Tbi swap build thread

[rfmaster]

Originally Posted by mocajoes

Wow that is a vast amount of information thank you again. I am glag to hear that it will work. Yes I am going to use a th350 tranny so I will be trying to decide the best way to go. I had to go out of town till Saturday so I will try to catch back up then. First things first I need to get the old engine out and get the new one in. Not sure how to address the fuel tank. I have the factory 94 tank with pump in it but, it seems way too big to fit under my truck and Im pretty sure the original behind the seat wont work as there are no return lines and no vent line. Thank you for the great in depth info be back soon.
Brian

Brian
You may want to replace that 'original' gas tank any way. After 41 years in service a steel tank probably has bunch of crud and rust accumulated in the bottom. I am not familiar with 70 SWB gas tanks first hand, but from a quick catalog search it would appear that there are two tanks available - non EEC and EEC tanks. The EEC stands for Evaparotive Emission Control - simply put charcoal canister purge (CCP) is used to capture gas fumes and burn them in the engine instead of being lost into atmosphere. This is system costs nothing in terms of engine performance, but it keeps HC's from escaping into the air. The EEC tank probably has 1/4" CCP line which is too small for fuel return, but you better have it since EFI fuel circulation heats up fuel in the gas tank increasing fuel vapor pressure - EEC Hollander 869, GM 6272124, GM49B. To plumb return line you'll have to tap into filler neck with 5/16" barb - use external fuel pump and 3/8" fuel line for fuel supply.

//RF

[mocajoes]

Rf Thanks for the info, What happens if i just plug everything in without electric tranny ?
will it seriously affect performance or just mileage. I am trying to do this as low dollar as possible. with having to do something different with the tank and chip etc. just wondering if it will work with out the flash, or just not optimally.

[rfmaster]

Originally Posted by mocajoes

Rf Thanks for the info, What happens if i just plug everything in without electric tranny ?
will it seriously affect performance or just mileage. I am trying to do this as low dollar as possible. with having to do something different with the tank and chip etc. just wondering if it will work with out the flash, or just not optimally.

Bryan

PCM will throw whole bunch of transmission related fault codes. As for engine operating with these transmission related fault codes PCM more than likely will revert to limp mode which will adversely affect engine performance.

The best and lowest price course of action you can take is:

purchase:

1) G1 adapter from Moates for $35
2) C2 SST 27SF512 Chip $5 - get at least a couple of them
3) PM me

This is what a retrofitted PCM looks like (note that I have ZIF socket, which makes chip swapping a breeze):



For the fuel system - well I have seen some less than ideal solutions. Remember that without fuel your engine will not run - enough said. You still have to plumb a return line - at least 5/16", 3/8" is better. Most retrofits can make due with external fuel pump. There are several good choices - search thread for part numbers. You are looking into couple hundred dollars to get fuel system ready for TBI - pump, filters, fuel line, fuel line retainers, clamps, etc.
It is not bad, but it takes a bit of planning and a work space to execute.

//RF

[Tx Firefighter]

Bringing this one back to the top for a question...

I'm converting my 78 dually to TBI using a complete 87 model donor truck. I'm using the entire harness and the gauges with VSS.

My question is this...

The 87 donor was an automatic truck. My dually is a 4 speed. On the part of the 87 harness that goes to the steering column, neutral safety switch, I have two pairs of wires. One pair is blue and green. The other pair is black/white stripe and orange/black stripe. Now, of course I'm using a floor shift, so the column mounted switch is useless. Do I just leave these unplugged since I'm running an auto or do I need to jumper them together ? I assume one pair is backup lights and I'd want them disconnected.

Thank you,
Kevin

[mocajoes]

Originally Posted by Tx Firefighter

Bringing this one back to the top for a question...

I'm converting my 78 dually to TBI using a complete 87 model donor truck. I'm using the entire harness and the gauges with VSS.

My question is this...

The 87 donor was an automatic truck. My dually is a 4 speed. On the part of the 87 harness that goes to the steering column, neutral safety switch, I have two pairs of wires. One pair is blue and green. The other pair is black/white stripe and orange/black stripe. Now, of course I'm using a floor shift, so the column mounted switch is useless. Do I just leave these unplugged since I'm running an auto or do I need to jumper them together ? I assume one pair is backup lights and I'd want them disconnected.

Thank you,
Kevin

Kevin, Welcome to the thread.
I want to make sure I am understanding you correctly. You are getting rid of the 4 speed in your dually and going with an automatic, just an aftermarket floor shifter? If that Is the case then you can jump the nss but the new shifter should have a nss in it to be wired as well as b/u lights. if you want it to be able to start in gear just jump it and forget about it. I dont have the schematics to tell you which wire is which however it shouldn't be hard to figure out. For tech questions RFmaster seems to be incredibly knowledgeable.
Again welcome.

[Tx Firefighter]

My truck is a 4 speed floor shift. My wiring harness donor was an automatic truck. When I removed the donor harness I now have a neutral safety switch just hanging out of the harness with no place to put it since I'm using floor shift 4 speed. I'm wondering what to do with the two plugs on that now useless neutral safety switch. One plug is green wire and blue wire. The other plug is orange w black stripe and black w white stripe.
Posted via Mobile Device

[Jonboy]

Take a look at the original wiring from your truck. I think the NSS should hook into the switch on the clutch pedal, and there should be a reverse switch on the trans.

[FRENCHBLUE72]

Hey kevin what did you do to hook up the vss?

[Tx Firefighter]

I'm using the instrument cluster out of the 87 donor truck. It has a built in VSS that plugs into the factory harness.

[FRENCHBLUE72]

I see thanks... Does anyone know if the performance of the motor will suffer if the vss is not hooked up?

