235 inline 6 running of fuel injection
 

all that is really left is to just load the tuning software onto my laptop and set the egr so that it will never come on. Currently it has a slight high idle, at about 900rpm. Im going to check for vacuum leaks as that can cause it to want to idle high.

If anyone is interested and as time allows I will post a list of everthing I used. The basics are a 4.3L V6 TBI unit, sensors (some not used) and harness (unused circuits removed) out of a 88-92 Chevy 1500 w/ of coarse a 4.3L V6.

See the link in my signature "Various pictures of my 52 Chevy 3600" to see my photobucket album. TBI conversion pictures are under album "TBI conversion".




Dammit I made a spelling mistake in the title, oh well.

Re: 235 inline 6 running of fuel injection
 

nice project, looks great, good use of junkyard stuff. that efi should help with mileage and driveability.

Re: 235 inline 6 running of fuel injection
 

would love to see more detailed info, parts list, how-to's!

Re: 235 inline 6 running of fuel injection
 

nice work,,,very inpressive! Post what you can on the parts list.

Re: 235 inline 6 running of fuel injection
 

thanks for the compliments


I will be working on a tech tip that will be posted in the tech tips section at stovebolt.com

Re: 235 inline 6 running of fuel injection
 

OK im putting together a rough draft how-to on installing Throttle body injection on these older inline 6's, but this can also be used for other vehicles as well if you pick the correct donor vehicle.

Anyways it will become a tech tip over on the stovebolt.com board and here as well. Before I get that finished I plan to post a basic list of everything needed.

Re: 235 inline 6 running of fuel injection
 

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.

Re: 235 inline 6 running of fuel injection
 

For the distributor I used a modified to fit, GM 250 Inline 6 HEI distributor. To make it computer controlled I removed the stock ignition control module, vacuum advance and mechancial advance (welded the mechanical advance arms so they would not move) and wired in a 8 pin GM ignition control module that I removed from the vehicle I got the throttle body unit and harness from (a 91 Chevy K1500 pickup with 4.3L V6). The module would not mount in the distributor so I remotely mounted it on the passenger side inner fender (as you can see in the video).

The only sensors used are the
Throttle Position Sensor (TPS)
Idle Air Control Valve (IAC)
Manifold Absolute Pressure Sensor (MAP)
Coolant Temp Sensor (CTS)
Electronic Spark Control Module (ESC) used for the
Knock Sensor
Electronic Timing Control Module (ETC) used for timing
O2 Sensor

No cam or crank sensor is used in this setup. The computer uses the ETC module which sends a pulse to the computer when a plug fires. The computer also uses this pulse to know when to fire the injectors.



Im working on the tech tip and am almost done with it. Its getting to be a few pages long already but I wanted to fill it with as much info as possible.

Re: 235 inline 6 running of fuel injection
 

I worked on it a bit more today. Working out the bugs that come with doing something like this.

I believe its getting a bit more fuel than needed. It starts up nice, runs nice, revs nice but when I let it idle for a long period it starts to struggle. Nice thing about fuel injection is that it won't let the engine die. I took the air cleaner off and from the top you can watch the idle air control valve (IAC) coming to save the day. When the engine starts to see it struggle, it opens up the IAC and the rpms pick back up, then repeats and it continues to do this unitl I shut it off or rev it. Revs fine even when its doing this. Took the spark plugs out and they seem a bit wet, not horribly, but wet. The spark plugs are black, mostly because of the 4bbl. This week I'm going back to the u-pull-it yard and will pickup a 2.8L injector unit to see if it corrects the problem.

Also have to get a can of starter fluid to see if there are any vacuum leaks around the adapter plate I made to mount the TBI unit.

Re: 235 inline 6 running of fuel injection
 

OK, have a question. Can't quite tell from just watching, but I was wondering if the computer fires both injectors at the same time or one after the other or ???

I was thinking, what would happen if I unplugged one of the injectors? I still plan to try the 2.8 injectors, won't get to the yard until saturday though.

Anything else I should try from the 2.8?


Did a bit of researching and comparing of my wiring diagram to a 2.8L V6 diagram from a 88-92 s10 and the wiring is the same, so when I go to the yard for the injector unit, I am also going to pickup a 2.8L computer.

This leads me to my next question, do I also need a 02 sensor from a 2.8 or will the one I have work and what about the map sensor, grab one too?

Re: 235 inline 6 running of fuel injection
 

Very cool mix of old and new!

Re: 235 inline 6 running of fuel injection
 

Ok did some more researching and thinking. The 3.1L which uses the same 2bbl tbi220 unit came in the 91-93 chevy lumina, 89-92 olds silhouette and 91-93 pontiac trans-sport. The wiring, like the 2.8 is also the same as the 4.3

I may buy at the yard 1 2.8 injector unit/pod, 1 2.8 computer, 1 3.1 injector pod and 1 3.1 computer and do some mixing and matching. A nice thing about the 3.1 computer is that it has a trigger wire for a cooling fan relay. Not sure if I should also get the 2.8 computer or not. The yard charges about $20 for computers. 3.1 is probably a bit closer than the 2.8 and the fan relay trigger is a plus.

