[Amc-list] Re; EFI install on [anything modest] a bit of a Rant.

["John Elle" <johnelle@xxxxxxxxx>]

Knowing full well that at least 4 people on this list run a form of fuel
injection on the AMC I-6 it would seem some how to me that there would
be more specific information available as to how to accomplish it. This
includes my self. At least 3 of the people run a 4.0 with the factory
fuel injection. 
Mine is a conversion on a 258 and I assume others out there have some
form of a throttle body or mpfi system. 
It seems to be implied that you wander around a junk yard and grab an
assorted hand full of parts and with the help of a soldering iron and a
couple of alligator clips you can retrofit almost anything anywhere. 
While there may be an element of truth some where, I just do not think
it is that easy or frankly worth the cost. 
I can with some degree of luck sit here and look up just about any fuel
injection system on an American car that has been used since the first
one on the Cadillac Seville. ( I am referring to electronic only
although I can also look up early mechanical units too). 
I am not saying as a technical curiosity or an exercise in capability it
should not be done or even thought about. After all with a budget and
some curiosity and the need for the end result to be smog legal it can
be done. 
But to grab a throttle body off some form of a 2.8 or other GM car with
no clue as to what else you need to have along with the throttle body
and even less of a clue as to what sensors are required and where you
put them on an AMC I-6 the planning effort is a bit more than vague. 
I looked up the 2.8 Chevy TB and found for one thing, there were at
least 5 different engine controllers called out for the S10 in 1984 on
the page of information I was on. 
I frankly have no idea how many more different engine controllers were
also called out for other applications, but as the smog requirements
varied all over the map in 1984 I would be willing to bet that the same
package in a car had different controllers again. 
I dunno, but if some one is interested I can look. I can also get the
fan out required to satisfy the engine controller. And they very around
a bit too. 
That of course does not answer the question as to whether any of the
sensors would fit any place at all on an AMC I-6 application. 
 
Mark, 
as close as I can tell there is no requirement for the input from an oil
pressure sender for the engine controller for the Renix Jeep unit. For
the Chrysler mpfi unit there is non either. 
The Chrysler Unit is a speed density system and because of that it less
flexible then the older Renix unit on it?s applications. However if
something out there uses an air flow sensor it has quite a bit of built
in flexibility. Staying with in the operating parameters of a Speed
density system is not all that hard and as far as Jeep units go I
understand that it is basically more reliable. There is also no knock
detector working with it. Thus you want to make sure you follow the
directions with the use of this unit. The recommendation is high test
gasoline. And at a dime more per gallon at $4.00 per gallon, it is
hardly an imposition. ?Specially since I built my engine to run on 91
Octane. 
However if there is a capability of changing any of the operating
parameters on either unit I am not aware of it, thus getting it to work
with a different set of parameters  is not feasible.  As far as I am
concerned my unit could use a more aggressive advance curve and greater
advance. However there is no way to 
1 Measure it. 
2 Change it. 
My fuel injection is an engine management system too. It also runs the
ignition. I would think that the older less sophisticated systems would
retrofit in some way or anther and just run the carburetor and ignore
the ignition. Some of the older units might even trigger off of the
distributor. It would take a bit of looking to figure it out.
 
Cost, 
These things are not cheap to do. I have yet to run across anyone who
has a working system under 2 Grand, with the possible exception of some
one who bought a donor vehicle and then stripped it for parts, which is
probably just about the cheapest and most reliable method that I can
come up with to obtain the parts.  
Horror stories accompany other applications where parts were attempted
to be found at pick a parts. Incompatible parts are the biggest
problems, and then making parts try to fit with machining operations is
not cheap either unless you have your own fully equipped machine shop.
Numbers I have seen spent to accomplish this ?replacement for a BBD?
Carburetor have been aprox. $2500 to $3500 on the whole. 
 
Detroit did not design Fuel Injection because they had a change of heart
in the design departments, Performance increases were not necessarily
prime criteria nor was fuel economy, if there was any at all. 
 
Smog requirements drove the design. The feds wanted a 50,000 mile smog
engine and one way it could be done was to fuel inject it which requires
no wrench turning to make it run. Spark plugs and air filters were
designed to last 50,000 miles. Detroit made Washington Happy. The buying
public could suck eggs or by a Bimmer or a Toyota. 
 
The only problem I have had with the BBD carburetor was advanced neglect
and gross miss-adjustments. I can guarantee you a rebuild kit and an
afternoon in the garage mine will run well and cost 3-4 x 10 to the 3rd
less than my fuel injection kit did. Not worth it to change it. I wanted
more carburetor when I was done. With the cfm rating of the BBD at 195
cfm at 3,000 rpm the engine was beginning to fall on it?s face. Smog
legal was the biggest requirement for me. With fuel injection I got it.
Now the engine will run out to 5500 with out the slightest provocation
and still pass smog. 
However I fought that damned fuel injection for 2 years before I was
able to determine the MMAP sensor was either defective or out of
calibration from the get go. Oh yeh, it would pass the computer self
check! Go figure. 
 
I still am fighting the fuel injection. I have eaten up 4 fuel pumps so
far. At $100.00 a pop that is a bit pricey. Recently I discovered why,
using the fuel pick up built into the car when the tank was about ¼ full
and you stepped on the gas, or went up a 7% grade the gasoline would
slosh to the back away from the pick up and the pump would run dry. It
did not take too many times to kiss off the pump. 
Summit has a modification that you can do to your gasoline tank to pick
up from the bottom of the tank. Maybe I will make that change this year,
maybe not. But in the mean time I keep the tank no less than half full. 
 
Some of these problems are subtle and take a while to find them. Having
a working knowledge of one unit does not make you an expert on all fuel
injections, just a little bit smarter. 
 
The one on my Eagle Summit Wagon had an EGR sensor in it. If the EGR
tube plugged the sensor went into an out of tolerance condition and
flagged an error code. 
Boy was that fun to find and ferret out. When I pulled the assembly off
of a junkyard Mitsubishi engine, I felt good, until I got it home and
this one did not have an EGR sensor. Yuh, I figured it out eventually
and fixed it. Yes I do my own diagnostic and repair work for the most
part. But I will buy a service manual for the car that I have
to tell me what to look for and where to find it. However even with that
I have hit one impossible to fix situation with the Dodge Caravan I used
to own. It quit one day. 
After 3 weeks of working on it, it still wasn?t running. I sold it to a
mechanic who could fix anything. That was a year ago, it still isn?t
running. I don?t know why and I don?t care. It is not my problem any
longer. 
 
Yes fuel injection systems are reliable, far more so than anything in
the past. But remember, I bought my 10 year old 100,000 mile Town and
Country at about what the same price would be to by a New Donohue
Javelin in 1970. Something should be more reliable even if I can not
keep a transmission in the thing. 
 
If some one wants to package information on getting something cobbed
together that just might get the job done. I have data I am willing to
share. Just ask. But for me, the next I-6 I build will have a Carter AFB
on it or maybe an AVS and I think I know how to make it smog legal too. 
Not end of Rant, but done anyway. 
John. 
 
 
 
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