TBI Conversion Questions (1 Viewer)

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Feb 7, 2009
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Location
Kalispell Montana
Hey everyone. I am currently trying to install a 95 tbi 350 in the pig. Got all the adapters from downey and got it all put together Yesterday. I slapped the whole assembly in for mock up and ran into a few issues.

I knew it would be tight but at the moment I cannot get the stock 3 speed to line back up for the stick. I have searched the forum all morning and only seen mentions of people heating and bending the shifter to accommodate this issue. Can anyone elaborate on this and let me know if it is in fact necessary?

Right now I have a few issues but most of them I knew about, like the ram horn exhaust needed and the offset to the drivers side for driveshafts but one thing I was not aware of is the need for the shortening of the driveshaft in the front. Right now it looks to be 3 inches to long... bummer.

I have at least 7 thread open and am taking notes as I go but I'd really like to get some words of wisdom from those who have done it themselves.

One last thing... if anyone has tbi'd before I'd really love some pointers on that. I have all the schematics and took the whole harness but not sure how much I really need. When I sit down and look it over I really only need a few circuits... seems like I'll be throwing alot of the harness out.
 
Probably not a lot of help, but yes, every 350 swap I have seen on a 40 or 55 has required some adjustment to the shape of the shifter. I also had to cut a notch in the bottom on the heater body on my 72 FJ 40. On my Piggy, I have the engine fairly far forward. My H42 shifter is a wee bit rearward from the stock position, as I used the Ranger Overdrive/Underdrive as the conversion unit. It is about 8 inches long. IMHO, driveshaft length should be figured/adjusted after you get everything else in place. Not that expensive for a re-tube/balance. I'm a little surprised that your going to all this work and staying with the original 3 speed. Even with the 35" overdrive on the tires, I wish that I had a 5 speed with OD for the hiway. Good Luck, John
 
Yeah John

I am pretty sure I will go to a 5 speed at some point but at the moment I just want to get my pig back on the road and was able to get all this together on the cheap. I figure I can upgrade later as long as I get my tbi stuff figured out.

I'm attaching a schematic I got from a parts store and wanted someone who may know better than me clarify if that is all i need to get my motor going.
0996b43f80231a15.jpg
 
have you looked on a Chevy forum for a wiring diagram for your year ?
 
Yeah thats where I ran across the schematic I have... just checked it to autozone and it was the same one.
 
I'm not a TBI expert but I know a little... enough to be dangerous. ;)


You will need most of that stuff across the bottom of the diagram.
Must have MAP sensor
must Throttle Position Sensor
need coolant temp, but will run without it
need oxygen sensor but will run without it
must Idle air control
dont need A/C wire

-vehicle speed speed sensor, I have heard both needed or not needed. I figure its needed to run correctly. There was a good thread over at marlincrawler.com about the VSS if I remember correctly.

across the top...

don't need the knock sensor but very good to have
And I think you need everything else I didn't mention with the exception of the check engine light and the upshift light.
Not sure about the EGR stuff but you might as well hook it up I think

You'll need to do some more research on options for the VSS.


Hope this helps a little...
B.
 
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FWIW check out gearhead-efi.com for tbi info. Good group of guys with a lot of knowledge. Thirdgen.org has a tbi forum also, but they can be pretty snarky with basic questions.

Sent from my iPhone using IH8MUD
 
Thanks for the help guys... great info
 
Lets see:

two fuel injectors, a temp sensor, throttle position sensor, iac, Manifold pressure sensor, speed sensor and either heated or non heated O2 sensor, (depends), Ignition control for distributor. check engine light and ALDL connector and fuel pump, and fuel pump seloniod and fuse. I always place a ballast resistor inline to fuel pump. This is your basic TBI setup.. There is an awesome book made on these by Holley just for info. But I can e-mail you a few of the stand alone wiring harnesses we have used? I will not toot my horn, but from years of creating my own harnesses I have learned a lot.


The diagram you have will get it done. That is the basic setup.. We always call it the five wires to fire. It is almost as simple a system as doing a Chrysler setup...LOL JEEPS
 
Sorry to hijack....

Good info copper204,
Can you tell me the purpose of the ballast resistor on the fuel pump, and what type do you use? Thanks
 
Ballast resister drops the voltage pull on the fuel pump. It allows for those instances when getting stupid in the sand and bouncing the rigs when low on fuel. it was a recommendation from a very dear friend who works for Penske racing. it has worked for me for years. he was also specific on which one i use. a ford one from teh early 70's for a ford truck.. it drops the voltage to 10 volts. Kind of similar to what was done by Heep for the old renault renix multi-port..


Ok I am sorry for Hi-jack also
 
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Great to know, thank you!
 
shhhhhhhhhhhhhhhhhhhhhhh don't tell anyone...

http://www.jeepforum.com/forum/f12/junkyard-tbi-write-up-1066016/


But it does breakdown the computer ports for the layman on about the 2nd posting. and the 7747 computer is commonly used as a generic one.


:bang::bang:
Not sure if it would work on a Chevy TBI, but while helping build a 2FE, we found that the AC wire could be setup as a switchable ground to cause a higher idle. Nice for running junk like extra lights, compressor, winch/etc. John
 
Probably not a lot of help, but yes, every 350 swap I have seen on a 40 or 55 has required some adjustment to the shape of the shifter. I also had to cut a notch in the bottom on the heater body on my 72 FJ 40.


Easiest way to resolve this issue with a Toyota 4 spd. is to substitute the top plate and shifter from a FJ60. It'lll bolt right on and move the shifter back about 3.5 inches. Problem solved.
Ironically, I'm about to go the other direction, having added a Ranger overdrive. I now need to move back forward to avoid having the shifter too close to the seat.
 
ok guys and gals, started cutting up the stock harness and have a few questions. Do I need the idle air control unit stuff? Also is the oxygen sensor something I can bypass?

When and if I bypass a system, do i just cap it or loop it to another location... seems like it may need a dummy signal to allow the ecm to work properly.

And the notorious vss, what do I do there?
 
ok, forget the idle air control... gonna integrate that. Still researching the rest.
 
do not

You could bypass it ?" But why? It determines and'or sets the engine richness or lean for a basic description. But it is also a primary sensor for the check engine light and assists in throwing your fuel system into closed loop. so in my opinion(take it for what it is) YOU NEED the O2 sensor
 
Thanks copper, i'm going to keep the idle air control for sure. Good to know on the 02 sensor. I'll work on that.

Another question. I got all the wiring thinned out and found all but two sensors... googling and looking for ones that look the part but i have no idea where the knock sensor module is. According to the digram above it should have been on the circuit for the knock sensor but I don't see it. Any idea where gm hide that little thing?

Also apparently I didn't pull the fuel pump cycle module or the fuel pump relay. again any idea where i'd find those. I know the relay is suppose to be on the shock mount drivers side. I'll go grab that tomorrow but any help on the rest would be sweet. Thanks
 

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