need help 3.0 to 4.0 conversion

[RonD]

Instead of "hitting the inertia switch", turn key on, press gas pedal to the floor and hold it there, this will turn off the injectors while cranking.
It is a routine in all EFI computers to clear a flooded engine.
If computer is on(key on), and there is no pulse from CKP(crank position) sensor, and it gets 4.5v, or higher from TPS sensor(pedal to the floor) it will disable grounding for fuel injection.

If fuel pump is coming on then EEC relay is closing so engine electrics should all be working.
So I doubt it would be a harness issue.

Did you test the spark?
Do you have an old timing light so you can check if #1 is sparking at TDC mark?

While the CPS is important, it only times fuel injectors after startup and some spark advance functions, the CKP sensor is the important one, it starts and times spark and injectors for startup.
Engine will start and run without CPS pulses.
So test for spark, if you have spark CKP sensor is working, because you have fuel on the plugs it is also most likely working

 

[redneck1959]

I checked the timing its at tdc on cyl 1 compression stroke, also when its there its at 0 degrees on the crank balancer, I made sure it was there and checked the camshaft syncro and it was set right using my cam syncro tool you get when you buy a syncro

 

[redneck1959]

ive done quite a few of these 4.0 conversion but never in a flex fuel truck so im guessing I either have a wiring issue or something in the fuel system cause its like its flooding the motor, whats different in the fuel system between 2000 ranger 4.0 ohv and 2000 ranger 3.0 flex fuel

 

[redneck1959]

or is there a way to test this 4.0 computer and see if its bad?

 

[redneck1959]

I see people talking about the flex fuel sensor? could this be a problem

 

[RonD]

I wouldn't think the 4.0l computer would have a circuit for the flex fuel sensor.
That sensor is on the gas line near the fuel filter, you can always disconnect it(the power/ground).
And they are worth $650 new so.......removing it and selling it would net you some $$.

But I doubt that would be the problem, you have stopped fuel flow with same results.
Hold down gas pedal while cranking would clear any flooding.

There is no way to test a computer, you can try "talking" to it, with a reader/scanner and see if it is responding as it should.

Just as a thought is the coil the correct one for the 4.0l, there are 4 connections, 12volt, coil 1, coil 2 and coil 3.
12volts comes on with the key(EEC relay)
The 3 coils are grounded by the computer when they need to be charged then ground is removed to fire that coil, just like any engine ignition coil.

If this was the wrong coil then firing order could be messed up in the coil pack, which would give you your symptoms.
Some coil packs are:
12v, 1, 2, 3
some are
12v, 3, 2, 1
some are
3, 2, 1, 12v

 

[redneck1959]

the coil im using is the one that came with the motor swap so im guess would be that it is right, so your saying to probe my coil plug and see where the 12 volt power supply goes in

 

[redneck1959]

and when I hook my scanner to it reads the computer and tells me no faults found

 

[redneck1959]

so i have pulled all the injectors and rail up and checked for injector spray, and heres what ive come up with when you turn the key on no spray when you roll the motor over all 6 injectors spray at the same time, is that normal

 

[RonD]

It should be 3 at a time, I believe on startup the computer uses Batch fire, so on a 4 cylinder 2 injectors open, 6 cyl 3 injectors, 8 cyl 4 injectors.

It would appear all 6 were spraying fuel because it would alternate between the 3 at each cylinder's TDC while cranking, so every time a one spark plug fires, 3 injectors just sprayed.

Sequential fire would be each cylinder's injector only spraying just as intake valve opens and piston is going down, pulling in the air/fuel, this gives better MPG.
That would happen once engine was running and Cam Position Sensor was judged "sane" by computer and takes over injectors and some spark advance.

Batch fire is the startup and the default setting, most EFI engines use this on startup and in case CPS is "insane" it is the default mode

 

[redneck1959]

so the only thing really left is the computer im guessing if so does any body know what year i can get it from and is it the same as sohc 4.0 or only 0hv models

 

[RonD]

EEC swapping needs to be done for engine and trans, so 4.0l/auto EEC would not be good in a 4.0l/manual and visa versa.
4.0l OHV and 4.0l SOHC would have different engine operating parameters so probably wouldn't use the same EEC programming, but don't know for sure.

Also model/year can be a factor because of control wiring and PATS

Good read here on what to look for in an EEC part number
http://oldfuelinjection.com/?p=17

And here for what EEC does
http://oldfuelinjection.com/?p=3

May be worth while to "read" the EEC with an OBDII reader to see if it responds correctly.
Also after pulling it out, open it and look for circuit board damage.

 

[redneck1959]

on my obd2 scanner is connects to it and when i read codes it says no faults found and i opened the computer last night and it is clean with no burn spots