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Unread 07-09-2010, 01:47 AM   #1
greyarea
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1990 YJ Wrangler 
 
Join Date: Aug 2009
Location: gwinett, GA
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The Junkyard TBI write-up

I decided to go to fuel injection after trying to start my Jeep in cold weather while in Wyoming this last winter. I looked at all the commercial kits available, by they are not cheap ($900 to $3000). I looked at a junkyard MPFI off a 4.0 but, I like simple, so I decided on a GM TBI for a 4.3l. The problem I ran into was there is nowhere that has all of the information that one needs to complete this swap with no prior knowledge of the system. After many hours spent on the internet and the phone I gathered all the information. Before I go any farther I want to thank everyone on this forum and all the others that took the time to post their knowledge so others could benefit.

If anyone has corrections additional info PLEASE let me know I am doing this to share the most correct and complete information as possible.

Now the write up.

Things to do if you are doing fuel only.
Nutter
Team Rush with the TFI coil or whatever flavor of distributor, coil, and module combo you like.
Order a tach filter from Howell so you don't cook you ECU it is $50.

The trip to the junkyard.

All of the information I have found was for using parts from a full size truck, well there are not many of those intact around me so I chose an 88 Chevy Astro van as they are cheap and plentiful in pick and pull yards.
What you need to pull.
The computer . The number I used 1227747 since it has the most aftermarket support but, you can use any of the 4.3l computers. The computer is located behind the passenger side kick panel.
The wiring harness. Pull everything starting from inside the engine bay on the driver side there is a bundle of wires going through the fire wall cut them there. Then pull everything that that is connected to. This is more than you will need but you wil remove the un needed wires later. And pull the relays on the passenger side firewall.
The sensors and modules. You will need the MAP sensor (the same part number as the one jeep used on my 90 4.2l). You will need the Knock sensor (optional) located on the side block. You will need the ignition module located inside the distributor. The coolant temp sensor located on the intake. The O2 sensor from the exhaust The same as used on my 90 4.2l).
The throttle body. Pull it as a complete unit with the throttle position sensor and the idle air controller.

That is all you need to pull. The rule of thumb is pull anything you think you might need.

The tear down.

What I started with.

PIC

Remove carb, linkage, coolant temp sensor in the intake, and all the associated wiring. Just put the existing wiring aside. Remove the fuel lines and the pump. Remove the vacuum lines and anything else you will be eliminating. I eliminated the pulse air tubes and replaced my cat with a modern 3 way cat with no air injection.

Hard parts install

I chose to install all of the hard parts first so I could size the wiring harness properly.

Mount the adapter plate to the intake using a new carter carb gasket, locktite, and a torque wrench.

Mount the throttle body in the same way as the adapter plate and torque to 20 ft/lbs.

I am reusing the o2 sensor that was already in the jeep as it is the same part number for the doner Astro van. Fro those who don't already have one you will need to weld in a bung as close to the manifold as possible and get a o2 sensor. I would suggest a new one as they are cheap I am reusing mine as it is only a year old.

I mounted the map sensor on the bracket I made for my TFI Ford coil. you will also need to connect a vacuum line from the front port on the throttle body to the Map sensor.

Install the coolant temp sensor in the same location as the stock on the intake manifold.

If you are controlling spark also you will need to mount the ignition module to an aluminum plate as they create a lot of heat. Mine is on top of the valve cover.

If you are going to be using a knock sensor it will mount in the side of the block by removing one of the plugs in the water jacket. You will also need to mount the Spark control module I mounted mine to the same bracket that I made for the ignition module.

You will need to mount the ECM where it will stay dry and away from engine heat.

As for the throttle linkage you will need to adapt it as needed to get it hooked up.

I will be adding pics when this is all written.

__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 07-09-2010 at 03:47 PM..
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Unread 07-09-2010, 01:47 AM   #2
greyarea
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The scary part Wiring
The first middle and last thing to remember is lable everything if you are not the best at wiring and if you are lable it.this step is really not the hard.
There is going to be a lot of scematics and diagrams in this section because it is the most complicated and this information applies to the 7747 series computer only. If you have another one feel free to ask me some questions.

