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2.3 Duratec pinging/loss of power


Pony Boy

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2010 Ford Ranger extended cab, auto, 2wd, 75,000ish miles, 235/75/15 tires. Over the last year and a half it's started pinging at high rpms. At first it was no big deal. I had an EGR code, I can't remember exactly what it was, but I believe it was PO400. I cleared the code once and it never came back. The pinging began to get worse, and I started noticing a loss of power, basically right now the Ranger won't go over 74MPH, I couldn't even drive the interstate with it. It used to cruise fine, so I started digging into it. Replaced fuel filter, spark plugs, and wires. No change, spark plugs look normal. Fuel pressure is at 65 PSI engine running. Removed EGR valve from the rear of the engine ( what a job that was...), it was perfectly clean, I was expecting to find alot of carbon buildup like my old Lima 2.3 used to get. Air filter and MAF are clean. I'd heard that the timing chain tensioner has a tendency to break on occasion once and a while causing similar symptoms, so I've just finished removing the timing cover and inspecting that, the tensioner is perfectly fine, locks in place as it's supposed to, and has plenty of travel left. Retime the engine since the crank pulley had to come off, and still no change. I did a cylinder contribution test with the Solus scanner I have available, it showed cylinder 3 being weak. The results were
Cylinder #1 "5"
Cylinder #2 "3"
Cylinder #3 "-9"
Cylinder #4 "3"

I'm at a loss what could be causing the issue. There are no codes, pending or otherwise. When I step on the gas it revs but just doesn't go, like something's holding the engine back. I need a good compression tester to check compression as that's the only thing left I can think of. Has anyone had any similar issues? Point me in a direction!
 


RonD

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2001 to 2012 Ranger 2.3l Duratec engine will have a Knock sensor, so you should have never had any Pinging/knocking, as it WILL damage the engine, eats away at pistons and valves, also eats away at head gaskets ring.

Google: ford 1S7Z-12A699-BB

Thats the part, an it should be bolted to the block, usually under intake manifold, never looked for one on the 2.3l Duratec so can't say where, but can say it is there and either unplugged or bad

Because of the higher compression(9.7:1) this engine will ping on regular 87 octane fuel under load, same as the 4.0l SOHC engines
So Ford had to use a Knock Sensor to avoid engine damage.

If knocking is detected the computer will advance the spark timing to ignite the air/fuel mix before it can self ignite(the pinging), this WILL reduce available power because full explosive power happens too close to TDC so less power is added to the crank.

Now at this point after "...the last year and a half it's started pinging at high rpms", there could be some engine damage, or computer is now holding spark too far advanced so no power.

In any case find that Knock sensor
 
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Pony Boy

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Thank you! I know exactly where it is, I've seen it multiple times when pulling the intake manifold, it's located directly on the block between cylinders 2 and 3. It is plugged in, but I will be looking for a new one.
 

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A little more diagnostic information. Spark advance is at 15* at idle, when revving in neutral spark advance goes up to 41*. When driving, full throttle spark goes up to 36*, and back to 22*, but still pings, and it doesn't retard any further.

Short term fuel trims stay close to 0, at idle, fluctuating between -2 and 3. At 2,500 rpms , short term trims fluctuate between -3 and 5, in neutral.
Long term fuel trims are at 7-13 at idle, and goes to around 9 at 2,500 rpms, in neutral.

Temperature of header measured with infrared heat gun is around 550 F, temperature of front part of converter near the first O2 sensor is around 475-500 F, Temperature of rear section of catalytic converter is where the converter ends and exhaust pipe begins is about 475 F.

Thoughts on any of this?
 
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RonD

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Run 93 octane and see if Pinging goes away, maybe you are dealing with something else.

If those temps are really F degrees, then they are way too low, they would be correct if it was C degrees

An O2 sensor only starts to work when it is above 650degF
Cat converters run at 1,000-1,200degF

Easy way to check if Knock sensor is working is to warm up the engine and let it idle
Tap the block with a metal wrench, knock sensor should "hear" that, and computer will advance timing quickly, idle will change then come back.
 
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Pony Boy

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I've used 93 octane, it helps the pinging, but still has a loss of power. Those temps are in Fahrenheit.
 

RonD

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I would test that temp reader on another vehicle.

Did you change the knock sensor yet?
 

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Yes, I replaced the knock sensor yesterday, it didn't make any difference. Some more diagnostic info, Compression test was perfect
Cylinder 1 200 PSI
Cylinder 2 215 PSI
Cylinder 3 215 PSI
Cylinder 4 200 PSI

Vacuum test on the engine is pulling 22 PSI, drops to 0 every time the throttle is blipped repeatedly, doesn't indicate any exhaust blockage. I'm completely out of ideas at this point.
 

