Advice on 91 to 94 ranger 4.0l thank you

wrench · Jul 17, 2014

I have a 94 ranger I got, the motor that was in it was a 4.0 that blown/smoke. The person I bought it pulled the motor, found a rolled ranger from 91 to 93 and started that motor so he put it in the 94. He did not switch the computer, he said he rebuilt some of the under like oil pump ect. He gave me 2 computers, he thinks one is from the rolled ranger. I have tired all three the truck will not start, there's fuel, spark. I have tired starting fluid just a squirt still not starting if so half start, the motor cranks but does not start or run,
My question mainly is there a cam shaft sensor or cam synchronizer, nothing at all on the 4.0l from 91 to 94, if there is would this cause my problem also I have a Hanes Book, searched the web cannot find were it is supposed to be located if it's supposed to be there it's not, no open holes nothing thank you for time.

SenorNoob · Jul 18, 2014

From what I've read 94 might or might not need a camshaft position sensor. If it does and doesn't have one, that could your problem. If the engine came from a 93 or earlier it's fairly likely that it doesn't have one.

As for where to look, it's right behind/under the intake. (You don't need to remove the intake to see it. At least not when the engine is out.) Think right where the 2.9 distributor goes..

If it doesn't have the sensor, it'll have what looks kinda like a "freeze plug" there. Just look for the obviously different material round spot back there.

RonD · Jul 18, 2014

No, no CPS(cam position sensor) on those years, and they wouldn't cause a no start in any case.

The 3 things needed for a gas engine to start are:
Fuel, in the correct amount
Spark, at the right time
Compression, above 100psi, 4.0l should be 150+psi, my '94 4.0l with 300k does 165psi average.

Could you have too much fuel?
Do you hear the fuel pump come on when key is first turn on, it should run for 2 seconds then shut off, it is not a quiet pump, lol, you should hear it.

Spark is timed by the CKP(crank position) sensor located on the passenger side of the main pulley.
The signal from the CKP sensor goes to the EDIS-6 module, located by the battery but on the FRONT side of the rad support, it is a smaller black box with a single connector with many wires.
The EDIS module runs the spark, it "talks" with the computer but the EDIS works on its own.

How have you tested the spark?

How are you applying the Starting fluid?
Best is to leave the MAF sensor and air tube in place, then remove Brake power booster hose and spray fluid in to intake then replace hose and try to start, PCV valve hose works as well.

wrench · Jul 18, 2014

I opened the throttle flap and sprayed inside then tired to start, I felt the plug were the cam/disturber is supposed to be, I pulled of 1 spark plug from drivers side held it against ground and I had spark and the spark plug was wet,
I pulled the pass anger side spark plug closet to the front, same thing but no fuel on spark plug so I pulled one spark plug back and I have fuel on it

hank857 · Jul 18, 2014

did it ever run after the engine change? If not recheck the plug wires for proper position. Trying to remember but I think there is a code on the door frame for the ecm also. It should help tell ya which is the correct one. Also the computer should be under the driver side fender/firewall as I recall.

You can try to pull codes although this is obd 1 and uses a series of flashes to diagnose with. Not sure how it works but there is a fuel rollover/cutoff switch. supposed to be under the passenger side kickboard. check and reset for Gp's.

wrench · Jul 19, 2014

So I have checked the compression on number 1 spark plug and it reads 130 psi
So I made sure the wires are in order with firing order, so I checked all the park and 2 and 6 have no spark, I have switched spark wires and spark pluges, still no spark on 2 and 6 so would this be the coil pack? And if it is would the truck start with 2 sparks Down and run rough or would this be my problem for not starting.

