Adding a knock sensor to a 5.0 Explorer

[Dono]

As we are bumping performance on our Explorers, were dreaming of a knock sensor that would work with the stock pcm.

So, What about the 1996 F-150? It has a knock sensor, and I started wondering how close the PCM is. My guess is that its pretty close.

The knock sensor is located at the top, back of the F-150 5.0 blocks part number E3AZ-12A699A. If the hole isnt there, (As I think [MENTION=61294]vroomzoomboom[/MENTION] saw it isn't, so it would need to be tapped).

The knock sensor is on pin 6 of the pcm on the f-150's.
http://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/pcm-pin-out-table-1

It also looks like pin 6 of our 5.0 pcm's is unused.

It makes me wonder it could be as easy as just attaching the f-150 knock sensor to pin 6 on our current pcm's. I'm starting to think it is.

So, I guess the next one of us with our motors out will have to install a knock sensor in our blocks so we can try connecting it to pin 6 of our pcm's and see if it can be tuned.

 

[vroomzoomboom]

i wanted to add (and hopefully he see's this) [MENTION=17554]NICE59FORDF100[/MENTION] (russ) gave this to me in a pm. this is for a 98, but not sure about anything else.

"Ok. The knock sensor has three wires...a ground, one that goes to pin 57 and one that is a signal return that basically goes to pin 91 but shares that circuit with all the other sensors"

 

[Dono]

Ok, so pin 57 shows:
57 ---
YEL/RED Not Used (5.0L, 5.8L Only)
Knock Sensor Input (4.9L Only)
http://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/pcm-pin-out-table-2

So, from the reference Im looking at, its pin 6 for the 5.0.

Maybe I need to pick up a knock sensor, and wire it in and test (Tap it) while logging.
With it wired in, it would be reasonably easy to try both pins 6 and 57 and see if you can see the knock sensor working in the pid.

It would be a pretty cool mod.

 

[2000StreetRod]

not just hardware

The PCM has a collection of input and output devices as well as computing devices. The strategy is a collection of software modules that has been compiled or assembled into a vehicle specific program. The same PCM hardware can be used for different functions by changing the collection of software modules. For example, the 1997 & 1998 VIS control output was changed to a fuel cap off indicator in 1999. Typically, inputs are self tested for within range values and a DTC is set when the input is out of range. Normally, software modules are only compiled for functions available since they consume processing time.

My strategy has several functions compiled that can be enabled or disabled with the setting of calibration constants. An example is PATS. I have looked thru the source code for Ford's knock sensor and it is fairly complicated. There are detection window variables (duration and offset), as well as sensitivity and threshold for each cylinder, advance and retard rates and limits. There are more than 40 calibration constants supported by my SCT tuning package and another 20 or 30 in the code that are not supported. I doubt the knock sensor module has been compiled for your PCM but it is possible. The easiest way to find out is to ask someone who has a tuning package for your strategy and get them to check for knock sensor support.

I suspect the only reasonable way to achieve knock sensor initiated spark retard is with an aftermarket package similar to what John (4pointslow) is using.

 

[Dono]

I'd still be interested in trying. If the pin is on the pcm, it could very well work.

If the pin is there for the knock sensor, it might just need to be turned on with a minor change to the pcm programming. Setting sensitivity is another thing all together.

The f-150 had it, and I find it hard to believe a completely different pcm would be manufactured. It would be very interesting to find out.

Step 1: find a knock sensor

 

[2000StreetRod]

ask your tuner

James should know if the function is available for your strategy.
If you purchase a sensor get one compatible with the J&S Vampire in case you decide to go that way: Vampire Direct Ignition

 

[Dono]

I think I want to go with one or the other. The vampire system looks great, but id prefer to have something that can be logged.

What are your thought on the possibility of the vampire knock sensor being compatible with a factory pcm? The more I read about them, they all seem pretty similar in frequency response

Edit: scratch that question.... its completely compatible

 

[2000StreetRod]

datalog

The Vampire has a 0 to 1.3 volt output for datalogging. I don't know if the SCT X3 is fast enough to catch the pulses. Maybe John has tried it. The problem is the X3 only has 2 channels. You can't simultaneously log boost, AFR and Vampire knock retard.

 

[decipha]

the problem isn't the tune or software its the ecu, henry doesn't usually include internal components on ecu's not equipped with such, so although you can enable the knock sensors the ecu most likely does not have the internal hardware to read the knock sensors

best bet would be to upgrade to the 99-04 mustang / f-150 ecu that came equipped with a knock sensor and use that, here's the custom tuning software to tune it correctly

http://info.efidynotuning.com/fbfg2.htm