Matching your computer chip profile with your customized engine build

[skullandbones]

Hello All,

I have monitored discussions about various aspects of the computer sensor controls for the 5.0 EFI system. I have had some specific issues such as too short 02 sensor leads because of 4 into 4 headers (just one example). I think I will extend the leads correctly (solder) and weld bungs in the side pipes just where the 4 tubes meet. All advise I have gotten says to use them even though the 02 sensor input is only authorized to make small changes in air/fuel mix (app 1%). The experts say the computer will stay in open or full throttle mode if the 02 sensors are not used.

There are a few courses of action:

1. Take go kart to speed shop for burning new chip and dyno test for $550 to $800. That's if nothing else needs to be changed or fixed.

2. Send information to a company with your engine build profile and receive a new chip that fits that profile for $385.

3. Start up without changing anything and use prior knowledge for diagnosing performance of chip. I can recognize rich, lean, and timing issues but all experience is based on carbirated systems.

Note: I have heard from some that the stock chip will make adjustments for performance as long as you don't exceed the 400 hp range in your modification of the engine. Don't know if there is any truth to this. Personally, I don't think the computer is that "smart".

The only sensor I don't have a connection for after doing the 02 sensors is the SPOUT sensor.

I'm interested in what the EFI folks have found while doing their project. What is really necessary and what is optional? I am planning on a start pretty soon. Thanks, WEK

[Mike N]

If you don't have it get this book http://www.bentleypublishers.com/ford/repair-information/ford-fuel-injection-elec-eng-88-93.html It's one of the best books on the EECIV As far as tuning your car a mail order chip is not going to do it at all. You will have distinctly different exhaust and intake plumbing to any factory car so I don't believe that anyone except maybe Wayne Presley will have a tune that will work for you without getting your car on a dyno. If you only want to pay for things once then get a tuner such as a TwEECer or Moats quarterhorse and a wide band O2 set up, combined they will cost you around the $800 that you would pay for a dyno tune. There is quite a steep learning curve with this stuff but it's not that bad really. You can start with the factory calibration which will probably be pretty close and tweak the fuel and spark timing from there. If you don't get carried away and just make incremental changes then you will be fine. I have a TwEECer and it has worked out well for me but I think the Moats is probably a little easier (simpler).

[skullandbones]

This quote was on the Moates website: "Wait, be very afraid. EEC Tuning has a learning curve with an addictive, slippery slope of obsession on the back-side". So I guess that means back to school, again. I think I have spent more time on the EFI part of this project (thought process) than anything else. I can hear the carburetor guys laughing in the background:D:D:D I think you and I had a conversation about turbos. There was another good book: "Maximum Boost" (for engineers only). Well. I signed up for the EFI thing so I guess I should just go for it and quit whinning.

But seriously: I see the cost of the book and the QH at about $250. Will I need a burnable chip and other software as well as the time spent getting up to speed? It sounds like I could start my own EFI tuning shop before it's all over. Thanks, Mike!

[Morgan]

I have found that it is easy to fall into the "it has to be perfect" hole. I used the TwEECer to get things close and let the factory computer do it's job :) I dove in for a few hours before my first start and haven't thought about it until recently. I treat it like the infomercial says "set it and forget it."

Everybody has an opinion about carb and EFI, but I found it very rewarding to figure out how to tune my own car with a computer. (dont listen to the carb guys, or the EFI guys for that matter when it comes to making the decision, do what makes you happy) Since I've recently become fully legal, I've been contemplating setting up different tunes to suit the situation. (economy for the freeway, performance for most of the time, valet for obvious reasons and maybe even an e85 tune) it only takes a flip of the switch and you don't even need to shut the car off... Time to invest another 6 hours to re-learn :)

I guess what I'm saying is good luck, consider the TwEECer RT and I hope you enjoy the journey!

