Looks GREAT Steve! You are going to enjoy the overall smoothness and starting of the FI system. Further, one BIG benefit of FI is you will not have the severe wash down of the cylinder walls during cold weather starting that you will get with auto choke carburetors.

Do you have a cold air tube for the air cleaner?

Good call! I will be fitting a 4 inch aluminum dryer type hose for cold air input. There is a hole next to the radiator for it.
I will do some more work on the final version for the fuel lines, thinking AN fittings. If you do not have a return line system you will need to install lines. I used the old ones.

I could have replaced both in-tank fuel pumps with later GM TBI pumps, but I had previously converted to a single inline pump, which I replaced with the higher pressure one very easily, seems to work fine.

Mods needed were: the O2 bung welded into the exhaust pipe, extend O2 sensor cable 3 ft, put a 1 inch spacer under the air cleaner, new throttle cable clamp bracket (simple L bracket), hole in doghouse.

Engine temp sensor fit into the existing threaded hole in the front of the intake manifold.

MAP sensor mounted on the old bracket for the smog pump check valve.

Distributor is a drop-in replacement.

TBI and adapter plate bolted right on. With the 1 inch spacer under the air filter, the air filter is in the same place it was before.

Overall a straight-forward install process. So far I'm pleased.
Now for a test drive!

quote:

Originally posted by MWrench:
one BIG benefit of FI is you will not have the severe wash down of the cylinder walls during cold weather starting

LOL. My choke is set very lean to minimize washdown. A little longer warmup in winter, though. Particularly with blocked heat-riser passages.

Wow. Just got back from the road test. 86Barth has never run so well. Smooth, strong, good throttle response, good idle.
Definitely more torque in the 2300-3000 rpm range. Cruise control can handle bigger hills without sagging.
I am totally pleased so far. We'll see about mileage on the way to Black Hills.

One of the arguments for conversion to the TBI system came from these GM graphs, from the 95 motorhome guide.



Before: The 82-89 454 4 barrel shows peak 240 hp @ 3800 rpm and 375 ft-lb @ 3200 rpm.

After: The 90-94 454 TBI shows peak 230 hp @ 3600 and 385 ft-lb torque @ 1600 rpm! From 1600 rpm to 3000 rpm it is making more torque all the way.

Since I spend most of the time between 2000 rpm and 3000 rpm the TBI should give me more torque when I need it.

The graphs indicate the same displacement and compression ratios for both engines. There may have been a camshaft change but no one has confirmed this for me. Other than that, it must be the TBI making the difference.

Having made the switch, it looks like the graphs may be right.

I can't do dyno testing but I think my road testing confirms better throttle response and WOT acceleration in that rpm range. It will pull up a steep hill slightly better than before.

Road tested 1231 miles from MI to Black HIlls SD. Mileage about the same, maybe 5% better. Drivability on hills and at higher altitudes (so far 5325 ft) is WAY better. Starting, idling and throttle response are improved.

With the carb I could hardly move at 5,000 ft now it is running smooth and has more power. I totally recommend this change if you intend to run a gasser at higher altitudes.

"I pity the fool...", oh wait, wrong A-Team character..."I love it when a plan comes together!"

Sounds great!
What was the overall cost?

There are several options.

If you have access to salvaged parts, you can remove the entire system and reuse almost everything. You can get a computer chip custom burned for under $200.

If you choose to use the salvaged parts and want a custom harness you're looking at about $300 more.

I went with the basic "complete kit" all new GM sensors, rebuilt TBI, adapter plate, new injectors, new harness, computer with custom chip for about $1000. I added in a new ECM distributor for $80 more and a new fuel pump for another $80. With State sales tax it was about $1200 total.

I considered going the salvage route but I figured I'd still have at least $500 for the used stuff and the harness, then still have to "reinvent the wheel" when I could get the stuff ready to go from AFI. Bolt in, attach harness, runs great.

So far I am quite happy with the results. If you are reasonably skilled it is not a bad job to install.

AFI has a web site listing many options, including more sophisticated multiport sequential system if you want to spend even more!

That's cheaper than I thought it would be.
Good luck, hope it works out well.

I think you made the wise decision to go with a complete system ready to "plug & play". My experience with early GM throttle body systems on a 454 were not great. I had to have the EEPROM reprogrammed before the full throttle response and torque was acceptable. I think I paid $400 for that service.

Good luck with yours and I don't think you will look back, well maybe, "why didn't I do that sooner.

Update on fuel injection system:

Over 5000 miles running great, then last time the idle was racing and rich. Played around while, decided I had air control problems.

Found a vacuum leak on the adapter plate. The plate has two sets of holes depending on the manifold you are using. I am using the inner set of holes.



Both of the holes at the right rear corner end up under the corner of the TBI gasket. The gasket is unsupported under this corner and developed a vacuum leak. I should have noticed the gap under the TBI when I installed it.

old gasket: notice gap at lower right.



Solution: I cut an oversize gasket.



I filled in the holes.



Extra gasket showing now. No more air leaks.
The idle was now at the correct rpm. I also set the Throttle Position Sensor.



Good news: I thought the OBD1 computer could not provide real time data stream sensor information but it can!

With an ALDL to USB cable adapter (about $60) and free ALDL software (comes with cable or download free at WinALDL.com) you can view and record data with any PC with Win98 or newer.

I had an old beater Win98 PC I hadn't run in 7 years... fired it up, loaded the software, plug in cable and watch the data stream. Makes diagnosis and tuning very powerful! (More to follow on another thread)