I can try a few different combinations
4.3 computer with 2.8 injector pod
4.3 computer with 3.1 injector pod
3.1 computer with 3.1 injector pod
3.1 computer with 2.8 injector pod
3.1 computer with 4.3 injector pod
2.8 computer with 2.8 injector pod
2.8 computer with 3.1 injector pod
2.8 computer with 4.3 injector pod

anyone know or can get the specs on the 2.8, 3.1 and 4.3 injectors

not sure what sensors and that will interchange, I imagine the IAC, TPS and CTS won't make a difference, MAP might need to be changed and MAYBE??? the O2 sensor.

I also read somewhere that the vac port on the MAP must be pointing down. TRUE?

Re: 235 inline 6 running of fuel injection
 

OK a little update

I changed out the 4.3 injectors for 3.1 injectors and the stumble/struggle at idle was less frequent. IAC still has to save the day and keep it from stalling, but not as much as before. BUT (and I found out something by using a computer tuner) when the engine starts to warm up and gets around 130degF the computer wants to start to lower the idle rpm from 1000/900 to 600. When it starts to do this, the engine struggles and stalls. Im still guessing to much fuel.

I have a few more things Im going to try and then Im taking the leap to MS. I want to try the 3.1 computer as well as the 2.8 injectors. Im not positive that these will fix it but I have to try.

Ive been talking to EFI-DIY about the MS system and will be buying the unassembled kit and the 746/747 adapter board if the above don't work. Nice thing about the MS is if I ever switch to a different engine (inline of coarse) the ms is adaptable. Total for the MS system comes to about $400.

Re: 235 inline 6 running of fuel injection
 

Set the timing to zero (pointer and ball bearing on flywheel match up)

Installed the 3.1L computer and left in the 3.1L injectors. Let it idle until it got up to around 190 degrees and actually did better than I expected. Has a slight fluctuating idle but not bad. Idles around 800. The next time I have a chance Im going to experiment a bit more. Plan is to try both the 4.3 and 2.8 injectors with the 3.1 computer and see how it goes. Still wondering about the 261 running better with a 4.3 computer and 5.0 injectors. Maybe I will have the same outcome with the 3.1 computer and 4.3 injectors.

will see!!!

Re: 235 inline 6 running of fuel injection
 

The Throttle position sensor checks out fine, the map sensor I'm not quite sure on. I get 5.1 volts across terminals A (sensor return/ground) and C (sensor 5v reference), which seems correct. Across terminals A and B (sensor signal to computer) I get like 4.2 volts. Across terminals C and B I get about .3 volts. All this is with the key ON and engine OFF. From the testing procedure that I got off of a automotive repair site, this is backwards.

I have to test the IAC valve yet.

More than likely I will just end up purchasing a new MAP sensor anyways and getting a few IAC valves at the local yard.

Re: 235 inline 6 running of fuel injection
 

Wow looking good

A few things

1. Whats your voltage durring crank- run are you using a relay? Its no less than 11.2 volts. Any less that 7 and it wont run.
2. Your ground cables are also big.. form battery to motor motor to cab cab to frame then frame back to motor.
3. Take an ohm meter and check the housing of the o2 sensor to the header. There should be no resistance the o2 sensor
needs to be grounded for it to work correctly.
4. Do you have any vacuume leaks? Are you shure? Are all your vacuume lines not in use pluged?
5. Your tps what is it set at at engine off full water tempature. Did you ajust this and tamper with its setting?
6. Your distributor you modifyed to make it work. When your setting the timing there should be no advance at all
from 1000rpm to redline. If your getting advance your not setting it correctly. Also im not shure if your to set it at O btdc.
I always assumed that it was 10 deg btdc but the timing marks wold say 0 and align on lets say a 4.3 5.0 and 5.7.
7. Your map sensor this is the most important of them all If it is not working correct everyting will be incorrect. You ask
if the position matters? YES it should be mounted is the stock position. Also if your using another port then what it was in
orignaly you will have problems. Do Not run a tee off the map sensor to lets say a vac gague. Also of your not using the
stock size and legnth vacuume hose you will have problems.
8. The coolant temp sender is it in good shape is it within book specs. The cold fuel enrichment relys on the sender.
The t-stat should be 20deg. Higher than when cold fuel shuts off and goes into normal mode.

"when the engine starts to warm up and gets around 130degF the computer wants to start to lower the idle
rpm from 1000/900 to 600" This is cold fuel pulling off.

9. Do you have an air fuel ratio gauge? A vacume gauge?
10. What fuel pressure you got?
11.The injectors should be firing at the same time. A meter should tell you.

12. Your connector to the power side of the hei distribitor is an oe syle
snap in one. You kill the spark and not the fuel you will have major issues.
It will think its killing off and will poor fuel like no tomorow. I speak first hand
on this one. Watcing a hot gas engine diesel backwords not cool.....

The ecm is set up into cells invac @ rpm. One major key is the camshaft. You inline 6 may have different vacuume at blank rpm
and blank invac compaired to what you can get off the ecms your trying. Also weight of car to a truck gear ratio ect.
This is why without a custom tune your not gaining much over a carb.

