Oil pressure switch making me scratch my head...

[Alex98]

Alright I have swapped the 03 sohc into the ranger and got it started and it runs well. Anyway I have no oil pressure at the gauge. It goes into a ready mode and moves off the needle but when started does not move. I got another oil pressure sender (not a 03, i think its a 99) off an sohc, but it didn't to seem to have any effect. I have read up on the issue and each set of specific years seems to work differently. I'm pretty sure the wiring is correct also. Connections seem fine as well. Does the oil pressure sender have to be from the same year as the engine to work properly??

Also one more thing. I have an extra breather tube coming off the intake that I have connected to the 98 purge valve. The original engine was a 98 ohv. Where exactly is the purge valve connected to the engine?? I don't think I have it right as its throwing a check engine code and running slightly off. It's the purge valve code obviously. I'll post the exact code that it's throwing shortly.

 

[ashleyroachclip]

The sending unit is different for a gauge as opposed to a warning light.
Install a mechanical gauge to be sure you do have oil pressure.

 

[RonD]

Ford uses an oil pressure switch, above 5psi it shows normal pressure, or no Idiot light.
Below 5psi it shows no oil pressure or Idiot light on.

You want the oil switch off your old engine, or get a new '98 switch to match your '98 gauge and wiring.

NEVER use sealing tape on a 1 wire sender, 1 wire means the threads are the ground for the circuit.
If you must use sealer, leave the bottom threads bare.

If your lifters are not "tapping" then you have oil pressure just no gauge, if lifters are "tapping" then you have a good gauge but no oil pressure....stop running the engine

 

[Alex98]

I definitely have oil pressure, that's not the problem here. The oil pressure sender has already been wired up to the 2003 computer and everything. This is the second time I'm putting this motor in a ranger. I use to have a black 98. So it should work anyway. I guess the fix might be to get a 03 sender. Thank you for the advice. Sorry for the lack of previous info. It's pretty much finished. Just have several small issues. The code being thrown is a p0443 code.

 

[Alex98]

How is the evap purge solenoid grounded? it seems open all the time, I can hear the vacuum to it. When I unplug it it stops. This is leading me to believe that it is somehow always grounded.

 

[adsm08]

All electronic valves or solenoid used for engine control (fuel injectors, EVAP purge and vent, EGR vacuum, even the trans shift solenoids) are always powered key on and the computer switches the ground to turn them on and off.

If you suspect that a component is stuck on then unplug the component and the computer and check continuity to ground.

 

[Alex98]

Continuity to pcm is confirmed. If I'm thinkn correctly this points to a bad pcm unless it receives another signal to determine to purge the system or not.

 

[adsm08]

I think you misunderstood the test I wanted you to do.

I want you to unplug the valve and the computer and see if that wire still has continuity to ground. I am looking for a pinched or shorted wire. If you have no continuity to ground with the computer unplugged then you suspect a bad computer.


The computer program tells it to open the valve when certain conditions are met, usually low or medium throttle, certain temps, and a few other conditions that I am not 100% sure of.

 

[Alex98]

Thats what I did, on the 03 computer its pin 56. Continuity has been confirmed with it unplugged if its on all the time then there must be something telling the computer to purge all the time. That's what this is telling me.

 

[adsm08]

So you are saying that you unplugged the valve, unplugged the computer, and tested the wiring continuity to the battery negative cable and it tested as having low resistance. Correct?

 

[Alex98]

I tested the ground between the computer and the valve .5 ohms. I'm not getting anything at battery ground. Do you mean continuity between the pcm and battery ground??

 

[adsm08]

Ok, I would suspect the computer at that point.

 

[Alex98]

Does the pcm switch all grounds to a dedicated pcm ground to body ground? I'm guessing the continuity test from the pcm ground wire to body ground(pin 24&25)? I'm misunderstanding a lot here apparently.