Tto start find all the wires in the harness that do not make ti back to the computer and remove them, some of these will be needed later so don't cut them right at a connector.

There are various ways to deal with the sealant arround the harness at the firewall. I used the cut and splice method since everything was too short.
What I did was cut all the wires lableing as I went at the firewall sealant and pluged all the connecters into their sensors and modules for routing and length measurement.
I did all splicing by saudering and shrink tubing everything. That is the way it should be done for a reliable system.
After all the splicing I used a good quality electrical tape to wrap the harness. When I sap a good quality tape I mean spend atleast $3 a roll. I am electrition and I have seen the results of crap tape and it gets bad with age.
I will be using split loom to cover everything once I get my order from the big brown truck.
I used the stock Astro van fuel pump relay and the extra relay on the same bracket to power everything that is on with the ignition switch including the fuel pump and injectors. I think is is reliable to 40 amp and GM shows it as a 55 amp relay. I used a 30 amp fuse on this relay.

ECM connector Identification in my terms

A1- grn/wht- this wire is used to energize the fuel pump relay.
A2- not used
A3- not used
A4- gry- to EGR relay.(optional) This is a ground from the ECM to control the EGR relay. I did not use it.
A5- brn/wht- SES(service eng soon) light. This is a ground to turn on the light. Feed ignition switched power to the light and connect the ground here.
A6- pnk/blk- switched 12v from the ignition relay.
A7- not used
A8- orn- ALDL Serial data. This is your ALDL pin E data for your laptop.
A9- wht/blk- ALDL pin B diag mode. When jumpered to ground will set the ECM to ALDL diagnostic mode.
A10- brn- VSS speed sensor signal to the ECM (optional) Not needed
A11- ppl or blk- MAP sensor ground.
A12- blk/wht- System ground. Can be tied with D1. Goes to engine ground.

B1- orn- 12v fused from battery. I use an inline fuse on this. It also ties into C16. I used a 20 amp fuse for both.
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 12v thru this wire to turn on the fuel pump, at the same time it tells the ECM the fuel pump is on.
B3- blk/red- EST reference.
B4- not used
B5- ppl/wht- EST high reference
B6- not used
B7- blk- ESC signal This is the knock sensor signal to the ECM. The knock sensor circuit is optional. If not used, tie this wire to C14 the 5v reference.
B8- dk grn- AC signal. This tells the ECM that the AC is turned on. This can be used to set the idle speed higher when you turn the AC on. I use it to increase the idle when using the compressor for on board air. Same thing!! Just tie it to the wire going to the AC clutch. This can also be run to a switch and fed 12v to idle us whenever you want to
B9- not used
B10-orn/blk- Park/Neutral sw. This is optional. It tells the ECM when you are in Pk or N. It can be used to give a slight adjustment to idle speed when switching from park to drive and back.
B11- not used
B12- not used

C1- not used
C2- not used
C3- IAC- Idle air control
C4- IAC
C5- IAC
C6- IAC -The ECM controls the IAC motor. It adjust the amount of air that is bypassed around the butterflies to adjust the idle speed.
C7- not used
C8- not used
C9- ppl/wht- Starter crank signal. Goes to the solenoid.
C10- yel- Temp sender signal
C11- lt grn- Map sensor signal
C12- not used unless you get one with a manifold air temp sensor
C13- dk blu- TPS sensor signal
C14- gry- 5v reference signal to map and TPS.
C15- grn- inj B ground signal. Most systems do not use this. It was used on some of the bigger engines to share the load of the injector signal.
C16- orn- fused 12v tied to B1

