Ok folks,

I've been having an intermitentent problem for the last few weeks and can't seem to figure it out. First off, I have a 86 F150 4x4 with the EFI 302. It will take spells where if cuts out, runs really rough, sputters and bangs and will usually stall. I can sort of keep it running by feathering the throttle, but it misses really bad. When I pull the codes, it comes up with code 18 which is IDM circuit failure/SPOUT circuit grounded. It only seems to do it when the truck is good and warmed up. It's almost clock work where it starts to act up after 12-15 minutes of running. Here's what I've done so far. The timing is set to 10 degrees and the SPOUT connector has been reconnected. The PIP sensor and ICM was replaced which didn't make any difference. I later questioned if the rotor in the distributor could be the culprit so I put in a remanufactured distributor with another new PIP sensor and ICM, no change. Since it only acts up after 10-15 minutes of running I thought maybe the ICM was acting up after getting hot, but the second new one didn't make any difference. I've unraveled the PIP SPOUT wiring leading to the ECM and didn't find any broken insulation or anything. I went ahead and replaced the pigtails on the distributor and the ignition coil which didn't help. Oh, the coil has been replaced twice as well. I've replaced a resistor in the coil wiring as well as a diode and no difference. I was leaning to a faulty ECM at this point, but I just pulled one from a local pick-n-pull junk yard and it still does the exact same thing. The part numbers weren't an exact match, but the problem is still the same. The TPS has been replaced and is is adjusted to 1.0V at idle. It is just under 5V at full open throttle. If I disconnect the Spout connector and start it up, the problem is still there. If I wait a few minutes, the truck will run fine for a few minutes and then the problem reappears. It seems like something is getting hot and shorting out. When it cools off a little it resets and will run again. Any suggestions or guidance would be greatly appreciated. I've been searching the forums and have done almost everything everyone else has been doing. I've been wiggling a lot of wires, but it never seems to act up while I'm doing this. What do I need to do? All of my parts have came from Advance auto parts.

kc

 

Stop before doing anything else, Run two bottles of heet and two of iso heet on
whatever is in the tank. Run it to 1/8 tank and refill with fresh fuel and some lucas
or stp fuel treatment. You could also pull the o2 sensor if that doesn't do it and see
how dirty it is and clean it with a 15-20 seconds or so in a propane torch flame.
If that truck has sat or is run with less than a full tank a majority of the time it is
most likely water. It is a lot cheaper than replacing the components that the comp
will throw codes for so try that before anything else!!

 

Blue Beast,

It sounds like you think it is fuel related, what makes you think that?

kc

 

I would look at the Ignition Switch and the plug that plugs on to it.
Sounds like it may be getting hot and dropping voltage.

 

Did the shield on the dist wiring look in good shape? Was it grounded on one end of the wiring?

 

The shielding looked ok, I guess. There is about a 1 foot section at the end (going to the ICM connector) that isn't shielded. Do you think that would make a difference. Is there a particular type of foil that needs to be used to repair it?

I looked at the power supply to the ICM as suggested by subford. Everything looked good. To make sure, I ran the truck until it started acting up and tested the voltage at the ICM. It was good, to be absolutely sure, I jumped a wire from the battery, it didn't make a difference. I tested the ICM ground the same way. Also, the pulses (flashes) from the coil looked good (rhythmic) when I cranked it over with the coil wire disconnected. I did find something out though. I pulled the Air Charge Temp connector and the truck seemed to pull out of the sputtering. It still wasn't running 100%, but it wasn't cutting and missing like it was. When I reconnect it, after 4-5 seconds it starts again. Could this sensor be the culprit? I don't see how it would affect the timing that much or signal a code 18 (Spout Grounded). I didn't know if the sensor being unplugged would affect something else and cause the truck to run better. Thanks for the advice so far!!!

kc

 

I do not know where you got the information that a Code 18 was “Spout Grounded/spark word angle failure”

My chart say a code 18 = pinpoint PA1.

And PA1 says:

PA1 CHECK FOR POWER TO PROCESSOR

NOTE:
Before proceding with this Pinpoint Test, verify that the base timing check in Quick Test Step «4.0» has been performed.

Key off.

Disconnect processor 60 pin connector. Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.

Install breakout box, leave processor disconnected.

Key on, engine off.

Measure voltage between Test Pin 37 and Test Pin 40 at the breakout box.

Measure voltage between Test Pin 57 and Test Pin 60 at the breakout box.

Is each voltage greater than 10.5 volts?

Yes
GO to «PA2».

No
For Tempo/Topaz, Taurus/Sable, Continental:
GO to Pinpoint Test Step «X1».
For all others:
GO to Pinpoint Test Step «B1».

PA2 CHECK SPOUT CIRCUIT CONTINUITY

Key off.

Breakout box installed, processor disconnected.

Disconnect TFI module.

Measure resistance between Test Pin 36 at the breakout box and SPOUT circuit at the TFI module vehicle harness connector.

Is resistance less than 5.0 ohms?

Yes
GO to «PA3».

No
SERVICE open circuit. REMOVE breakout box. RECONNECT all components. CHECK timing as in Quick Test Step «4.0».

PA3 CHECK SPOUT VOLTAGE AT PROCESSOR

Key off.

Breakout box installed.

