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Custom tune by Henson


Moderator Emeritus
May 26, 2009
Reaction score
City, State
Greenville, SC
Year, Model & Trim Level
00 Sport FI, 03 Ltd V8
For my Christmas present I purchased an SCT X3 Power Flash with custom tune from Henson Performance. There has been a lot of praise posted on this forum about James Henson's tuning knowledge and customer support. From my experience to this point in the custom tune development process the praise is warranted. James has been very responsive to my performance requests and my numerous questions. He has drawn on his extensive knowledge to provide a tune that enchances performance while maintaining and even improving driveability compared to the stock PCM program.

My 2000 SOHC engine, transmission and rear axle are completely stock except for the air intake system that consists of a Spectre high flow cone filter with 4 inch diameter outlet feeding a Ford Lightning 90 mm MAF sensor. The 4 inch diameter intake tube reduces to 3 inches just prior to the Ford 75mm ported and polished racing throttle body. An adapter transitions the 75 mm throttle body outlet to the 65 mm upper intake manifold inlet. The photo below shows the intake system.

The PCM utilizes the voltage output from the MAF sensor to calculate engine load. Increasing the MAF sensor diameter from 55 mm (stock) to 90 mm results is a large decrease in sensor output voltage for any given airflow. Therefore, a custom tune was required to prevent engine damage due to an excessively lean fuel mixture.

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Getting started

After ordering the X3 I called James to discuss my desires and to learn more about the tune development process. He informed me that I could go to SCT's Technical Support webpage and download the documentation and software that I would be using.

The first thing I downloaded was the X3 Product Manual. It describes the capabilities of the X3 and how to program the PCM with a custom tune as well as how to monitor engine related parameters available via the OBD diagnostic port. It also describes how to read diagnostic trouble codes and to clear them from PCM memory.

Next I downloaded the LiveLink software. This program allows the selection of PCM data to be logged by the X3 to record the selected data to a laptop file. The software provides a Help capability that explains how to install a required driver and how to exercise the software capabilities. There is additional help on the SCT Technical Support webpage. LiveLink allows examination of the stored data and a "replay" of data in time sequence. The photo below is of LiveLink executing on the laptop.

The table on the left lists the recorded PCM data items and displays the values for a specific time represented by the red vertical line in the main plot display. Any stored data item may be plotted. Shown are engine coolant temperature, rpm and air flow vs time. The circular dials at the top can be assigned to any of the recorded parameters.

Nice set did you go about attaching sensors and other tubes to your intake. I need to make my own intake tube and wondered how you went about that.

Turbo hoses

I used silicone turbo hoses with 5 layers of cord. I cut holes in the hoses slightly smaller in diameter than the fitting for the IAT sensor, IAC valve tube and the PCV flow hose. The long blue hose is a 4 inch to 3 inch diameter 45 degree angle reducer. I also used a 4 inch long 4 inch diameter aluminum tube by Spectre.

Cool thanks:thumbsup: So basicly everything was a press fit after cutting all your holes slightly smaller or did you have to use some silicone sealant to finish it up?

Friction only

That's right. I didn't use any sealant. The turbo tube cord reinforcement is very strong and it took most of my strength to force the fittings into the holes.

X3 Arrives!

I was excited to open the package containing my X3 Power Flash when it arrived. The contents of the package are shown in the photo below.

Included in the package was a USB cable to connect the X3 to a computer. The X3 comes with a built in cable that connects to the vehicle diagnostic port. The X3 automatically powers up when connected to either the vehicle OBD port or the laptop USB port. I plugged the X3 into my laptop to make sure it worked and to exercise some of the menu options to become more familiar with using the device.

The X3 also has a connector for a two channel analog cable which I mistakenly did not initially purchase. The cable allows X3 data logging of any analog output that varies from 0 to 5.0 volts. This cable is required to data log wideband A/F ratios during WOT testing.

Also included in the package was a CDROM containing documentation and a software program called X3LW Updater. This program allows transferring a tune from a laptop to the X3. I installed the X3LW Updater following the instructions included on the CDROM.

My first use of the X3 was to read the stock "strategy" code (identifier) in my PCM and send the code to James. He used the code to verify the configuration of my stock tune.

