Hello, I'm new to this thread and website, I have a 96 ford ranger with problems. I'm not exactly sure as to whats causing it. But I can say I think it's running lean or for a better term backfiring and or misfiring. I've been dealing with this truck for about a month trying to fix the problem to no avail.

This is a list of whats been fix and or replaced.

Mass Air flow senser
Electric Fuel Pump Inertia Switch
Air filter
Standard Motor Products CP416 Purge Flow Sensor
Fuel pump relay
Full throttle cutoff AC (Wac) Relay
Compression test
Pcm replaced
Fuel regulator
timing

Now none of this has fixed it.

the problem is when it's at idle and in park or neutral and you rev the motor up about 1/4 down on the throttle the truck starts to back fire and run like it's skipping. now the only other time it does this is when I'm giving it gas trying to pass a car or merge into traffic.I'm talking about hard acceleration.

Last night I decided to switch out the new coil packs I bought last year with the one's I replaced them with. and the truck is still doing the same thing but further down the throttle. meaning you have to press the throttle further in park or neutral to get the truck to do it.

here is a video of what I'm talking about

https://www.youtube.com/watch?v=PSDz...ature=youtu.be

Now in the video the check engine code is p01443

I have resolved that issue

now there is no check engine light on and when you press the throttle and it starts to do it the check engine light blinks on and off. it will blink on when it skipps and off when the throttle dies down and blinks again when the throttle picks back you. you notice that the engine light flashes in the video while it's on.
also, I've been posting on the ranger station forums as well trying to figure this problem out. I'll also, give that link as well

96 Ford ranger 2.3L 4 cylinder acceleration hesitation - The Ranger Station Forums

 

Welcome to the forum


Blinking CEL(check engine light) means hard misfire and engine damage can occur so best to back off throttle when that happens.

Triple check the coil packs firing order, then have someone else do it, lol.

Fuel injected engines do not have gas pedals, they have 'air pedals' now, no Jets or accelerator pump to get extra fuel from, so the "pedal" only lets in more air.
So on the throttle plate there will be a TPS(throttle position sensor), this tells the computer when to add more fuel based on Driver input, gas pedal position.
TPS is similar to a volume control or light dimmer, a variable resistor and easy to test.
Top wire will have 5volts, key on
Center wire will have .69-.99volts(under 1 volt) when throttle is closed, as you open the throttle voltage will increase steadily no jumping or dropping, at full throttle voltage should be 4.5 to 5volts
Easy to test with volt meter and a sewing pin.
Use pin to pierce the center wire
Ground volt meter and test voltage on center wire, key on engine off
Now slowly open throttle manually and watch voltage


What were the compression numbers?
Above 160psi average would be expected for the 1996 2.3l

If under 130psi average then timing belt is off.

Also check Fuel Pressure, should be 35-40psi, idling, then raise RPMs to 2,500-3,000 and hold there to see if pressure starts to gradually drop, a bad thing.


After engine is warmed up and idling, unplug the IAC(idle air control) valve, engine RPM should drop to under 600 or engine may even stall, either is good, it means no vacuum leaks, if RPMs stay above 700 then you have a vacuum leak.

There is a long shot problem that can occur on the 2.3l, the spark and fuel injector timing comes from the Crank sensor that reads a Tone Wheel on the back of the Crank pulley.
Second picture down here: 96 1996 Ford Ranger Engine Harmonic Balancer - Engine Mechanical - ATP, Dayco, Dorman, Pioneer Cables - PartsGeek

Tone wheel looks like a gear, but has 1 missing tooth, each time a tooth passes the CKP(crank position) sensor a pulse is sent to the computer, the teeth are spaced 10deg apart, when the gap(missing tooth) passes by that tells the computer that #1 piston is at top dead center, so that's how the spark and fuel injection is timed.

This tone wheel is a "press fit" on the back of the main pulley, there is no key to hold it in place and the long shot is that it has moved, I have only read about this happen one time, so long long shot.
If it has moved you would have a lack of power and also popping and backfiring as RPMs increased.
You can use an old fashion timing light to check if spark timing is correct, if it is then tone wheel is OK.

 

the truck was doing it before I had the timing redone. I had the timing redone 3 weeks ago. and the crank shaft position senser was replaced.
The compression test I had preformed reveled 176 psi across every cylinder. or so that's what the shop i took it to said.

 

When it was in the shop the shop replaced the tps senser, but took it off and put the old one back on because the new senser made the truck run worse.

 

I don't have a way to test to see what the rpm's are but when I disconnected the iac valve the truck's rpm's dropped and it did try to stall.

