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Repinning TBI to Speed Density TPI

Old 02-21-2009, 07:34 PM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by MStefak View Post
Ok well I read through the whole thing and myquestion is as follows.

I have an 88 GM Z71.
The plan is a Single turbo 383 TPI setup running 10 lbs.
How do i re pin my 747 to the 749 ? I read the chart on the first page but they are both for the 746.

And am I correct in understanding that you CAN use the 730 instead of the 749 and just use the 749 code with the 730 ?
Any help would be great.


found this might help
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Old 03-25-2009, 09:54 PM
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Re: Repinning TBI to Speed Density TPI

looking to do a TBI to MAF TPI swap to fix my 88 IROC. Started my own thread https://www.thirdgen.org/forums/tpi/...ml#post4094963 opinions and advice would be greatly appreciated.
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Old 04-11-2009, 08:14 AM
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Re: Repinning TBI to Speed Density TPI

Everyone please cross there fingers and pray for me, I'm going to try this over the weekend. And what happened to steps 4-8?
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Old 04-13-2009, 09:36 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by anesthes View Post
Step 9: 1227730 conversion

Splice the right bank injector wires to 4 injector plugs. All the grounds go together to one wire, all the positives go together to the other wire. Now, splice the left bank in place to the left 4 injector plugs. If using TPI plugs, the green plugs go on right side, the red plugs go on left side.

Remove the ESC module. Cut the connector off, and splice wires C and E together. Tape up, and hide someplace neat.

Connect MAT, TPS, CTS, and IAC. Extend wires if needed.

Step 10: Repin

Now, repin ECM connector using following table:

Alright I got all of this done (quicker than I thought) and the only thing I have a question about is the last 3 items 1) Correct me if I'm wrong I just cut the grn/wht wire at the fan relay and and run it to GE8 2) I'm not very good at wiring and I don't understand the last 2 items, if someone could treat me like a 2yr old and tell me what to do that would be great
Anesthes you are the man you have saved me and I think alot of people time and money, THANK YOU!!
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Old 04-13-2009, 10:21 AM
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Re: Repinning TBI to Speed Density TPI

From memory and reading the table, BD6 and BD7 is the grounds the ECM uses to fire the two injectors, so you need to tie them into the body some where. D1 is already grounded, so you could splice it there. (although in theory you could run the risk of running too much amperage for the gauge of wire). Just splice them to a black wire, and screw it into the body/frame under the dash.

Good luck!

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Old 04-13-2009, 11:52 AM
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Re: Repinning TBI to Speed Density TPI

Ohhhh, Ok so I just need to put a pin into BD6 and one into BD7 and ground them somewhere. And if I do nothing to GE8 will it work like it did on my TBI setup, or do I have to run a wire from the relay to GE8 and change something on my PROM, because I don't have the stuff to do PROM work right now. Thanks
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Old 04-13-2009, 12:04 PM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by dwolfe88 View Post
Ohhhh, Ok so I just need to put a pin into BD6 and one into BD7 and ground them somewhere. And if I do nothing to GE8 will it work like it did on my TBI setup, or do I have to run a wire from the relay to GE8 and change something on my PROM, because I don't have the stuff to do PROM work right now. Thanks

E8 runs the fan. Just run that to the green wire on the fan relay.. the fan is controlled by the ECM on the '730, not the switch in the cylinder head.

D6, and D7 need to go to a ground or your injectors will not work, and you will get a 'no start' condition.

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Old 04-13-2009, 02:31 PM
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Re: Repinning TBI to Speed Density TPI

ok....so I hate to sound like complete retard but I have an 87 Z with a 305 tpi thats MAF setup right now....and MAFs are expensive and mine is bad of course, so I was contemplating going to a later model 91 or 92 SD swap, I have a spare 91 tbi car complete with harness and '730 ECM....is the stock harness on the 91 the '746 everyone keeps referring to? Would I just refer to the above instructions and charts? Also my car has a cable type speedo, would I still need to follow the instructions about the VSS buffer box? I realize the major difference is a magnetic pickup coil going through an analog to digital converter as opposed to an optical hall effect that just outputs a digital signal. I'm a student out at wyotech and I've been through EMS so I am familiar with what all the sensors do and how they work, just not familiar with the GM numbers on ECMs and harnesses...sorry if this is a repeat question.
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Old 04-13-2009, 02:45 PM
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Re: Repinning TBI to Speed Density TPI

Ok I think I have it now, I Thank You and my 91 Formula Thank's You.
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Old 05-19-2009, 01:58 AM
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Re: Repinning TBI to Speed Density TPI

Awesome post!

