The double rev

[Cheechingbacktolife]

Hello looking for some help. My truck is a 95 ranger 2.3 and it has the apparently legendary double rev. It’s so common that it’s known by some mechanics I’ve talked to as a common characteristic of that engine. Now being a man of logic and being how my automatic truck has stalled in the middle of intersections multiple time lol i know that something isn’t right. I did my research and learned that the rough idle, stalling, and double rev is caused by a design flaw which causes the engine to break its intake manifold gasket quite often. The gaskets are already on there way but I don’t feel I know enough about to work on it yet. Forums parts and general info seems to be hard to find on my truck. I was wondering if it’s true that this a common issue with this engine and which gasket is it. The upper or lower manifold?

 

[RonD]

Welcome to TRS

"Double REV"????

Sounds interesting but never heard or read about it

2.3l SOHC Lima engine was first used in a 1974 Pinto
And last used, as a 2.5l in the 2001 Ranger
27 years of use, and no real design flaws I have heard about

If your engine stalls it could be a vacuum leak, or faulty IAC(idle air control) Valve
On cold start(do NOT touch gas pedal), start your engine, it should REV up past 1,500 RPMs then drop down to about 1,000-1,100RPM and stay there
As you drive and engine warms up idle should drop and then stay at about 800rpm "in gear"
IAC Valve and ECT sensor are working

Easy test after warm up, let it idle
Unplug the IAC(idle air control) Valve
RPMs should drop to 500-600 or engine may stall, either is GOOD it means no vacuum leaks
If idle doesn't drop then you have a leak

 

[Cheechingbacktolife]

Welcome to TRS

"Double REV"????

Sounds interesting but never heard or read about it

2.3l SOHC Lima engine was first used in a 1974 Pinto
And last used, as a 2.5l in the 2001 Ranger
27 years of use, and no real design flaws I have heard about

If your engine stalls it could be a vacuum leak, or faulty IAC(idle air control) Valve
On cold start(do NOT touch gas pedal), start your engine, it should REV up past 1,500 RPMs then drop down to about 1,000-1,100RPM and stay there
As you drive and engine warms up idle should drop and then stay at about 800rpm "in gear"
IAC Valve and ECT sensor are working

Easy test after warm up, let it idle
Unplug the IAC(idle air control) Valve
RPMs should drop to 500-600 or engine may stall, either is GOOD it means no vacuum leaks
If idle doesn't drop then you have a leak

After warm up idle sat at just above 1500 I adjusted the idle screw and ended up turning it down all the way. Now the engine sits at 1000-1200 rpms.

 

[Dirtman]

A 95 2.3 doesn't have an idle screw... what you adjusted was the anti-diesel screw and you should not have touched it. It's for setting the TPS sensor voltage not for adjusting the idle speed.

 

[Cheechingbacktolife]

A 95 2.3 doesn't have an idle screw... what you adjusted was the anti-diesel screw and you should not have touched it. It's for setting the TPS sensor voltage not for adjusting the idle speed.

It says adjustment on a yellow sticker in top of the throttle body and pushes directly against the throttle control. Turn it clockwise and it opens the throttle, counter clockwise and it closes turning the idle down. There are no sensors or wires attached to it it is completely mechanical and is a component attached to the outside of the throttle body itself.

 

[Dirtman]

Yes it opens and closes the throttle plate like a carbs idle screw, but fuel injected engines don't work the same. The idle speed is set by the computer and is adjusted by the idle air control valve (100% out of your control). The throttle position sensor tells the computer how open the throttle is, once the throttle is open at all the idle speed is non relevant and the idle air control valve is shut off. That screw is used to set the 0% rate of the throttle position sensor (i.e throttle closed). Using it to adjust the idle as you did throws off the throttle position sensor. And no the throttle position sensor is not directly attached to the anti diesel screw but the sensor still detects how open the plate is (which is moved by the screw).

When that screw is adjusted properly the engine should barely run or not at all with the idle air control valve disconnected. You need a voltmeter to reset it.

 

[Snoranger]

It says adjustment on a yellow sticker in top of the throttle body and pushes directly against the throttle control. Turn it clockwise and it opens the throttle, counter clockwise and it closes turning the idle down. There are no sensors or wires attached to it it is completely mechanical and is a component attached to the outside of the throttle body itself.

There's a sensor on the other side of the throttle body. It may not touch it directly, but it is affected.

 

[RonD]

+1 to the above ^^^

You are in a bit of a quandary since you adjusted that screw, as far as testing for vacuum leaks

As said "unscrew" it and close the throttle plate see if the IAC Valve is even working, on all fuel injected engines the fuel injection computer must be in control of the idle because there are no "idler jets", like on a carb engine
So to prevent over heating at idle the computer needs to a air valve(IAC) to set lower RPMs
And its quite accurate, +/- 3rpm when working correctly
This is not a Ford thing, all fuel injected engines use this "air valve" method

Pull off IAC Valve and plug in its wires
Turn key on
Look inside IAC Valve and unplug its wires, valve should close
Plug in wires and it should open
Only moves maybe 3/8", but does move
If not you can check for 12volts on its wires but IAC Valve is most likely the problem

You need to use a Motorcraft IAC Valve, 3rd party don't seem to work to well, even a wrecking yard Motorcraft IAC Valve is preferred over a new 3rd party valve

 

[Cheechingbacktolife]

Ahhh I see I’ll go test the iac when I get rid of this cold and maybe pickup a volt meter and yes the engine does run with the anti diesel screw backed off fully