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1997 Ranger 2.3 and a 5 speed manual.


I'll list some info, then watch the video...


It had this condition when I bought it a couple months ago. I start the engine and it will idle smooth. I rev the engine, then it will idle and run rough. After a while it will return to a smooth idle. For example, the engine will idle smooth, accelerate through first gear and shift then it will run rough in second, third, and so on.

After driving about 20 miles or so, the engine runs fairly good and this problem almost goes away.


I get a P1443 code every time I drive it.

I get a P0303 about every 800 to 1,000 miles.

It has new plugs, wires, coil packs, oxygen sensor, and IAC valve.

The MAF voltage was within specs according to autozone's website.

Sprayed MAF cleaner = no change.

The fuel pressure is at 30 psi smooth idle, 34 psi rough idle, and it will briefly jump to about 40 psi when I rev it.

The catalytic converter sounds like it has a crack in it and it leaks quite a bit.

I sprayed starting fluid everywhere and found no vacuum leaks.



All of the following are in "closed loop":

I can unplug the throttle position sensor and it will still run just the same. Should the engine still rev with this unplugged?

Unplug the IAC valve = no change

Unplug MAF sensor = engine will idle, but will stall when attempting to rev. Small "blip" in idle when connector unplugged.

unplug coolant temp sensor = no change

unplug air temp sensor = no change

I have a ScanGauge II that I use, and it shows -40 when unplugging the coolant temp sensor or the air temp sensor. Both sensors read normally when connected.

Unplugging all of these caused NO check engine light.



The following video has 3 parts in it. You can watch the throttle lever to see what kind of input the engine has. The engine was shaking quite a bit in most of the video, but for some reason it doesn't look or sound as bad on tape as it does live. It's worse than it appears.

The first part is the engine cold and running in open loop. The engine actually dies in this segment and is very difficult to restart. Then I shut the engine off. The next part is in closed loop. The final part is the exhaust.

 

Have you double checked timing? If the timing belt slipped it would screw with the way it runs. Hopefully someone else with a little more knowlege will chime in soon, but that's where I would start.

 

It sounds like the engine runs out of fuel. When was the fuel filter last changed. It acts as though it gets enough fuel to start and idle, but not enough to run at higher RPM's. Have you checked fuel pressure? Do you hear the fuel pump run before the engine is cranked? Also, I notice that you have the 4 cyl engine with dual exhausts. At what point does the exhaust pipe split - before or after the muffler?

 

I don't think I've checked the timing yet. I'll have to look up the procedure and check it. I can peek in behind the cover and see that the belt appears to be frayed a little bit on the edge.

The fuel filter looks new... but looks can be deceiving. The fuel pressure is around 30 psi at idle. I can hear it turn on for a couple seconds when I turn the key on. It seems to run almost normal when the engine is warm, even at high rpm. The truck has no muffler. The pipe splits a foot or two after the converter.

 

The reason I asked about your exhaust system was because I'm wondering if you have insufficient back pressure. The lack of a muffler and two exhaust pipes may reduce back pressure too much.

 

If you can disconnect all those sensors without throwing a code, your ECM is dysfunctional. Can't say how much, but it has a problem. That is the procedure the CARB 'referees' go through when they are testing a vehicle that won't pass SMOG test. They unplug a sensor to see if a code is thrown. At least that is what they did when I had a problem. I think they were assuming that the ECM was ignoring codes, as in dysfunctional, and that was why it would not pass when it was almost brand new.
I didn't watch the movies...
tom

 

Would this mean a new computer is needed?

I picked one up at the junkyard today for $20. It's from a '96 with a 2.3 and 5 speed manual. Mine is a '97... hopefully they're the same.





I need a new catalytic converter for sure, and I'd like to have a close-to-factory type exhaust put on it.



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Evaporative Canister Purge Assembly, connects the intake manifold to the charcoal canister, made up of hoses, a valve and a sensor. Check hoses for cracks, leaks, replace sensor.

 

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Ok, I had some time to mess this thing...

When the engine is missing out, I can rev the engine a little and hear pinging from the engine.

I set the engine at TDC of the compression stroke and the timing marks lined up in each inspection hole in the timing cover.

I pulled the plugs from the passenger side - cylinder 1 smelled odd and had some brown/red specs on it. Cylinders 2 and 3 both smelled like unburnt gas. Cylinder 4 smelled normal. These plugs have only 1,500 miles on them.

The engine gets a P0303 (cylinder 3 misfire code) about every 800 miles, and only when the engine is cold.

I was going to do a compression test, but I can't find my adapter to screw the hose into the spark plug holes.


Pics... Cylinders 1 through 4, left to right, of the passenger side of the head.

 

Are your plugs single or double platinum?

What do the plugs on the drivers side of the engine look like.

Your #1 plug looks like you are getting some water on the plug. Is there something leaking above it, or is the fan blowing water from somewhere that gets the plug wet?

 

Here's a link to a discussion of repairing a P1443 on a 97 2.3,

How to fix code P1443 for a 1997 Ford Ranger - OBDII

Probably not related to your issues, but fixing that code might clear up some of the confusion.

I wonder if you have a fuel issue that gets 'corrected' when it goes closed loop and the O2 sensor is reporting. Maybe it's naturally a little lean for some reason.

Also, does your CEL work? Only reason I mention it is that the 1443 should have it on all of the time.

Just a few random thoughts. We now return to people who actually know things.

 

The center plugs look brand new -- because they are not firing? 1 & 4 are paired, as are 2 & 3, coil wise. I think.
Fix the above code, Can_p(urge), 1443, leaking hose of some sort, as suggested. This can be the cause of the weird performance. Downstream of all this hullabaloo are two O2 sensors. One before the catalytic, and one immediately after. Again, I think most '97 models have one pair per converter. You are feeding the cats a funny mix that the ECM is trying to maneuver back into compliance. If you have a 'holy' converter, bless 'em, then it will allow extra O2 to enter, thus making the sensor think the mix is too lean - left over O2 means there was not enough fuel to burn up the Oxygen. It will add more fuel within its limits. If you are adding more O2 through leaks to the system (Can_P? why yes..) than the ECM knows about. It thinks that it is getting the truth from the MAF sensor, and sends more fuel as more air is passed based on a table lookup, I think. That is how the chips work- fiddle with the tables at different MAF positions. (along with other stuff, I'm sure, but not gonna yammer too much)
If you confuse the ECM with too much bad info, expect it to run poorly. Disconnect the O2, disconnect the MAF, and I bet it smooths out (back to limp-home default mode - bad gas mileage, and probably fail SMOG check). If your injectors are working correctly, and the mechanics are sound (valves, rings, etc), and the spark system works, your engine will smooth out. If you make sure there are no extra openings to the intake manifold.
My hands are tired from typing.
good luck
tom

 

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Ok, about 3 months ago I gave up on the 2.3 and pulled it out to swap in 5.0 HO. I've got the 5.0 running now, so I thought I'd tear into the 2.3 to see what the problem was.

Blown head gasket, cylinder #1. The engine has basically no ring wear on it and looked to be in great shape inside. Oh well... at least I'm having fun with the 5.0!

 

Thanks for letting us know, wow, that's a small break in the gasket, but that's all it takes. Good to know you have a rebuildable core, just slap a new gasket on it and go?

 

If the 2.3 was still in the truck, then yes, I would just put a new gasket on and resurface the head. But the 302 is in the truck and running good, so the 2.3 is destined for the scrap pile.