94 4.0 cranks, fires, dies

[MarkMopar]

Hi all. As evidenced by my username I'm not a Ford guy. I have this Ranger here that's making me nuts.
When I got it I replaced the non working fuel pump assembly and filter. It ran fine.
One day it was idling in the yard and died. Now it won't run. It cranks, runs for a second, then dies.
I can hear the pump running before I start it. It has fuel at the rail.
Swapped around the relays. No good. Cleaned IAC. Nope. Tried disconnecting MAF.

Suggestions?

 

[franklin2]

Pull the codes. Here's how to do it with a testlight or old multi-meter. Digital meter doesn't work that well.

Thorssell.net

 

[RonD]

Welcome to TRS

Do 50/50 test anytime you have a crank but No Start............on ANY engine, lawn mower to V12

50/50 test
spray fuel into the engine, i.e. gasoline, ether, carb cleaner, ect.............

Try to start
If it starts, runs and dies then you have, good/timed spark, but no fuel delivery
If it doesn't fire or start then you have no spark
50/50, instant results on where to look

The ONLY sensor that can cause a No Start is the crank sensor, just FYI, and it causes No Spark


When you turn on the key the CEL(check engine light) will come on, it means computer is powered up
When you activate starter motor the CEL should go OFF, that means Crank Sensor is working, computer is getting a timing pulse

There is one other sensor that can fail in an extremely RARE way, the throttle position sensor(TPS)
Unplug the TPS 3 wire connector and see if engine starts and runs, if TPS shorts fuel injectors are shut off

New fuel pump means NEVER TESTED fuel pump, unless its a Motorcraft, and they are way too expensive, lol
So "new part" doesn't mean "working part"
If possible test fuel pressure


I just had to change the capacitors in my 1994 computer, after 20+ years they leak and fail, under $5 to fix
So if you have odd issue it worth a look versus just randomly replacing parts that can'[t fix a computer issue
And it's free to have a look
You can see the 3 blue capacitors in this picture: http://www.auto-diagnostics.info/ford_eec_iv

 

[MarkMopar]

Welcome to TRS

Thanks for the welcome!
The new fuel pump was put in when I first got the truck after it had sat 10 years. It was running well and just quit. Unfortunately, I'm not equipped to test pressure.
CEL works as you described.
I disconnected the TPS, no difference.

 

[franklin2]

Thanks for the welcome!
The new fuel pump was put in when I first got the truck after it had sat 10 years. It was running well and just quit. Unfortunately, I'm not equipped to test pressure.
CEL works as you described.
I disconnected the TPS, no difference.

What codes did you get?

You can buy a simple fuel pressure tester at harbor freight.

 

[MarkMopar]

So the new eBay fuel pump is junk. The ground wire is broken off. Then I touched the blue wire and off it came. This thing is only 6 months old and looks 20.

 

[RonD]

Yes, common complaint about 3rd party fuel pumps, "keep the warranty because you will NEED IT", some go thru 3 or 4 pumps before they get one that lasts beyond 1st year

But still 4 times cheaper than a Motorcraft fuel pump

 

[MarkMopar]

It gets better. Now we've gone from no fuel to ALL the fuel!
As soon as I turn the key on, the injectors fill the cylinders with fuel, hydro-locking the engine.
Swapped the damper on the fuel rail, no difference.

 

[Robertmangrum.rm]

I went through 3 autozone ones on my 98 before traded it off. After second I cut a hole in bed for quick access. So of course the 3 never failed hahaha figures

 

[RonD]

It gets better. Now we've gone from no fuel to ALL the fuel!
As soon as I turn the key on, the injectors fill the cylinders with fuel, hydro-locking the engine.
Swapped the damper on the fuel rail, no difference.

1994 Computer may need to be pulled out and opened up

The fuel pressure regulator(FPR) would be the first guess for this symptom, pull the vacuum hose off FPR and turn on the key to see if fuel comes out the open vacuum port
If so that's where the fuel in the intake is coming from
No Damper on the 1994 so I assume you mean FPR, Damper was used in place of FPR on 1998 and up Rangers

The fuel pump should only run for 2 seconds with key on
If you are getting enough fuel for hydro lock then its running full time, so something else is wrong as well


The 1994 and earlier computers have 3 capacitors that will leak and fail, I had to replaced my 1994 Caps last June
Under $5 to replace them, and runs like new now
If you pull out the computer and open it up, you will see the 3 Blue Caps and can see the leaking and broken pins

My 1994 was having various running issues and fuel pump running full time was one of the symptoms

Looks like this inside: http://www.auto-diagnostics.info/ford_eec_iv

Move the 3 blue caps with finger, should be tight if their 2 wires are still connected to board
This article has pictures of leaking Caps and replacement procedures: http://support.moates.net/capacitor-repair-ford-a9l-ecm/

 

[MarkMopar]

RonD, you nailed it. Took out the computer and found this:

 

[RonD]

Yup, that would be a problem, replace all 3 Caps, and clean off the board with isopropyl alcohol

 

[MarkMopar]

If you look closely, you can see that cap is touching the component next to it, too. They're melted together.

 

[RonD]

+1 ^^^

Didn't notice that, could be used or rebuilt computer time
1993/4 computers were the same
Need to match engine size, and EGR or no EGR
And Manual or automatic transmission

2WD or 4x4 don't matter