D1- blk/wht- System ground, ties to A12 and engine.
D2- blk- MAP sensor ground
D3- not used
D4- wht- EST control
D5- tan/blk- EST bypass. This is the wire that has a plug near the distr that you disconnect to set your timing.
D6- Tan- O2 ground to engine.
D7- ppl- O2 sensor signal
D8- D13 not used
D14- lt grn- Injector B ground signal
D15- blu- optional injector A ground signal
D16- blu- Injector A ground signal
__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 07-09-2010 at 02:18 AM..
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Unread 07-09-2010, 01:48 AM   #3
greyarea
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Here are some diagrams
89ftbi_1.jpg   89ftbi_2.jpg   89ftbi_3.jpg   89ftbi_4.jpg   747ecm1.jpg  

__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 07-09-2010 at 03:23 AM..
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Unread 07-09-2010, 01:49 AM   #4
greyarea
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Location: gwinett, GA
Posts: 293
Here are some more diagrams
747ecm2.jpg   747ecm3.jpg   747ecm4.jpg   747ecm5.jpg   747ecm6.jpg  

__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 07-09-2010 at 03:26 AM..
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Unread 07-09-2010, 03:17 AM   #5
greyarea
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Location: gwinett, GA
Posts: 293
Here are some more diagrams
747ecm7.jpg   duraspark-tfi-8-pin-hei-module-revised.jpg   durasparkwiring.jpg   gm-aldl-connector.gif   1227747_ecm.gif  

__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 07-09-2010 at 03:30 AM..
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Unread 07-09-2010, 03:30 AM   #6
greyarea
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Now after All of the wiring I installed the fuel system.

Lets start in the engine bay.
Remove fuel pump and install a block off plate (use one for a big block chevy). Then remove all the hardlines from the engine you will nolonger use them.
Next install the short hardlines from the doner car into the TB and run soft lines to the hard fuel lines on the frame. the smaller of the 2 is the return. If you have a pump running higher than 14PSI I would reccomend a regulator before the throttle bodyeven though there is a built in regulator in the TB.
Now back to the pump.
I installed my pump behind the drivers side tail lisht in that cavity under the tub. Mount your pump as close to the tank as possible and out of the way. I chose the location I did because I bought a larg rotery pump that is taller than the frame rails. I installed a basic strainer type filter before the pump and and a standare in out filter on the out put of the pump to keep the really small stuff out of the injectors.
Wire the pump to the fuel pump relat and tie that to the computer. see above Connect the ground to the frame or the tub.

Now the Spark control
If no spark control is used you will need to tap the negative side of the coil to B5 on the computer with the Howell tach filter in line.

Do this before disableing the carberator as you will need to set the timing to 0 BTDC ( once running you can run a little mor static advance for better proformance max at 5-6 BTDC is safe) For the computer to be able to function properly.

I started with the distributer. You will need to lock out all mechanical advance. You will start by removing the cap and rotor and if team rushed the base adapter. Then remove the vacuume canister with the 2 screws and it should lift free. Then you need to remove the reluctor ring ( the star shaped ring in the distributor shaft) by using 2 screwdrivers to pry it up and off the shaft, there is a small roll pin that keeps the ring from spinning on the shaft, don't lose it. You also need to keep the orientation correct to the shaft, it can be installed 180 out. Now remove the the rest of the screws that are left on the top and lift the plate off, you will see some springs an weights remove them. You need to lock the plates together by a screw or a tack weld. Reinstall the top plate, now you will need to lock the movement in this plate in the same manner as before. Reinstall the base adapter cap and rotor.
Now the wireing
Disconnect the connecters at the original ignition module.
starting at the negative side of the coil tap into the wire and connect it to the "C" position on the ICM. Do Not break the original connection.
Now the positive side tap in and run it to the "+" on the ICM Do Not break the original connection.
Now the connector at the distributor for the pickup coil . Cut the harness side off the jeep and connect the orange wire to the "N" position of the ICM. Cut the purple and connect it to the "P" position of the ICM.
Now we will connect the ICM to the computer (ECM)
Connect ICM "A" to ECM ''B3"
Connect ICM "B" to ECM "D5" with a quick connect inline to disconnect to set the timing
Connect ICM "C" to ECM "B5"
Connect ICM "D" to ECM "D4"

