1994 E150 5.0 no start.

[MISWFL]

I've got a 1994 E150 high top conversion van, with 153K that I'll be selling soon, but need to use a bit before that. It's been gutted into a work van. I've had it a bit over 2 years and it's been pretty reliable overall, with just some minor issues. Recently it died at a gas station and I replaced the fender mounted ICM with a Motorcraft one and with actual heat paste, not silicone grease. It ran normally after that. The day before yesterday, it took a few cranks to start, which is unusual. Normally it fires up on the first crank or so. Yesterday it refused to start. Cranked perfectly, but nothing else. I disconnected the key chime to listen for relays clicking when turning the key on, but heard nothing. I checked all the fuses and nothing was blown or melted. I swapped around the 3 matching relays and nothing changed. Starting fluid confirms lack of spark. Unless it's a wiring issue, I think it can be narrowed down to just a few things, unless I'm missing something.

1) Ignition switch, the electrical part. The plastic push rod thing seems good and fully travels forwards. The OEM switch isn't burned or smells, but the post doesn't move as freely as I'd like. I'll be replacing this ASAP, even though I kind of doubt this is the issue.

2) ICM, which is a brand new Motorcraft with real heat paste on it. Not sure on this one.

3) PCM ( engine computer brain ) relay, which I swapped around. It's OEM. I'll replace it ASAP.

4) PCM ( brain ) looks good, including inside. It's OEM without any signs of burning, smells or corrosion. I'm thinking of buying a rebuilt one.

5) CPS ( cam sensor in the dist ), which seems doubtful. You'd think it'll still fire up, just run bad.

6) Distributor. I haven't checked to see if the rotor turns and what the cap and rotor looks like. Supposedly the timing chain was replaced by the PO. I did get some parts receipts from him including the timing chain stuff.

7) Coil. I haven't tested it for voltage or resistance yet.

Any ideas?

 

[RonD]

Does the CEL(check engine light) come on with key on, that means the computer has booted up
Does CEL go off after starter motor is turning the engine over, that means computer is getting a good timing signal from distributor/ICM
If CEL stays on then no spark

Cam sensor issues won't cause a no start

EEC-IV PCM's only opens injectors, so if it doesn't start with starting fluid then its a spark issue for sure, PCM only advances spark timing after engine is running, on start up spark ICM only

ICM and coil should get 12volt with key on from ignition switch, no relays involved
PCM gets 12v from EEC relay

 

[MISWFL]

I'll have to check again, but I believe the CEL was on both during key on and while cranking. I'll check again later tonight.

As I understand it PSOM issues won't cause running/starting issues, just drivability ones? I think my van has intermittent PSOM issues and probably some questionable grounds.

What's a good code reader for my van? I tried the jumper procedure with a light bulb, but couldn't make sense of it.

When running the CEL is usually off, but comes on when driving, but seems to be tied into throttle position. Give it a bit of gas, and the CEL will come on, but then go out a few moments after letting off on the gas.

 

[RonD]

PSOM = programmable speedometer/odometer module
It should only cause issues with Automatic trans shifting, and of course speedometer

Yes, if you have a misfire the CEL comes on until you let off the gas pedal

The early Ford Computers(PCMs) only operated the fuel injectors, 60-wire EEC-IV computers
So these vehicles would have separate spark system/module
In 1994 it was probably a TFI module

Counting flashing CEL for codes is easiest, but you can get OBD1 readers
Your 1994 uses 3 digit codes

INNOVA 3145 OBD1 reader is usually $40 and gets good reviews overall

 

[MISWFL]

I cranked it again and the CEL is on both when the key is on and while cranking. I'm going to pull the cover and check the coil and distributor next.

 

[RonD]

Yes, if CEL stays on when cranking then computer is not getting a timing pulse from distributor/TFI

Coil wouldn't matter but most likely also wouldn't be sparking if there was no timing pulse, from distributor/TFI
Coil and TFI share the 12volts from ignition switch(key on), so no 12v and no timing pulse

 

[MISWFL]

I just checked it real quick and the distributor does turn when cranking. I don't have my tools or a meter. I also noticed the 2 relays next to the ICM. I didn't check those by swapping them around.

The distributor is basically just mechanical ( cap and rotor ) with the CPS for signal generation, unless I'm missing something. I can get a new distributor for around $70 or a new pickup coil/CPS for around $30. Not sure if the CPS is a typo from RA, as they look the same as the pickup coil. My ICM is fender mounted and the distributor has a round 7 wire plug that goes into a 5 wire plug on the engine harness.

I'm planning to buy coil as well.

Any tips? I can rig up a test light.

 

[RonD]

No relays involved with Spark system, just for computer and fuel pump and those are most likely working since CEL comes on


Key on, test if Coil has 12volts, either wire should show 12v, + side or - side
If you see 12v and you have a spark tester you can hook it to the coils spark wire, and when you unhook either or both + and - wires you should get a spark, key on of course, that means coil is OK, it should spark each time wire is connected and then disconnected

Test light on - side coil wire and battery positive or + side
Crank engine, test light should go off and on as TFI module grounds and ungrounds the coil to spark it
If it just stays on then no pulse from TFI(or hall effect sensor in the distributor)

Up to you on what you change first, the Hall effect sensors rarely fail, but rarely is not never
TFI modules or the wiring is more likely

Red/light green stripe wire is what Ford used for 12v power to Coil and TFI, it comes thru firewall from ignition switch
Look at the coil's wires, should see that color
Unplug TFI connector and test that color wire for 12v, key on of course

In 1994 there still may be a 2 wire setup on ignition switch, which was used for Ballast Resistor setups
If ignition switch has a problem then you can have 12v at coil, key on, but no 12v with key in START, so no start but you have 12v key on
So test for 12v key on and watch to see if there is still 12v cranking

 

[MISWFL]

I did some checking with a test light. No power to either side of the coil. It looks like the coil uses a ballast resistor.

Here's the results of checking my ignition switch:

#37 Yellow (x2): Hot off, on and cranking
#687 Grey/Yellow (x2): cold off, Hot on, cold cranking
#41 No wire: cold off and on, dim cranking

#297 (x2 only 1 wire) Black: Hot off and on, cold cranking
#262 Red/Yellow: cold off, Hot on and cranking
#16 Red/Yellow: cold off, Hot on and cranking
#32 White/Pink: cold off and on, Hot cranking
#977 ( offset pin ) purple: cold off, dim on and cranking

 

[MISWFL]

The Red/Green wire to the ICM is Hot on and cranking.

 

[RonD]

I don't have a wiring diagram for your vehicle so those numbers and wire colors won't help me much

Hot wire the coil
Jumper wire from battery positive to Coil +

Ballast resistor should have 12v on both ends with key on, one end may be down to 8volts, 8volt end goes to Coil +, so you can hot wire to there
12v end comes from ignition switch

In START the ballast resistor is by passed so coil + gets battery voltage directly which is about 10v

 

[MISWFL]

Apparently the part I thought was a ballast resistor is a radio noise suppression filter. E7TF-18801-AA

 

[RonD]

LOL, that would make more sense in a 1994

 

[MISWFL]

I was going to ask about just jumping the + side of the coil to the battery to see what happens.

 

[RonD]

The good ol' days before locking steering wheels, "hot wiring cars"

Yes, battery positive to coil positive