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no auto, currently running a 3 speed saginaw but will be swapping it out for a T5 some time soon.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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The VSS was used on some calibrations to lean out the mixture once cruising speed was reached. And to run the LU TC. If you want to use it, you will have to get an inline speedo cable VSS generator.
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was the vss used on all vehicles or just some. I have two diagrams, 1 from a full size pickup and the other from a s10. The s10 shows the vss but the full size does not.
Im trying to spend as little as possible so more than likely the vss will be taken out. If I found a transmission with a electronic speedometer drive instead of the mechanical would I be able to keep the vss?
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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If I found a transmission with a electronic speedometer drive instead of the mechanical would I be able to keep the vss?
Yes - but is your speedo cable driven?
It'll run without the VSS connected.
Last edited by efi-diy; 02/25/09 10:04 PM.
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I will eventually need to get a speedometer for my truck. I have a auto-meter tach currently and have been looking at their speedometers that match the tach. They have both electronic and mechanical. If I found a T5 transmission with the electronic speedometer drive I would then get the electronic speedometer and then use the vss. If not then I would get the mechanical and ditch the vss.
If I run it without the vss connected, will it show a check engine light? I just can't drive a vehicle with a engine light on, bugs the hell out of me.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Re VSS - I'm not 100% sure if it will turn the CEL on. Why not ask Tom BOTP - he has a '89 parts truck thats still intact I think - ask him to unplug the VSS at the transmission and drive it - see what happens.
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Post up your revised wiring diagram.. so folks can see its not that scary...
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http://i175.photobucket.com/albums/w124/rockfan1815/TBI%20CONVERSION/TBIWIRING-2.jpgShould be going to the yard to get the TBI parts tomorrow. Then I will need to place my order with summitracing.com for the other needed items. Soon very soon. Im thinking of doing a tech tip on the conversion w/ Plenty of pictures.
Last edited by drummin52; 03/01/09 12:27 AM.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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OK got a harness, tbi unit and computer and most of the sensors. Working on getting the unused wires out of the harness.
Question, what should I do with the knock sensor? The vehicle I got the harness out of had a knock sensor in it (I got the harness from a 1500 Suburban, which had a V8, but its the same harness thats used with the 4.3L TBI. In that busted jeep link he mentions splicing the knock sensor into pin c14 to eliminate the use of a knock sensor, not sure what wire he means, the one coming out of the computer to the esc module or the one coming out of the esc module to the knock sensor.
A guy on stovebolt also says that I can use a GM 250 knock sensor.
Im just trying to find out what I need to remove and what I need to keep and if I need to go back to the yard and grab a esc module.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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I'm going out on a limb here a little bit.. I guess that the '81 California 250's that had electronic spark control used a knock sensor. Since these motors never made it north of the border - its an guess at best.
If they did use a knock sensor - get a knock sensor and the ESC module for the '81 250 - they are tuned to the engine size. I'd keep the ESC module to ECM wiring and run the knock sensor.
Did this help?
Last edited by efi-diy; 03/01/09 09:44 PM.
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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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It' helping me to. Do you want me to find and unplug the VSS on my '89 to see what happens?
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
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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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Just two lists of what I have so far and what I need to get, this way others can see what all is needed for the conversion
Prices are just what I payed I picked up the following so far -4.3L TBI Unit off a 90 s10 - $20 -Wiring harness off a suburban, had a v8 but the harness is the exact same as what is used for the 4.3L v6 in the full size vehicles. - $20 -Engine Control Module (ECM, computer, etc), serial 1227747, came out of a 5.7L v8 so I grabbed the eprom & calpak out of a computer for a 4.3L v6 (didn't take the computer because the model wasn't a 747 or 746). - $30 -Also grabbed a map sensor and coolant temp sensor as well.
I need to get the following and then I can get to work - TBI rebuild kit - TBI Adapter. Im thinking of just making one, design on CAD and then have the local machine shop cut it out of 3/8 or 1/2 steel or aluminum, I have some 3/8" aluminum plate at home so I might use that. I know they sell 4bbl to tbi adapters but this way I can eliminate a few gaskets and problem points and bolt the tbi plate directly to my clifford 2/4bbl manifold. - External mount fuel pump, a post pump filter and some various fittings and 3/8" fuel line - Eproms and calpaks for a 2.8L v6 to try a few different combinations of chips and injectors. Maybe I should check the computers in a 3.8L v6 and see if those chips will work as well, might be a better match. - I currently have a 250 HEI distributor but it is vacuum advance, I need to get the parts to convert it to computer controlled. - I also have to get a knock sensor and electronic spark control module (esc) off of a 250 inline 6, if I can find one, if not I will try the one for the 4.3. Was also thinking about parts from a 292 if they would work and I can find one. - O2 sensor, not sure which one would be best, one from a 250 or a 4.3L
Last edited by drummin52; 03/02/09 02:15 PM.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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just came across a link that may help others look for a suitable tbi unit if they are also considering going the efi route. Gives a list of what vehicle, the year it can be found on and the size motor it came on. http://www.championparts.com/tbi_applications.pdf
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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I finished sorting through the harness I got and updated my wiring diagram. http://i175.photobucket.com/albums/w124/rockfan1815/TBI%20CONVERSION/TBIWIRING-3.jpgI also just bought the remaining parts for the conversion. Just waiting for my tbi plate to get cut out. First part I will ever have thats been cut by a water-jet machine. Amazing.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Man, You're moving on this! Would you come finish mine when you're done?
