Jeff’s PEFI Wiring Harness, Your input please… Options

[JeffBowlsby]

PEFI (programmable electronic fuel injection) is here to stay and will become a necessity in the future to keep our 914s on the road and I want to be part of that revolution. (IMG:http://www.914world.com/bbs2/html/emoticons/burnout.gif)

Studying the different available PEFI systems and 914/4 engine layouts, they are all very similar in terms of their electrical and harness requirements. So I have been working with other club members (EE’s!) who shall remain nameless for the moment, to develop a universal 914 fuel injection wiring harness specific for the 914/4 or type 4 engine, that can be easily adaptable to most of not all aftermarket programmable electronic fuel injection (PEFI) systems. I have attached a couple of diagrams of our ideas and would appreciate anyone’s feedback, because this harness is for all 914/4 owners and I want it to serve our needs to the fullest. If its not a good solution that will serve most peoples needs, then I won’t make them.

The concept of this harness is clear: Create a PEFI harness that is simple, and adaptable to all or most aftermarket PEFI systems, built of high quality parts and workmanship for durability, and be reasonably priced. I realize it won’t meet everyone’s needs, but it should be a good solution for most. My intent is that it be Plug N Play and take the R&D, pain and expense out of building a harness that most dread. Buying this harness gives you reliability and gets you on the road much faster than having to build your own harness. I know some of the PEFI systems have harnesses available, but they are not the best solutions, they are not complete, and they are not made for the 914, although they can be a good start. My PEFI harness features include:

FI systems – A fuel-only PEFI system would be nearly Plug N Play, which I think most 914 owners will want when their MPS dies, most do not want to fuss with complex systems, but this harness will work for those who do. If someone would package an ECU with preloaded maps for specific engines, the install would be nearly painless. I bet the time to install a simple system could be accomplished in an afternoon if coordinated. If ignition control is needed, then my PEFI harness with additional wires, has the expandability to accommodate your needs.

2-piece harness with a weatherproof main disconnect in the engine bay – This allows the production of a standard engine harness configuration which will universally fit all type 4 engines, 1.7, 1.8 and 2.0L. The ECU harness segment can be made to the length you require, so the FI box can be located in the cabin or anywhere you select. The main disconnect allows the harness to penetrate the firewall and become mounted to the chassis, and also allows easy engine drops. Wires on one end of the ECU harness are long (is 18 inches enough?) and not terminated, so you can hook them up to whatever FI equipment in whatever arrangement you want.

Auxiliary wires – The PEFI harness connects all the standard 914/4 engine mounted FI sensors and fuel injectors to the ECU controls – TS1, TS2, TPS, and Tach. It connects to power and the fuel pump relay at the stock relay plate and to grounds in the stock engine case location. It is convenient to use the stock D-Jet AAR, controlled through the ignition harness, but if you want a fast idle solenoid or even a stepper motor you can have it. The standard harness includes 4 undesignated auxiliary wires for your use which might serve a fast idle solenoid, stepper motor or ignition trigger. If 4 extra auxiliary wires internal to the harness are not enough (it will be for most people), then I can provide as many as you like for an additional charge using a different main disconnect configuration.

TPS – At additional cost, I will provide a new TPS potentiometer with a disconnect and casing, or you can send me your TPS and I will install the disconnect and casing.

Connection hardware - D-Jet hardware is standard (new boots!) so you can reuse the stock FI components. Optional L-Jet connectors can be installed for a small cost increase. The harness can be configured for FI power resistors, or not, depending on your needs.

WBO2 cable – Use the cable from the WBO2 manufacturer and run it separately from the FI harness to keep things easy and protect the WBO2 warranty.

High Quality - The PEFI harness cable is fully cased to protect the internal wiring from chafing, fluid contamination and heat damage. All new, high quality parts and workmanship are used in its construction, this harness does not use any old parts and there is no core charge, although I might buy your D-Jet harness for my D-Jet harness customers. The Tach wire includes a shielded ground.

Price – What might all this cost? I honestly don’t know yet, but considering the parts cost purchased in bulk quantities, and the amount time required to make them, I think I can make them available in the $400-450 range or thereabouts. Is this price range reasonable? If not, where does the price need to be for you to buy one?

So talk to me my esteemed colleagues…and thanks in advance. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) My intention is to bring these on line in the next few weeks if possible.

[JeffBowlsby]

Thanks for taking the time to comment Dave, most especially coming from you.

I considered making full packages of ECUs, harnesses and all the goodies, but there are endless variables. Everyone wants something unique to their engine configuration, ECU choice, ignition options etc. The investment needed to stock and configure various ECUs and all the other requirements is substantial and more than I am interested in doing right now. But people still need a good harness, and thats my Espesh-E-Al-Ity. (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

The wiring harness requirements for all PEFI systems is similar enough, that one common basic design can be made to fit most or all PEFI systems to the 914/4 with only two easy-to-make variations: 1) Harness length to support different ECU locations, and 2) Enough undesignated wires to offer the flexibility to connect all the needed components together for unique requirements.

By PEFI I am generically referring to all the systems I have looked at and that interest most 914 owners: MegaSquirt, Microsquirt, Emerald, SDS, Perfect Power, Autronics etc.

Let me ask the rhetorical question that no one here has really discussed:

Besides all the other decisions made about a selecting and tuning and installing a PEFI system, how much time does it take and at what cost does the wiring harness take to fabricate? Its a hidden cost, because of the learning curve and special parts acquistion. What was the quality like when completed? I bet those that have actually built a decent harness will realize the harness is a major cost item in terms of hours and dollars. My harness will provide a cost effective and high quality solution for some, hopefully many 914 owners converting to any PEFI system.

The harness design I am proposing in its simplest form is fuel only, and has 4 additional undesgnated wires for optional upgrades. Its a direct D-Jet (or L-Jet for 1.8 owners) replacement so if your MPS dies, then swap in this cable, an ECU, a TPS, a WB02, tune it and its play time. Use the stock relay board for power and fuel pump control, the stock AAR and distributor, and the stock fuel injectors and sensors - I dont see these parts as part of the main problem of a disfunctional stock FI system for most 914 owners (its the MPS if you have to ask). We need to be mindful to minimize 'scope creep' for the swap to PEFI. If someone were to make premapped ECUs available, (perhaps for stock engine configurations) then the swap would be a bolt in, Plug N Play. I would love to work with someone willing to premap the ECUs for a turn-key system.

If someone wants crankfire or other ignition control, a fast idle solenoid, a stepper motor, and other options, I can easily put a few more wires in the harness to make it work for them. The basic harness configuation does not need to change.

What is DIS?

I have been making the 914/4 engine bay harnesses now for about 7 years. I do make a small profit on each harness to keep the venture viable, but its not enough to put my kids through college, which has never been my intent. If it was not viable, I wouldn't spend my time and energies doing it.

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