The L03 in my '91 RS just blew up a few weeks ago, I've been building a 355 TPI motor to replace it

engine is done, and I just repinned the TBI harness for my NVSRAM'ed '7730 this morning thanks to the information in this thread. The swap went perfect, the only wires I had left over were the crank signal and the 2 extra injector wires

should be pulling the L03 and dropping in the new motor this weekend
Attached Thumbnails Repinning TBI to Speed Density TPI-img_0952_resize.jpg   Repinning TBI to Speed Density TPI-img_0956_resize.jpg  
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Old 06-08-2009, 02:11 PM
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Re: Repinning TBI to Speed Density TPI

Ok, I'm completing my TBI to TPI swap right now

My main question right now, is it looks like my throttle and TV cables are too short

I heard no mention of this in this thread, do they need to be changed or is there a way to make them work?

Throttle cable looks easy to change, TV cable is going to be a PITA
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Old 06-08-2009, 09:44 PM
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Re: Repinning TBI to Speed Density TPI

Yes, They need to be changed, As far as I know you can't make the old TBI ones work. There are 2 different Throttle cables depending on the year your TPI unit came off ( unless your using a aftermarket Throttle Body, they usually come with brackets for both styles ) The TV cable is the same for all years, I believe. I just bought a throttle cable from TPI Parts and it was pretty cheap, and a factory original, They also have the TV cables. Good Luck
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Old 06-09-2009, 06:56 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by Ruiner View Post
Ok, I'm completing my TBI to TPI swap right now

My main question right now, is it looks like my throttle and TV cables are too short

I heard no mention of this in this thread, do they need to be changed or is there a way to make them work?

Throttle cable looks easy to change, TV cable is going to be a PITA
Sorry. I was more getting into the specifics of the wiring when I first wrote this post years ago. You, along with whatever new induction you get (hsr, tpi, singleplane, etc) you would need the correct throttle cable and TV cable if you have an automatic.

When I did my swap, I used a singleplane manifold which puts the throttle body in the same location as a TBI car, so the stock cable would be fine.

Good to see this thread is still getting hits years later.

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Old 06-09-2009, 11:30 PM
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Re: Repinning TBI to Speed Density TPI

Yeah I just ordered the cables from tpiparts.net, thanks for the link dwolfe88

Got the new engine started today, sounds good, but needs a lot of tuning. The wiring diagrams were spot on though

Still runs super rough, very rich, won't idle. I have my regulator set at 48psi with 24lb LT1 injectors. I was still trying to set the fuel pressure so I haven't connected the vacuum line to the regulator yet, I'll connect that and see how much it lowers my pressure at idle, I'll lower it more on the regulator if I have to then start tuning the PROM
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Old 06-13-2009, 01:34 PM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by anesthes View Post

Good to see this thread is still getting hits years later.

-- Joe
This is an awesome thread. In fact, I'm planning this swap on my 1988 C1500. I'll let you know how it goes. I have to give you a big for putting this together.
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Old 06-15-2009, 11:35 AM
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Re: Repinning TBI to Speed Density TPI

This is probably the best thread I've ever found on TGO. Thanks Joe for creating this and answering questions about it for the past however many years! And Ruiner, No problem glad I could be of some sort of assistance.


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Old 08-02-2009, 10:44 PM
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Re: Repinning TBI to Speed Density TPI

Maybe I'm going about it backwards, but I have a TPI motor, moved a few pins on the harness and am running a 7747. It's still not on the road yet, but should be in a month or so. I also had to add a MAP.
http://www.youtube.com/watch?v=-fNfa0DvL8I
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Old 09-15-2009, 01:41 PM
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Re: Repinning TBI to Speed Density TPI

i have questions cuz i did a swap on my 88 camaro it was the 305 TBI and put in the 350 5.7 TPI took everything out of an iroc from ecm, wireharness, fuel pump etc and now cant get it to start?? can any1 help it cranks over but dont start
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Old 01-19-2010, 12:45 AM
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Re: Repinning TBI to Speed Density TPI

Anyone have a "re-pin" chart to go from a 7747 Ecm to a 7730?

