I bought this pickup and I am just lost what is causing the problem. I was thinking possibly the cat is clogged as that's the only thing I haven't replaced or had checked using a back pressure gauge.

New Parts since purchased.
New injectors
New PCV
New Coil on Packs
New Mass Air Flow Sensor
New Motorcraft Spark Plugs
New Fuel Filter
New Air Filter
New Coolant Temp sensor and Thermostat
New Oxygen Sensors
New Tires
Tranny Flushed and new filter
Oil Changed and new motorcraft filter
5 STAR tune 87/90 octane tunes... Went with tow/performance

Things shops have tested
Had cat measured using a heat temp gun and they said it seemed good.
Stock computer Flash to see if this fixed issue, it did not.
Fuel Pressure tested and verified good
Plugs look good.
All exhaust bolts are good.
No vacuum leaks, smoke tested multiple times.
Intake and valves cleaned using BG product and machine.
Compression checked on first two cylinders.

I run 90 octane in the truck ALL the time (chevron gas).. Truck gets about 11 mpg no matter if its a short in town driving or a long drive. I drive (26) miles one way to work highway cruising miles. I am also a very light footed driver.

I was told possibly the timing chain could have jumped a tooth and they would have to tear the engine down to figure that out. I didn't want to spend the $1000-$2000 for the shop to do this just on a hunch.

Oh, at idle I can feel a slight stutter every 5-10 seconds, RPM needle never moves, I have verified with a computer scanner as well. So I don't think IAC is bad. But that's the only other symptom that the truck exhibits that I would consider not normal. Truck has over 210k miles on the engine. Oh and just recently I have started to hear what I would call lifter tick, truck does need another oil change. Going to do that at lunch.

My brother has the same year vehicle but his is an excursion. He is running 265 tires vs my 285 tires but his vehicle seems like it has way more ***** and I imagine he is about 400-500lbs heavier with that huge gas tank... My pickup just seems low on power.

Any ideas?

 

Your subject description of the sound sure sounds like detonation (pre-ignition) is occurring. If so, that's really bad. The rattling or marble sound ls like little hammers smashing into the pistons, with ultimately bad and expensive results. In theory the knock sensor should tell the ECU to retard the timing when that happens, so something clearly isn't right.

Has this truck been "tuned" by chance?

 

Assuming the same transmission in both your truck and your brother's, compare the axle ratios.

I'd try a tank of 92-94 octane next time to see if the preignition-like noises settle down. If they do, then you know that pre-ignition is the issue and you can focus on the knock sensor and the timing of the engine.

 

I am unable to get anything above 90 octane where I live.

My brother and I are both running the same axle ratio.

Tune was done by Mike @ 5star tuning, however.... the noise was there before his tune.

I was able to get some VP 110 from a friend and just put it in the tank... Drove a few miles and didn't seem to make a difference.

 

Anyone know what stock timing is on these engines?

Mine is a 2001 V10.

 

Hmm.. So how long have you had this rattle on acceleration? Did you add the 'tune' trying to get rid of the noise? Is the rattle consistent, or does it change with load? For example, if you go up a hill and apply throttle to maintain speed, does the sound of the rattle get louder and more pronounced the more you apply throttle? Or do you still hear the rattle even when at speed, but off the gas? If it's pre-ignition, then there is something adding too much ignition advance timing and your knock sensor isn't, or unable to retard the timing. If timing is too far advanced and causing knocking, that may also explain the sluggishness you're concerned about. It would be nice if you can get a reader to monitor live what your ECU and parameters are doing when this issue occurs. Some independent shops and dealers would have one. It might be worth a trip around the neighborhood with a reader connected to see what's going on before you destroy your engine.

 

I have an SCT programmer that will let me datalog and view the data. I have looked at the data numerous times and couldn't find a reasonable explanation as to why I would be pinging. If I am off the go pedal at said speed (we can use 55mph for this scenario) I have zero pinging. If I lightly push the go pedal up any "slight" hill I start pinging. I have a buddy with a 1200HP hot rod and he said its pinging, its not an exhaust leak, or any other weird sound. I have had 2 shops listen to it and they agree its pinging. I can get it to ping if I slightly push the go pedal from a dead stop on flat ground.

No one has been able to fix/determine the cause of the issue.

The only thing that makes sense to me is I have some type of un-metered air entering the system after the Mass Air Flow Sensor causing a lean condition, thus pinging... I have checked the elbow multiple times and can not find a crack in the system.

I never get a check engine light and when I scan I never get any codes being thrown. Basically the Electronics all pass according to the ECU.

It really doesn't matter what RPM range I am in, it will even ping at WOT sometimes. When I push the pedal slightly or below 1/2 way down I can ALWAYS get the truck to ping. Any slight grade it will ping. It's been driving me nuts.

Only time I was able to get rid of the pinging was with a different MAF that was ordered incorrectly for my truck. I threw a MAF code of course, but the truck ran great.

I am running 98 octane in the truck currently... Still pinging.

