Tbi swap build thread

[FRENCHBLUE72]

I am running the vss just not hooked to anything..... As far as the adapter I used one and just put the sensors close to where they were stock.... I ran a stock coil so I cant help ya there....

[rfmaster]

Originally Posted by cjracing15

1) I would put the sensors as close as I could as the factory did it.

2) As for the coil I am not sure. I am sure RF will chime in on it. He rocks on the wiring diagrams.

Thanks CJ

Pancake - you can mount coil on the fire wall (or in its original location). If you do so make sure to run a ground strap (braid) between intake and coil mounting bracket. Low resistance ground return path is required between EST and coil.

I have seen third gen boys mount monster sized coils (lots money) on the firewall. Generally, performance coils can be saver and trouble all rolled into one. The problem stems from current requirement that these coils place on EST module (inside dizzy). To get HV coil to deliver joules of spark energy (at 40 - 50kV) requires more current flowing through the primary (12 volt winding). EST module operates as a switch which turns on & off current flowing through the coils primary windings. More current = more heat. Semiconductor devices do not like heat and fail over time if subjected to operation beyond rated limits. For our trucks, with engines spending most of their lives below 3000 RPMs use of 'monster' coils is not necessary.

One of these days I'll setup experiment in my lab to measure primary coil winding current and publish my results. I have factory coils, but I do not have any 'monsters' for obvious reasons.

As to recommendation on coil - I have never used anything but stock, hence I can not recommend one.

Sensor placement. I prefer to mount my sensors away from heat sources for the aforementioned reasons. I mounted my MAP on the firewall, ESC module is mounted on fender skirt. All my relays are mounted away from engine. GM mounted the same sensors on a bracket bolted to intake manifold.

//RF

[cjracing15]

SEEEE I told Ya.
I knew RF would have a very good answer.

[pancake]

It has taken a bit longer that expected to get this TBI swap done.

After going 4 wheeling to a hard t rail here in Colorado I was motivated again to get this TBI swap done. The blazer would die and be hard to start and would not run on its side. This was a huge hassel and made the trails harder.

So needless to say I am going to get this swap done.

Ordered the VSS and the 4 wire O2 sensor. I will pick up a KS and I should have everything.

I decided to use the stock intake and just drill/machine out the 4 center holes. This solves the issue of coil mouint and sensor mounts.

I will have a question when I wire the O2 sensor when I get it. I have the relays but do not know what color O2 wires go to what parts of the relay? I bought the AC delco AFS75 O2 sensor and the relays are off a 83 ish caddy.

I am hoping to start wrenching on it next weekwend.

Thanks again for all your help and all the great information in this thread.

[cjracing15]

I understand what you mean about taking longer than you think it will to do this swap. It took me about two months longer than I thought it would take. What takes longer than anything is the little things you just thik of untill...

Good luck and if you have any questions just ask. We all will try to help ya out.

[smogdave]

I like all of the information about your TBI swap. This is very interesting. I'd like to share pics of my swap. It is not quite done yet but is driveable. I have a 1976 c-10 long bed that had a 250 I-6 and installed a 1988 454 TBI in it. It has all went fairly well so far. I hope the pictures work. I had to use a fuel tank and sending unit from a 1987 RV to work for the fuel injection system. I have to complete the wiring conversion for the instrument cluster. I used the complete wiring harness from the 1988 GMC 3500 Dully.

[FRENCHBLUE72]

First real drive yesterday and it was awesome still have a few small bugs to fix but no big deal... My map sensor was bad so I replaced that and I have a small vacuum leak at the tbi/adapter plate. Only code I seem to have is the vss code which I knew was gonna happen as its not hooked up.. I would like to say thank you very much guys as you have helped me more than you could ever know...

[mcbassin]

Hi guys this is a great thread thanks CJRacing for starting it and all the others that have added to it. My son and I are diving into this swap out well kinda. The plan is to remove the motor and tranny in tact and plug it into the 86.Thread here: http://67-72chevytrucks.com/vboard/s...d.php?t=356697 So far we have unhooked just about all the wiring and mechanical on the donor. I will be junking the car when done so I can keep the complete wiring harness if necessary.