I then used my X3 to "read" the stock program in my PCM and store it along with the vehicle identification number (VIN). This "locked" my X3 to my Sport while allowing me to restore the stock program to my PCM if desired. The X3 can be locked to up to five VINs. I then used the X3LW Updater to transfer a copy of my stock program to my laptop to store as a backup for the X3.

While waiting for James to email me my first custom tune iteration I practiced using the X3 to read PCM parameters and to replay and examine data logs using LiveLink.

Starter tune file

I wanted to get the most out of my tune and did not want existing poor performance issues to complicate the tune development process. I knew that my intake manifold gaskets were leaking and the leakage was getting worse with the increasingly cold weather. So I decided while I was waiting for James to develop the starter tune file I would perform the 00M12 kit installation. I limit the time I work on my vehicle to two hours per day and I found a lot of carbon build up in the intake manifold and head intake ports. It took me two days just to clean the carbon! By the time my engine was back together and running (5 days) James had already emailed me a starter tune file.

Since neither James nor myself knew the current performance condition of my Sport with over 150,000 miles on the odometer, he cautioned me that there might be a brief time during the tune development process that my vehicle would not be driveable. I told James that would not be a problem since I have other vehicles to drive. I am pleased to report that throughout the tune development process to date my Sport has started easily and ran well without dying even once!

The tune development process consists of James emailing me a tune file, I transfer the file to the X3 and then program the PCM, I use the X3 and my laptop to record engine parameters, and then I email the data log to James to review and make appropriate modifications to the tune. The steps are repeated until James is satisfied with the data log results. I point out that anyone from anywhere in the world who has email capability, a laptop and an X3 can acquire and install a custom tune.

James develops the tune in two phases. The first phase is to achieve acceptable driveability. I've posted before on this forum that one of my success criteria for any modifications to my Sport is that my wife can drive the vehicle without any special instructions. From the tune results so far, James' success criteria appears to be that the vehicle be more driveable than it was when new from the factory. The second phase is the performance phase with the PCM mostly in open loop.

Along with the starter tune file James listed the data parameters to log. I have had a Windows based scanner for several months and am very familiar with the generic parameters supported by the software. I was truly amazed when I saw the great number of additional Ford specific parameters that are supported by the X3 and the LiveLink software.

I programmed the PCM with the starter tune, started the engine (on the first try) and logged some data at various engine speeds while parked in the driveway. I emailed the short data log file to James to make sure I had actually recorded the correct parameters. James emailed me a revised parameter list to utilize on my first test drive.

First test drive

For my first test drive and data log I planned a route that would allow driving at various vehicle speeds for at least 30 seconds so the engine loads and fuel trims would have enough time to stabilize. Since I live in upstate South Carolina, the foothills provide numerous hills to climb and descend which varies the load for a constant engine speed. The route takes about 30 minutes to drive and ranges in speeds from 25 mph to 55 mph.

The first thing that was immediately apparent from the custom tune was the change in the way the transmission shifts. When I test drove my Sport prior to purchase I started from a stop on several occasions attempting to count the shifts to determine if the transmission was the four speed or the 5 speed. The shifts were so soft that I was never able to tell. The softer the shift the longer both ratios are engaged simultaneously and the greater the wear on the transmission. With the starter tune the shifts were firm, positive but not jerky. That improvement alone was worth the cost of the X3 with custom tune!

Overall, the engine had more power than stock at the lower engine speeds due to the modified intake system and the tune. The transmission did not downshift as often when climbing hills and accelerated from a stop more briskly. The power improvement at high engine speeds is exhilerating! The large diameter intake system generates an inrush sound that I find as much or more exciting than a high flow exhaust sound but does not attract the attention of law enforcement nor does it offend listeners in the immediate vicinity. My Sport is vastly more fun to drive and now warrants its name.

There were only some minor issues with the starter tune. The engine speed dropped too low when coming to a rapid stop and the engine would stumble and then recover. Also, I noticed the A/F ratios were rich during moderate acceleration but that part of the tune is adjusted during the performance phase. I was very pleased with the initial results!

Upon completing the test route I let the engine idle for a few minutes in the driveway before stopping and saving the data log. Then I emailed the data log file to James for his analysis.

