235 inline 6 running of fuel injection

[Dusty4]

Hey, how about an update on this cool project? Have you got to drive it to figure out mpg?

[drummin89]

Gettting close to being able to drive it, but not on the road, just up and down the private road I live on. All that is left so its mobile is to finish the brake lines as I just installed a disc brake kit for the front and a firewall mounted brake pedal assembly.

On the fuel injection, I ended up swapping out the 4.3 computer for a 3.1 and swapped back in the 4.3 injectors. It seems to like the setup, but it doens't have any road time yet so I can't say much more.

On the subject of power steering. I have a 3D rendering of the pump bracket for the later 235s and 261s, I just need to verify that it will work.

[Bigblue29]

Can't wait to hear the results from a good test drive. Looks like a lot of work but I bet it will all be worth it in the end!

[capev86]

that is just plain awesome. shows how much people are thinking. great way of reusing derelict parts, improving driveability (can automatically adjust to altitude unlike a carb), and getting better fuel economy to help combat gas prices. may also help with when extreme politicians start smog testing everything on the road. thank god they did away with smog testing up here in maine, but who knows when it will be back!

bet this would be a good upgrade for vehicles that tow. next you should look into doing the same thing on a 292 which is a stealth hot rod swap for 47-54 chevy trucks.

[Palf70Step]

Very interesting build. I am anxious to see how this works out.

[drummin89]

thanks guys!

Getting close to being able to drive it, not legally on the road though. Got all my brake lines done, went to bleed the brakes and ran into a few problems. Had to install new rear wheel cylinders (done and at least now I know what the rear end came out of) and now need a new combination valve (came off a 80s chevy pickup and the brake fitting stripped out the threads on the aluminum housing). It won't be much of a test drive, as the road I live on is only a little over 1/4 mile long, but its better than nothing.

[allen57]

i was just wondering if u have any updates on this truck? also what intake manifold did u use? i wanted to do this for a long time, but i wasnt sure how to get around the distibutor problem but u figured it out. thank u. also good jobs on those bracket.

[drummin89]

Im satisfied with how the engine is running. Ive started it about a dozen times since I last posted and have yet to see a problem with it. Everytime I start it, it starts at the first turn of the key. Runs strong, no stumble and sounds really good.

Got to drive it as well. Good throttle response under load. Can't wait until I can actually drive it on a paved road legally.

For the intake manifold Im using a clifford 2/4bbl aluminum intake. I designed my own plate to mount the GM 2bbl TBI directly to the clifford manifold. I had it laser cut out of 3/8" steel. If you go this route let me know as I had a spare plate cut out that you can have.

Yup switching to a GM HEI distributor from a 250 inline 6 is a easy way to go.

Thanks for the comment on the brackets, Im starting to have some extras made, for all 3 engine sizes 216, 235 and 261.

[Truck Dr.]

How's the truck running?? this type fuel injection project is what I've been pondering for quite awhile and you've done it.
Would like to know more about the wiring and the fuel pump used.


Dave

[dougw]

I'm glad to see an application of the TBI system to the 235. I'm running a junkyard TBI on my jeep wrangler 258 inline 6. I love it! No more struggling to get the beast started. I pulled the injection and computer off a running 91 chevy 4.3L pickup. I pulled the advance springs off my distributor and wired the weights together with piano wire. You disconnect the vacuum advance as well since the computer will handle all advance. I've got an edmunds 2x2 with two ford 94s that I'm going to try out on my 235 in the 51, but I might set myself up a nice injection system one day too. I'm thinking a good setup would be a megasquirt system with 3 injectors drilled into a clifford manifold and using a stock TBI unit sans injectors as the throttle plate. Should be able to provide even fuel to the cylinders.
Doug

[NONHOG]

Very cool, add a low boost turbo now ? Just for MPG of course

[AMSLJim]

Hey Drummin,
Do you know what your Cam Lobe separation is?
And, How much Vacuum are you pulling at Idle?
Jim

[sailed2japan]

Great work getting done here how did it all turn out?

[drummin89]

A bit of a update on this. I have not given up on this, I just recently in the last 3 months started working on my truck again after taking a break for about a year it seems. Othe hobbies took over, almost to the point of complete lost of interest in the truck and going as far as listing the truck for sale. After I listed it for sale I started working on it and decided to keep at it.

When I stopped, I had the 3.1L computer, a 4.3L throttle body unit and injectors and was quite happy with how it ran. Truck never seen pavement yet so I can't say much more about that. At startup the truck idled ok, started with a bit of a high idle (about 1000rpm) and as normal would start to drop the idle to about 700rpm. Problem was when the idle dropped and the computer started to lean it out at idle the computer would have to give it a bit of a jult (Idle air valve would open and idle would increase slightly) to keep going.

Just recently I picked up a few things to try out. I grabbed a TBI unit off of a 3.1L at the local u-pull-it yard. The 3.1L TBI unit has smaller throttle openings then the 4.3L (1-3/8" compared to 1-11/16") and also a lower flow rating for the injectors (33lb/hr to 40lb/hr).

First I tried the 3.1L computer with the 3.1L TBI unit and 3.1 injectors. Result - would not idle at all. Started fine but if throttle left unattended it would die instantly. Guess is too lean of a mixture.

