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4.0L OHV & SOHC V6 Tech General discussion of 4.0L OHV and SOHC V6 Ford Ranger engines.

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Old 09-18-2016
Thread Starter
Join Date: Sep 2016
Location: East Bernard
Posts: 2
94 4.0 won't start

I just bought this truck , 94 4.0 ranger xlt 4x4 auto. Guy said he put gas in it one day at the station and it wouldn't start . It is getting spark , and the fuel pressure is 40 psi. It will start with starting fluid . I am stumped here . What can it be ? Would the cam position sensor keep it from starting , but run with starting fluid ? Has under 100k miles . Again the fuel rail is getting fuel , but not sure if the injectors are popping off , guessing they are not as it runs with gas or starting fluid dumped into the TB. Any help is appreciated.
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Old 09-19-2016
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Join Date: Jan 2014
Location: Vancouver, BC
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Welcome to the forum

Yes, reads like fuel injectors are not pulsing.

First test would be to unplug the TPS(throttle position sensor), there is a "Clear Flooded engine" routine in the computer that will shut off fuel injectors if throttle is held wide open during starting.
So if TPS has a short computer may think it is wide open so no fuel injectors, it is a long shot but not a no shot.
If unplugged it would remove the short, unless short is in the wires, look at them.

CPS(cam position sensor) was not added to 4.0l until 1995, except in calif., so it must be a calif truck.
It shouldn't cause a no start in 1994, but unplug it and try starting.

Crank Position(CKP) sensor failure can cause no start but there would be no spark either so engine wouldn't start even if you added fuel manually.

In 1994 the computer's only job is to open the injectors, there is a separate EDIS module that runs the spark.

The fuel injectors will get 12volts when key is turned on, test a couple of injectors for this 12volts(battery voltage).
This is the red wire, it just daisy chains from one injector to the next, but either wire on each injector will show 12volts if connected to an injector.

If you have a CPS then you will have sequential fuel injection, so each injector will have a different colored Ground Wire that runs back to the computer(PCM).
The PCM Grounds that one wire to open that one fuel injector for a few milliseconds to allow gas to flow into the intake.
You usually can't detect this Ground Pulse with a volt meter, there are "Noid Lights" that can be plugged into injector wires that will flash on and off if there is a Ground pulse when cranking.
But I think you(we) already know there is no pulse or......no Voltage.
So test for 12volts first.

If there is 12volts then you need to get the Codes from the computer.

When you turn on the key the CEL(check engine light) should come on, that means the computer got power and is booting up.
If no CEL then bulb could be burned out or computer may not be getting power or is bad.

You need to check bulb first, which means pulling the instrument cluster, bulb could even be covered with black tape or removed, people often do this when CEL is on all the time, or when selling a vehicle.....................

If CEL doesn't come on with the key then you need to sort that out first.

If CEL is working then it is easy to read the codes in computers memory.

Look at this video first: www.youtube.com/watch?v=X07hu0kAuzE

You need to find the EEC test connector in the engine bay, and use a short jumper wire to put the computer into Test Mode
Then write down the codes that flash on the CEL

1994 use 3 digit code numbers, list is here: OBD-I Diagnostic Trouble Code (DTC) Applications - Ford 3-Digit Codes

What you are looking for are codes that are there, and codes that are NOT there, because the codes that computer doesn't use are as important as the ones it does use.

111 System checks OK
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Old 09-19-2016
Thread Starter
Join Date: Sep 2016
Location: East Bernard
Posts: 2
Thank you

Ron d thank you for answering my question ! Also thanks for the welcoming me to the group. I never would have thought about the tps! I don't know why I didn't . Also I didn't know about it not having a cps , my 96 has one on the 3.0 , I was wondering how come I couldn't find it on the 94..I will definitely try changing the tps ! It's cheap and a lot easier than doing anything else at the moment . I only paid 300 for this truck and it only has 96k, it's spent most it's life on the beach in Matagorda,Tx and was driven primarily on the beach. I think it's a great buy , I just don't know a lot about Fords . If I figure out how to post a pic of it I will , I know that's not going to help the issue at hand, but just to show how nice of a truck it is for 300 bucks . Again thank you for all the information and ideas !
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Old 09-20-2016
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Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,263
I wouldn't replace the TPS, it is a long shot, just unplug it and try to start engine.

I would get CEL working, if it isn't, and get codes if there are any.
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