[skullandbones]

Hey guys,

Morgan, you say that the TwEECr RT will do the job as is. I guess from what I have read that means you let the EEC read the AFR at 14.7 to 1 only (or as I said before 1% narrow band reading). So that's what you meant by letting the computer do it's job, I think.

Mike, If you incorporate the wide band module that allows the AFR to be measured between 10 to 1 and 20 to 1 or wide band O2 reading. So how much has that helped you fine tune your engine? How much difference in performance? Are you utilizing boost?

Also: does the module allow you to display the AFR in real time directly from the EEC without a PC attached? It look's like it does. That would be pretty neat.

Thanks, WEK

[Mike N]

Go and download the TwEECer or Moats software and hack around a little. It will probably intimidate you to start off with because of all the maps and tables that you can change but if you just start with the basic stuff it's not overwhelming. For the most part the Ford software will take care of the part throttle settings quite well until you get a little crazy with things but the nice thing is that you can set the open loop (not necessarily wide open throttle) to what you want for best performance without killing the driveability.

What I found is that I needed to adjust the MAF sensor transfer function probably due to the fact that I have a very different air filter and intake plumbing to the factory set up. My A/F ratio was very lean at the top end of the rev range under WOT which besides being bad for the engine also robbed HP. Having a wide band O2 set up allows you to dial things in close to perfect. The next thing that you can change is the timing curve. Because the FFR is so light it can handle more timing at lower revs without risk of detonation, I have all my timing in by 2000 rpm under WOT and then pull out a couple of degrees starting at the torque peak to keep detonation in check with the supercharger. The simple fuel and timing changes added 80ftlbs and 60hp at the rear wheels. This didn't happen in one tuning session or overnight but during the course of many data logging sessions and tweaks to the tune. If you find this stuff challenging and fun you will love it, if you find it frustrating then you might be better off going to a well respected tuner and have them set the WOT stuff for you. But understand that virtually no tuner will be changing the factory part throttle settings, in fact be careful that they don't just disable the closed loop functionality of the EEC so you are driving on WOT settings the whole time as that will kill your fuel economy, this is a very common trick with a lot of tuners.

[Morgan]

Hey guys,

Morgan, you say that the TwEECr RT will do the job as is. I guess from what I have read that means you let the EEC read the AFR at 14.7 to 1 only (or as I said before 1% narrow band reading). So that's what you meant by letting the computer do it's job, I think.


I haven't invested in a wideband yet and have been very pleased with the drivability so far. Initially I just had to load the MAF transfer table and change other variables like the displacement and injector size. The TwEECer software let's you look at your long term fuel trims so you can see how much the ecu is compensating to achieve an optimal AF ratio. If the fuel trims are too far off it is not difficult to modify the tables. What I see as the "perfection trap" is that people try and perfect these part throttle tables when they change all the time due to environmental changes and aging sensors. It's like tuning your carb every time the weather changes. The computer does that for you.

Mike offers some very sound advice about downloading the software and playing with it. Two other software programs that you may want to look into are EEC Analyzer and Binary Editor. These are used in conjunction with the TwEECer.

[skullandbones]

I think this discussion could go on for a while but it would be theoretical at this point. So I won't bother you any more with the details until I get into a real live event. However, I want to reserve the right to revisit this when the time comes.

I'm a six sigma green belt so I am not only comfortable but enjoy the graphs and tables (if you can't measure it, you can't manage it). I did look at some of the data on the website. The real challenge will be getting familiar with the terms, acronyms, and figuring out which subprocesses are critical and which are optional. You both have helped to clarify some of those issues already. Now, I will have to get comfortable enough to work with the tools. The TwEECr RT looks like it would be the better choice, I think.

I know the subject doe not follow strictly with building the roadster but I think it will help others as well as me get their build out of the garage faster and make it easier for DIY tuners. Honestly, I didn't even know what a TwEECr was when I saw it mentioned several times on the forum. By the way, if you still want to talk more that is OK with me.

Thanks a bunch you guys!!! See you later. WEK