I noticed pretty much everyone on here is using a 87-90 truck or aftermarket tbi harness. I picked up a 92 buick 5.7 with a 700r4 (i think) for $300 on craigslist to put into my Son's 86 swb. It runs and shifts good...we drove it home with the AC on. Anyway, this is a super low buck build just to get him a driveable truck and then sell later to invest in his 69 (we are probably gonna do a 5.3 conversion on it). Or if we stay hooked up on it he may just drive them both who knows?

So here is my list of questions for now:
1. Can we use the car harness and ecm ?
2. What parts will we need to buy?
3. What is the K.S. talked about on this thread?
4. I have never even touched a tbi engine until yesterday
Can we do this project? I haven't worked on trucks since the 90s.

[68 TT]

The car TBI computer is a little different than the truck version because the car computer does additional things the truck one doesn't (like electric fans) but it will work just fine in the truck swap, actually better.

Check out thirdgen.org for tuning the engine after the swap. The guys over there are very knowledgeable about the TBI motors and computers.

K.S. is knock sensor. It is on the block down by the starter threaded into the water jacket.

The Buick should be plenty big enough to allow you to use its wire harness and get the ECM into the cab of the truck. It must go inside as it is not weather resistant.

[68 TT]

Wire the heated oxygen sensor relays activation wire to the fuel pump power wire coming off the ECM.

This way the heating element is only working when the fuel pump is running and not at all times the key is on. It will make the sensor last a lot longer.

[rfmaster]

Originally Posted by mcbassin

Hi guys this is a great thread thanks Glock for starting it and all the others that have added to it. My son and I are diving into this swap out well kinda. The plan is to remove the motor and tranny in tact and plug it into the 86.Thread here: http://67-72chevytrucks.com/vboard/s...d.php?t=356697 So far we have unhooked just about all the wiring and mechanical on the donor. I will be junking the car when done so I can keep the complete wiring harness if necessary.

I noticed pretty much everyone on here is using a 87-90 truck or aftermarket tbi harness. I picked up a 92 buick 5.7 with a 700r4 (i think) for $300 on craigslist to put into my Son's 86 swb. It runs and shifts good...we drove it home with the AC on. Anyway, this is a super low buck build just to get him a driveable truck and then sell later to invest in his 69 (we are probably gonna do a 5.3 conversion on it). Or if we stay hooked up on it he may just drive them both who knows?

So here is my list of questions for now:
1. Can we use the car harness and ecm ?
2. What parts will we need to buy?
3. What is the K.S. talked about on this thread?
4. I have never even touched a tbi engine until yesterday
Can we do this project? I haven't worked on trucks since the 90s.

The 92 B-Body with 5.7L with 700R4 will make a perfect donor for a '86 (that's what I did for my conversion). Do you know that 90' B bodies were around 5000 lbs!!!. Save full harness. Car ECM 16136965 belongs (different pgm mask) to the C3 ECM family and is similar to 1228746/1227747 ECMs. There are five additional control lines (I/O) that '6965 uses that are not found in truck 7747 ECM. They are:

A3 Dark Green/Yellow 428 Canister Purge Solenoid
C1 Black/Pink 429 Air Divert Solenoid
C2 Dark Green/White 459 AC Compensation Relay Control
C8 Light Blue/Orange 495 Power Steering Pressure Switch
C12 Tan 472 MAT (or IAT) Signal

out of the five I/O MAT (C12) you must keep or otherwise ECM will set error code. IAT improves AE and PE over wide range of temperatures.

Use car harness as is - no need to buy anything.

KS part number is a bit tricky - use the same as on donor engine. Make sure to keep ESC module that was used on B- Body - it is mounted on AC relay bracket - passenger side fender. I'll have to look up this part, but OE part number should be good for your conversion.

Swap is straight forward. It is not to difficult just take your time and plan ahead. If you have questions - drop a a line.

I took a look at your donor photos - I hope that you re-sealed your donor engine (oil leaks can ruin clean compartment).