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
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Sure pay for my ticket to and from Nevada and I will have it together in no time. A vacation in Nevada sounds nice. How is the weather?
Here is my plan: -I will be gitting my fuel system stuff from summit tomorrow, plan is to have the fuel system ready this weekend. -Local auto parts store will have my tbi rebuild kit in today, installed before my tbi plate is done sometime within the next 7 days or so. -Then I will install the TBI Unit on the intake and all the sensors on the block. -Computer will be mounted on the passenger side kick panel in my 52 3/4 ton chevy pickup. Im going to cut all the sensor wires about 2' before they go into the computer, plug the connectors into the sensors and run the wires into the cab through the firewall to the computer. Engine wiring will be completely seperate from all the other wiring (lighting, accessories, etc). -After I make the trip to the local u-pull-it yard, I will convert my distributor to be computer controlled. A question on this below. -Last thing, I hope, I need to finish the first project I started, which is adding power steering. Im also waiting for a few other pieces to get cut out. Those pieces are the belt adjusters for the power steering pump and alternator. This way when I start it on the TBI I can let it run instead of having to turn it off to keep it from overheating (no belt driving the water pump or fan)
Question on the distributor - The distributor is out of a 250 inline 6, with the coil in the cap. My question is, since there aren't a whole lot of 250's in the yard, are any distributor parts from a v8 usable. I think they are somewhat the same aside from the 6 to 8 cylinder internal differences.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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http://chevythunder.com/1227747_ecm_198892.htm found it while searching, post it for those who may want to see it. Its not the clearest but usable.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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1 more question
Looking at some wire diagrams for my harness, what is or where do I terminate the crank in wire on C9. Looks like there should be a fuse inline. Does this get connected to the start terminal on the ignition switch or a terminal on starter solenoid?
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Yep your correct - a 1Amp fuse goes to the starter wire that comes off the ign. sw. Doesn't matter where you connect into it. What it does is force the ign. module to run on base timing during cranking.
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Sweet....water jet guy just called and said my part is done (tbi adapter and belt adjusters for the p/s pump and alternator). Got my tbi rebuild kit yesturday. Might work on that tonight as well as making a mount for the computer.
Going to the yard tomorrow to get what ever else parts I need, hopefully I get everything Im looking for. Going to take a break for half the day and go to a car show at the local armory.
Now I just need a coolant thermostat housing with two 3/8"npt ports. Anyone know what else works on a 235 (261, 250, 292, etc)
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Last edited by drummin52; 03/06/09 09:53 PM.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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I made an opps on the TBI plate. I need to weld a small piece on because I didn't make one of the sides long enough so currently about a 1/8" of the IAC chamber is exposed, making for a really bad vacuum leak.
Got my list ready for tomorrow to go part hunting.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Chris,
Don't forget to revisit your alternator size... you'll be surprised at the extra load the fuel pump puts on. Get an alternator off of a TBI donor vehicle.
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Yup, was actually thinking of getting another alternator anyways, don't know what the specs are for the one I have now as the previous owner installed it. Plus I have more plans it the works than the PO had, like power windows, seats, door poppers, a nice stereo, etc.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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got another computer, this time out of a Chevy 1500 with the 4.3L so everything matches. For those interested I have a spare 122747 ecm if anyone wants it. Just needs the chips.
I got a ESC, just need to get a knock sensor. I also got a EST to change the distributor over to be computer controlled timing advance.
Im working on the tbi plate, Tapping out the holes for the 3 tbi bolts. One the first hole, the tap snapped and broke off in the hole when just about through. Ended up driving it out with a chisel and a BFH. The other hole went great, on the last hole the tap was just to warn out and didn't cut the threads deep enough.
Still need to get a fuel pump, thinking it might be better to just buy a new pump as most of the vehicles that I know have external mounted electric pumps are from the late 80s to early 90s. Within a few weeks I should have something going.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Remember the TBI is a constant flow return system to the tank so the lines will stay relatively cool when the fuel pump is running.