All I can say is if you have a poor setup to begin with ( fulty sensors, leaks, incorrect wireing, poor timing, incorect tps ajust. ect)
You will never get it to run right. No matter what injectors stock computer or even a custom tune if the base calabraton is not correct it will
be like putting jam over moldy bread.

Re: 235 inline 6 running of fuel injection
 

1. I will check the voltage during crank when I get time. The starter solenoid gets activated through the starter post on the ignition switch.

2. Battery cable from battery to bellhousing is 4ga, from there I have 3 8ga ground wires, 1 to each frame rail and 1 to the cab.

3. I will also check to make sure there is 0 resistance where the O2 sensor is mounted.

4. I am pretty sure I have no vac leaks, at least not around the TBI unit to the adapter plate and the adapter plate to the intake. I sprayed starting fluid to see If I get a rpm change and all was fine. The only vac line off the intake is the one for the MAP. All unused lines are plugged.

5. TPS I did not touch at all.

6. The initial timing was set (with the bypass connector disconnected) to where the pointer on the bellhousing and the ball bearing on the flywheel line up. This is 10deg btdc

7. I will remount the MAP sensor so the vac port is pointing down. The vac line to the map goes directly to the map from the same port the donor vehicle used. Nothing tees off anywhere on that line. Size and length is correct.

8. Coolant temp sensor is new

9. Im looking at purchasing a Innovate Motorsports LC-1 wideband O2 sensor kit that also comes with a tuning/datalogging software so I can view what the sensors are sending back to the computer.

I have a vac gauge just need to hook it up.

10. Fuel pressure unknown. Pump is a new Carter P50001 external pump made for TBI systems. Feed line is 3/8", return in 5/16', just like donor.

Once I get the wideband O2 sensor kit and the datalogging software I should be able to see what is going on.

Re: 235 inline 6 running of fuel injection
 

was wondering how u got the CPP power steering to work on ur 235, im pretty sure that they only work on V8's but i may be wrong. did u have to make any modifications to the pulley system? where on the straight six block did u put the pump/reservoir? i really want to install power steering on may GMC 270 straight six. thanks for the help

Re: 235 inline 6 running of fuel injection
 

came up with my own set of brackets to mount the pump where the gen/alternator was and then moved the alternator above the pump.

http://i175.photobucket.com/albums/w...p/100_0563.jpg
http://i175.photobucket.com/albums/w...p/100_0618.jpg
http://i175.photobucket.com/albums/w...p/100_0882.jpg
http://i175.photobucket.com/albums/w...p/100_0883.jpg

Re: 235 inline 6 running of fuel injection
 

These brackets work for 216 and early 235's, I'm currently working on designing brackets for someones 261 which will also work for later 235's.

Send me some pictures of the engine and I will see what I can come up with.

Re: 235 inline 6 running of fuel injection
 

hella cool!!! looks hard and time consuming tho

Re: 235 inline 6 running of fuel injection
 

Not all that it looks. Some initial measurements and about 20 minutes on autocad. About another 10 and I get these.
http://i175.photobucket.com/albums/w...pbracket-1.jpg
http://i175.photobucket.com/albums/w...verside3-1.jpg

Re: 235 inline 6 running of fuel injection
 

i dont have any pictures right now, but i think that all the GMC blocks are pretty similar to the chevy blocks, but again couldn't be sure

Re: 235 inline 6 running of fuel injection
 

how did make the pulley system work out?

Re: 235 inline 6 running of fuel injection
 

Pulley system???

I will try to answer anyways....The power steering pump runs on the same belt as the crank and water pump. The alternator runs off the second groove of the power steering pump pulley. First I measured the length needed for the main belt (p/s pump, water pump and crank), bought and installed the belt and then measured for the alternator belt, bought and installed that. So far its staying quiet.

Re: 235 inline 6 running of fuel injection
 

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

Re: 235 inline 6 running of fuel injection
 

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.

Re: 235 inline 6 running of fuel injection
 

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!

Re: 235 inline 6 running of fuel injection
 

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.

Re: 235 inline 6 running of fuel injection
 

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

Re: 235 inline 6 running of fuel injection
 

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.

Re: 235 inline 6 running of fuel injection
 

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.

Re: 235 inline 6 running of fuel injection
 

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.

Re: 235 in line 6 running of fuel injection
 

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


Dave

Re: 235 inline 6 running of fuel injection
 

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

Re: 235 inline 6 running of fuel injection
 

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

Re: 235 inline 6 running of fuel injection
 

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

Re: 235 inline 6 running of fuel injection
 

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

Re: 235 inline 6 running of fuel injection
 

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.

Re: 235 inline 6 running of fuel injection
 

This is currently where I have the narrowband O2 sensor. Just a stock GM replacement that goes to the ecu.
http://i175.photobucket.com/albums/w...s/100_0862.jpg

I was wondering if it would be better to mount it closer to the header or in the header at the collector.
http://i175.photobucket.com/albums/w...e/100_0094.jpg