Or is "back into the wiring diagrams" for me.......

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Old 03-05-2010, 11:13 PM
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Re: Repinning TBI to Speed Density TPI

do u have any pictures of how u wired it im not understanding how to wire those four wires i need to put injectors on tbi any help

Last edited by 310cid; 03-05-2010 at 11:21 PM.
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Old 03-06-2010, 05:36 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by 310cid View Post
do u have any pictures of how u wired it im not understanding how to wire those four wires i need to put injectors on tbi any help
Injectors are batch fire. So all 8 injectors, just need power and ground.

The power is supplied by the fuse block, you will find two of the wires going to the old TBI injectors have power. The other two wires from the old injectors go to the ECM, which provide a pulsed ground to fire the injectors.


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Old 03-06-2010, 10:10 PM
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Re: Repinning TBI to Speed Density TPI

so hook the injectors to the blue and red and white and green on top of motor and ground the injector wires to the body im kind of slow and i have a ppl/white and a blue wire left over what do i do with those i think the blue one is injector a wire and after plugging in my connectors to the 7730 what wires will i have left i have a green wire and blue and purple/white wires left any hepl with this stuff

Last edited by 310cid; 03-07-2010 at 02:14 AM.
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Old 03-07-2010, 08:39 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by 310cid View Post
so hook the injectors to the blue and red and white and green on top of motor and ground the injector wires to the body im kind of slow and i have a ppl/white and a blue wire left over what do i do with those i think the blue one is injector a wire and after plugging in my connectors to the 7730 what wires will i have left i have a green wire and blue and purple/white wires left any hepl with this stuff
No.

I don't remember the colors. It's been 7 years.


The ECM provides the pulsed ground - that is what makes the injector fire.

The power is constant, and goes to the fuse block.

If you get a whole v8 injector harness, you'll have 8 injector plugs, a bunch of wires, which are all wired together and somehow end up with 2 or 4 wires. The positives go together, and the negatives go to the negative feeds from the ECM.


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Old 03-07-2010, 02:52 PM
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Re: Repinning TBI to Speed Density TPI

so hook two wires to the fuse block going to injectors then ground the injector ground wire to the ecm

Last edited by 310cid; 03-08-2010 at 01:33 AM.
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Old 03-08-2010, 10:50 PM
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Re: Repinning TBI to Speed Density TPI

I have a 1988 trans with a 305. When i set the timing at factory specs, The engine hesitates then takes off. When I set the timing at say 8 to 10 degrees BTDC, the engine backfires thru the intake. So basically no matter where I set the timing the engine runs crappy and I get no engine check lite or codes.
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Old 03-09-2010, 07:05 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by 310cid View Post
so hook two wires to the fuse block going to injectors then ground the injector ground wire to the ecm
You have four wires to the old injectors. Two of them should show power with key on. Connect those to the two wires with stripes on them from the donor v8 injector harness. Connect the other two to the ECM.

Now when you look at each injector connector, one side should have power with key on.

Get a test light.

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Old 03-09-2010, 07:06 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by scottysbird View Post
I have a 1988 trans with a 305. When i set the timing at factory specs, The engine hesitates then takes off. When I set the timing at say 8 to 10 degrees BTDC, the engine backfires thru the intake. So basically no matter where I set the timing the engine runs crappy and I get no engine check lite or codes.
Does this have anything to do with you swapping to TPI?

I Suggest you start a new thread.

Your problem is fuel starvation I'd guess, but I'd still like you to start a new thread.

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Old 03-11-2010, 04:44 PM
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Re: Repinning TBI to Speed Density TPI

can i use a 89 prom on the 7730 ecm to run tpi or do i need a 90 prom
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Old 03-11-2010, 05:48 PM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by 310cid View Post
can i use a 89 prom on the 7730 ecm to run tpi or do i need a 90 prom
No, you need the '90-92 prom.

