Hi Guys,

Lately I have been getting what appears to be ‘load-based denotation’, which only seems happen when I am on accelerating heavy to pass someone (note: air-conditioning is on). This also only happens around 2300 rpms.
I understand that it might be that I just got some bad gas?
I pretty much only use Unocal 76 from the same gas station (89 octane), but due to the high gas prices here in Los Angeles I have filled up with Mobil and Chevron several times.
My Superchips 9100 tuner programmed for 87, 89, and 91 octane ~ currently the truck is programmed for 89 octane.
I plan to drop it back to stock and reset the PCM to see if the detonation goes away.
My truck (2003 Supercrew w/5.4 L, auto-trans) currently has 45K miles on it and I know I should probably have replaced the upstream O2 sensors and the fuel filter.
Is there anything else I should look for to resolve this pinging?

A few more questions:
What are the part numbers for the Bosch O2 upstream sensors?
How much do you think the dealer service department would charge to install them?
What brand fuel filter should I get?

Thanks in advance for any\all replies.

-James

https://www.f150online.com/galleries....cfm?gnum=2443

 

Motorcraft fuel filters are the best..the part # is FG.986.B
I would also use the Motorcraft O2 sensors...if you can slide under your truck you can replace them yourself and save some money

 

Ping and detonation are different.
Not nit picking but is an important difference.

 

Bluegrass, please explain the difference between the two.
What ever I am hearing it does not sound good!!

 

Hi MrTude,

Virtually all of FoMoCo vehicle's O2 sensors are in fact made for them by Bosch - and are thus actually BOSCH O2 sensors merely packaged in a Motorcraft box and sold at a much higher price. They are available at about HALF the price from a quality parts store compared to the average Ford dealership - just FYI. Now I DO strongly advise using Motorcraft fuel filters - absolutely! I won't put anything but a Motorcraft fuel filter on our vehicles (well, my Lighting is about at the end of Motorcraft fuel filter capacity, so the next upgrade will be to all Aeromotive/CPR, of course).

On the fuel - we advise staying away from that Chevron & Mobil stuff in *your* area if you are experiencing detonation when using those fuels, and try going back to Unocal - with performance tuning, you'll always want to use ONLY the very best quality fuel - NEVER buy gasoline based on price. That is the second-worst thing you can do to your engine, exceeded ONLY by not changing the oil. Our docs that we send out with our custom tunes go over various aspects about fuel quality, and those who follow them rarely have any issue with detonation - however, we DO from time to time see where a given fuel works fine in an area for some time, then something changes in it's formulation, and the same fuel that used to work well no longer does - that can happen sometimes, too.

The bottom line is, detonation that is consistent cannot be allowed to continue, nor will it be solved here - Id' say to pick up the phone & call your tuner (if that was us, then please call us & we'll be happy to go over this with you - just tell our staff I said to put you thru & give them your F-150 Online screen name so I'll know to be expecting a call from you directly!) and go over this in appropriate detail for diagnosis & resolution - and remember, "cheap" gas is NEVER a bargain - you pay for it with a lower BTU content and thus a lower detonation threshold, as well as lower fuel mileage and a dirtier fuel delivery system & engine.

There can be MANY causes of detonation, but when it's "load-based," that's a pretty sure sign of cheap gas or a clogged fuel filter, etc., being the culprit, especially when you've had the tuning for some time and have not always had that problem. You can even have things like a fuel formulation change happen in your area that can suddenly cause a problem where none existed before - Bottom line? Call your tuner for proper advice is my suggestion.

Good luck!

 

Mike what type of gas would you recommend. We have exxon, sheetz, speedway, gomart gas. Which would u recommend. The octane ranges from 87-93. I've been using exxon, is that a good choice or bad?

 

Hi Mike,

Thanks for providing all the great information. Yes I purchased my 9100 tuner and a few other mods from Troyer Performance.
I had called and spoke to Anita late last week, I had asked to speak with you but I guess you were busy at the time. However Anita as always does a great job and she basically instructed me to perform the same things you just outlined.
I have since went to 3 different auto parts stores in my area (Pep Boys, Autozone, and one other) and not one of them carried the O2 sensors for my 2003 truck. For giggles I went to the Ford dealer this afternoon and they wanted $101 per sensor.
Hopefully I can find these sensors before this weekend, as I would like to resolve this problem ASAP.
Also, in the future I will only use Unocal 76 gas and not take any more chances with cheaper\less expensive gas of other brands.
Roughly what is the cost of the Ford fuel filter and is it only a dealer sold item?
One other question, would having a ‘not so clean’ air filter also be part of the cause?
After I get all this done I will re-post and let you know how things worked out.

-James

 

MrT -
I would suggest shopping on line for a parts like sensors when you can identify the part easily - good prices, and you find these neat little packages UPS leaves on your door step.

 

MrTude and anyone interested in Motorcraft filters at a reasonable price check out Tabby’s Parts.

Tabby's Parts

FG986B $8.66, 12/$98.15

 

Hi James,

Thanks for your response.

