Hi all

Recently purchased my first Ranger from 2nd owner - 4-cylinder, 5-spd, 175k miles for $2500. Runs great but at 13.67 city/17 hwy gas mileage is far below the original 19/24 rating. Unfortunately because of that price and long list of other buyers after me, I didn't discuss MPG with seller although he mentioned the camshaft position sensor should be replaced. No smoke but from tailpipe soot it's running rich. I've purchased Haynes manual but it seems to focus on V6. Example: It talks about I4 sensor replacement but doesn't even say where it's located LOL.

1. Wishful thinking here but could sensor be the simple culprit even with no check engine light?
2. If sensor should be replaced, is there a better repair manual? I also searched YouTube videos w/o success (found one for later model I4 but really bad lighting).
3. Maybe it best just to start with major tune-up?
4. Lastly, anybody know of good Ranger mechanic in this corner of the country - Bellingham, WA.

Thanks for your sharing your knowledge,
Larry

 

Welcome to the forum

Yes, that is poor MPG for a 2.3l SOHC Lima engine

O2 sensors last 12 years or 100k miles, you just have the one in a 1994 4cyl, if it doesn't look new change it
O2s are THE ONLY sensors that wear out

My 1994 4.0l has all original sensors except O2s, 400k miles

Inspect a few spark plugs, see if its time for a change, there are 8 so not an easy task

You can test the Dual spark plug setup by unplugging the 3 wire connector on one coil pack
Start the engine
If there are misfires then one or 2 spark plugs on that side are not working well
Then repeat test but unplug the other coil pack

Benefit of Dual Spark plugs is more power
Downside is you can't tell when one of the spark plugs in a cylinder is not working, lol

 

Hi RonD

First off, thanks for your quick response post! Also apologies for my slow response as shortly afterwards my 95 year old mother fell and broke her arm. So it's been a little distracting of late. She's doing fine other than being grumpier than normal LOL.

Your reply had lots of good info for a Ranger rookie. Regarding the oxygen sensor, if it was bad, wouldn't the check engine light be on? The previous owner had told me about the dual-plug engine which amazed me for an engine of this vintage! I'm familiar with dual-plug motors but thought that was a thing of Porsche and such sports cars.

Thank you,
Larry

 

No, O2 sensors start to fail after 12 years or 100k miles and all you will notice is lower and lower MPG as time goes by, they will eventually set a code but not after costing you $100+ doilars in wasted fuel over the years, as the MPG drops

O2 sensors can only see Oxygen in the exhaust, and once they are warmed up(600degF+) the chemicals they use generate a voltage, under 1volt
0.1v = lean, add more fuel
0.9v = Rich, add less fuel
Computer tries to keep the upstream O2 voltage at 0.45v average
As the O2s run out of the chemicals the voltage goes down, so computer adds more fuel that the engine doesn't really need, to maintain the 0.45v, so money out of your pocket, and not instant, its a slow process, insidious is a word that comes to mind, lol

The 1989 2.3l was first years for the distributorless model, so adding dual spark plugs was fairly easy
Dual spark plugs with distributors was hard to do, the caps were a nightmare, lol, 4cyl seen here: https://www.partsklassik.com/images/...large/2265.jpg
6cyl seen here: https://cdn2.pelicanparts.com/catalo...53-015CW_1.jpg


Once car makers started to go distributorless dual spark plugs became more practical, but...............................................
Dual Overhead cams with 4 valves per cylinder were also coming into their own, and that's even more power, so available head space was better used for 4 valves than dual spark plugs

 

More good info and, right after I asked about "check engine light", I also thought, if that's even working as I noted it doesn't light up in the initial ignition switch "on" position. I'm installing the new O2 sensor tomorrow and I'll let you know results after a week. If that doesn't do the trick I'll follow up with your spark plug suggestions. I'm curious about the Pelican Parts distributor example, you don't happen to also own one of those German cars :)?

Since I have it but after O2 results, I'm going to replace the camshaft position sensor. Anybody know where it's located on the I4 and of a better repair manual for the I4 other than Haynes per my original post or of a YouTube video?

Thanks

 

You will want the 1994 Ford shop manuals for Rangers, like this one: https://www.ebay.com/itm/26634324968...sAAOSwO9RkuxGr

And this one for wiring and vacuum lines: https://www.ebay.com/itm/14516713210...EAAOSwzfxkeKq-
Called EVTM

There were 3 manuals in the set, body/chassis is the 3rd

Set seen here with drive train and body manuals: https://www.ebay.com/itm/37441625476...8AAOSwzwtktoUt

These are basically FREE to use because you can resell them when you don't need them any more, just like the people you are buying them from are doing

 

Hi all

Since last year's post I've done everything advised and more including new oxygen sensor, major tuneup (done by reputable shop), compression check (all 175 range), shop manuals, etc. Mileage still bad at 14 city/19 hwy.
I had mentioned camshaft position sensor replacement to shop but they said not necessary since check engine light not on. Couple months ago out of desperation I decided to change it anyway per following video (couldn't find one specific to a 1994). After much work removing everything for access to its location (per video - driver side of engine, lower front, adjacent to timing belt cover), nothing there nor any place to install one WTF!!!

Questions:
1. Truck has oversize tires 235/75/15 and I use a 1.17 mileage factor for MPG checks. I've heard oversize tires reduce mileage but that couldn't be the only factor???
2. Where the hell is my camshaft position sensor??? Anybody know of another video to help?
3. Yes, I know it's a 30 year old truck, so maybe I just need to live with the 14mpg. However I'm amazed at how many other Rangers of this vintage I see on the road who claim to be getting much closer to 19mpg.

I've spoken with tune-up shop, they say bring it in but did not sound hopeful other than getting some additional diagnosis $$$.

Thanks once again,
Larry