The '89 uses an esc module, the '90 has the circuitry for that on the prom, plus the memory locations for the starting point and all that are different, and the program itself is intended for the pinouts of the '89 harness which differs GREATLY from the '90+.

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Old 03-11-2010, 06:28 PM
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Re: Repinning TBI to Speed Density TPI

do i put c15 and d15 in to d6 and d7 for grounds
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Old 03-11-2010, 06:29 PM
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Re: Repinning TBI to Speed Density TPI

my car just keeps turning over
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Old 03-11-2010, 06:30 PM
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Re: Repinning TBI to Speed Density TPI

thanks
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Old 03-16-2010, 03:21 PM
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Re: Repinning TBI to Speed Density TPI

why does my tpi stumble at idle and barely runs is it my map or cts it has a 305 in it but the fuel injectors are 21lbs could the injectors be the problem and when its running the check engine light stays on i just repinnined my tbi to tpi probs help plz
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Old 04-11-2010, 03:36 PM
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Re: Repinning TBI to Speed Density TPI

okay, so I have an 82 Vette, CFI, wanting to go to the 92 GTA Speed Density set up, I have two iacs, will that make problems for me? ECM is 1225550. Excellent write up, you may have just saved me a ton of time and money

Last edited by Contrail; 04-11-2010 at 04:03 PM.
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Old 04-11-2010, 11:28 PM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by Contrail View Post
okay, so I have an 82 Vette, CFI, wanting to go to the 92 GTA Speed Density set up, I have two iacs, will that make problems for me? ECM is 1225550. Excellent write up, you may have just saved me a ton of time and money
I never intended on someone using the '730 fbody speed density ECM to controll cross fire..

If you are intending on keeping the two throttle bodies (and two iacs), I'd suggest trying dynamicefi. RRob should be able to help you.

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Old 04-13-2010, 06:00 PM
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Re: Repinning TBI to Speed Density TPI

No, i don't want to keep both Throttle Bodies, I'd rather go straight TPI, was hoping this was an option to having to get an aftermarket harness, but I guess not. Painless has one for almost 400 bux, but that seems kinda steep. Anyone know of a more affordable alternative? I have the complete set up ready to go, just was hoping to do a pin swap to control it. CFI is nice, but not very well supported, so I want to move away from it to a true TPI system and use my existing harness if possible with the '730 ecu I have.

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Old 04-13-2010, 10:05 PM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by Contrail View Post
No, i don't want to keep both Throttle Bodies, I'd rather go straight TPI, was hoping this was an option to having to get an aftermarket harness, but I guess not. Painless has one for almost 400 bux, but that seems kinda steep. Anyone know of a more affordable alternative? I have the complete set up ready to go, just was hoping to do a pin swap to control it. CFI is nice, but not very well supported, so I want to move away from it to a true TPI system and use my existing harness if possible with the '730 ecu I have.
In that case, you should be able to perform the repin, but you're going to want to find a corvette schematic first and figure out the pinouts from there. I imagine there will be a hand full of left over wires.

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Old 08-26-2010, 06:46 PM
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Re: Repinning TBI to Speed Density TPI

hello i have to old tbi ingector wires that have power were do i put the other two should i splice wire to the ecm or splice them to the injector wiresthat are a solid color
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Old 08-27-2010, 05:48 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by 310cid View Post
hello i have to old tbi ingector wires that have power were do i put the other two should i splice wire to the ecm or splice them to the injector wiresthat are a solid color
The negative side of the injectors go to the ECM. The hot side goes to those power wires.

-- Joe
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Old 08-29-2010, 02:16 PM
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Re: Repinning TBI to Speed Density TPI

d7 and d6 get grounded to the body and the injectors negative gose to the ecm where
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Old 08-29-2010, 02:44 PM
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Re: Repinning TBI to Speed Density TPI

hello where do the negative wires on the injectors go on the ecm thats not what im getting
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Old 08-29-2010, 02:51 PM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by 310cid View Post
hello where do the negative wires on the injectors go on the ecm thats not what im getting
C11, and C12.

