Penny-pinching 258 TBI

[carnuck]

The Renix TBI had an external stepper motor.

[tgreese]

Some progress...

I've made some changes, which basically invalidate the cost spreadsheets that I started on the first page.

First, with this Ford throttle body, there is no need for the Idle Air Control (IAC) stepper motor control that comes with the MegaSquirt 2. The first board I bought was a V3.0 model, which is also not needed for this conversion. So, I purchased a MS1 with the V2.2 board, which can run the MS 1 Extra code in MSnS (MegaSquirt N' Spark) mode. The injectors in this TB are low impedance, but not super low (2.5 ohms) so I'm going to run without the flyback board http://www.megamanual.com/v22manual/minj.htm#fb and add 4 ohms of resistance http://www.megamanual.com/v22manual/minj.htm#injresist to each injector circuit. This will bring me into the constant 200 mA per injector range that the V2.2 board without the flyback circuit can handle. And I have the resistors in my junk box. Should be ok ... we'll see. If I need the flyback board, I can build it from my junk box plus about $6 in parts so that's not an issue.

The MS1/V2.2 kit is $169 from DIY Auto Tune http://www.diyautotune.com/catalog/mega ... p-128.html - they are the only USA supplier that I know of. The MS2/V3.0 kit is $279, a significant savings. (The MS2/V3.0 board will be used on my CJ-6). You can also buy a minimal kit with the circuit board, CPU, and MAP sensor for $125. I started to add up all the extra parts you would need to use the minimal kit, and it easily went over the $44 difference. So the full kit seems like a no-brainer.

I also determined that the fuel pump I was going to use won't be adequate. Originally I was going to put the Bosch 69238 fuel pump in the gas tank, but that pump is only rated for 43 psi (3 bar). That's enough for the GM throttle body which operates at about 15 psi, but it's not enough for the Ford CFI pressure regulator, whose set point is 39 psi. It might be ok, but I'd have no opportunity to increase my fuel pressure if I needed to. So I bought an Airtex E2000 fuel pump, an external pump that is the factory pump for some Ford cars and trucks. Airtex rates this pump at 70-95 psi, which should be adequate (Amazon, $63.23 http://www.amazon.com/gp/product/B000C1 ... UTF8&psc=1 - I have Prime so no shipping, otherwise RockAuto is cheaper). I also bought a Mann MF1002 filter to go with the pump (Rock Auto http://www.rockauto.com/catalog/moreinfo.php?pk=2265212 $3.41). Both of these use the Ford barb fitting which are meant for nylon line (Dorman 800-080 http://www.rockauto.com/catalog/moreinfo.php?pk=4391574 at $1.87/pair close-out). You can get these at the junk yard easily ... they work fine with the rubber EFI hose.

Normally I would have looked for the pump and filter at the junkyard, but we have lots of snow right now, and I probably won't be able to go on a junkyard expedition until April... certainly I won't see my lawn until April, the way things are going now.

I grafted the Mustang air cleaner base to the original 258 air cleaner. Here are a couple of pictures of that -





Soldering works pretty well for this. The graft needs to be a little off-center for clearance with the wiper motor. You can see that here -



I will make a new air cleaner stud with a jog, but I need to buy some steel rod. No opportunity to go to the Home Center yet, due to the weather. The alternative would be to drill a new hole in the air cleaner lid, but that seems like too much of a hack.

A little clean-up and paint and it'll look like a factory installation.

[tgreese]

This is the completed MegaSquirt 1 (MS1) with the green V2.2 board, running on my bench with my home-made stimulator. You can see that the part count for MS1/V2.2 is much lower than for the MS2/V3.0 with the blue board that I built earlier.



DIY Auto Tune sent the MS1 kit quickly, but be careful of shipping charges. Their web site defaults to the most expensive shipping method, and if there is any change or delay in your order and you must re-enter your credit card info, the web site resets your shipping choice even if you previously picked standard shipping. Assembly of the MS1 went quickly - I can't say how long it took, because I took my time over a few evenings. But it seemed to go very quickly.

The kit also comes with a nifty custom-cut black anodized aluminum case, which unfortunately has the DIY Auto Tune logo and contact info silk-screened at maximum size on the top cover. The logo dissolves away cleanly with a little paint remover - it would probably come off with lacquer thinner too.

Another minor point - the MS1 assembly instructions tell you to clean the soldering flux from the board with alcohol or acetone. I suggest you use a product like this - http://www.amazon.com/gp/product/B00AF0OFVU/ - or another electronics cleaner. (DeOxIt is the best, but wildly expensive. The WD-40 product seems fine, and the applicator is very convenient.) Contact cleaner is something you should keep on-hand if you own old cars - very helpful when you need it. And this stuff removes rosin flux splendidly. A 2-3 sec spritz for the whole board, scrub it around with an old toothbrush, and wipe up with a lint-free rag.

Here's the Mann MF1002 fuel filter and Airtex E2000 fuel pump:



The fuel filter comes with quick-connect ends like the fuel pump, and here I've put a couple of Dorman 800-080 barb fittings on the inlet and outlet. Unfortunately the design of the Dorman part - different from the OEM Ford part - means that the Dorman fittings wont go onto the E2000 without some modification - they are too long. The distance between the raised ring on the inlet/outlet and the body of the fuel pump or fitting is too short for the Dorman part to snap on. Note that the Airtex fuel pump is made by Carter in the USA.

[tgreese]

Another accounting ...



This isn't completely honest ... a couple of the items I've bought, I later found for much less at Del City than where I bought them. I've used the cheaper prices. And I've used the actual item cost that went into the project, not how many I actually had to buy. For example, fuses from Parts Express are $1.80 for a box of 5, or 36c each. I need 8 fuses, so that's $2.88, but I've spent about $10 on fuses in the past several weeks.

I've also given up trying to account for all my shipping costs. If I can buy something from Amazon and use Prime shipping, that's often less expensive than the same item with a lower list price at RockAuto or wherever. So I've simply added an additional 10% to all the prices for shipping. For some items, that's too little, and others, too much. So maybe it evens out.

And ... conditions here don't allow me to look for used parts right now - it's either buy new parts or wait for better weather. More determined scrounging could likely lower costs further.

[Nutz-n-Bolts]

Great project Tim. Nicely documented too. I'll be watching with interest. Mine may get the same treatment some day.

[Bill usn-1]

The fittings for the pump are 800-119
I don't remember any of my airtex being made by carter and they are physically different in appearance than that one.
Maybe they were recently bought out?

[tgreese]

Thanks for the encouragement Nutz-n-Bolts. And thanks for the tip Bill. I'm using the 5/16" lines, and there appears to be an 800-116 that will work. http://www.rockauto.com/catalog/moreinf ... d=4&jpid=0 However, I think I can sand down the tabs on the 800-080 and it will go on. May never come off... but that's ok with rubber hose.

Re the fuel pump, the box says Airtex. Here's the listing - http://www.amazon.com/Airtex-E2000-Elec ... rtex+e2000 It's interesting that the picture has changed from what I got, and the price has dropped by $5. I Googled the numbers on the pump, and came up with nothing. Maybe you will recognize them - 14 F16A241.