1994 4.0l V6 Ford Ranger no start

[Aty]

Originally my Ranger was in a no start condition where it would crank but no life from the injectors or sparkplugs. The original owner had already replaced the ignition control module and had had no success. When I got the vehicle I went ahead and replaced the wiring harness since the original was badly worn in multiple spots but to no avail. At this point I was pretty suspect of the main computer especially since it seemed to output different codes or sometime no codes. The final nail in coffin was when I found that the capacitors had burst and dumped junk all down the circuit board and even soaked into a few of the traces. With a new main computer I am still experiencing pretty much the same issues but with plethora of new codes and I think fuel injection. (The sparkplug reeked of gasoline when I pulled it out to test it after cranking the engine over.)

The new codes:
159 (O,R) MAF sensor is/was out of range – MAF
114 (O,R) IAT sensor out of range – IAT
327 (O,R,M) EGR feedback signal is/was low – EVR or PFE
341 (O) Octane jumper installed (information only code to notify you if it is installed)
226 (O) Ignition Diagnostic Monitor (IDM) signal fault – Ignition Systems
565 (O) Canister Purge 1 solenoid/circuit failure – Solenoids
566 (O) transmission 3/4 shift solenoid/circuit – Transmissions
558 (O) EGR vacuum regulator solenoid/circuit failure – EVR or PFE or Solenoids

At this point I'm not sure what I should look into or replace. I'm thinking there might be a ground short or something similar but I'm not sure. Any help or guidance would be greatly appreciated.

 

[Brain75]

"new" main computer, so a remanufactured / one that has been re-capped and verified good, or a junkyard unit?

So lets assume that the PO didn't tell you the whole story (like it was loping and backfiring and sounded like all hell before he pulled over, etc)...
I would treat this just like the old 40's and 50's crowd does a motor that has been parked for 30 years.


A) Throw out the gas, clean out the tank, clean out the lines, clean out the injectors (dont want any bad gas flowing when we do the next steps).
B) Do a compression test to rule out catastrophic damage (broken cam, bent rod), etc - see that things are working internally at least decently.
C) Do a leakdown test (it's trivial when you are standing there with all the plugs out doing a compression and), it will tell us the condition of the valve seats.

expect slightly low compression if it has sat, once we get it running, compression will recover after a 100 miles.

after we know we are working on an engine that is sealed up internally correctly, go through fuel/air/fire
D) clean out the airbox of any mouse nest / tree debris - after this point we just assume air since it is good 99% of the time
E) put some new gas in the tank (enough to get the gauge off peg - at least 2-3 gallons typically), verify fuel pressure at the rail
F) use a timing light or spark checker to verify you are getting spark

see if we get any results at that point - tries to start / starts but dies / starts and runs crappy, anything.

 

[DPDISXR4Ti]

I agree with what Bryan has recommended above. In short, good diagnostics are required at this point rather than pulling out the parts cannon.

Focusing on fuel for a moment, there's a conflict in what you've provided above. You indicate "no life from the injectors" yet you say the plugs are wet with fuel. The only way you're getting fuel into the chambers of a fuel-injected engine is if the fuel injectors are getting activated. A noid light is a cheap and easy tool to use here. Heck, Autozone will "rent" one to you for free, but it's certainly worth having one on hand.

 

[Brain75]

Oh and hopefully this advice reaches you before trash day, save the old computer... if there is anything wrong with the "new" one, you can cleanup (rubbing alcohol) and re-cap you old one relatively painlessly, it is not modern surface mount micro electronics that takes surgeons hand and microscope, off the shelf big ole caps and a soldering iron. Even if the problem isn't in the new computer a spare computer that is right for your truck is worth hanging onto.

 

[Aty]

"new" main computer, so a remanufactured / one that has been re-capped and verified good, or a junkyard unit?

So lets assume that the PO didn't tell you the whole story (like it was loping and backfiring and sounded like all hell before he pulled over, etc)...
I would treat this just like the old 40's and 50's crowd does a motor that has been parked for 30 years.


A) Throw out the gas, clean out the tank, clean out the lines, clean out the injectors (dont want any bad gas flowing when we do the next steps).
B) Do a compression test to rule out catastrophic damage (broken cam, bent rod), etc - see that things are working internally at least decently.
C) Do a leakdown test (it's trivial when you are standing there with all the plugs out doing a compression and), it will tell us the condition of the valve seats.

expect slightly low compression if it has sat, once we get it running, compression will recover after a 100 miles.

after we know we are working on an engine that is sealed up internally correctly, go through fuel/air/fire
D) clean out the airbox of any mouse nest / tree debris - after this point we just assume air since it is good 99% of the time
E) put some new gas in the tank (enough to get the gauge off peg - at least 2-3 gallons typically), verify fuel pressure at the rail
F) use a timing light or spark checker to verify you are getting spark

see if we get any results at that point - tries to start / starts but dies / starts and runs crappy, anything.