//RF

[mcbassin]

RF,
I am so pumped that you saw my post. You have an awesome truck there!
I posted my own thread (http://67-72chevytrucks.com/vboard/s...75#post3455975) before I did a search on Google and found cjRacing's thread. I see that you are a bonafied expert on the subject and you have been through this before. You are welcome to chime in on my thread too. You right on the money about the oil/trans leaks. I am planning to put new v/c gaskets and pan gaskets and any other easy fixes since the engine is out already.
Right now I'm a little overwhelmed with the wiring thing, but I'm sure I can work around that eventually. I will definetly have some questions in a day or two. thanks for your reponse,
Mike

[cjracing15]

Take your time and sort the wires out one at a time and you can do it. That is why I started this thread in the first place was to show my swap and smoke out others that have done a tbi swap and want to share and, help with others that need help.
So if you get stuck just ask and we will try to help.
Good luck, Jamie

[mcbassin]

Originally Posted by cjracing15

Take your time and sort the wires out one at a time and you can do it. That is why I started this thread in the first place was to show my swap and smoke out others that have done a tbi swap and want to share and, help with others that need help.
So if you get stuck just ask and we will try to help.
Good luck, Jamie

Thanks Jamie,
I'm so glad I found this site....I wouldn't even attempt this swap without having found this thread. One thing I'm wondering, if you look at my pics, you can see that the original harness is complete and still on the engine. So can I track down the wires that need to be tied into the 86 truck and splice with it still attached? Or would it be better to take the harness off the engine and do a wire by wire splice up? My plan was to leave everything like it was in the car and just tie in where I need to and make it look stock.

Also, my harness will require about 2.5" X 3.5" rect. cut out in the firewall for a stock look. Maybe I missed this detail but how did you do yours? thanks,
Mike

[cjracing15]

You can go back to the first page of this thread and look on post # 8 and I listed all the wires by color and what pin that it goes to. It should be the same with the harness you have with maybe a few extra wires throwed in. Then you can look on page #3 of this thread starting with post # 65 and see what me and RF did as far as routing the spaghetti of wires that you will have left over. You need to get real familiar with a soldering iorn . Later

[rfmaster]

Originally Posted by cjracing15

You can go back to the first page of this thread and look on post # 8 and I listed all the wires by color and what pin that it goes to. It should be the same with the harness you have with maybe a few extra wires throwed in. Then you can look on page #3 of this thread starting with post # 65 and see what me and RF did as far as routing the spaghetti of wires that you will have left over. You need to get real familiar with a soldering iorn . Later

Yes, soldering iron skills are a definite plus to have, but for the most part a professional grade crimping tool and barrel wire crimps are just enough to do the job. My preference is to solder and double shrink. Note, that the B-Body bulkhead pass though header contains AC vacuum lines and ECM harness. It's a square looking bracket - see my photos. Needless to say making a square opening in the firewall is tough. I used a 2-1/4 punch (52mm) and standard OE rubber bushing to pass ECM wires since there was none in '75. In your case you should have CCC harness that will have to come out, but you can save OE rubber bushing by gently removing CCC harness wires and replacing them with donor wires. For ease of re-installation I just cut through rubber grommet to allow ease of wire installation. Then I used vulcanizing rubber (windshield) sealant to make it whole again - not very clean, but it good enough.

//RF

[mcbassin]

Originally Posted by rfmaster

Yes, soldering iron skills are a definite plus to have, but for the most part a professional grade crimping tool and barrel wire crimps are just enough to do the job. My preference is to solder and double shrink. Note, that the B-Body bulkhead pass though header contains AC vacuum lines and ECM harness. It's a square looking bracket - see my photos. Needless to say making a square opening in the firewall is tough. I used a 2-1/4 punch (52mm) and standard OE rubber bushing to pass ECM wires since there was none in '75. In your case you should have CCC harness that will have to come out, but you can save OE rubber bushing by gently removing CCC harness wires and replacing them with donor wires. For ease of re-installation I just cut through rubber grommet to allow ease of wire installation. Then I used vulcanizing rubber (windshield) sealant to make it whole again - not very clean, but it good enough.