 

I went down to the shop that done the compression test. and I had them to look up the results of the test not just take their word. and the paper said 125 psi per cylinder. So I guss I need to throw the engine back into the loop.

 

I know the timing isn't off. so is 125psi meaning the motor is that wore out.

 

125psi average on all 4 cylinders means valve timing is off, so belt was either installed 1 or 2 teeth off or it slipped.
That would explain the popping and backfiring as well.

1996 2.3l engine shows 9.4:1 compression ratio, rule of thumb is to use 18 X (compression ratio) to get expected average range
18 x 9.4 = 169.2psi
So 165 to 175 would be expected

If 1 or 2 cylinders were 125 and 2 or 3 others were 175 then could be burnt valve(s).

Worn out rings would be higher compression but low for that engine, like 150, and if you added a teaspoon of oil to a cylinder and retested compression it would come up to 165 or so because the oil temporarily seals worn out rings.

And at 125 engine should be hard to start cold and lack power across all RPMs, since there is some doubt I would retest it.

Proper test is cold engine, or barely warm
Removed one spark plug from each cylinder, 2.3l is a dual spark plug engine
Both coil packs unplugged
Throttle propped open, just put something on the gas pedal, doesn't need to be wide open, 1/2 is fine
Test compression by getting at least 5 "hits" of compression stroke, you will know what that is when you hear it.
Write down results, and put DRY next to that number
Pull out compression gauge and add a teaspoon of oil via spark plug hole then retest compression
Write down result and put WET next to the number

test all 4 cylinders this way.

WET will ALWAYS be a higher number, how much higher tells you if there is a problem and what it might be.

Compression numbers are base on gauge itself, battery condition and starter motor condition.
A metal piston with metal rings pushed against metal cylinder walls is not air tight, and metal valves sitting against metal seats is also not air tight, it is not suppose to be air tight.
It leaks, brand new it leaks, lol, so the speed of the crank pushing the piston up to compress the air needs to be fast, the faster the piston speed the higher the compression numbers.
Which is why you remove 1 spark plug from each cylinder for the test, so the other 3 cylinder have no compression to slow the crank down for the test and you have faster piston speeds

 

I do have to say it's very easy to start. I don't even need to get into the truck and start it. it fires within 1 turn of the switch 1-2 seconds. I noticed this difference when I installed the old coil packs, it ran a lot better, and now it's only doing it when in park or hard on the throttle 3/4 down. before with the newer coil packs it was 1/4 on the throttle. and when I rev the motor up I can hear the valves chatter. going down the road however, I don't.

 

the motor does seem to lack power.

 

Worn cam shaft ???
And a new shop to take it too.
Any shop that first says 175 PSI and then 125 on paper _ oh sorry for the mistake.
Sounds pretty incompetent.

They've even replaced the PCM too, they're throwing parts at it and just guessing _ and expensive parts !

EDIT:
In the other thread, you said you had a code light for the EVAP system.
I'm not familiar with the 4 cylinder, but from the EVAP system there should be large vacuum line that comes from the EVAP system that connects into the intake manifold.
Through this the gasses from the system are entered into the intake manifold and burned.
If the EVAP is having problems (we don't know where yet) there may a possibility that it's causing a vacuum leak that's only noticed under hard acceleration.
Find that line that enters the intake manifold, disconnect it, and plug the port off on the manifold and see if things don't improve.

 

thanks I'll look for that line, I did replace the purge flow senser, it's a black senser after you get to the purge canister. I reset the battery yesterday and the check engine light hasn't came back on. but sometimes it can take a few days. the line that goes below the truck is old I'm assuming that's the one that goes to the manifold. I don't like the looks of it but without car ramps I can't get under the truck and trace it do to the damn lowering kit it came with.
and your right I'm looking for a different shop at the moment. I hate to say it because it's going to be high but I might need to take it to the ford dealership and have them check it out.

 

I've learned from Ron that 90% of the time it's never the sensors.
It always turns out to be a bad ground, bad connection, dirt on the sensor (MAF sensor), bad connection, worn mechanical parts... etc...

Another thought, what about your PCV valve, I'm assuming it has one ?
There's no sensor involved, it's totally mechanical and it may be contributing to your problem.
I like to go after the simple things first before delving into the pricey stuff _ a process of elimination if you like.
In all honesty though, I'm going to agree with Ron about the timing belt not being installed correctly _ for now anyway...

Also know that disconnecting that big vacuum line from the EVAP system will probably throw up another code, but don't worry about that for now.
Ron will probably know about that better then me.

