I need to know where the knock sensor is on my 98 4x4 XLT 5.4. The search featuer is disabled for some reason so I cannot look thru posts???

I obtained a data logger and am needing to figure out why it is pulling timing back to 19 advance down the hwy.

 

I'm not 100% sure but I believe it is under the intake manifold.

If you have the ability to datalog, chech your knock counts. That should be a start.

Brian

 

Will check it out. Not much guidance from my Sniper software on what I can datalog. Looking thru the current log it does not capture knock by default.
Thanks

 

Knock sensor is under the intake

 

Any chance I can reach it to to unplug? i amm thinking of plugging one in to replace it but not have it bolted to the motor for a test. With 4.56 gears and the timing I am seeing, thre is no way this truck would ever ping. This may be what I have been chasing for MPG on the truck.

 

19 is actually about right for these trucks when crusing. The terribly restrictive intake manifold makes them very knock constrained,and they have a very low ignition timing curve due to that intake.
Apparently Ford changed their minds on the intake design-the '07 model truck 4.6L 2V's now use an intake that looks almost the same as the old '99-04 Mustang GT 4.6L intake.
JL

 

Thanks for the info.
It cruises 25-33 with dips down to 15-19 for no apparent reason. I do have a lot of valve train noise so am suspecting this thing is dropping off timing due to that. Regardless, this truck has never made audible pining. Before the gear change, required 91 or better just for the stock truck.

It also pulls timing back to about 15 under full power. I have trouble understanding why this engine is set so lazy on timing. Now some on the board are claiming 15-21mpg on the same truck with similar parts. Looking at the ign curve, I would suspect theirs is not yanking out timing that agressively. I know I can get 2-5 mpg improvement on any other motor on these numbers. The lazy modes it gets in appear to be when it fails to ever put timing in. So if I identify and fix this, life should be better.

 

I'll bet it's pininging,just not audible to your ear-that valvetrain noise will not trigger the knock sensor,or may actually just sound like valvetrain noise when it's actually ping you're hearing.Look for a datalog parameter marked with something like knock sensor retard or advance.There is a plug that you can disconnect on the front of the engine right next to or behind the alternator-that's the feed for the knock sensor.
JL

 

I understand that you are not aware of my background to discern pining and valve train. The audible noise is definitely not pinging. I suspect I have some lifters that are bleeding down at times.

Most knock sensors I have seen do not filter to the specific freqs of pinging. Rather they have a pieziode crystal that reacts to any noise the motor makes. Part of why agressive cams and solid lifters have been a no no for fuel injection in the early years.

The timing pulls out at various power settings and RPMs. It will stay in at higher load/throttle. Then will yank it right after that with much lower power setting.

There is not any knock related parm in the list, But have not talked to the tuner company either. Actually been ill so have not done much to it.

It is possible to plug a new sensor in at the location noted? I don't want to go to default tune. Just to see the diff if disabled. Kinda wondering about how well the sensor is working.

 

You are using Knock and Ping interchangably.
This is not correct.
Ping will not normally activate a knock sensor. It's not a ping sensor.
Ping is normal for most operations and sensitive to changes in gas quality; with knock activation, the timing is pulled back to protect the motor.
Again, the two are different phases.
Ping is usually sleightly advanced timing.
Knock is an advanced form of severe advance and other conditions can enter the picture to crate the result.
Knock sensors are tuned to a bandpass frequency per the block/motor they are used in and are not interchangable with another type that may even fit the location.
If you have the capability, look at mass air meter output vs ign timing. You may see a direct relationship. This is program and not strickly load related.
Another thing you can look at is timing vs EGR activation. Watch the timing and manuelly open the EGR valve and see what happens to the timing when the motor senses exhaust gas in the intake.
There are many sources of ignition timing changes for both advance and retard.
The programming in these trucks is not for max performance we would like to have and are familuar with from years ago.
The torque mangement methods used are the reason they feel so soft on power and shift the trans so poorly..
They do indeed pull timing fast and early.
The weight of the trucks are another reason the timing can't be so aggressive as well as application loading/towing etc.
This is part of attempts to meet emmissions, lengthen life and reduce warrenty work that adds to reputation for being 'Tough' as well as chase the competiton.
The result is we don't get max performance and run to tuners, trying to get more power and mileage out of air intakes and exhaust by defeating the OEM program control.
This costs a lot of money for little gain and the selling vendors laughs all the way to the bank with your money.
Tuners are the best bang for the buck and leave everything else alone.