RonD

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Not perfect, Compression is too high, looks to be over 11:1 compression ratio which would ping even running 93 octane in some cases.
Assuming this was a static compression test, if it was dynamic test then its way way too high

Your 2.3l Duratec runs static 9.7:1 ratio
General rule of thumb to calculate "expected" psi in a compression test is to multiply static ratio by 18, 15psi outside air pressure(at sea level) + 3 for mechanical pressure added by pistons and valves
9.7 x 18 = 174 <<<expected from 2.3l duratec

11 x 18 = 198
12 x 18 = 216

So your 200 to 215 is 11.5:1 ratio

Dynamic ratio is always lower than static, but static ratio is what is used to determine if an engine will ping/knock(pre-detonate) on a specific octane, 9.5:1 is the limit for 87 octane, above that knock sensor would be needed, but only works to about 10:1 then higher octane needs to be used

Compression ratio is the volume of a cylinder when piston is at bottom dead center(BDC), divided by the volume when piston is at top dead center(TDC)
So if BDC volume was 900cc and TDC volume was 93cc then 900/93 = 9.7, so 9.7:1 ratio

If there is carbon build up on the piston's top and in the head's chamber then TDC volume gets smaller
900/90 = 10 so 10:1 ratio

Compression can also be increase somewhat with valve timing, I am not familiar with 2.3l DOHC's valve timing so can't say if a problem there would add to higher compression you are seeing.


But you found your problem, run 93 octane for now, knock sensor can't help with compression that high at least with fuel below 93 octane

You can use a snake camera to look inside spark plug hole to see how much build up is in there.
And there are methods to clean out build up while engine is running, but has to be done CAREFULLY!!!! or you will break a piston or bend a connecting rod
 
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Pony Boy

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I'm revisiting this, driveability is terrible. With the pedal held to the floor for over a mile, the truck will not go over 73 mph. I don't necessarily believe the compression readings are too high, there are many other posts on 2.3 Duratecs getting 200 PSI of compression, although I still haven't been able to find out what an acceptable range should be. Looking inside the spark plug holes I see very little carbon buildup.
A little more diagnostic testing, disconnected the catalytic converter, no change. Checked fuel trims while driving, long term trims are around +5, short term trims go all the way up to +22 under acceleration, I'm not sure if that's normal or not in open loop. Otherwise STFT is around 0-5 under normal driving.
Another question I have is when I check engine info on my Solus Scanner, it's saying there's a fault in the Keep Alive memory, but it's not throwing a code.
Disconnected the MAF and took it for a drive to see if there was a change, there was, it was even more of a dog but no pinging. I understand it was running in safe mode with the MAF disconnected.
Erased Continuous memory, checked fuel trims, both LTFT and STFT started out at 0, LTFT was back at +5 after 1 minute 30 seconds.
 
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RonD

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Multiply compression ratio by 18 to get expected static PSI for gasoline engines
2.3l DOHC runs 9.7:1, 9.7 x 18 = 174.6 PSI expected

Where does 18 come from?
15 psi is the outside air pressure at sea level
3 is the mechanical compression ability of the engine
So 18

Compression tests are more about being consistent across all cylinders, than the actual numbers, compression gauges vary, testing conditions vary

You could use a vacuum gauge in the cab to monitor intake vacuum at WOT, should stay above 1", 1.5" to 2" of vacuum is best.
If valves are out of time or are "floating", weak springs, then vacuum goes under 1" and basically there is no air flow thru the cylinders, so no new air/fuel mix is coming in and power is gone.
I can usually fit a vacuum line thru Parking Brake cable grommet

KAM(Keep Alive Memory) for the PCM will have a fuse in the engine Fuse box, I don't have a 2010 fuse lay out, it should be labelled KAM or PCM/EEC
 

Pony Boy

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Yessir, I checked the KAM fuse, it wasn't blown. I also have a question about the MAF airflow, measured in grams per second. At full throttle it's only reading 80 gr/second, according to the scantool. I know it's a small engine but shouldn't it be pulling more air than that through the meter? Everything else looks ok, TPS is reading .90 volts at idle, runs up to 4.50 volts at full throttle. MAF voltage was ok as well, I think, I'll have to double check it tomorrow.
I have a theory, but just a theory. If the MAF airflow is reading low, it's only calling for as much fuel as is required by what the MAF is "seeing", but in actuality it's pulling in more air, causing a lean condition, causing the pinging. I know I'm grasping at straws, but possibly the MAF is giving a skewed reading? That might be pointing back to a vacuum leak ( that I can't find, I've tried, it doesn't show up at idle at least. I can disconnect the IAC and the engine immediately stalls )or like I said above, a bad MAF?
I attempted to get a vacuum reading while driving a few days ago, but I need to come up with a better way to connect a gauge and be able to read it.
 
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RonD

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MAF only reads 15% of the air flow, its not all the air
General rule of thumb is that you should see engine displacement in gs/sc at warm idle, 700-800RPM.
its actually at 500rpm, so around 2.7gs/sc in your case

Yes, MAF sensor could be under reporting air flow, but..................O2 sensor is there so computer would see that instantly.
And computer would start adding the extra fuel for the "unreported air", similar to a vacuum leak, if computer starts to add 15-20% more fuel than it calculated then it will set Lean Code.
The 20% needs to be steady cruising, not on acceleration.
At WOT computer ignores MAF and O2 sensors, its all about the power, MPG is out the window when throttle is wide open, lol, so computer uses tables in memory for air/fuel mix, it knows engine displacement and RPMs so it can just look up the open time for injectors
 
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Pony Boy

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I was going to attempt to post a datalog, but I'm having trouble posting it. It's only viewable through this Diablosport data viewer

https://forum.diablosport.com//viewtopic.php?f=31&t=51448


but my datalog file is just a text file, when I try and attach it all it shows is gibberish. It reads in my data viewer fine, but not when I try and attach it.

Vacuum under heavy throttle when driving is from 0-.5 in/hg :(

Replaced MAF just to see with another one I had, no difference.
 
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