 

when I put the truck into the shop the first time I had them redo the timing because I thought that's what it was. and they did come back and told me that the timing was 3 teeth off and that the senser was shot. this was done after the pcm was replaced. then the truck stayed down there for two weeks because they were trying to figure out why it was doing it. I picked it up and it drove fine until i had to pass a car then it started the same stuff up it was doing before I had the timing redone.
while it was in the shop I started this post and with everybody's the truck is better.

the mas made the truck not stall out taking off or spit and sputter taking off

the fuel pump relay and full throttle cutoff ac wac relay fixed the low circut to fuel pump, which was causing most of the hesitation I was having and cutting out I believe.

the purge flow senser made what it's going now alot less harsh than before I replaced it.

the air filter made it's response time improved a little along with fuel mileage which is 23.4 in town.

the fuel cut off switch made the throttle not cut out going down the road

Fuel regulator noticed no difference at all.

and replacing the new coil packs with my old ones, made the truck do it at 3/4 throttle pressed instead of 1/4 pressed while in park or neutral. and driving it went from doing it in the entire mph range under hard accelerating to hard accelerating between 80-90 mph.

 

I'm not saying they done it right or wrong, I just can't afford another timing job

 

At this point if you can't or are not able to, due to lack of knowledge, I would go to another garage and have them do another compression test.
You can get a tester for around 30 bucks and do it your self.
I'm not convinced that it was ever done properly _ first too high, then too low, what is with that ??? Very fishy...
Ron described how to do it. You don't actually have to remove all the plugs, you can do it one at a time, but to be more accurate, one can remove the plugs.
On my 3 litre V6 the starter whips it over pretty quick, so I didn't bother taking the plugs out.

And how did it get out of time in the first place _ how did it jump three teeth ?
Hopefully that problem was addressed first.
Did they replace the belt, was it damaged ?
Even with a new belt, it still may have jumped again if the mechanism in place that holds the tension has not been corrected.

I'll mention again that I'm not familiar with the 4 cylinder engine, but normally with a belt, there is an idler puller that is under spring tension.
The spring initially tensions the belt and then the pulley is "locked" up with a bolt.
At least that is the way it was on my old Mazda B2200.
There is more to it as well, as the tensioner takes up the slack in the belt, the timing can become "off" as the slack changes the timing as the belt is tightened by the tensioner.
One has to compensate for this.
It depends upon the design I guess.

After the tension has been set and the idler pulley has been locked up, I rotate the engine by hand through at least 5 revolutions.
I then check the valve timing again, then I turn it over with the starter.

When I'm totally satisfied that there is still good tension on the belt and it's still in time, I reassemble the engine.
Maybe a bit over-kill, but I'm OCD about things like this.
I belive that a good shop should be the same.

 

thanks, and also, just created this video about 30 minutes ago the problem presents it's self between 5:13-5:25.

https://www.youtube.com/watch?v=Fq_6...ature=youtu.be

very windy had the windows down

 

well, the timing belt broke about 3 years ago give or take. and i took it to a shade tree mechanic to fix it since he owed me. and he had a tow truck. it never ran quiet right after that. If you can read the 6 pages on the other form it's all there.

 

Just as a heads you you DO need to remove 1 spark plug from each cylinder before starting compression test.
It isn't any "extra work" because you have to remove them any way to test each cylinder, so just remove all 4 at the same time.

"When I went to pass someone it started again........"
My bet is that the timing belt slipped at that time.
Cam gear or crank gear could be damaged so it causes bet to slip or tensioner is the problem.
Mechanics can miss those things, and engine will run good until stressed and then belt slips

Test compression to confirm or to remove valve timing as the problem, don't waste time or money on anything else until then.

 

that makes sense. that the timing belt is or has slipped. I did watch a you-tube video of how to do a compression test. can't remember all the steps. Since I have a truck with 8 plugs I'll need to pull them all at the same time or one at a time. I'm actually afraid to do anything with the plugs because I don't want to cross thread them. because if that happens I'm screwed more or less. I take it they make a compression gauge. so what you screw it into the spark plug hole.open the throttle and turn the key. would you do this more than once for each plug. and write down the numbers you receive. I'm not a mechanic, in fact I'm a computer technician. it's funny how some of this stuff laps over one another.

 

You take one spark out of each cylinder which ever one is easier to get to, not both

 

so since there is two plugs per cylinder do I need to just take one plug out or both

 

One plug, so you can screw in the compression tester.
As Ron said, "which ever one is easier to get to".

 

you missed 1 part

the fuel filter should have been replaced first before any other part

if the hesitation still occurs , then you could rule out the fuel filter

 

the fuel filter has been changed 4 or five times in the past 6 years, and the last time it was changed was 3 weeks ago.changing the filter did improve things.