I thought just for the heck of it I would check the codes on my truck today (the one in signature). It gave me a code 18. The fault code definition is "Loss of tachometer input / IDM circuit failure / SPOUT circuit grounded". What does this mean? Thanks.

-Matt

 

Sounds like a wiring problem between the negative side of the coil and the computer. I'd also check for a short to ground on the SPOUT circuit. There's only two wires it could be - the SPOUT wire or the IDM wire (goes to the negative side of the coil). It's probably one or the other, I doubt it would be both at the same time.

 

I have heard about the spout wire before. Where exactly is it? I believe my truck is EEC-IV computer controlled if that makes a difference. It is fuel-injected. Thanks

-Matt

 

It runs from the TFI module to the computer. I'm not sure right off hand what wire it is, but there is a jumper plug near the distributor on this wire. Find a good wiring diagram and start probing. SPOUT stands for spark output I believe and when connected, allows the computer to control timing advance.

 

Just wanted to jump in with my own dilema. I've been having similar problems to start with. Now, after reading through this thread, I think we may have something here. Read through and tell me what you think.

(From another thread I had submitted)

Hey there Mustang 5.0 or anyone else with the knowledge of this TFI module. I've been reading through the forums looking for similar situations and this one may have scratched the surface. My '86 E-150 (5.0) has been stalling lately and it has been getting harder and harder to restart. I usually have to end up recharging the battery before I can get it going again. Anyway, I did the first thing that came to mind and replaced the electronic fuel pump in the tank. However, since then I can get it to crank at all. Either I'm doing something wrong with the prime or... it may be another animal altogether. Mustang 5.0 touched on a TFI module with exceptional failure rate. My question is, "If I replace this, and it is not the problem, what other devices are involved woth gettin fuel to the injection system?" Thanks for your help, in advance. I love this site.

(The Latest Situation)

I have checked the fuel line all the way up and the gas is pumping. Next, I checked for a spark at the plugs--none. I went on to the coil---none. Even though I replaced the plugs, wires, cap and rotor about a year and half ago, I went ahead and replaced just the coil, cap, and rotor this time. Now, still, I'm not getting a spark at the plugs but, I am getting voltage out of the coil. I'm confused.... what could be wrong here? My meter was reading 13 volts out of the coil plug and at the positve wire to the coil with my neg. probe on the battery neg. but, when I would put my neg. probe on the neg. wire to the coil and the positive probe back on the positive wire to the cable I got erronneous readings. Is there something interrupting the coil voltage or possibly something interrupting the output under the distributor cap? Please help. I'm trying not to Easter Egg, as you put it, I can't afford that or a mechanic right now, that's why I have to keep trying some of the easier DIY type troubleshooting methods. I'm thinking it must be something in the electronic nature but, I don't know what else to look for. Thanks again, in advance, for yours or anybody's input. Oh, by the way, we're talking about an '86 E-150 5.0 liter 302 V8. Have a great day... or night.

THis TFI module. Where is it?...What's it look like?...I hope this is the problem 'cause I'm exhausted. Thanks.

 

The coil fires by switching the negative side on and off. This sends an induced voltage through the secondary output of the coil to the plugs. The distributor could be at one of the spots that would cut that circuit. The TFI module is either on the distributor (big gray plug, about 6 wires coming from it) or on the drivers side fender near the firewall in a heat sink (same number of wires on the gray harness).

 

I've noticed a spliced wire from the neg. side of coil that runs to a huge box on the driver side fender. The wires are at the rear of the box and the front of the box has a cable that runs to the throttle line at the injection system. Is this it? or.. the wires at the distributor? Thanks for your timely repliy by the way.

 

I think you are seeing the cruise control vacuum servo on the fender. I don't know why the negative of the coil is going to that. The TFI has a flat gray plug, about 2" wide, and has about 6 wires on it. It should be on the distributor on an '86.

 

1986 TFI Module. I believe there are used from 86-95
This is located (held on with two recessed screws) on the side of your distributor. It is a Grey Module about 4.5 inches long X 1.75 inches high and 3/8 inch thick. TFI is Thin Film Integrated Module. T
he module is mounted on the side of the distributor with a thin film of Ford dilelectric grease to protect it from heat and reduce EMI effects. Use only the the Ford grease specified
This module picks up and sends out spark out ,puts out tach info and relays it to the EEC for feed back and timing advancement. The EEC can then determine and control EFI firingand timing, spark timing advancement also using other inputs like the the MAP sensor and O2 sensor.

I am not a computer wiz and only use a code reader to pick up error codes when they happen. Some time I wish these error codes and the associated fixes where a bit more specific.

Regards
Bruce P

 

Early TFI pics:

 

well you guys have peaked my interest!! I've got a 87 bronco 5.0 that has had new plugs, cap rotor, coil and TFI. It has a slight bog like a acc pump on a car (this one is EFI) but the realy wierd thing is that when you put your foot in it you get the bog and the tach turns BACKWARDS

 

woops must have hit the wrong key.

Anyway my question is do you think this hesitation and a tach leads to another bad TFI? I have never seen a tach turn backwards. It only does it with your foot in it during idle and normal driving it reads correct.

 

No, honestly, I don't think that means you have a bad TFI. Sounds like you have some other kind of problem. Have you pulled the codes.?

 

Well thats another story. When my son got this bronco froma friend he told him that the engine had been swapped out ( I looked up the vin and was built with a 5.0ho) I don't realy know how to tell the differance but no where on the intake or engine can I find any evidence of this being an ho) anyway the explination leads to the pulling of the codes I have looked on the drivers side and can't find the single wire, Ibelieve it has a grey connector \ at least that is what was on my stang. So , no I havent pulled the codes. Is the single wire a ground can I work around this some how? BTY I also put on a new TPS and cleaned the intake plenum.

 

I think you can short to ground instead of the single wire, but I'm not sure. It should be right next to the other plug. I think you might have more of a bad tach than anything with the ignition. The tach gets a reading from the negative side of the coil, so it's not directly connected to the TFI.