Full Story: The GoWesty Fuel Injection Component Replacement Kit

The whole story about what it took to design, create, and release the GW-EFI Fuel Injection Component Replacement Kit to replace the antiquated, no-longer-available, and unreliable parts of the Bosch Digifant Electronic Fuel Injection (EFI) that came in all 1986-91 Vanagons. The main goals of this effort:

• Replaces old, corroded, prone-to-moisture intrusion and NLA harness
• All modern completely sealed connectors (no rubber boots to rot away)
• Replaces no-longer-available new (NLA) Bosch components
• Improves reliability
• Improves fuel efficiency
• Improves performance

Our first attempt is pictured below. At one time we had 50 prototype systems running, including two in Syncros driving to the tip of South America and back. We achieved a combined 120,000+ miles of testing of this first system. Overall the performance was considerably better than the original Digifant system, and reliability was excellent.

Here is a basic description of the components of our first system attempt, and an explanation of the approach:

This first system was comprised of:

1. Rebuilt throttle valve housing (aka throttle body) —features precision ball bearings, replaces worn-out NLA original
2. Modern throttle position sensor (TPS)—replaces outdated NLA throttle on/off switch
3. Modern manifold absolute pressure (MAP) sensor—new feature for better fuel management control
4. New oxygen sensor—modern 4-wire design with sealed electrical plug (duh!)
5. New knock sensor—new feature to protect engine against detonation regardless of fuel octane rating
6. Modern electronic ignition coil—replaces antiquated original design
7. All new injection harness and power delivery harnesses:
• Replaces old, corroded, prone-to-moisture intrusion and NLA harness
• All modern completely sealed connectors (no rubber boots to rot away)
8. Single ground point—bolts to factory location in engine bay
9. New Delphi electronic control unit (ECU)—replaces NLA Digifant ECU and ICU (idle control unit)
10. New, totally sealed EFI and fuel pump relays, located in original location in black box above coil
11. Air flow meter replacement (exchange, not pictured)
• Thoroughly cleaned inside and out
• Swinging door permanently affixed wide open
• Tested and good intake air sensor (AIT)
• Clean and tested electrical hook up for reliable signal from AIT within to ECU

There are only four connections to be made to the vehicle:

(1) Ground (#8 above)—brown wire bolted down at factory location in engine bay
(2) Constant power—red wire bolted down inside the factory weather-resistant junction box in front left corner of engine compartment
- New GoWesty Alternator Wiring Harness Upgrade Kit will be included to improve reliable power to this point
(3) Ignition power—black wire splice connection inside same junction box
(4) Tach signal—green wire splice connection inside same junction box

The following components of the original Bosch Digifant system are re-used and their proper operation is critical for the new GW-EFI system to work properly and reliably:

• Fuel injectors
• Distributor
• Fuel pressure regulator
• Fuel pump
• Idle air control (IAC) valve
• Coolant temperature sensor
• Power steering pressure switch

Timing is set just like with original Digifant system: 35 degrees +/- 5 degrees at 3000 RPM. Idle speed and fuel mixture is not adjustable and is completely automatic, as it was (supposed to be!) with Digifant.

Once installed, the current system had an appearance that was almost indiscernible from Digifant:

The price of this first system being tested was targeted to be $1995, and was to be sold "exchange," with an appropriate core charge old Bosch harness, ECU, ICU, AFM, and throttle body. This system had some minimal fault code storage and downloading capability.

We have had no trouble passing tail pipe emissions standard easily with any of these systems. This system was functionally superior, in that it actually runs cleaner than Digifant. However, this system was not legal in some states, including California, because it is not exactly original. No effort was ever made to get a CARB Executive Order for this system because we decided to go in a considerably different direction.

All the effort we put into the programming of the first system failed to work flawlessly on the installation we have done—without a fair amount of "custom tuning." In other words, all 50 systems required lots and lots of iterations and fine tuning. Even small deviations between two of the same engines, coupled with slight differences in things like AC or power steering load, would make idle control difficult to nail down perfectly.

We eventually came to the conclusion that it is necessary to step up the sophistication of the system design substantially in order for it to better adapt to variations between engines and vehicles. To that end, we took two steps back... but a HUGE leap forward.

The main changes in this new direction are as follows:

1. Addition of a mass air sensor—replaces the air flow meter housing
2. Addition of crank and cam position/speed sensors—replaces the distributor
3. Change from one coil to four coil-on-plug coils
4. New software system with OBDII-like diagnostics with full ScanGauge compatibility

The change from the one coil/plug wires/distributor to a coil-on-plug system is made possible by an ingenious device designed and created right here at GoWesty: a cam and crank position sensor assembly that completely replaces the Bosch distributor. 