Idle adjustment & subsequent tunes

From the time I purchased my Sport it has seemed to me that the idle speed was too low for a V6. I asked James to increase the idle speed as part of the custom tune. I also did some internet searching and found an idle adjustment procedure used by Ford racing. I experimented with the IAC valve and the closed throttle adjustment screw and generated a revised Idle adjustment procedure . My idle adjustment coupled with the changes performed by James eliminated the deceleration stumbling and resulted in an engine that would continue to run even when the IAC valve was inoperative.

James noticed while reviewing the data logs I sent him that Bank 2 was running leaner than Bank 1. He said it might be due to an intake leak, an exhaust leak or a degraded O2 sensor. After checking I did find a slight exhaust leak at the manifold and another between the header and downpipe. I also realized that moving my stock O2 sensor downstream 3 inches so I could install the A/F ratio meter wideband O2 sensor as close to the exhaust port as possible may have created an inbalance. I restored the stock O2 sensor to its original position.

It only took a few iterations of data logging, emailing the log file to James, receiving a revised tune, and loading the PCM with the tune before I was totally satisfied with the driveability of the custom tune. We were now ready to begin the performance phase.

Engine oil, analog cable & 1st performance test

Several months ago when under my Sport I noticed a slow rear main seal oil leak. About a month ago I added a bottle of leaking seal treatment to the engine oil. I did not want to run maximum engine speed with the treatment so I replaced my engine oil with full synthetic oil. I also changed my economy remote engine oil filters with a Modil 1 full-flow filter and an Amsoil bypass oil filter.

Air/Fuel ratio data is needed to properly adjust the mixture during wide open throttle (WOT). The stock O2 sensors have a narrow A/F ratio detection range (14.4:1 to 15.0:1). The theoretical maximum power occurs at an A/F ratio of 12.6:1 and a wideband O2 sensor and meter is needed. The analog output voltage of the meter varies according to the A/F ratio. James sent me an analog cable with a connector on one end that mates with the X3 analog inlet port and pigtails on the other end. I purchased male and female two pin connectors from Radio Shack and installed one on the analog cable and the other on the meter cable. I determined the relationship between the A/F ratio and the analog output by reading the meter documentation and by experiment.

With the engine idling in Park I used the X3 to monitor the A/F meter output and verified the X3 was receiving voltage data from the A/F meter. During my last driveability test I added some brief WOT accelerations and sent the log file to James. He later informed me that the LiveLink program was able to convert the analog voltage to A/F ratios and walked me thru the process of entering the conversion formula into the LiveLink configuration file.

James had noticed unusual knock sensor related ignition timing retard on my data log and inquired about the type and quality of fuel I was using. I admitted that I was using discount unleaded regular gasoline and would switch to quality mid-grade at my next fill-up. Since my tank was almost full and I don't drive that much James decided to go ahead with the first performance test using the "cheap" fuel.

Initial performance testing can be performed on the highway by accelerating only in 2nd gear at WOT from below 2500 rpm up to a safe speed. I chose a straight uphill grade to decrease the rate of acceleration by increasing the load and increasing the instrumentation time. During the run I noted that the A/F ratio decreased to around 10.5:1. This was later verified by reviewing the data log. I also noticed on the data log that at 3500 rpm (just after torque converter lock) the knock sensor retard changed from +0.25 degrees to -1.75 degrees and then increased in 0.25 degree steps to 0.0 degrees as the engine speed increased to 5800 rpm. I emailed the data log to James for review.

I will continue 2nd gear highway tests until the tune gets close to the optimum A/F ratio at WOT. Then I will schedule and perform some "pulls" on the local DynoJet dynomometer for high speed testing.

Simply amazing Dale, I have never seen such an in depth write up of the process and everything is spot on such as if I would have written this myself. WOW-amazing!:thumbsup: Usually during a write up there are things which are left out for this reason or that reason but the detail and accuracy is impressive. I am subscribing.-j

Good write up, nice and informative especially since I want to get some tunes in the future when I'm rich. :)

My copilot

The photo below shows my "copilot" for on the road data logging. The OBD cable runs from the vehicle port to the X3. The A/F ratio meter cable also connects to the X3 analog port. Then there is the USB cable that connects the X3 to the laptop. I set up the data configuration file while parked in my driveway.

