1985 TFI IV on 4.9 and conversion to single wire HEI distributor

Hi Gentlemen.

I have read both threads on the HEI distributor and its wiring with 12 gage wire, relay and where to get relay trigger signal. Thanks. My question is about the Engine Control Computer, its relay mounted near ECC.
All great, I am ready to proceed.

what I havew not read on these wonderful links is about disposition of the now ( or soon ) to be defunct EEC and its related inputs and out puts. has anyone de-powered that ECC and EEC Relay?  

Question: do I leave the EEC powered and the big ECC harness connected, and all the vacuum solenoids and those attendant ( related ) wires? check engine light seems disconnected, I have never seen it on.

seems odd to just leave TFI IV 6 pin connector and coil connections " possibly powered up w cranking or ignition power heading out into the engine bay.

the ECC has so many emissions duties and needs alot of data, is the Coolant temperature one of those EEC inputs?

I do not want temperature gage not working if I disable the duraspark TFI IV system  - Thanks Don "newbie"          

Unless you are also eliminating the feedback carburetor (essentially going back to what my 1977 F150 came with) you are going to have some issues. The EEC controls spark advance (solved by the French distributor), fuel mixture, EGR function and Thermactor function. removing any of these puts the system in limp mode. It will probably run ok for a while, but unless the catalytic converter is removed it may clog. The 1975-79 F100s had a non-feedback system so depending on the type catalyst it might work fine.

Pretty much the only reason people would resort to HEI is to eliminate the troublesome computer, all it's sensors and the distributor, & carb it controls

There is a coolant temperature sender for the gauge (one white/red wire)

And a engine coolant sensor (two wires) for the computer...

The EVTM is your friend and you can find it under documentation/electrical/evtm/1985

I swapped over to the Duraspark II for my 85 300, and yanked the entire large wire bundle out.  Can't recall offhand about the temp sender wire, but know for sure the oil pressure sender wire was included in my donor Duraspark harness.

Don,
This is DS-II



This



And this,



And this.....



Are EEC

Thank you for prompt replies.

I will leave the 62 pin engine control computer connected,  then will gather up the 6 pin distributor wires and the remote coil wires and the radio suppression condensers (2).

Physically, all vacuum devices as EGR, and vac delay module, and Evap canister, and the lines are spaghetti splices and such. I will route vacuum lines from carb to HEI distr, evap canister with reducing air volumn installed ( constant light bleed of phumes to manifold, and PCV as it was, and certainly the HVAC vacuum sourse as it was. I will unplug the vacuum solenoids each ones connectors.

the 2 temp sensors will still likely hace instrument temp still working. and there are some wires from starter solenoid and possibly some power wires that I will leave un disturbed.

I may try removing the EEC relay just for giggles.    

Again owner never saw ck engine light and O2 sensor was also disconnected for years.

comments of the group are most welcome...Don        

1987 was the first year for a check engine light. 1986 had an emission reminder light.

I too sometimes forget about check engine lights. it's like second nature that old trucks don't self-monitor. on newer cars I am always asking about the light first.

Starting think 83 is when the 300 started with the feed back system.
As posted if any 1 thing is not working the system goes in to limp mode, locks the timing and richens the carb.
So if you replaced the feed back dist. with an HEI unit I bet you are in limp mode now.
FYI if the temp sensor for the feed back system, different than the dash gauge sender, you are in limp mode.

What most do after installing a HEI or pre-feed back 83 dist and pre-feed back 83 carb is start at the computer inside the truck.
Unplug the harness from computer and remove the box.
Fish the wire harness out the firewall. You may want to open this harness up to better follow the wires.
Just follow the wires and remove 1 at a time.
As was posted I think only the oil PSI is tied in and you cut the wire on the computer side not the sender side.
The temp sensor wires(2?) go out to the Tstat housing and plug in there, just unplug.
Other wires go to the old dist. and coil. Coil can be removed as the HEI has it built in and I think the wires to the old dist. unplug from the trucks main harness on the left fender well.
You may have a power wire just follow it back and cut at the end.

At this point the computer and wiring should be disconnected from the truck and removed. Block off the hole in the firewall and you are done.
I have not done this as my truck is a late 80 making it a 81 pre-feed back.
Dave ----

BTW the dash gauge sender for the 300 is on the right side of the block, kind of under and to the rear.
The wire should run around the rear of the valve cover to the sender.

Hi guys, TFI IV on 1985 inline 6 automatic converted to HEI update from Don:

worked some 15-20 hours w no spark confirmed. the ECC replaced the relay next to computer that powers the vacuum solenoids, one in car buzzed like key warning buzzer, then measured TFI distributor and inner Hall effect wires and volt age was low, replaced w Cardone new distributor Rock Auto as was relay. then ran OK except opening SPOUT connector did not retard to base timing, and the coil read higher resistance, so coil and EEC Computer were bought, then good, SPOUT was at 6 degrees sighting all by eye. spark then advanced to 10 at idle. truck then lost spark again after 8-10 minute, running flawlessly before that from cold. if sat for 2 minutes, a cool off would have engine restart, yet pre-warmed spark disappeared in 1-2 minutes. Pin checked grounds for ECC and examined wire harness and ordered new TFI module ( 6 wire ) for distributor thinking new cardone dist module may be cause. No, it still stalled at 8-10 minute point.

so HEI distributor secured and fitted and timed and the 1985 150 runs for hours now and 200 miles.

I have many new parts now that were installed, but not returnable, new TFI dist, second new TFI module, new Coil, new computer plugged in for 15-20 minutes. make a heck of a deal if anyone interested. email or text 919 451 6812

HEI Install notes : I found power wire near brake booster for relay, this is running through the ign switch, and w key on measured 11.97 V, gosh knows what this volt lowers to under cranking. so I got single wire light bar relay and wire kit. the regular power to light bar I switched 87 and 30 terminals at relay connector and there was a 40 AMP inline relay. to trigger relay I now use just that ign switch power from booster area. now with Key on, the "open voltage " ( not connected to HEI dist ) is 12.5 V, and essentially this wire setup replicated the OEM starter solenoid bypass voltage circuitry that went to TFI module to help module have higher voltage during cranking. Kit: https://www.amazon.com/Nilight-10014W.

verified that new HEI did accept cap, rotor, coil, and hall sensor from 1967 Chevy Camero inline 6 model
parts.

OMGosh also put in column ignition switch, and for fun, the captive nut that accepts the 2 nuts that hold down the ignition switch broke off. broke off the column tube. I devised a fix for this occurrence with out welding a new stud on. describe would take page more to write up.   Fordland fun, did I get my share. Don  

Good to hear you got it running
When I started reading about buying the not needed parts I was like NNNNOOOO!
Sorry to see you spent time and money on parts we knew would not work.

So you are still running the feed back carb?
You should be able to start pulling the feed back computer and wiring from the truck if you have not as it is not doing anything with part of the system missing.

As said start from the inside. Unplug computer, push plug thru firewall and work the wires from there.
Only wire I know of that is tied into the feed back harness is a wire to the oil psi wire.
Dave ----