This little device makes it possible to gather exact engine cycle data, which in turn makes it possible to eliminate the antiquated ignition distributor (hurray!) along with the cap, rotor, wires, and firewall-mounted coil (double hurray!). Instead, small individual coils will be fitted onto each spark plug—the same system that all modern engines employ. The other huge advantage to this system (besides eliminating the distributor) is no more high-voltage wires running all over the engine compartment. The #1 cause of engine fires is a fuel leak that is ignited by a stray spark from an ignition wire. Now, instead of running 60,000 volts between the coil and the distributor cap, though the rotor, and back through another wire to the spark plug—exposing the entire engine compartment to a potential fire hazard—all high voltage is contained between the coil and plug. No wires to maintain, no more cap and rotor to replace!

This new system is also sequential-fire instead of batch-fire injector control. The original Digifant system, and our original approach, fired two injectors at a time in “batches" (thus called "batch-fire"). Fuel injection is not timed in any particular way—the injector just squirts fuel near the intake valve, and the cylinder sucks it up the next time the right engine stroke comes around. Sequential fire means each injector can be controlled precisely independent of the other three. So, injection timing can be optimized, which equates to better fuel efficiency.

The target price for this new system will be more than for the old due to the additional components involved. We have a new target price of $2995, an increase of about $1000 from our original approach. But, all things considered, it is well worth it.

This new direction will, of course, mean a longer wait for release. But this longer wait is not only because of the change in direction. Clearly, we have had to pour a LOT more engineering time into this project. Indeed, we've had one mechanical engineer devoting a great majority of his time on this project since December, 2013. But the other reason this will take longer is because of the time it will take to get a CARB Executive Order for this system. This is truly a complete, modern engine management system, and will be fully compliant. Bottom line: It will be worth the wait.

JULY 2015 UPDATE: We now have two systems working: the one at the electronics laboratory in Michigan, and a second here at GoWesty. The one in Michigan is a 1990 model with air-conditioning, automatic transaxle, and is powered by a completely unmodified 2.1 liter water-boxer. The second vehicle is here at GoWesty and is a 1988 model with air-conditioning, manual transaxle. As stated above, the main reason we switched to this new strategy from the first one was due to the system's inability to adapt from one vehicle to the next—even when the two vehicles were practically identical. We have verified that our new system adapts as we expected it to. The exact same programming works perfectly in both completely different vehicles. It idles flawlessly with AC on or off, power steering fully locked or not—it does not matter. It won’t stall. We have ten complete systems on order. The next phase will be getting ten vehicles running in all sorts of conditions, getting lots of miles under our belts, and getting started on full C.A.R.B. approval for use of the system within California.

NOVEMBER 2015 UPDATE: We now have ten systems on hand, four of which are already installed and running. All ten systems will be running in the next couple weeks. We are down to just a couple of unresolved issues that will require some software changes by the manufacturer of the ECU. We have a software engineer scheduled to visit GoWesty later in November to handle the custom programming that will knock out these remaining hiccups.

As for testing, one of the systems is slated for our LeMons race van—because, yes, we're running that race again in early December. In addition, five vehicles outfitted with this system will be heading out for an extended southwestern USA and Mexico adventure in December and January. Come early 2016, we will be looking to clear the final remaining hurdle: getting C.A.R.B. approval for the system!

JANUARY 2016 UPDATE: We now have much more testing under our belts!

The LeMons race in December went off without a hitch. The EFI performed flawlessly. We ended up 3rd in class and 54th overall. For more details on the race, check out this page. Our holiday Baja adventure, which included three Syncros outfitted with 2.7 engines and our new EFI, was extremely successful, as well. Total miles driven: 9300, about 4500 of which were off-road miles. Under the exact opposite conditions of the LeMons race, the EFI worked great. We are talking about super low-speed, rocky trails, low engine speed/high load conditions common for off-road adventures. We are moving forward by ordering 20 new systems for a beta-test program, and obtaining a CARB Executive Order is in the works.

SEPTEMBER 2016 UPDATE: Two additional LeMons races are in the bag. We finished 3rd in our class in Sonoma (March 2016), and we got 2nd in our class at our first racing experience at Thunderhill (May 2016). We also took three EFI-equipped Syncros to Baja between the middle of December and the middle January. That trip provided another 10,000 combined miles of testing, including over 7,000 rugged off-road miles.

One of these three Syncros continued up to the top of North America and back on the same system. The only hitch they ran into is having to clean the coils due to getting inundated with gooey, stick, slimy mud—piles and piles of it! That led to an improved coil sealing system that our production kits will include.

Our EFI system continues to prove its reliability and robustness.

We are currently installing another 30 beta systems in select vehicles, with installations taking place right at GoWesty. These first systems are not legal in all 50 states. We are fully engaged in the CARB Executive Order process, anxiously awaiting their reply.