Connect processor to breakout box.

Reconnect TFI module.

Timing switch to "DIST" position on breakout box.

DVOM on 20 volt AC scale.

Start engine.

Measure voltage between Test Pin 36 at the breakout box and battery negative post.

Is AC voltage between 3.0 and 10.0 volts?

Yes
EEC system OK. REMOVE breakout box. RECONNECT processors. GO to «Section 8A» for Ignition System Diagnosis.

No
REPLACE processor. REMOVE breakout box. RERUN «Quick Test».

 

SUBFORD,

My Hanes manual (which I know is Junk) and the www.fordfuelinjection website show code 18 as SPOUT Grounded/Spark angle word failure. I will however do the test you described for "pinpoint PA1". Is the processor they are referring to the ECM? What is a "breakout box"?

kc

 

I looked in my fuel injection book, and it says code 18 is "loss of tach signal to the ECA". I did a double take though when you said it was something else, because I hadn't double checked it, and thought maybe that was the problem.

It says; if this code comes up during the engine running test, it means the ECA has detected an open in the spout circuit during the on-demand codes. Since it came up during the on demand codes, the problem causing it is a hard fault-an existing problem- and therefore should be easy to trace.

If the code 18 is in the memory codes, it will be a little more difficult to trace. Because the code 18 did not come up in the on demand codes, the problem is intermittent, and may be difficult to locate.

He goes on to say, to troubleshoot a KOER on-demand code, begin by locating the SPOUT connector. This is the connector that has a yellow and green wire that runs from terminal 2 of the TFI module to terminal 36 of the ECA. Code 18 could result if the connector was left out or disconnected during the last tune-up.

If the connector is in place, connect a timing light. Run the KOER self-test. After the last code check the timing. It should be initial timing, usually 10 degrees BTDC, plus 20 degrees + or - 3 degrees. If the computed timing test meets this spec, and the code 18 was again received as you prepared for the computed timing, you have a puzzle. Logically these results are mutually exculsive. Repeat the computed timing test, and if the code 18 is received. and the timing is still within spec, the ECA is making erroneous decisions and should be replaced.

If the initial timing was 10 degrees, but the computed timing was incorrect, check the power supply voltage to the ECA. With the ECA connected, the key on, but the engine off, check the voltage between ECA terminal pin 37 and pins 57 and 60. It should be battery voltage. If these are ok, check the voltages between pins 40 and 57, as well as pins 40 and 60; the voltage should be battery voltage.

If all these voltages are ok, connect a digital tachometer to the yellow and green wire that runs from the ECA pin 36 and terminal 2 of the TFI module(the spout wire). Start the engine. The tachometer should read a rpm greater than 0. If the tachometer reads 0, inspect the wire for opens or shorts to either ground or voltage. If the wire is ok, replace the ECA. A reading greater than 0 on the tach means that the ECA is producing a SPOUT signal, and the TFI module must be impeding the timing control ability of the system.

I know you have done some of this stuff above, but possibly you can gain some more knowledge from something above. About the shield; this wire is shielded for a reason, possibly to keep the sparkplug wires from interfering with the tach signals on the wire. I would rig tin foil or something on it to see what happens. Just make sure the shield is only grounded on one end of the wire, and not touching ground on the other end. Grounding the shield on both ends can cause a ground loop and make the shield noisy.

 

The above translation for code 18 was from the FORD Engine/Emissions-Diagnosis 1992 Shop Manual.
It is a fast look-up and usually works for me. I have checked in the 1989 Manual for Code 18 and it says the same thing.
These are the Manuals that all of the after market manuals are supposed to be copying from.


The 1989 Manual also says:
For TFI Vehicles:
Indicates that the SPOUT circuit is open.

Possible causes:
-Open harness
-Processor
-TFI module

Then it goes through the same steps that I posted above from the 1993 Manual.

Yes the processor is the ECM (EEC/PCM) Module.
The "breakout box" is a device to bring all of the inputs to the ECU out so you can test them without back probing them.

 

After rethinking this one it sounds to me like the START wire is always hot or is has power off and on while the engine is running.

This will send the timing back to base timing and could cause an error 18.

It is either the start wire or a bad ECU.
You could try removing the start wire from the TFI module to test this.

Dave F
The information that you posted is almost word for word what it says in the Engine/Emissions-Diagnosis 1992 Shop Manual for Code 18.

I just left out the timing check, as I did not think it was important at the time but I see now it was. I did post a reference to it in the NOTE.

 

[QUOTE=subford;5355414]After rethinking this one it sounds to me like the START wire is always hot or is has power off and on while the engine is running.
This will send the timing back to base timing and could cause an error 18.

It is either the start wire or a bad ECU.
You could try removing the start wire from the TFI module to test this.

Dave F
The information that you posted is almost word for word what it says in the Engine/Emissions-Diagnosis 1992 Shop Manual for Code 18.

I just left out the timing check, as I did not think it was important at the time but I see now it was. I did post a reference to it in the NOTE.[/QUOT

i have a '94-'95 f150 302 that is having the same issue. I have tried most everything in this post.
Did you fix the issue? What was the fix?

 

Did you figure it out? What was he fix?

 

You have checked the spout connector and it' good and in place?

 

Yes. I have had it in & out several times while timing it.