I am almost at the point to disconnect the MAF all together.

 

Another simple (sort of) things to check for are vacuum leaks, but I'm not convinced an air leak post MAF sensor would necessarily cause detonation, no more than a lean-burn condition would necessarily cause it either. Disconnecting the MAF sensor would only make the engine run even worse, assuming it runs at all.

Have you had any MIL (check engine) lights with this condition? You may want to use your scanner and check the ignition timing under load. If over 43 degrees under acceleration, or timing is swinging around significantly, something is definitely up.

The fact the truck isn't running right and pinging violently, clearly indicates there is something really wrong. If it were me, I'd consider putting the stock settings back and start troubleshooting from there. If the SCT tune is already advancing timing more than stock, you're just making the problem worse.

Good Luck!

Kelly

 

i would borrow your brothers mas air flow sensor for a test and see if the problem moves. is the mass air flow sensor in your truck new or rebuilt. if its rebuilt it could be calibrated wrong and reporting to the computer more air flow then it is really getting. then causing the system to run lean. I don't think it will show a code .

 

MAF is NEW.

Long Term Fuel Trim Bank 1 = .93
Long Term Fuel Trim Bank 2 = .95
Vehicle Speed 65mph, Spark Advance 28
Vehicle speed 68mph, Spark Advance 27

I can't stress enough I was running 98 octane fuel today....

Lowest I saw spark advance was around 12, highest was around 34.

Kelly: You can unplug the MAF and the truck will run just fine. Most OBDII compliant vehicles require multiple things to happen to go from open loop to closed loop... If they don't happen the truck just runs in open loop (doesn't look at 02 sensors) to adjust the air/fuel mapping. (Uses pre programmed data).

Vechicle operating temp up to 160 or above.
MAF needs to be reading correct specs
02's need to be heated and working

I know there is some other things that might need to happen... But the truck will run fine by unplugging a MAF. I used to unplug the MAF on my older camaro all the time and use open loop operation to see what the computer was doing as I would (datalog) the base stock tune so I could adjust my custom tune after I did a bunch mods to the car.

Anyhow, the ECU is reporting normal within spec variables from what I can tell.

Something like a clogged CAT, the computer has no way to check that as this model vehicle is not equipped with a post cat 02.

 

Ok, if you want something done right apparently you do have to do it yourself.

like I was stating before the ECU was showing everything running correctly and after running 98 octane and still making the same noise I was determined it couldn't be pinging like every shop or car buddy said it was. Audibly it literally sounds like pinging/detonation.

HOWEVER, I think I'm on the right path now. I was tired of the sound so I put on some decent gloves and just started grabbing around by the y pipe area and heard a tap tap. I kept feeling around and found these two bands loose. I imagine under certain hills or under load the truck vibrated enough to make these straps sound like detonation. I removed them, filled up with some 87 and drove 10 miles.... sound seems to be gone, will know more as I continue to drive it. It wasn't helping anything I can tell you that much. Can't believe I took it to a few shops and they couldn't find these things loosely rattling under there. Makes ya wonder what your paying for eh? If I didn't tear my shoulder and have back surgery I would have just dealt with it myself originally.

Here's to hoping these stupid metal clamps were the issue.

 

Glad you found the rattle! Another example of when asking for assistance on a discussion board where none of the people trying to help can hear the noise or see what's been done to the vehicle, you get what you pay for.

 

The V10 has some funny harmonics, and it'll make anything rattle that's not tied/glued/bolted down good. The bellhousing inspection cover is a perfect example of this. Glad you found your problem!

One day I heard a really bad rattle, and got to the point where I KNEW it was the muffler innards rattling. It wasn't. The support in front of the cat had come loose and it was only under load that it made a HUGE racket. Fun stuff...

 

Well, it helped but didn't cure the issue. Seems it's around 1500-2000 rpm mainly. I towed my side by side today and it was non existent above 2500 rpm. Every now and then I would hear it at those rpms, but it was very rare.

I am going to remove the trans bell housing cover tomorrow and drive it around and see if the sound goes away.

Really hoping it's not an internal issue, but at this point no idea where else to look.

I have never heard the y pipe flutter people talk about so no idea if that's what I'm hearing, but it literally sounds too loud to be flutter. Sounds like pinging.

The wife is no mechanic and she asked today what is that awful rattling sound.

 

Removed the transmission dust cover today and drove around. I can now tell clearly, I have two sounds going on.
One is an exhaust sound. Maybe it is the dreaded flutter everyone talks about or maybe I just have a bad motor. Power seems fine now other than my transmission seems to shift late like its lazy.

When going up grades I can hear the knocking/pinging sound and I guess I am just gonna have to live with it. Turn up the radio and call it as good as its gonna get.

Without spending 20-30k on a newer truck I think its gonna be as good as it gets.

Otherwise I would be looking at a new transmission and converter along with a new engine. Which I imagine would run me somewhere around 11k?

It's just not worth the fuss. I am going to drive this bad chicken until its dead.