The rollover valve in the top of the tank should prevent liquid gasoline from ever reaching the carbon canister, but even if it did, it should purge normally with no effect on the engine.

 

Hey Guys, Sorry for the wait, but I finally had time to check out the TPS and the Purge Control Solenoid.. here are the results...

TPS Ref Voltage ---------------------------------------- 4.98 Volts

Signal Check IDLE - KOEO, (SIG RTN and TP)----- 0.84 Volts
Signal Check Wide Open Throttle------Gradual to 4.51 Volts

Potentiometer: IDLE - KOEO, (VREF and TP)------ 2.9 Kohms
Potentiometer: W.O.T. ------ Gradual increase to 400 ohms

According to the haynes manual, everything is within Spec from the TPS... I dont know, how strict to spec those numbers have to be, but these were the readings I got.

Now the weird thing is, After this much time has passed since my post, the "ghost cruise control" problem has slowly faded away. It still haunts me from time to time, but maybe it was just one of those things that was meant to go away on its own... Oh well..

Now, as for the P0442 Code, i got to checking the Purge Solenoid, and here are the results. Which I think I may need a new one..

Setup 1:

Engine---Vacuum Control Line----T-------V.C.L.------ Purge Sol.
I
I
Vac. Guage

Engine Running, Power to the Solenoid steady @ 17 InHG
Engine Running, Connector Disconnected --17.5 - 18 InHG
Idle @ 850 - 900 RPM

Setup 2:


Engine-- Vacuum Control Line---T---XXXXXX Purge Solenoid
I
Vac Guage

(I disconnected the Line to the solenoid from the TEE and held my thumb over the open end of the TEE)

Vacuum Shot up to 19.5 InHG and held Steady. Engine sounded and idled better...

I dont have a vacuum pump, but Hopefully I will soon have one, but for now, The haynes manule says the solenoid should hold a vacuum for 20 seconds, So after unplugging the electrical connector, I took the loose Control line from the solenoid and sucked on it ...

1. All I could taste was fuel Vapour from the solenoid
2. The best way I could describe it would be imagine sucking on a fresh Milkshake or slushie through a straw.. I could literally fill my mouth with "fuelly" air from the solenoid and when I describe A milkshake feeling through 5 miles of straw, I mean it didnt want to seem to hold any kind of vacuum for any length of time. but it still had a "pull" feeling to it, and it took a smidget of lung power.. ( approx 1-2 InHg on the guage.. something didnt seem right here...

Maybe its the fuel vapours in my head talking.. i dont know..

I'm assuming with no power to the solenoid, it should remain in a closed positon.. and when the engine is running, vacuum is obviously present at the control line and 12.5 Volts is present at the connector..

How long does 12 Volts stay at the Purge Control Connector?
I was a dummy and reset the MIL Just before Geting these readings so the PCM was still trying to do its OBD 11 EV test. Im not sure if the PCM opens the Purge control when it thinks it needs to or if it is always open when the engine is running..

any ideas?

anyways, sorry for taking so long..

cheers,
Jim

 

sorry for the cruddy ascii diagrams, the Vac guage is supposed to be under the "T"..
cheers,
Jim

 

The purge valve should shut when the engine is idling and hold engine vacuum. Make sure it's installed the right way - it's directional.

 

Your Quote from previous reply:

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"Well From What I understand so far the IAC Maintains the idle depending on the TPS position and the Load on the engine..
IE.. When the A/C cycles ON and OFF, the PCM Sees a Load on the engine and "Magically" Signals the IAC to compensate for the demand by increasing the Air going past the throttle plate to increase the Idle just enough so that it won't drop below 750.
I say magically for lack of better words, because I do not yet know exactly how the PCM signals the IAC..
I think this also justifies why the engine wont drop back to normal idle when the stick is in neutral until I push the clutch to the floor disengaging the transmission.. I think that the PCM sees the input side of the transmission as some sort of a load and keeps the idle high until the load is gone - like when i push the clutch in.. hmmm....
At least on mine (at idle) when the compressor kicks in, the RPM drops to approx. 700 RPM then increases to about 1000 RPM then drops back to 750. (all taking place in about 1 second)
Also From my own findings I believe the IAC also helps smooth out shifts..
Just for a test I unplugged the IAC connector and went for a drive around the block.. The instant I pulled it out of gear,and off the gas, the RPM's dropped so fast, it made it difficult to shift into the next higher gear. I had to feather the accellerator a bit to get the gears to mesh.. ( shifting without the clutch)
Before this stupid problem the gears would mesh like butter and now because i believe the IAC is stuck open or slow.., the RPMS are always too high for it to shift nicely into the next gear, it holds it way too long and the RPMS dont drop they just stay at 2000 RPM when I pull the stick out of gear
so I believe the Secondary duty of the IAC ( especially in standard vehicles) would be that the instant the TPS sees a closed position the IAC "holds" the engine at the last highest RPM it was at, for the gears to engage (approx 1 "Jiffy" ) then releases, and then the process starts all over again...
Only in my situation, a "jiffy" is more like 5 -10 seconds, not 0.5 seconds like it should be.
Am I right or even close on this? If I am, I came up with that all on my own... if i am not well I guess I put my foot in my mouth and return to my cave.... thanx,jim"

-______________________-
Jim,
this is the EXACT same thing that has and is happening to me!!!
I've had this problem for ever and ever but it was very intermittent until now!
I have checked the Haynes manual the I have and it has no mention of an IAC at all! SO I'M STUMPED! I've checked my TPS and it checks out okay (correct voltages and everything). What is the check for the IAT?
When I depress my foot on the clutch, the idle jets upward for a moment and slowly starts to drop. All of your others symtoms you described above are all like mine as well ect. "unplugging the sensor and the truck almost stalling". This IAC definetly (sp?) helps with keeping a smooth shift by letting the idle and truck keep momentum.
Speaking with a friend of mine, (the one that unplugged the sensor for me) described the IAT as a 'dashpot' type of accuator. The needle sticks or something along those lines.
I bought a new IAT but i am not 100% sure if this is the problem. If I install it, I can't return it and I want to make sure it is it!
What was the check again for this? Voltmeter while running?
Would really appriciate a response!
Dubra aka "KUJO"

 

kujo, what happened ? jerry

 

This sounds like the same problems I am having. So how do we fix it? I replaced my map and tps with no luck! Replace the throttle body next? what?

 

Hi All;
Have this valve that I have seen in a pictorial and is on the throttle body of my 90 Ranger 2.3 ~ 4 banger. It is called an "Air Bypass Valve Idle Speed Control". The TPS is also on the body, (that I know is there). Does anyone know if this valve t goes by another name? Can't find it in my Haynes Repair Manual!

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Take a walk on the wild side + you'll find me there!!
The Brain Is Always On The Move

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My Beastie:
90 Ranger 2.3L EFI 2wd Mazda < with many new parts!

 

Your problem is tps (throttle postion sensor) if this issue occurs when driving and idling then the tps needs replacing. if its the IAC (idle air control valve) then it would only do it at idle and would idle quite high. As far as purchasing it always buy new especially when it electronics, cause you never know if the used one even works or how long till it breaks, trust me i know from experience. sorry that this reply is 11 years later