Then I tried the 4.3L computer with the 3.1L TBI and 3.1L injectors. Result - same as above but not as bad, but still would not idle. Probably because the 4.3L computer has a longer injecter pulse width then the 3.1L computer so it wasn't as lean.

Next I left the 4.3L computer hooked up, but instead used the 4.3L injectors on the 3.1L TBI. Result - much much better, idles very nice, starts at 900rpm and as the engine warms up and the computer starts to lower the idle rpm and lean out the fuel it goes down to about 650rpm.

This time around I'm getting technical. Using a ALDL to usb cable and diagnostics program called WinALDL loaded on my laptop so I can monitor the computer and see whats going on. From reading different forums online about tuning I know I can find out if I'm running lean or rich by monitoring the BLM table, a number above 128 means the O2 is seeing a lean mixture and below 128 its seeing a rich mixture.

I've also come to realize that the stock computers tune just isn't going to do. So from doing some research on thridgen.org (camaro forum), they have a few computer tuning forums. http://www.thirdgen.org/techboard/diy-prom/ & http://www.thirdgen.org/techboard/dfi-ecm/ I found a few options for tuning. First option (which is what I'm going with) is an adapter from moates.net, since the eprom thats used in the earlier GM computers require expensive equipment write to, this company has came up with an adapter to use a later flashable chip. A little solder work is required but for $135 for all thats required its probably the cheapest option out there. Parts needed:
http://www.moates.net/g2-memory-adap....html?cPath=64 - adapter gets soldered onto the board after the old 24 pin socket is removed
http://www.moates.net/s2-aries-28pin...cket-p-44.html - 28 pin socket
http://www.moates.net/c2-sst-27sf512-chip-p-39.html - new flashable chip
http://www.moates.net/burn2-chip-pro....html?cPath=64 - used to burn or write the program to the new chip

The other option, also requires a bit of soldering is the EBL flash.
http://www.dynamicefi.com/EBL_Flash.php
It replaces the part of the GM ecm where the eprom or memcal and calpak reside with a new board that allows you to flash a new program through a serial data cable, so no need to remove the chip to program. Also includes datalogging and the way I read it the ability to have multiple tunes that you can switch back and forth using the software or a switch. This option was a bit more at $350. I liked this the most but wanted to keep this project as low cost as possible. I have not read any negatives with either route so I shouldn't have a problem.

I also came across a program that will take a saved datalog file from WinALDL and make the changes to the bin file(ecm file that is burned/written to the eprom/chip) for you. That program is called ALDL to BIN

On top of that I am using another program called TunerCATS to edit the bin file to disable the egr valve and maybe a few others. I can also use this program to burn/write the new bin file to the chip.

To also help I purchased a Innovate Motorsports LC-1 wideband O2 sensor kit so I can monitor the air/fuel ratio more closely.





The thing I need to figure out is what TBI unit would be better. I'm thinking I should switch back to the 4.3L TBI unit so everything matches. 4.3L computer, TBI unit and injectors then start tuning. When I open the throttle when using the 3.1L TBI unit just the sound of the air rushing in sounds restrictive.

I'm going to post a picture soon and ask were would be best to mount the O2 sensor. Im not certain the location I have it at now is the best place for it. And I may end up changing the narrowband O2 sensor to a heated version. I don't know if its OK to always run using the LC-1 wideband kit.

[drummin89]

This is currently where I have the narrowband O2 sensor. Just a stock GM replacement that goes to the ecu.


I was wondering if it would be better to mount it closer to the header or in the header at the collector.

[Warrens69GMC]

The engine computer from the 4.3 would be better if its the 7747 computer, it can be re-programmed by the laptop. If everything is ok other than the "too much fuel", try narrowing the fuel injector pulse to compensate.

The air cleaner can also be a restriction - use a taller filter rather than the stock "spectre" filter in the photos. The air has to make too sharp of a turn and can send the fuel against the intake walls causing a rich condition when it gets to the cylinder.
If I remember right, a fram ca3588 or a ca192 are a direct replacement.

[drummin89]

Thanks I will look into that. The filter I have on it now is even smaller so its probably worse.

[drummin89]

Anyone have a part number or a car I can use a heated O2 sensor from.

Thanks

[55dude]

cool project! subscribed.

[ebfabman]

updates???

[lmdangerous]

Very cool, keep diggin.
LMD

[dicer]

Originally Posted by rss396

Subscribed. What distrubutor did you use? Crank sensor, cam sensor, map sensor, coolant temp, oxygen sensor, and spark advance. Cool !!!! Points and carbs suck compared to simple TBI fuel injection. My opinion.

Unless your out in the middle of nowhere, and don't have the part or the stuff to trouble shoot the electronics. There is nothing easier and simpler to work on than the good old stuff.

Heres a way to go with EFI, http://www.ms3efi.com/

[Junkpyl]

I have been considering this for some time and just stumbled onto your post. It looks great Any updates? My truck has the 292 and I have a clifford intake and a pair of headers for it, just trying to decide if the fuel injection is the way to go or bite the bullet and purchase a new carb for said manifold. I have a turbo that I plan on installing and think the injection would be more forgiving.

[SouthernRodder]

nice

[Junkpyl]

Updates?