So you had your old injector plugs right. One side was positive, the other side went to the ECM on I think D14 and D15. You simply move those to C11, and C12 on the new '730 ECM.

Now on the engine side, you just wire all the negatives together to one negative wire to C11, and all the negitives on the other bank to C12. Power comes from the fuse block.

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Old 08-29-2010, 03:31 PM
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Re: Repinning TBI to Speed Density TPI

ok when i wired the negatives to each bank the car keeps turning over i ran wires from fuse block to the injectors and on the old tbi wires two have power and two do not the injector wires for the tpi are green and blue and two have a black stripe which ones go were i need some help
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Old 09-02-2010, 10:55 AM
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Re: Repinning TBI to Speed Density TPI

The pink and black striped wires are the hot wires on the tpi harness. On the TBI harness the hots are red and white. green and blue on the tbi injector wires are ground.

Then the green and blue are negative on the tpi side. Greens passenger side and blues driver side. (not that it really matters)


Make sure you get a 90-92 V8 Memcal with the swap or the engine will run very rough with the v6 memcal. However there is a way to turn the v6 memcall into a v8 one by grounding a pin on the chip itself. However I do not reccomend that route unless you are set up to tune the vehicle being that the v6 tune is not sufficient for the 5.7 tpi motor.


Oh and thanks again Joe!!! My swap is running!! Turns out I had a bad maf and I just happened to have everything already to convert to SD. Did it the 749 way cause I plan on a procharger kit at 10 psi. Thanks to you man my 71 chevelle has a new heart!

Last edited by 71ChevelleSS; 09-02-2010 at 10:58 AM. Reason: forgot to say thank you
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Old 09-09-2010, 07:45 PM
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Re: Repinning TBI to Speed Density TPI

thanks for all of ur help my tbi didnt come with a pulsation dampener so i bought one today and put it on now i burning tires like crazy dam thing made car stumble and have flat spots
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Old 09-17-2010, 10:31 PM
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Re: Repinning TBI to Speed Density TPI

I have a 92' RS TBI that I put a 350 in place of the 305. Now I'm getting ready to switch to TPI but I bought an ECM for a 1990 TPI Corvette. It's a 727 ecm. Can I use the same chart for this ecm from my 746 instead of a 730 or?
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Old 09-18-2010, 09:59 AM
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Re: Repinning TBI to Speed Density TPI

Originally Posted by JP92RS View Post
I have a 92' RS TBI that I put a 350 in place of the 305. Now I'm getting ready to switch to TPI but I bought an ECM for a 1990 TPI Corvette. It's a 727 ecm. Can I use the same chart for this ecm from my 746 instead of a 730 or?
Hrmm.. No but if I have time this week I'll make a new chart.

Honestly, I'd keep the memcal and swap the memcal into a '730 ecm, and sell that weatherpack ECM on ebay. It's worth WAY MORE to a corvette owner than it is to use, and because it uses weatherpack connectors it's more trouble than it is worth.

Keep the v8 memcal however!

'730 ecm's were in just about everything so you should have no trouble finding one in the junkyard.

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Old 09-18-2010, 01:25 PM
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Re: Repinning TBI to Speed Density TPI

Cool, thank you for the info. I will just keep the memcal and get a 730 ecm. Going to the junkyard today to track down injectors, connectors and an ecm. With a 350 I think I need 24# injectors but not sure. I believe I read that they used 24# inkectors in early 90's 3.8 V6s. I hope I'm right because that's what I'm going to find today. Thanks again Joe,
Jeremy
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Old 09-22-2010, 05:34 PM
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Re: Repinning TBI to Speed Density TPI

I have a 1990 tunedport intake and custom wiring harness speed density that i'd like to use on my 1994 GMC sierra, how will this work together and what about the 4l60e trans.
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Old 10-05-2010, 09:32 PM
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Re: Repinning TBI to Speed Density TPI

I have a 92' Camaro and my memcal is from a 90' Corvette. AZ TPI said that I have to get the Vette memcal's vats disabled. Is this true? I'm getting ready to do this swap and this is a big speed bump cause they want 150 dollars to disable it for me. I thought because I have a 92 that it would be fine. Am I wrong? Or will I be ok not having it disabled?
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