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I connected the wires as the diagram called for with the violet to green and orange to violet and I got nothing for a signal. I figured the msd box wouldn't need anything else, but that was something I was just kinda throwing out there since I'm baffled. The only thing I went away from on the diagram was to connect the "small red" wire to a switched 12v (I ran a connector through the firewall to a socket on my fuse box that gets 12v when the key is turned on.) I did this bc I didn't have the duraspark harness to allow me to connect to the duraspark coil plug. Thanks for the replies guys. I feel like it's gotta be something so minor and stupid.

 

Is having the msd box hooked up to the tfi distributor counterproductive? The way that they say to wire it to the tfi system doesn't make it seem like I'm eliminating anything from the computerized advance.

 

You need advance one way or the other.

The DSII dizzy uses vacuum and centrifugal advance.
The TFI dizzy uses the TFI itself and the ECM to achieve the same thing.

All the MSD box does is to fire the coil a few times instead just once below 3,000 rpm.
By using capacitors to dump higher voltage into the ignition coil it is able to reach saturation with much less dwell.
I don't see how that helps if the plug has already lit the charge the first time.

 

So without having the duraspark distributor hooked up, I'm still going to get the ill effects of having my feedback carburetor gone and my timing controlled by my ecu correct? (Bad fuel mileage, worse performance)

 

Here's the PDF file for my ign box just for quick reference.

http://www.msdignition.com/uploadedF...ions1/5520.pdf