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#1 |
Registered User
Join Date: Jan 2007
Location: Lexington, TN
Posts: 1,427
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Tbi swap build thread
I am going to atemped my first build thread for who ever wanted to swap in a 87-94 STOCK TBI SYSTEM. I am going to use the intake (& all the hardware),throtlebody,stock wiring harness and all the other things you need to do this swap. I am going to go pin by pin, wire by wire ,and tell you where everything goes.
I know this is a common swap now a days but when I started looking for info for this swap i had do go and find info from alot of deferant web sites. I would like for people that are intrested in doing this swap when they google "tbi swap" they come to this site (67-72chevytrucks.com). So here we go. Here are some pics of my truck and motor. The motor is a 90 model 350 tbi motor. I swaped this motor in last year and i used it because I had plans on doing this very swap then. The reason I did not do the tbi swap then was because this truck came stock with a 4.3 in it. I did not want to swap a deferent motor and try to swap the truck to tbi at the same time. So I rebuilt this motor and bouhgt a eldebrok carb intake for tbi heads and used a quadrajet. I will have some more pics tomarow so stay tuned.
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The fleet 94 Chevy 4x4 reg cab 2018 Traverse (wifes car) 1977 SWB stepside 1949 Chevy truck |
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#2 |
Registered User
Join Date: Jan 2007
Location: Lexington, TN
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Re: Tbi swap build thread
Ok here are all the pin outs and the color of the wires. My computer is the standard #1227747
A1- grn/wht- this wire is used to power the fuel pump-relay. A2- no wire A3- no wire A4- gry- to egr-relay. This is a ground for the ECM to control the EGR relay. A5- brn/wht- service soon light. This is a ground to turn on the light. A6- pink/blk- switched 12v from the ignition relay. A7- no wire A8- ornange aldl serial data wire pin-e A9- wht/blk-aldl pin B When jumpered to ground will set the computer to diagnostic mode. A10- brn- VSS speed sensor signal to the computer, (This wire I will wire this to on side of a after market VSS sensor and the other wire on the sensor goes to ground). A11- blk- MAP sensor ground. A12- blk/wht- System ground. This wire is tied to other grounds in the harness and goes to engine ground. B1- orn- 12v batt power ( I looked and traced down this wire on my 87 cab harness and this is fuesed I think it was a 15). I will probably use a inline fuse. B2- tan/wht- Fuel pump signal from the relay. This one ties into several places, the fuel pump, the relay, and the ecm. When the relay is on it sends 12 volts to trun on the fuel pump. B3- blk/red- Distributor plug B4- no wire B5- purple/wht- Distributor plug B6- no wire B7- blk- ESC signal This is the knock sensor signal to the computer. B8- dk grn- AC signal. This tells the ECM that the AC is turned on. I am going to tie this into the ac clutch wire. B9- no wire B10-orange/blk- park neutral switch wire. some people say this is optional but I do not think it is because it gives a signal to the computer to give the engine a slight bump in rpm.(if you don't need it why did they put it there?) B11- no wire B12- no wire C1- no wire C2- brn- wire is not needed C3-grn/blk- Idle air control C4-grn/wht- Idle air control C5-blue/wht- Idle air control C6-blue/blk- Idle air control C3-C6 all go to the Idle air control valve plug on the TBI it's self. C7- no wire C8- no wire C9- purple/wht-Starter crank signal wire. Goes to the small terminal of the starter. C10- yel- Temp sender C11- lt grn- Map sensor C12- no wire C13- dk blu- throtle position sensor C14- gry- signal to map and TPS. ( you will see it tied together in the harness) C15- on wire C16- orange- This wire is tied with B1 so it is a 12volt wire D1- brn/wht- system ground goes to the engine. D2- blk- tied to the wires for the engine ground. D3- no wire D4- wht- distrbutor plug D5- tan/blk- distrbutor bypass. This is the wire that you disconnect to set your timing. D6- Tan- O2 sensor ground to engine. D7- purple- plugs in to the o2 sensor D8- D13 no wire D14- grn- Injector plug plugs into the top of injector D15- no wire D16- blue- Injector plug plugs into the other injector
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#3 | |
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Location: Lexington, TN
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Re: Tbi swap build thread
Quote:
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#4 |
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Join Date: Oct 2003
Location: OC CA
Posts: 1,374
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Re: Tbi swap build thread
Pancake
Looks like you are digging into retrofit - full speed ahead For P/N switch functionality you'll have to wire a small, simple circuit which requires some wire (12 AWG purple and 16AWG, 1/4" crimp connectors (female and male), BOSCH 30 amp relay, and silicon diode 1N4001 - Radio Shack. Questions??? //RF
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"The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) ![]() New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17) |
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#5 |
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Join Date: Apr 2009
Location: Arvada, Colorado
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Re: Tbi swap build thread
Ok...almost ready to put the tbi on my Blazer.....but have another question. I understand the wiring for P/N switch but do I NEED this for a manual tranny?