So far I have drained the tank and got fresh gas in it as well as checked the rocker arms for any looseness. The whole engine bay has been cleaned out with the main engine bay harness being replaced (by me) with another used unit that I continuity and resistance checked.(I have not replaced the two engine harnesses just the engine bay with the fuse box and computer plug) I have not run a compression test yet but the pistons have some kind of compression at least just from shoving my thumb in the spark plug hole.

The old computer was giving out random codes inconsistently and when I disassembled it I found the blown capacitors. I was just going to replace them but i then noticed that multiple traces were damaged if not shorted. It looks like it had time to soak into the board for a while. When I installed the new (remanufactured) MCU that’s when I got fuel injection and consistent codes. Currently I still have no spark (tested with spark plug and tester) and the 226 code. I also checked for any signal down to the coil pack and the ignition or the three coil wires and there’s nothing. The ignition computer was replaced by the previous owner but I’m wondering if a combination of sketchy wiring and dead main computer killed the ignition control module.

PS(I have not trashed any components)

 

[Brain75]

well.... only one solution to a OBD1 code 226 that I found real quick - replace the Ignition Control Module.
Will spend a minute researching a little more, but that is probably on the horizon.

I would also write down all codes (probably have done that), just in case we go back to em, then clear all codes out so we are only looking at what it still thinks is wrong as opposed to a laundry list that might already be fixed.


Clearing codes at the bottom of this page:

Testing EEC-IV Equipped Engines - The Ranger Station

The EEC-IV equipped engines use an older diagnostic system to monitor and report engine related malfunctions. This system is known as On Board Diagnostics (OBD-I). The Diagnostic Trouble Codes (DTC’s) are two or three digit numbers and can be … Continued

www.therangerstation.com

longer descriptions on the ford OBD1 codes here:

OBD-I Diagnostic Trouble Code - 2-Digit Ford Codes - The Ranger Station

Differences in test mode noted as: (O) = Key On Engine Off test (R) = Key On Engine Running test (M) = Memory code Code Definition 11 System checks OK 12 Idle Speed Control motor or Air Bypass not … Continued

www.therangerstation.com

OBD-I Diagnostic Trouble Code - Ford 3-Digit Codes - The Ranger Station

Differences in test mode noted as: (O) = Key On Engine Off test (R) = Key On Engine Running test (M) = Memory code Code Definitions 111 System checks OK 112 (O,M) Intake Air Temperature (IAT) sensor is/was low … Continued

www.therangerstation.com

 

[Brain75]

Since you pulled the gas out, I got to ask - did anything to clean the injectors? The rail will hold crappy gas in it, and first attempt to start you shove the crappy into the injectors clogging em.... For the time being lets ignore that cause we should be able to get it to start on ether a/o start by itself and just throw misfire codes most likely.

 

[Aty]

I haven’t cleaned the injectors but I did purge the fuel rail when I emptied the fuel tank. I also bled the air out with the new fuel. I’ll look at getting a new ignition computer and go from there. It’s only about $40 on rock auto for a cheap one.

 

[Brain75]

How to Test Ignition Control Modules with a Multimeter (Guide)

Learn how to test the ignition control module on your car with a multimeter. The process is simple and should take about 10 minutes.

toolsweek.com

 

[Aty]

Thank you! I’ll take a look when I get back home.

 

[DPDISXR4Ti]

It's certainly worth testing the Ignition Control Module, but I have never, ever, found one replaced in a EDIS vehicle in the junkyard. That tells me it's a very reliable part.

 

[SenorNoob]

If it's anything like mine (91 4.0) it's supposed to be mounted to the fender for heat dispersion. Mine had been zip tied in place for 11 years now.

 

[DPDISXR4Ti]

If it's anything like mine (91 4.0) it's supposed to be mounted to the fender for heat dispersion. Mine had been zip tied in place for 11 years now.

The EDIS modules are WAY less susceptible to heat failure than the TFI and DIS modules that came before them. They don't even really have a heat-sink like the earlier stuff. It's nice if they get some air-flow on them, but in some factory applications no attempt was even made to do that.