So, I have a 1995 ranger that I just got running after it set for about 3 years. It has the 2.3 liter with a 5 speed manual, I’ve done a lot of work to get it back into running condition and the only thing I can’t seem to find resolve for is that when idling EXACTLY every 55 seconds the idle goes rough and I get a open loop fault message on my scanner, if I tap the gas it goes away and runs fine for the next 55 seconds. It drives fine but I can’t stand the intermittent rough idle and I just know it’s something simple and stupid I haven’t done yet.. so far I’ve done the EGR purge solenoid to resolve a vacuum leak, repaired the exhaust leak, replaced both O2 sensors, and messed with and taken readings from every sensor I can find. All sensors appear to be reading in normal parameters until it drops into open loop fault and I am at a loss and don’t know what else. It currently has 2 codes p0443 evap emissions purge control valve circuit, and P1445 purge flow sensor circuit High input. Any help would be much appreciated

 

Welcome to the forum

Open Loop is when engine is cold, coolant under 150degF, ECT sensor
Or a main sensor reading "can't be trusted", i.e. MAF or upstream O2 sensor

Rough idle could be Computer is turning on CHOKE because it "thinks" the engine is cold enough to need to be choked
Choke means richer running

I assume when to tap the gas pedal computer goes back to Closed loop?

Can you see "live data" on your scanner, if so watch the data for sensor that changes when Open Loop fault shows up

 

This is the reading from the sensors when it goes into the OL_Fault

 

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84c = 180f so temp is OK

Need to switch to O2 sensor Voltage, Fuel trims are the computers data

0.1 to 0.9volt is upstream O2 sensor voltage range, it jumps around a lot, average should be about 0.3-0.5volt
downstream O2 will be more steady at 0.75 to 0.85 volt

 

They would be at those volts and would slowly go down, all the way down to zero

 

Well that would cause Open loop
Check fuse 20 in engine bay fuse box, 15amp, its for the O2 heaters, but should set a code, well 3 codes if its a V6 engine

And these are new O2s?

 

Brand new, I’ll check the fuze when I get off work in the morning

 

I could not find fuse 20, do you know where it is on the 2.3?

 

Never mind, found it but it seemed to be good. I’ve now checked every fuse and they all are good. But now bank 1 o2 sensor 2 is reading V0.000

 

B1S2 is the rear O2 sensor

O2 sensors need to be warmed up to output voltage, they need to be above 650degF

They generate their own voltage, check the 4 wire connector, make sure it is clean and dry, doesn't take much corrosion to knock out the under 1 volt output
Wires are also near exhaust pipes, so they can be damaged if they touch exhaust pipes