again, thanks for all the info and advice. |
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#6 |
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Re: Tbi swap build thread
pancake
To get things going it is not required, but having a neutral position sense switch will improve driveability (i.e. ECM alters idle and timing somewhat (depending on ECM, other parameters as well - EGR operation, AIR) between neutral position and being in gear. Leave B10 (orange-black) unconnected for now (this way ECM will see that truck is always in gear). //RF
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"The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) ![]() New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17) |
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#7 |
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Location: Lexington, TN
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Re: Tbi swap build thread
Thanks for the info and the pics. If i were to use a frame mounted pump witch one would you recomend?
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#8 |
Windy Corner of a Dirty Street
Join Date: Jun 2003
Location: Pueblo West, Colorado
Posts: 2,926
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Re: Tbi swap build thread
Man, I don’t know. The frame mounted pump I had was a Summit Racing house brand. I hear good things about the Walbro pumps. I actually bought a slightly used low pressure Walbro from a board member, Rust Buster, for my ’72 C20 that I just completed the TBI swap on a few weeks ago. The damn truck is still at my buddy’s getting the exhaust hooked up so I haven’t had a chance to find any bugs with it yet. The Walbro pump is what all the TBI conversion kitters like Howell sell with their complete TBI kits.
Here is the Walbro mounted on my ’72 C20 with a TBI 5.7L. Not a very pretty install but it is not a very pretty truck either. ![]()
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Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles
Last edited by augie; 04-19-2011 at 11:43 PM. |
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#9 |
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Location: OC CA
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Re: Tbi swap build thread
Hey Cj
A while back DirtyLarry and I had a bit of discussion going about EFI retrofits and engine swaps. In this thread I posted my setup details - double posting is never a good idea... http://67-72chevytrucks.com/vboard/s....php?p=2950627 //RF
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"The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) ![]() New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17) |
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#10 | |
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Location: Lexington, TN
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Re: Tbi swap build thread
Quote:
Thanks, Jamie
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#11 | |
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Re: Tbi swap build thread
Quote:
I belive in this way, if chevy did'nt need it why would they spend the money to have it installed in the wiring harness. How does your truck run with out it?
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#12 |
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Join Date: Jan 2008
Location: Pincher Creek, Alberta, Canada
Posts: 141
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Re: Tbi swap build thread
The truck runs great. The VSS is for the electric speedometers and cruise control, but I'm wondering if it does anything else. If it is supposed to control the issues you mentioned above, but is unable to, would you get a code?
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#13 |
www.73-87chevytrucks.com
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Location: Birmingham, AL
Posts: 6,935
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Re: Tbi swap build thread
FYI you don't HAVE to get EFI tanks, just don't run the truck less then 1/4T or so if you are offroad/camber often.
Walbro is a good pump, but in the tank is the best location.
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Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com |
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#14 |
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Location: Lexington, TN
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Re: Tbi swap build thread
Well being that you have a 4 speed trans what did you do with your prn/nurteal wire for the computer?
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#15 |
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Location: Pincher Creek, Alberta, Canada
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Re: Tbi swap build thread
Park/Neutral? That's some thing I would have to check into; I don't recall. The truck has the original Muncie 4 spd.
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#16 |
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Re: Tbi swap build thread
B-10 is the signal wire # for the ecm that is you park nutreral switch wire. If it is grounded the computer thinks it is in nuteral all the time and will not throw a ses light. A-10 is the vss signal wire. it runs the the vss sensor it's self.
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#17 |
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Re: Tbi swap build thread
So what you're saying is if there is no VSS signal going to the ECM, it will not run as efficiently as it could? And also stay in open loop? Now that you mention it, B-10 must be grounded because I don't get an SES light other than start up.
