94 ford 4.0 vacuum???

Tbarnes93 · Jul 11, 2014

Every diagram I looked at for this year says I have an egr and a evr but I cannot locate either. Here are the pictures that follow my vacuum except for the canister side I know that is right.

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RonD · Jul 11, 2014

Good pics

My '94 4.0l doesn't have an EGR system either, at that time it was a by State requirement in the US.

The EGR system lowers NOx levels when engine is under load, they were first used in 1973.
They were added to engines as needed based on changing federal and state emissions levels each year.

By product of using an EGR system is reduced pinging/knock(pre-ignition) because cylinder temperature is lowered.
The point of an EGR system is not to "reburn" exhaust gas to make it cleaner, when you add exhaust gas to the air/fuel mix in a cylinder it lowers the cylinders temperature, yes odd effect, lol, add hot gas to lower temp???
The lower cylinder temp lowers NOx levels.
And since pre-ignition is caused by heat igniting the air/fuel mix before the spark plug does, it also reduces pinging/knocking.

Because of stricter emission standards most engines now have EGR systems.
I believe any vehicle sold in Calif. had to have an EGR system since 1973, including the '94 Ranger 4.0l

Tbarnes93 · Jul 11, 2014

Okay I see so I wouldn't have a evr either? Does my vacuum look correct? I had the fuel regulator unhook and had the vacuum hooked to the nipple next it on the intake so I figured I might have messed something else up lol

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Tbarnes93 · Jul 11, 2014

A little off topic but I was trying to do a cylinder balance test with my obd1 scanner and couldn't get it to work is the 94 4.0 sequential or batch injected?

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RonD · Jul 11, 2014

Tbarnes93 said:
Okay I see so I wouldn't have a evr either? Does my vacuum look correct? I had the fuel regulator unhook and had the vacuum hooked to the nipple next it on the intake so I figured I might have messed something else up lol

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No, no EVR either or DPFE

Yes, everything looks fine.

The "nipple next it" is the test port for fuel pressure in injection system, it is called a schrader valve, same type of valve is used on your tires.
If you have an old tire valve cap you might want to put it on there, having dirt in the valve won't hurt anything unless you want to test the fuel pressure at a later date, then they are a PITA to clean out, lol.

RonD · Jul 11, 2014

Tbarnes93 said:
A little off topic but I was trying to do a cylinder balance test with my obd1 scanner and couldn't get it to work is the 94 4.0 sequential or batch injected?

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Look at the fuel injector wiring, each injector will have a Red wire, look at the color of the other wire on at least 3 injectors, if you see two wires of the same color then it is Batch fire only, i.e. the PCM only has 2 wires to control 6 injectors so fires 3 injectors at the same time, Batch fire.

If 3 injectors have 3 different colored wires then it can be sequential injection, PCM will have 6 injector wires, one for control of each injector.
PCM can run in Batch fire through even with the sequential wiring, Batch fire is default setting if PCM gets confused, lol.

My '94 4.0l is Batch fire only.

In '95 when Ford switched to newer PCM(EEC-V, OBD II) they also added a Cam position sensor(CPS) and most if not all engines were sequential injection.

While sequential injection can be done with just the CKP(crank position) sensor, it works much better if Cam position info is available.

adsm08 · Jul 11, 2014

My 94 is sequential fire. California Emissions required sequential back then, but from what I can find all the Explorers used SEFI in 94, and my setup is mostly Explorer parts.

The best way to be sure is to reach down behind the intake and feel for a cam sensor. No cam sensor means batch fire. It also means no cylinder balance test.

Dazzlin' Dave · Jul 27, 2014

The pics you posted are of the Heat Riser System (runs hot air from around the exhaust manifold into the intake in order to warm up the engine faster... pos I got rid of mine!)
I couldnt find an EGR valve on my 94 4.0ohv... maybe they thought of a better system?
The purpose of an EGR is to reduce the combustion temps so the motor won't produce NOx (in other words Nitrogen components that contribute to Acid Rain)
Is there a problem you're having?

Tbarnes93 · Jul 27, 2014

Yeah hesitation on warm start starting to be cold start to was thinking vacuum leak but I guess it's either my fuel pump or tps

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adsm08 · Jul 27, 2014

Could also be a cam sensor. On the 4.0 usually the first noticeable symptom of a dying cam sensor is a hesitation.

Tbarnes93 · Jul 27, 2014

I don't have a cam sensor

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SenorNoob · Jul 27, 2014

RonD said:
...having dirt in the valve won't hurt anything unless you want to test the fuel pressure at a later date, then they are a PITA to clean out, lol.

Might not be the case for all of them, but my valve is threaded into the fuel rail. Just have to be prepared for the pressure behind it. It'll blow the valve away if you're not careful. Besides wasting gas and polluting the environment. They are much easier to clean when you can get to the back side.

94 ford 4.0 vacuum???

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