//RF

RF,
I have sufficient soldering skills, I'm confident about that part and I prefer heat shrink tubing also. As far as the cut-out in the fire wall, I looked at a coworkers 93 blazer and his is just like the car and is just left and under the AC equipment. ( I like this idea) I have some sheetmetal experience too. I have been in the Tooling and Machine shop business since the late 80s, so I can fab just about anything necessary. Right now, this is low on my priority list. I'm really worried about the interface with the truck harness more than anything. I am confident with you guys helping me we will have this puppy running in the next few weeks.....months....before Christmas....Before he hits 16 next Feb.
It's all good boys!
Thanks,
Mike

RF, I found this pic on that Jeep thread link you posted on page 3, it should help me a lot:

[rfmaster]

Mike

I do not want to sound overly optimistic, but harness should not be to difficult to manage. The ECM harness (in grand scheme) is a standalone by design. The B-body car harness has couple extra circuits - AC controls and extra power circuits which can be left alone.

Interfacing with your truck you can break it up into two sections - under the hood and underdash.

Under the hood:
1) +B - fused from battery
2) Grey wire to fuel pump.

Under dash.

3) SES light wiring.
4) Brake actuated switch for TCC control
5) P/N switch - this will require a diode, and relay circuit - very simple to construct.
6) Constant +B (12VDc) (must be always hot)
7) Switched - Ignition ON +12 volt line (Use another to provide sufficient current as existing fuse panel may not sufficient current handling capacity)
8) ALDL connector wiring (3 or 4 wires all together)
9) System ground

To fire transplanted engine, at a minimum, you need to have 1, 2, 6, 7, 9 connected. You can search through this thread and IFRC I have outlined color codes for wires which must be connected. If not drop a line.

A word of advise - start a note book!


//RF

[mcbassin]

Thanks RF for breaking that down for me. I am going to try to pull the harness today and start dissecting it. BTW, you don't have a link to your build? What's up? that is a very impressive truck you have there!
PS I will have questions I'm sure.

[rfmaster]

Ahhh yes, never got around to writing up my build up and TBI swap although I must have taken well over 300 photos outlining numerous details of my TBI swap. One of these days (hmm, I wounder when that is going happen ) I'll put together a post factum write-up.

//RF

[mcbassin]

Originally Posted by rfmaster

Ahhh yes, never got around to writing up my build up and TBI swap although I must have taken well over 300 photos outlining numerous details of my TBI swap. One of these days (hmm, I wounder when that is going happen ) I'll put together a post factum write-up.

//RF

RF,
You mind sending your photos with any notes? I'm really confused about this wiring stuff. I really don't know where to start. I see all these pics of harnesses that you guys have customized and I'm really overwhelmed with it. I started to pull the engine harness then backed off when I broke one of the connectors. I really don't want to build a custom harness when it was running good in the car. Tell me if I'm wrong but, can't I just add the oil sender, temp sender, starter wire and any other necessary wires from the truck harness? What about just running some of these connections under the dash? Keep in mind this isn't going to be a show truck we just want it reliable. thanks,
Mike

[FRENCHBLUE72]

Well guys I have been driving mine almost everyday and the fuel mileage is great.. The only problem I have now is when its cold it does not wanna idle but as soon as it warms up its good to go. I have been told it is the water temp sensor so i guess that's the next piece to replace.

[rfmaster]

Originally Posted by FRENCHBLUE72

Well guys I have been driving mine almost everyday and the fuel mileage is great.. The only problem I have now is when its cold it does not wanna idle but as soon as it warms up its good to go. I have been told it is the water temp sensor so i guess that's the next piece to replace.

Before swapping CTS you can check it with a DVM. Set DVM to measure ohms, disconnect harness connector from CTS, probe CTS terminals. At room temperature (22C) AC-Delco CTS should read about 2950 Ohms. At normal operating temperature (80C) CTS should read 338 Ohms. Cold engines require richer mixtures and your engine just needs to a richer fuel mixture than a stock calibration is delivering. This were ECM tuning comes into play - solving these pesky drivability issues as no two engines are alike.

//RF

[68 TT]

You really need to data log what is going on to know what the ECM is seeing that makes it run poorly when cold then clean up when the engine gets up to temp.

It sounds like an open loop vs. closed loop issue to me. The CTS is a possible source giving the ECM faulty info but there could be several other causes.

Data logging is a good place to start. It helped me diagnose a vacuum leak that two mechanic friends thought was a fuel system issue. It will also let you see where you can fine tune the programming to suite your particular setup.

[FRENCHBLUE72]

I do remeber my friend sayin that it was jumpin from open to closed loop untill it warmed up? I should have written it down....