Also be sure to use rosin core solder for any splices and double wall heat shrink, the stuff that has glue in it so it seals to the wire insulation. I usually us a double layer for under hood splices, small heat shrink just big enough to slip over the solder joint about 1" long - shrink it then slip a bigger diameter heat shrink over the smaller one once its cool. Make the bigger diam. shrink about 3" long this provides excellent support and sealling for the splice.
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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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Looking good!! The TBI is located like we did on the 270. All those wires still spook me but I know I'm close to finally sorting that out when I get the MS done. It will be very interesting to see what you get from the GM ECM. Truly a junk yard dog in the best rodding tradition.
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....Also be sure to use rosin core solder for any splices and double wall heat shrink, the stuff that has glue in it so it seals to the wire insulation. I usually us a double layer for under hood splices, small heat shrink just big enough to slip over the solder joint about 1" long - shrink it then slip a bigger diameter heat shrink over the smaller one once its cool. Make the bigger diam. shrink about 3" long this provides excellent support and sealling for the splice. I use the Rosin core and the HD heat shrink (with the glue inside) but I had never thought of doing it as a two layer setup, sounds good, thanks.
My, what a steep learning curve. Erik II#5155
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OK, made some good progress today, I will post pictures tomorrow of what I got done. I went to the local yard and got a thermostat housing off a 261 that has two ports so I can install the coolant temp sensor and keep my hot water heat for my clifford intake. I got about 75% of the wiring done, most sensors are wired. Whats left is the power wires from the fuse block, distributor modification, fuel pump wiring, esc/knock sensor wiring and some smaller stuff. I was reading online about others doing fuel injection conversions using tbi and what fuel pump to use. A bunch of mixed out comes with different pumps. The ford external pump got a lot of mixed reviews, some said it worked fine, others said it didn't provide enough pressure. I ended up buying a new pump from summit racing. I went with a Carter P5001 pump made specifically for TBI conversions, that supplies a max 20psi and 50gph. A bit more than I wanted to spend at $150, but everyone that used it was very pleased with it and I figured it would be better than a 20-/+ year old pump from the junkyard. http://store.summitracing.com/partdetail.asp?autofilter=1&part=CRT-P5001&N=700+115&autoview=sku
Last edited by drummin52; 03/14/09 11:41 PM.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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At least you know the pump won't let you down.
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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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I though I had got lucky and got the stuff to change the gm 250 distributor over to computer control and keep it all in the distributor but it didn't turn out as I expected. I pickup up the ignition control module and such out of a mid 80's v6 car, and even test fitted it in another 250 distributor in the yard, but when I got back home, I tried installing it in my distributor but the two screws that hold the module down were about 1/4" further apart. When I go back to the yard Im going to try the ignition module in the dist. that I test fitted it in to see if maybe they changed it at some point as I thought the mounting holes lined up. Here is what I picked up. http://i175.photobucket.com/albums/w124/rockfan1815/TBI%20CONVERSION/100_0775.jpgFor now I'm just going to mount the ignition module on the passenger side inner fender and run the wires over to the distributor like the guy did on the bustedjeep.com junkyard tbi conversion that was posted earlier.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Chris, You're making so much progress a little setback is expected. This may help, I don't know. GM HEI & MS
Last edited by Beater of the Pack; 03/16/09 10:27 PM.
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yeah Ive been hitting a few snags along the way. I found out today the new thermostat housing I got has a larger opening for the hose to the radiator. I have an idea of how to make this work, hopefully my thinking is correct.
I got a bit done to the distributor today, removed the mechanical advance parts (springs and weights) and tach welded the arms so they dont move. I also removed the vacuum advance and secured that down so it will not move. Im going to turn the engine over till its at tdc of the compression stroke on cylinder 1 and install the distributor and then make the wires to the ignition module. Im taking lots of pictures of this process.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Also because this ignition module use to be inside the distributor and was grounded through the metal plate on the bottom of the ign module to the dist. when I bolted it down to the inner fender I put a ring terminal on it and ran the ground wire to the engine block where I have all my other ground wires going to. Picture to show what I mean later.
Chris 1952 Chevy 3600 (3/4 ton) pickup w/54 235 Clifford Intake w/ holley 4bbl carb
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Chris
You might want to mount the HEI module on a piece of 1/8" thick alum say 2"x2" with some heatshink compound under the module... then bolt that to the fender.. or at least use heatsink compound under the module and ensure you have full contact between the HEI base and the fender surface. Hot spots can cause issues.
Keep a spare module in the glove box just in case while your shaking the bugs out.
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