I know it can be hard getting thru to me personally sometimes, due to what I do - which is a lot of R&D, the custom tuning, etc., so I have to watch how much time I spend on the phone or I don't get things done - even though talking to everyone on the phone is one of the things I enjoy the most! That is why I suggest in a situation like this, calling and letting our staff know your F-150 Online screen name and letting them know that I said to tell them your screen name here and to put you thru to me - that way I know whose call I need to be expecting and that a particular call is important enough that I need to interrupt what I'm doing (if I can) at that time and speak with you - if I am out or on another line when you call, please make sure to leave your screen name, real name, & your phone number so I can call you back - just a suggestion.

Sorry to hear you're having a tough time finding upstream O2's - if need be, just order them and it will just have to take a few days in some cases - and I'm not surprised that dealership charges that much for those sensors - in excess of $100 *each* is too much, IMHO, so I'd say to just order the right part thru a good quality auto parts store and wait the few days.

Going back to Unocal is probably going to solve your problem, so that would be my first step, of course.

Having a dirty air filter, if it's dirty enough, can cause fuel mileage and power to drop, but usually the filter element itself being dirty doesn't make the engine go lean and detonate - what happens is, the dirt makes it past the dirty filter, and then gets the hot wire inside the MAF meter dirty, and *that* causes a lean drift that can contribute to detonation. So technically, I'd say it's possible for detonation to be caused by a lean condition that was caused as a *by-product* of having a dirty air filter - absolutely! We also generally advise cleaning the MAF meter once a year on those vehicles that have a traditional MAF meter. Use electrical contact cleaner to spray on the wires inside the MAF (you have to disconnect the battery and remove the MAF meter from the vehicle to do this), and make sure to use a contact cleaner that will NOT attack plastic, of course. Then let it sit for long enough to dry (evaporate) all the cleaning solvent, and then reinstall the MAF meter and that takes care of cleaning the MAF. WARNING: Owners of 3-valve engines like the 2004 & up F-150 or 2005 & up Mustang should NOT do this, as they do NOT have a traditional MAF meter, but instead have a much different sensor apparatus.

So overall I'd say to change back to Unocal, just order a fresh set of O2 sensors, get a clean air filter element and clean the MAF meter too, and see how things are at that point - in the meantime, make sure to drive it in a manner that avoids the area where it tends to ping (detonate) - and if you continue to have problems, feel free to give me a call.

Good luck!

 

Hi Ski,

NONE of those brands would ever be run thru any of my vehicles, unless we were either doing testing, or walking was our only other choice. Those are all off-brands & no-names, except for Exxon. Surely you have more than just those few choices - we live so far out in the country that there is not even one single traffic light in our entire country, but we have plenty of good fuel brands to choose from. Of that very short list of low-grade fuels, Exxon would be my choice, but I'd also be looking for something better, even if you have to drive a few miles to get to it. I drive 10 miles each way to where I fill up, for example, but it's only because we live out in the country.

If you use the SEARCH feature here, you can look up many of my past posts where I advise specific brands -

Always steer clear of the off-brands and no-name fuels - and Exxon, though a good clean fuel, generally tends to be lower in energy content (BTU's per gallon), so the fuel mileage is not what it could be, and can contribute to less power & even detonation in a modified vehicle.

We as "layman" can do a couple of things to identify the best fuels in ANY area - try 2-3 tanks of each brand/source, and carefully track fuel mileage - at the end of all that, the fuel with the best MPG is the fuel with the highest energy content and generally the best performance - from there, it's a matter of detergency level. And make sure you do that during the same time of year, so you don't skew the results with winterized fuels versus summer blends.

Try Citgo, Shell, or Texaco, in that order. Shell's V-power premium tends to be a good fuel with high detergency, and Citgo is on both Ford & BMW's "good gas" lists.

Good luck!

 

Thanks for the reply mike. I was doing some searching on the internet for gas stations in my area, and I see that Bp is somewhat close to me. As for Shell, the closest one is about 20 miles away, same with citgo. I'll definelty be filling up with shell if there is one in salem when I come down on dyno day. I'm going to try bp around here to see if its better then exxon. So far exxon is the best almost 1.5-2 mpg better. Before using exxon i was getting about 13-13.5. When i use exxon i get about 15-15.6 mostly city, that is trying to keep the rpm's close to 2. When I get on the throttle its stays about 13.

Ski

 

I don't think BP is on the A list. Sunoco ain't bad

 

Hi Ski,

Understood - as John said in his post, we don't generally recommend BP/Amoco these days, and I really hate saying that, as Amoco used to be a *great* fuel!

But since the BP (British Petroleum) buyout of Amoco, their energy content seems to have gone down - I used to run Amoco all the time in my Lightning, but now I cannot run it at all due to it causing rampant detonation - of course, my Lightning runs 15-17 PSI of boost minimum, and in colder weather with thicker air tops 18 PSI, so it's gotta have top-notch fuel. But it used to run fine on Amoco anywhere, and no it won't tolerate BP/Amoco, I'm sad to say.

And yes, you will find *plenty* of Citgo, Shell, etc when you come to the dyno day!

 

Yeah I think there is a shell on every other corner in SW VA. And Citgo's inbetween them