Thats It If the timing is right and you have gas it should start.
__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 10-13-2014 at 06:36 PM.. Reason: correcting pin connection number
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Unread 07-09-2010, 03:31 AM   #7
greyarea
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All parts used were from or for a 88 Chevy Astro van with a 4.3l V6


Useful links and info


An ALDL reader software vender you use this with a laptop to look at codes fuel and spark map data that has been logged.
http://winaldl.joby.se/


For custom chips for your exact engine setup
AFI I like them better than Howell
http://www.affordable-fuel-injection.com/

Howell
http://www.howellefi.com/customer/
__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 10-19-2012 at 11:37 AM.. Reason: removed bad links
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Unread 07-09-2010, 03:36 AM   #8
greyarea
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Coolant sensor approximate resistance specifications:
177 ohms @ 212 deg. F. or 100 deg. C.
241 ohms @ 194 deg. F. or 90 deg. C.
332 ohms @ 176 deg. F. or 80 deg. C.
467 ohms @ 158 deg. F. or 70 deg. C.
667 ohms @ 140 deg. F. or 60 deg. C.
973 ohms @ 122 deg. F. or 50 deg. C.
1188 ohms @ 113 deg. F. or 45 deg. C.
1459 ohms @ 104 deg. F. or 40 deg. C.
1802 ohms @ 95 deg. F. or 35 deg. C.
2238 ohms @ 86 deg. F. or 30 deg. C.
2796 ohms @ 77 deg. F. or 25 deg. C.
3520 ohms @ 68 deg. F. or 20 deg. C.
4450 ohms @ 59 deg. F. or 15 deg. C.
5670 ohms @ 50 deg. F. or 10 deg. C.
7280 ohms @ 41 deg. F. or 5 deg. C.
9420 ohms @ 32 deg. F. or 0 deg. C.
12300 ohms @ 23 deg. F. or -5 deg. C.
16180 ohms @ 14 deg. F. or -10 deg. C.
21450 ohms @ 5 deg. F. or -15 deg. C.
28680 ohms @ -4 deg. F. or -20 deg. C.
52700 ohms @ -22 deg. F. or -30 deg. C.
100700 ohms @ -40 deg. F. or - 40 deg. C.


To check the TPS sensor you use a volt ohm meter and look for a smooth change in resistance with no dead spots
__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 07-09-2010 at 04:52 AM..
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Unread 07-09-2010, 03:37 AM   #9
greyarea
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Feel free to contact me with any questions, comments, or additions.
__________________
90 YJ Magnum 5.2 v8 , 1'' BL, 1'' booms, 4" Procomp, 35/12.50-15 MTR/kevlar Ford 8.8 4.10 lsd Aussie and TJ shafts up front.
KI4UTU

Last edited by greyarea; 07-09-2010 at 04:56 AM..
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Unread 10-04-2010, 12:56 PM   #10
mtnbikeidaho
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Excellent source for information. I just got back from the u-pull yard with spaghetti and a throttle body I plan to put on my '82 CJ7. This is EXACTLY what i needed to understand the wiring. THANK YOU!!!
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Unread 04-02-2011, 09:16 PM   #11
n9oig
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I just did this setup but I'm having starting issues. When I start it it dumping fuel so much due it floods out and won't start I have to disconnect the injectors to clear it the hook them up just before it dies. It runs good after that. Any ideas?

It's a 4.2 using the 4.3 tb from a 92 s10
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Unread 04-02-2011, 09:56 PM   #12
ja123182
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did you have the computer reprogramed with a new chip?
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Unread 04-02-2011, 11:16 PM   #13
n9oig
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It's the 1227747 ecm with the 4.3 chips in it
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Unread 04-03-2011, 12:04 PM   #14
ja123182
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i think that may be part of your problem. i used to work for a company doing retro fit fuel injection. I pretty sure you are going to have a new chip made. there are a ton of differnt factors that can goof this up.
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Unread 04-03-2011, 01:40 PM   #15
n9oig
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That's the recommend setup for a 4.2 to optimize it you want a chip burned.
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