Hi Mike;

Recently you posted a couple of statements on two different topics that tweaked my curiosity ( which summarily killed the cat ;-))...

This response to throttle lag: it's been generally understood that an "approved" intake kit need not require a tuning change,in and of itself, but the response suggests a possible issue with off-idle response that can be addressed via custom tuning ( and I assume is accounted for if mentioned in the CPW worksheets). Not a potentially damaging condition like a lean code - I understand that much.

"What we're talking about (or at least, what Ham & I are discussing) relates to the *newer* F-150's with the 5.4 3V engines & ETC (electronic throttle control), where there is no mechanical throttle cable linking the gas pedal to the throttle body - whereas in *your* truck, you don't have that problem, it has a solid throttle linkage, so a simple intake kit does help with certain aspects of throttle response - but also causes another little problem in off-idle response that we have a little trick for, but that's another topic............."



In this response to an O2 switching code issue: I'm intrigued as to the root cause you found for the harness knicks. I think you are talking specifically for the O2 harnesses. I immediately scurried under my truck to check this out ;-)). Alas, none found.

"Because the 1715 changes *nothing* in closed loop (cruise) regarding A/F's or O2 operation, and this happens only rarely & under 1 specific condition (and having 172K miles), I suspect this is a vehicle problem of some kind, somewhere - O2's (and all 4 should be replaced), and I'd bet $1 there are some nicks in the wiring harness and I have yet to see a truck with just 50K miles not have a nick somewhere in the harness somewhere - whether it's actually causing a problem or not. "

Anyway, when time permits, perhaps you can enlighten me yet again.

Thanks, as always.

 

Hi Vic,

If I correctly understand what you're asking, sure, I'll cover that just a bit...........

It's just that these are trucks, and so they tend to have things happen like the more aggressive tread pattern pick up rocks and sling them underneath the vehicle, and that can cause nicks in areas of harnesses over the years - you know, from the front tires picking up various sizes of smaller rocks, etc., with sharp edges here & there, and how they can be thrown out of the treads (sometimes at rather high velocities), and thus cause a nick in a harness here & there.

Usually by the time a truck has 50K miles or so on it, we can find some nick here or there in a harness somewhere, but of course that also depends on where & how the vehicle is operated. If it it always operated on-road, and never goes on gravel roads, never goes off-road, etc., then it will take longer to happen - some can maybe go 100K miles and not have anything significant, that's certainly possible.

Now with regard to what I mentioned about installing a good intake kit on the 1997-2003 F-150's (and even earlier models) causing a slight off-idle driveability issue and how we have a "truck" for that, we've discussed that many times here, though not recently - it's just setting the TPS voltage at 0.98-0.99 is all - and of course, making sure that the throttle body screw that some people mistakenly turn to attempt to alter idle speed is in it's original position, too. having the TPS on those models set at 0.99 is optimal, and gives a little bit better immediate light-throttle off-idle throttle response, which can sometimes take just a little hit from an intake kit reducing velocity just a tad off-idle at lighter throttle.

And so on.................