Automobile manufacturers prefer not to spend money on tows and warranty repairs. Consequently they have spend a great deal of money designing and refining EFI systems for reliability. A lot more effort goes into their EFI designs than goes into any after market design EFI system or EFI modification unit. I think that these days factory EFI systems are pretty efficient and reliable. So much so that most people forget to maintain them at their regular service intervals. My chief concern is that manufacturers have added more electrics then they need just for the sake of having electrical gadgets.
My Land Rover has been picking up additional wire since around 1992 when I ripped out all the 32 year old cut, spliced and taped wiring and started over with a new custom harness I designed to use an alternator instead of the generator, added a couple gauges and lights.
The next big step was when 1996-1997 when I converted my Land Rover into a Dormobile. I added a second battery and rear electrics to run a water pump, refrigerator, radio, and rear interior lights. Additionally I added a mains circuit. Plug the vehicle in and I have a duplex interior receptacle, 120V to the refrigerator and a permanently connected 3 stage battery charger on the second battery.
Then in 2006-2007 I made the really big step. I converted my 302 engine from a four barrel carb to 1991 Mustang EFI. I did this with a lot of trepidation and a lot of used parts (which was a mixed blessing)
Why did I go from a carb to a factory ODBI system????
- To increase fuel efficiency A carb is a simple compromise with 3 fuel flow circuits to handle all situations at all altitudes and all temperatures. You jet a carb for worst case where you normally drive. It is almost always running richer than it needs to be and should be rejetted whenever you change altitude 3 or 4 thousand feet.
My EFI system is constantly testing its environment (outside air temperature, engine temperature, air flow into the engine, altitude) and it is constantly retuning itself for best fuel efficiency and power. As I drive over a high mountain range my engine is tuned for the exact spot my Land Rover is driving.
- For better off road manners EFI engines run a lot smoother at high angles, especially when crawling through rocks at very low speeds. The throttle response is much smoother with EFI at low RPMs.
- For reliability Factory EFI systems are pretty reliable. Probably multiple times more reliable than after market EFI systems. My factory system self adjusts to handle such things as changes in components such as different cams. exhaust manifolds and different cylinder heads. It also self tunes to compensate for spark plug wear and sensor wear. The engine runs better longer. When a sensor goes too far off spec for the computer to compensate for it lets you know and switches into a limp home mode where it ignores most of the sensors. There are only two components that will kill my EFI engine that would not kill my carburettor engine: The computer and the throttle position sensor. Relays can be manually bypassed and the limp home mode works without everything else that would not also kill a carburettor engine. One nice thing about a stock American EFI system is that if something does break any auto parts store in North America will have a replacement either on the shelf or in their warehouse. Each of us has to decide how prudent we will be on the trial. We each do our own risk analysis and pack accordingly. That is often influenced by experience and space to fit spare parts that we hope to bring home unused. If you carry a spare fuel pump, it doesn't matter if it is a mechanical pump or a high pressure electric pump. The only thing's I've added to my spares list after the EFI conversion is 2 relays. I can bypass both if needed but replacements don't take up much space. Of course spare parts for things that have been changed were replaced with ones that work with the EFI system.
- I trust OBDI more than OBDII ODBI diagnostics are a lot more primitive than OBDII diagnostics but OBDI retains the distributor. The distributorless system uses a crank angle sensor which sits level with the crank. Immerse a hot crank angle sensor into cold running water and the sensor has a tendency to break. That's why OBDII vehicles have such shallow factory wading specs. If I had a OBDII vehicle I would make sure there was always a recovery vehicle stationed at a crossing and I would carry a bag full of crank angle sensors.
Converting to EFI was a big jump for me as the school of hard knocks had forced me to learn carbs and I am comfortable with the technology. I didn't know a thing about EFI and the mass of wires and sensors intimidated me.
Before making the conversion I bought and studied two books covering the EFI system I planned to install and I studied several web sites. Once I added the EFI system the school of hard knocks taught me the folly of using used electrical components purchased off ebay. Before the engine was running right I had replaced all the used electrical components, including injectors except for the barometer. The used electrical components blessed me with the knowledge and experience to diagnose EFI problems. My latest lesson taught me that OBDI does not diagnose fuel pressure levels but can let you if the fuel pump is not getting voltage or if the fuel pump voltage is low.
One thing I have been doing religiously is creating and maintaining current drawings of my electrical system. I keep my own custom manual in the vehicle. It has a parts list for non stock consumable components, electrical system diagrams, PCV & vacuum lines, and fuel lines (I have three fuel tanks) and the EFI has a return line). I have found accurate schematics to be very handy when making the conversion and when trouble shooting the initial teething problems.
My bottom line thought about added electrical system complication is that it is OK so long as you can diagnose and fix any problem that might be expected to occur in the field, carry needed tools and prudent spares. If you don't understand your electrical system to the point of being able to diagnose and fix any problem likely to occur in the field which would leave you stranded, you should not be out in the trail with that vehicle.
Excrement happens out on the trail and the prudent person has leaned how to deal with it and get going again.