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#18 |
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Re: Tbi swap build thread
Are you using a stock, or a aftermarket harness?
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#19 |
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Re: Tbi swap build thread
Stock harness from an 89 pickup.
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#20 |
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Re: Tbi swap build thread
Well I would re-trace the wires to see what they are doing.
A-10 is a brown wire from the ecm, and B-10 is a org wire with a blk strip on it. let me know what you find, I am just staring my swap as you can see. ![]()
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#21 | |
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Re: Tbi swap build thread
Quote:
VSS is extremely important for complete EFI operation. It is unfortunate that many omit VSS during conversion. In your case, having 4 speed manual, it is imperative to have a functioning VSS. Since you have 1227747 ECM you'll need to have 2-pulse square pulse VSS inline unit. These are readily available (JTR, others). VSS provides vehicle speed to ECM which uses this input to accurately set fuel mixture and timing. One common problem with absent VSS and manual tranny is a severe drive train jerking during deceleration. This due to inability of ECM, which uses TPS, MAP and VSS inputs, to enter DE/DFCO mode (Deceleration Enleanment / Deceleration Fuel Cut Off). When the ECM detects a sudden drop in throttle position and engine load, it reduces the injector pulse width while continuing to monitor engine load and vehicle speed. The purpose of DE is to produce a lean fuel mixture by reducing the amount of fuel gong to the engine. DE mode conditions are determined by ECM on a continuous bases provided that 1) Vehicle speed is above XXMPH (this depends on EPROM calibration value), 2) engine load decrease is below a limit value (this parameter also depends on EPROM calibration value), and 3) Filtered %TPS drop is <1%. The difference between DE and DFCO parameters is that DFCO parameters are based on fixed values stored in EPROM. The DFCO fuel mode is entered after moderate to heavy acceleration then followed by abruptly releasing the accelerator. Usually ECM will transition into DE prior to entering into DFCO mode as the deceleration continues. Interestingly enough operating conditions may or may not cause ECM to command DE exit by itself. However when ECM enters DFCO mode DE is automatically disabled. Usually DFCO is a 'long' term (self resetting) duration event - coasting down hill in gear for example. Both DE and DFCO are used for emission control, (keeps CATS from being burned up due to excess fuel during deceleration), but the two will effect drive train and exhaust longevity. There are many other ECM controlled parameters that are derived from VSS input. //RF
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"The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) ![]() New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17) |
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#22 |
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Re: Tbi swap build thread
I thoght that on OBD II they did not use a vss sensor, but the ecm got it's signal from the abs computer.?
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#23 |
Windy Corner of a Dirty Street
Join Date: Jun 2003
Location: Pueblo West, Colorado
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Re: Tbi swap build thread
VSS is still used today to provide data to the PCM/ECM for engine controls, speedo, cruise, trans shifting scheduling, torque converter lockup, etc but not ABS. These days, there is actually a wheel speed sensor at each wheel to provide input to the ABS module to control 4 wheel ABS system and traction control if equipped. In the TBI days the trucks only had rear wheel ABS which the rear wheel speed input to the ABS module was read from the VSS sensor on the tail shaft of the transmission.
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Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles
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#24 |
Senior Member
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Location: Panola County Texas
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Re: Tbi swap build thread
Many thanks for taking the time to post your info and progress. This will be a great help to myself and I am sure many others when I get to my drive train. Right now I have an 88 GMC for the donor but may look for the last year of TBI.
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#25 |
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Location: OC CA
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Re: Tbi swap build thread
My apologies - 7747 does not have DFCO - MPH threshold, which is used in 8746 ECM found in TBI passenger cars. Also, DE is mapped to MAP and RPM threshold in 8746.
Now that I looked back at my notes I know where I got confused - in my conversion I used 16136965 from 1991 B-Body which just happens to be almost pin compatible with 1227747 (there are couple more control outputs and MAT input) which in its stock form uses speed threshold for DFCO. In the end it did not matter to me at all since I have converted to EBL which provides full control over DE and DFCO. VSS in 7747 is used primarily for TCC control, Knock retard, Highway SA, EGR, & Idle speed compensation. //RF
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"The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) ![]() New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17) |
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