For obvious safety reasons I simply ignore the laptop while driving. I click on the start data recording icon and then turn the laptop so I can't even look at it. After recording the desired driving situation I pull off the road and then click on the stop recording icon and then save the data log file to the disk drive. Once back in my driveway I shut down the laptop and disconnect the cables. Then I email the data log to James for his review.

I have accomplished several performance data logs and the knock sensor retard continues to be a problem even with BP mid grade fuel instead of discount regular fuel. James is working the problem.

I anticipate that soon I will be ready to start testing on the dyno. I will data log the dyno pulls for later review and comparison with the dyno charts. I'm looking forward to comparing my stock vs intake mod plus custom tune results. Then I will perform some fuel economy tests.

I have accomplished several performance data logs and the knock sensor retard continues to be a problem even with BP mid grade fuel instead of discount regular fuel. James is working the problem.


Interesting.... I had/have the same problem, right from the start, with the custon tune. The only mod I have (or had on the truck last time it ran) was the K&N FIPK. Right from the start my logs were showing that the knock sensor was pulling out a ton of timing in the mid-upper rpm range. I was running premuim the whole time, multiple tank-fulls. I also tried adding MORE timing at WOT in these areas (on device adjustability), and it did allow more (actual)timing. This occured even though the knock senor would have still had more "authority" to not allow any more timing. In other words, if it really was knocking, then the sensor should have been even more aggressive in retarding it in those areas. Also tried manually pulling timing in that area. All it did was slow the truck down.

James and I discussed several times, but never reached a conclusion before I stopped driving it, and started the teardown/repair of the front suspension, that is still not complete. I had considered changing the knock sensor, but it's kind of hard to get too, to just change as an experiment.

I would be very intertested in what you find out about this issue.

My current speculation

I've spent quite a bit of time reviewing the data logs for the three different tunes. The knock sensor can retard the timing much faster than it can recover. This is necessary in order to protect the engine from detonation damage. Once a major retard occurs (7 degrees on one tune) then the timing never recovers at 0.25 degree steps. My thinking is to avoid the initial significant drop which seems to occur around when the torque converter achieves 1:1.

It appears that near max engine speed the richness should be less than at the low end to achieve max acceleration. Also, what would normally be considered as an excessively rich mixture (10.5 to 11.0:1) at low engine speed may prevent the rapid knock sensor retard.

I've asked James to consider generating a tune that almost immediately after WOT initiation provides an 11:1 A/F ratio until after the torque converter multiplication decreases to 1:1 (around 3500 rpm) and then slowly increases to 13:1 as engine speed increases to 5800 rpm. I don't know if such a tune is possible but I'll be glad to test it if James provides it.

My Bosch fuel injection book states that 12.6:1 is theoretically the A/F ratio for max performance but that's independent of timing issues. Another Bosch booklet states that the theoretical ignitable mixture ranges from lambda equals 0.7 (10.3) to 1.3 (19.1) for a normally aspirated engine. Personally while experimenting with my MAFAmp I achieved combustion for a brief period with an A/F ratio as low as 10:1.

In the next few days I'm going to revert to my richest tune and try a series of tests initiating WOT at 2000, 2500, 3000 and 3500 rpm to see how that affects the retard.

Knock drive

Yesterday I reprogrammed my PCM with the richest A/F ratio at WOT tune I had and went for a "knock" drive. I did 2nd gear WOT accelerations to 4000 rpm from start, 2500, 3000 and 3500 rpm. Even with the 89 octane fuel I still had significant knock retard unlike the full WOT test I had run weeks ago with 87 octane. I then programmed my PCM with the latest tune having a targeted A/F ratio of 12.6:1. Three of the five accelerations I ran had serious knock retard but two had very little.

James and I agree that the knock retard is excessively complicating adjusting the A/F ratio to optimum so he is going to provide me with a tune that disables the knock retard. I have intermittent timing chain rattle and exhaust rattle that the knock sensor could be detecting as detonation. The current tune has a safe A/F ratio and I have a pillar pod A/F meter to monitor so the risk of engine damage due to a lean mixture is low. After the WOT A/F ratio is achieved James will provide a tune with the knock sensor turned back on so I can try to isolate and correct the noise source. With the current cold weather I'm just not anxious to work on the engine.

Yeah, I know how to fix this one...Been there and done that.

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