NOVEMBER 2016 UPDATE: We are about 90% through the C.A.R.B. process. To date, we have provided all the detailed information they have requested, and we have passed the two required Federal emissions tests. All of the information and test result reports are now in the hands of C.A.R.B. and we are awaiting our official executive order number for this new system. Meanwhile, we continue to put test miles on our 30+ beta systems running all over the country, refining small component details (like improved coil brackets) and ordering up stock of all components in preparation for a worldwide release early next year! Stay tuned!

JANUARY 2017 UPDATE: We have received our official CARB Executive Order, which makes our new system smog-legal in all 50 states. Meanwhile, we continue to put hard test miles on our 40+ beta systems running all over the country. We're refining some minor programming tweaks and prepping the system for a worldwide launch!

MARCH 2017 UPDATE: We are scheduled to run the Norra Mexican 1000 Rally in April with this system as a final exclamation mark, and then we'll proceed with a full release by late spring! UPDATE: We ran (and finished) the race—check out the results here!

SEPTEMBER 2017 UPDATE: We are down to the wire on this system, but we ran into one last (and wholly unexpected) hurdle in August that threw us for a loop.

By August, we had over 40 systems running, and the only issue was an intermittent longer-than-ideal starting sequence marked by an occasional crank/no-start/crank-and-start. Again, this issue was not present all the time, and it was completely absent on some installations. The issue was not bad enough to derail the project, and we believed it was a minor software-related problem. We were literally weeks away from launching the system as-is, contingent on fixing the "software bug."

Then, in late August, we encountered two vehicles with much worse starting, idling, and knock-sensor issues that we could not figure out. We traced the problem to the way in which we were picking up crank position signal—via the crank/cam position unit, which utilizes what used to be the distributor drive gear to drive it. The drive spins a toothed wheel inside the cam/crank unit that provides camshaft and crankshaft position data to the EFI computer. We theorized there was too much free play between the distributor drive gear and the gear that drives it, which is pressed onto the crankshaft during engine assembly.

To test our theory, we sent out a dozen drive gears to the east coast for coating in various thicknesses—the coating is designed to take up "gaps" in internal engine gears. We installed one of these in a vehicle that was having chronic starting and hesitation issues, and voila: fixed! The result of this investigation was that using the distributor drive to determine crankshaft position was not going to work 100% of the time, and coating the gears was just not practical.

All modern EFI systems have some sort of toothed wheel mounted directly to the crankshaft in some way, thus avoiding inaccuracy. We did not do this originally, because adding such a device to a waterboxer was not nearly as simple as using the distributor drive already present. Clearly, though, that simple approach was not going to work. We decided to change directions and switch to an entirely different method of determining crankshaft position: add a toothed wheel right onto the V-belt pulley.

Our engineering team devised a very clever way of adding this wheel without having to replace the pulley or modify it—which would have meant exchanging pulleys with every kit. The toothed wheel is completely bolt-on:

The GoWesty engineers also came up with a very clever bolt-on bracket that fits under the breather tower, which locates the crank position sensor in just the right spot fore/aft and radially—and it's adjustable, so the installer can dial in the timing perfectly.


We installed this new system in one of the vans experiencing chronic starting and running issues, and BOOM: fixed! The parts are on order, and we're back on track for a 2017 launch!

We appreciate the patience so many of you have shown while we've worked on a suitable replacement for the aging Bosch Digifant system, and we are especially grateful to those brave folks who agreed to run one of our beta systems. Without the data gleaned from those installations, it would have been nearly impossible to bring this system to market!

JANUARY 2018 UPDATE: We are done. Our development and testing efforts are complete. The system is available online, and it is a legitimate game-changer!

  1. New ECU
  2. New OBDII Scanner Compatible Data Connector
  3. New Knock Control Unit
  4. New Knock Sensor
  5. Vehicle Connections and Fuses
  6. Coolant Temp Connector  [Uses Original Coolant Sender]
  7. Engine Position Unit [Replaces Distributor]
  8. Fuel Pump Wires [Uses Original Fuel Pump]
  9. System Relays
  10. Chassis Ground
  11. Fuel Injector Connectors  [Uses Original Fuel Injectors]
  12. New Coils [Coil On Plug Design]
  13. Tachometer Adapter
  14. New Oxygen Sensor
  15. A/C Connector
  16. New Throttle Position Sensor
  17. Rebuilt Throttle Vavle Housing (aka Throttle Body)
  18. New MAF Sensor and Housing [Replaces Airflow Meter]
  19. New MAP Sensor
  20. Power Steering Connectors
  21. Idle Air Control (IAC) Valve Connector [Uses Original IAC Valve]