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#49247 - 04/11/09 11:43 AM Re: tossing around the idea of efi for my 235 [Re: drummin52]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
Its getting better!

Picked up a 3.1L V6 Injector unit, cleaned it up, put it on and started her up. The struggle is less frequent then it was with the 4.3L injectors. It seems like every 4 minutes it will bog down and rev up a bit and then be fine then repeats after a while. IAC doesn't have to save it as much. I didn't want to buy more than needed so I found a good 3.1 computer and 2.8 injector and stashed them for later. Looks like when I go back I will grab the computer and 2.8 injector unit.

I would really like to use the 3.1 computer if possible because of the cooling fan trigger.
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Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#49248 - 04/11/09 12:05 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
drummin52 Offline
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Registered: 04/23/08
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Loc: Wapwallopen, Pa
What would be needed or what do I have to do to NOT have the computer control the timing. It seems to run better when the connector you unplug to set the base timing is left unplugged. I would either switch back to the HEI distributor or a stock distributor with a pertonix (sp?) unit and just have the timing controlled by vacuum.
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Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#49249 - 04/11/09 12:09 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
efi-diy Offline
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Where do you have the base timing set?
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51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them

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#49250 - 04/11/09 01:16 PM Re: tossing around the idea of efi for my 235 [Re: efi-diy]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
well Ive been trying it in a few different spots. originally had the pointer on the bell housing lined up with the ball bearing on the flywheel.
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Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#49252 - 04/11/09 02:11 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
efi-diy Offline
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Any way to degree the damper for 0*,10* & 20* BTDC. Without knowing where the base timing is will make tuning a real bear.
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51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them

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#49253 - 04/11/09 02:20 PM Re: tossing around the idea of efi for my 235 [Re: efi-diy]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
I bought a piston stop, but someone said it won't really help on a engine without a keyless crank pulley?
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Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#49254 - 04/11/09 02:21 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
what should the base timing be. 0 TDC?
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Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#49274 - 04/12/09 11:18 AM Re: tossing around the idea of efi for my 235 [Re: drummin52]
efi-diy Offline
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Starting point for the base timing is what ever GM used for the ECM donor. Try 0 or 10*BTDC
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51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them

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#49275 - 04/12/09 11:26 AM Re: tossing around the idea of efi for my 235 [Re: efi-diy]
efi-diy Offline
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Well the damper won't rotate on the crank once it tight otherwise you can drive your alternator with it. Measure the circumference and divide that number by 360. Write it down. That is inches/degree. Set up a reference pointer and using your piston stop mark the 2 lines on the damper. Measure the radial distance between them. Take that number/the inches per degree number. That is how many degrees between the 2 mark. Measure 1/2 way this is 0 deg. (at least until the damper is removed or the crank bolt lossened) Now calculate the distance for 10&20 deg and mark it on the damper to get 3 timing marks -20,-10 &0.
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51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them

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#49277 - 04/12/09 02:31 PM Re: tossing around the idea of efi for my 235 [Re: efi-diy]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
thanks sounds easy enough, now I just need the time. Going to be working about 14 hours overtime (40 normal) for the next couple of weeks. 1 weeks overtime will more than pay for the MS system when I turn to that to control the fuel injection. Before I do I just want to try a few things yet.
_________________________
Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#49308 - 04/13/09 03:18 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
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.

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.

will see!!!


Edited by drummin52 (04/13/09 05:45 PM)
_________________________
Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#49313 - 04/13/09 06:09 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
efi-diy Offline
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Registered: 11/21/04
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Loc: Calgary Alberta Canada
MAP sensor is fine. Your not at sea level so the sensor is reading absolute pressure. If you get a GM shop manual it'll give the voltage vs kPA. Start the engine and measure MAP out to gnd.

If you had a wideband O2 you would be able to sort out whats going on fuel wise. Also try advancing the base timing a bit say 5* btdc.

I'd say your not far off but tuning by swapping parts is really a coarse method and may not get you to the desired end result.

Try enriching the mixture using a propane touch (un-light of coarse :)) and flow some propane done the TB if the rpm increase your lean.
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51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them

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#49329 - 04/14/09 05:41 AM Re: tossing around the idea of efi for my 235 [Re: efi-diy]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
thanks again

I was corrected on the stovebolt site, when the pointer and the ball bearing on the flywheel line up it is not 0 deg TDC, its actually 10 BTDC.

Since I will need a wideband O2 sensor if/when I go to MS, Im going to get one now anyways.

I will try the propane as well. Unlit of coarse.
_________________________
Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

Top
#49336 - 04/14/09 08:41 AM Re: tossing around the idea of efi for my 235 [Re: drummin52]
Beater of the Pack Offline
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Loc: Northern Nevada
I got a smoking deal on an Innovate wide band kit on eBay. Sensor,controller, gauge, & CD for about 1/2 price.
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#49342 - 04/14/09 10:11 AM Re: tossing around the idea of efi for my 235 [Re: Beater of the Pack]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
thanks I will see what ebay has to offer.
_________________________
Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#60686 - 09/24/10 06:12 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
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-adapter-060-leg-spacing-p-36.html?cPath=64 - adapter gets soldered onto the board after the old 24 pin socket is removed
http://www.moates.net/s2-aries-28pin-zif-socket-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-programmer-p-197.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.
_________________________
Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#60687 - 09/24/10 06:46 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
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/w124/rockfan1815/final%20tbi%20conversion%20pics/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/w124/rockfan1815/engine/100_0094.jpg
_________________________
Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#60702 - 09/25/10 04:34 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
drummin52 Offline
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Registered: 04/23/08
Posts: 104
Loc: Wapwallopen, Pa
Anyone have a part number or a car I can use a heated O2 sensor from.

Thanks
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Chris
1952 Chevy 3600 (3/4 ton) pickup w/54 235
Clifford Intake w/ holley 4bbl carb

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#72538 - 11/18/12 09:04 PM Re: tossing around the idea of efi for my 235 [Re: drummin52]
Beater of the Pack Offline
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Registered: 10/06/07
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Loc: Northern Nevada
BTT
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