Destroyer000 · Jul 19, 2014

i would change coil pack. my 96 i got running on just starting fluid in the intake... so it willl run and you have to spray a LOT

wrench · Jul 20, 2014

So I Changed the coil pack and tired starting it, the motor wants to run if you keep the pedal down and keep cranking the motor but when you stop cranking the motor it will back fire the sound of a smooth burp not a pop of any sound thank you

AllanD · Jul 21, 2014

The first year for the Camshaft Synchronizer was 1994, but not all 1994's
(pretty much all 1994 Explorers, but rangers can go either way)

The issue is not that there is a "disconnected" Cam Synchronizer, but that three changes
happened on the 1994 4.0's with the cam position sensor.
1)The cam position sensor itself
2)The EGR system installed at the same time, (look for the square, cast aluminum DPFE sensor on the side of the intake)
3)Injector wiring is completely different because 4.0's with a cam position have it because the reason for the cam synchronizer is to implement "SEFI", Sequential Electronic Fuel Injection"

Either trying to run a NON SEFI engine on a SEFI harness and computer or a SEFI engine on a NON SEFI harness will result in you having a very bad (incredibly frustrating) day.

1993(ALWAYS NON-SEFI) and 1994 (Both SEFI & NON-SEFI) engines use the same injectors ("Red Tops") with a different (just different, not "Better") flow rate

That difference can also frustrate start-up attempts.

wrench · Jul 21, 2014

So if my problem is the sefi with no harness or no sefi with harness how do I fix that? I don't have the square aluminum sensor on my intake or the wire to go to the sensor if one would be there so I have 94 ranger with 90 to 93 4.0L

wrench · Jul 21, 2014

So I do don't have the square sensor on the side of my intake or a wire for it to plug into

RonD · Jul 22, 2014

Look at the injector wires.
Check at least 3 injectors, each should have 1 Red wire, look at the color of the other wire.
With non-sefi 2 of the 3 injectors will have the same color wire, Tan or White usually
If all 3 have a different color wire then it is sefi

AllanD · Jul 23, 2014

If you are attempting to run either an early engine on a late harness or a late engine on an early harness you must either change the "hardware" and computer to match the harness or the harness to match the harness.

If that is NOT your problem and you have an early engine on a Non-SEFI harness you still need to verify that the engine isn't a 1990-92 engine with the "grey" injectors.

Because to run on a 1993 or later computer it needs the "red tops" to run correctly.

But the problem I had when doing my 4.0 swap back in '07 was that I had purchased a late model (I bought a wrecked 4.0 Explorer in 1998) and the engine sat on an engine stand in my garage for nine years before I got around to installing it. and after verifying (three times) that everything was wired correctly when I finally turned the key I got a "Crank, No-Start" for my efforts...

The root problem? the fuel in the injectors had turned to varnish and only a trickle of fuel
got through... I had to build a temporary rig to push straight injector cleaner through them at high pressure, while "Firing" the injectors, until I got a clean even spray pattern from all four orifices, that took nearly an hour and a half of continuous running.

and even then I had to replace two of them...

Most other people would have simply bought six new injectors

I'm far more stubborn than that...

SenorNoob · Jul 26, 2014

OP, Ignore this post. It's for the lurkers.

AllanD said:
Because to run on a 1993 or later computer it needs the "red tops" to run correctly.

I know it has no significance to the question at hand but,I just wanted to say that the reverse is not necessarily true. I have a 92 ECU running the "red tops" and it seems to me to be working fairly well. At least unless I'm misunderstanding what you mean by the "red tops".

AllanD · Jul 28, 2014

The computer has a certain amount of "adjustability" to accommodate different flow rate injectors and for obvious reasons it's easier for a computer to adjust for an injector with a higher flow rate than for a lower flow rate, by adjusting the "open" time.

The early "Grey" injectors (the same flow rate as used on the 2.9) are 14#/hr
the later "Red" injectors are 24#/hr.

As a note many ford engines use the same flow rate injectors, the 2.3, 3.0 and most 3.8 engines use the 14#/hr greys, while the 3.8SC and some 4.9 Engines use the 24#/hr reds.

This does not suggest in any way, shape or form that the injectors are entirely compatible
as some have different electrical characteristics and others have spray pattern differences.

As a note if you want "Cologne engine" injectors and you cannot find an appropriate 2.9 or 4.0 to steal injectors off of look for a 3.8 engine.

Later production (mid-94 on) 4.0's have black plastic tops on the injectors but these are the same as the 1993-94 "reds".

Please do not get the idea that bigger injectors will lead to more power without the requisite quantity of air to burn it with.

THE reason for the change in the injectors was all about the future implementation of SEFI

Advice on 91 to 94 ranger 4.0l thank you

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