Been a while since I fed my Barth addiction.

Got a box of goodies from AFI: Throttle body fuel injection conversion kit.



Bottom left, clockwise:

Rebuilt Rochester 2 barrel TBI with 2 new matched injectors, idle control solenoid, TPS (throttle position sensor) and spread bore Qjet adapter plate.

rebuilt ECM Distributor

GM ECM (computer module with custom chip)

fuel pump

new GM sensors: O2 sensor, engine temp sensor, MAP (manifold absolute pressure) sensor, fuse, check engine light, manifold gasket and fuel filter

complete wiring harness (includes power and fuel pump relays), hardware.

There is a CD with many pages of instructions, reference, schematic diagrams, etc. So far, it looks like the works.

The ECM distributor and fuel pump are options. You can use your own if you have them. The cost from AFI was reasonable, though. The GM TBI expects about 15 psi feed pressure (internally regulated to 12 psi) my old pump does about 5 psi so it has to go.

Oh boy! Can't wait to get in the doghouse. Unfortunately it went from 75 and sunny for a week to 40's and rain today.

One positive note: the O2 sensor requires a threaded bung to be welded to the exhaust pipe to install it. I was already replacing the muffler, so I just removed the pipe from the header. This way I'll get the bung welded with the pipe already out, rather than move Barth to the shop.

When I get the weather, I'll start removing old stuff, cleaning the engine, and begin the conversion!

i am really interested in this conversion I looked into it before having carb redone , let us know the progress !!!

Very ambitious... I'll be following this post as I'm sure others will too. Good luck.

On my SOB, a '91 Rockwood 28' I had the 454 with factory fuel injection. Also had the 4l80E. Over all good system BUT one thing I noticed was that there was a flat spot in the throttle near full throttle. It would pull just fine until I floored it and then it seemed to loose power.

Turns out that (from a tuner in San Diego) that GM was worried about the first years of use of the 4L80E trans so they programed the chip to back off power at full throttle. I got a new program chip and all was fine from that point.

I am a fuel injection guy, Control of fuel from extreme cold weather to hot weather, low altitude to high altitude, is so much better than carburetors. Economy is generally better. It isn't as complicated as most want to believe. (at least it doesn't have to be)

Once dialed in you will never go back to carbs.

The #1 reason I'm converting is the higher altitude (lack of) performance. The usual dog becomes a pig... low on power and running rich.

As we will see, the transition should be fairly easy. TBI in for carb, new distributor in for old, new fuel pump replaces old one. The temp sensor has a convenient place where the EGR vacuum switch was. Harness should be easy.

The fuel lines will need upgrading, Map sensor mounted (probably under air filter) and O2 sensor in exhaust bung. I already have the bung welded to the pipe. I'll put the pipe back in next.

35 and snow here today.

AFI programs the chips in the ECM. They do everything from monster high compression high lift cam engines to stockers like mine.

I described my smog free setup, headers, 4.56 rear end, etc and requested tuning for max torque from 2000 - 3000 rpm rather than top end hp. I suspect it will work right out of the box.

Looking forward to this conversion.

Subscribed.

Well here we go. Since I had the pipe out to replace the muffler, I got a bung welded on for the O2 sensor. Reinstalled with new st steel bolts and headpipe gasket (FelPro 60584) back on the Thorley header. (BTW this is not an endorsement for Fram filters, they are NOT the best. When I change oil next week there will be Wix filters from now on.)



Then I started with the top of the engine.



Even after earlier de-smogging there is lots of stuff left.



See you later, carburetor! Next I will set the timing to the marks and pull the old distributor, followed by cleaning and painting the grubby engine.



So far it looks like everything will fit OK. The TBI and plate are correct. Some minor engineering is required: installing/welding the O2 sensor bung, throttle linkages will need modification (the throttle shaft on the TBI is about 2 inches back from the carb shaft. I will move the bracket back further on the manifold.)

I will also have to reroute the fuel lines: the TBI has both input and return lines out the back side. Also need to swap in a higher pressure (15 psi) fuel pump. Once I get the engine cleaned up I'll proceed with those changes.

When you are ready to get rid of the carb and distributor let me know. I could use some extra's.

I figured someone could use them. The distributor is OEM, works fine. The carb is OK but the idle mixture is a bit rich and the idle adjustment screws don't do anything (probably needs cleaning) I will have a 1 year old Carter fuel pump (6 psi) left over as well.

I was thinking I might offer them to interested parties for a nominal donation to Bill NY for the Barthmobile site. I'll bring leftovers to Milford III for the Barthmobile auction. I'm not sure what they are worth (not much to me any more!)

That would be a pretty radical SAAB or Volvo with a 4 barrel in it!

I am actually thinking of doing the same thing you are or possibly doing a complete 7.4 Votec upgrade with transmission if I can come up with a suitable doner at a reasonable price. Considering the possibility that nether one will ever get done I would like a good usable ignition and carb for spares just in case.

Steve, I was looking at the pic that showed the bung you welded on for the O2 sensor, but I noticed there was something missing! No snow on the ground
Jim

quote:

Originally posted by Steve VW:
Next I will set the timing to the marks and pull the old distributor, followed by cleaning and painting the grubby engine.

I like to clean the top of the engine before removing the distributor. The drive gear on the cam is one place you really don't want anything to fall.

quote:

When I change oil next week there will be Wix filters from now on.)

I agree - NAPA Gold filters are Wix rebrands. When I worked for Shell, it chose Wix filters to rebrand - no other is in the same league. The "secret" is they make their own very effective paper.

Got sidetracked as usual but got it cleaned up and a coat of paint.



(The top finally matches the bottom, which I painted a year back doing the crankshaft)

Now for the fun part: new stuff!

Started installing the TBI unit. Adapter plate, TBI and gaskets with no problems.

PCV valve reconnected. I need a couple fittings to complete the other vacuum hookups.

Connected fuel lines to the TBI also. The new fuel pump, return line, and selector valve will have to go in yet.



The throttle cable mount will need to be relocated, and the air cleaner interferes with the throttle linkage so it will need some modification, probably just a 1 inch spacer tube under the air cleaner.

The distributor should be a drop-in. (I didn't swap it yet since I didn't feel like rolling in the mud to rotate the crank to the marks. Should be dry enough soon.)

Once I get all the pieces-parts in I'll run the new harness.