[rfmaster]

Originally Posted by FRENCHBLUE72

I see thanks... Does anyone know if the performance of the motor will suffer if the vss is not hooked up?

A simple answer is yes - there are number of operational parameters (depending on calibration) related to CCP, EGR, AE and PE enrichment routines triggered by VSS data. In other words without VSS input ECM believes that truck is stationary and you are simply revving engine up.

//RF

[FRENCHBLUE72]

So I guess the question is how would I fix it? I have the motor and tranny (1987 tbi )combo in a 82 toyota truck with no speedo? Is there a simple fix or should I just pull out the rest of my hair now?

[Jonboy]

I used a VSS from Jags that run. It was $75, and screws to the side of the transmission, in line with the speedometer cable. Something else to consider is that your TCC will not work without a VSS, and that could lead to transmission failure due to overheating the fluid from the slipping clutch over time.

[FRENCHBLUE72]

My trans is a th350 I should have mentioned that I swapped that in..

[FritzA]

I just wanted to add a couple things I learned about the DRAC.

First, Dakota Digital makes a version of the DRAC called the SGI-5. It is a lot easier to adjust than the chevy one, works with lot's of different VSS signals and has different output signals as well. No soldering! Summit has it for $75. Not a bad deal. You can download the pdf installation manual and read up on it.

Second, I thought I was going to need the DRAC/SGI-5 then I decided to go with an Autometer electric speedo. Suprise suprise.....it accepts various VSS inputs, is adjustable and has a DC Square wave output tab to feed my 1990 ECM. I don't need the DRAC or SGI-5!! A lot less wiring to do. I do not have a cruise control so this is all I need. I just saved $75, can you tell I'm excited?

[rfmaster]

Originally Posted by FritzA

I just wanted to add a couple things I learned about the DRAC.

First, Dakota Digital makes a version of the DRAC called the SGI-5. It is a lot easier to adjust than the chevy one, works with lot's of different VSS signals and has different output signals as well. No soldering! Summit has it for $75. Not a bad deal. You can download the pdf installation manual and read up on it.

Second, I thought I was going to need the DRAC/SGI-5 then I decided to go with an Autometer electric speedo. Suprise suprise.....it accepts various VSS inputs, is adjustable and has a DC Square wave output tab to feed my 1990 ECM. I don't need the DRAC or SGI-5!! A lot less wiring to do. I do not have a cruise control so this is all I need. I just saved $75, can you tell I'm excited?

That's a very good point - however if you are using Autometer speedometer you are still dependent on VSS (5291 or what is available ) to provide correct number of pulses per mile traveled to ECM. For example, if you are working with 87 to 92 TBI system a 2000 ppm VSS (open collector) is required. If you are using 5291 VSS the speedometer output terminal provides buffered +5 volt DC Square wave signal. In other words VSS must match what ECM is expecting to receive.
The SGI-5 appears to be a "Swiss knife" between VSS and ECM/PCM. The later PCM's (93-95) actually required two speed input signals - DRAC provided these signals. I am starting to spend more time with 7427 PCM which expects two VSS signals (transmission input signal and vehicle speed).

//RF

[FritzA]

No, it is not dependent on the VSS to send the signal at the correct output. Both the Autometer electric speedo and the DD SGI-5 accept inputs at different signals but have an output tab that is converted to the DC Square Wave for the older ECMs like mine.

[rfmaster]

Originally Posted by FritzA

No, it is not dependent on the VSS to send the signal at the correct output. Both the Autometer electric speedo and the DD SGI-5 accept inputs at different signals but have an output tab that is converted to the DC Square Wave for the older ECMs like mine.

The input VSS signal can be either AC or DC - installation instructions for Autometer Spedometer clearly state that: 500 to 400,000 pulses per mile (ppm). However, there is no mention if buffered output from the speedometer can be altered (change pulse rate or signal wave form) to match ECM/PCM requirements. Instead, in the note they just mention the following:
NOTE: This speedometer provides an output (OUT) terminal that can
be used with late model vehicle installations using the existing Vehicle
Speed Sensor (VSS). In these installations, the VSS signal wire should
be connected to the SIG terminal of the speedometer only. The OUT
terminal should then be connected to where the VSS output was
originally wired. This will provide a buffered VSS signal to the PCM/
computer in the vehicle.

From retrofit perspective - it is important to be able to work with various VSS flavors - for example early TBI ECM's expects 2000 ppm oc signal, some TPI ECM need 4000 ppm AC and so on. After market VSS can be either AC or oc 2000, 4000, 16000ppm and so on. So, from that view point SGI-5 is a must have...

//RF

[FritzA]

We are close to being in agreement.

I did not say the Autometer output is variable. I said it has a "DC square wave" output.

My instructions from Autometer say the putput is "+5 volt DC Square wave signal". It is not variable, it is the only output option no matter what the VSS input into the speedometer is. But for my 1990 ECM that output is just right.

So no, I do not believe the SGI-5 is a must have for my situation.

[dropd80s]

I have a few questions I could use some clarification on. I have decided to use a E2000 style ford fuel pump. Both the lit. and the pump it self says 95 PSI max also 34 gph free flow rate.If I run 5/16" return line, will this be large enough to handle the volume? Also, my fuel lines will be a combination of OE steel line and EFI rated rubber hose. Does the return line in my setup need to be rated for the higher fuel pressure? Just don't want to spend extra money if its not needed.

Also, I am using the entire harness from a 90 burb for my 86 crew cab. I want to remove the RWAL system but would like to do something a little cleaner than just leaving it unplugged. Does anyone have pin out for the EBCM? I would like to remove what wires going to the EBCM I can from the under hood harness completely, but not blindly. I know some of the wires functions, input from the DRAC, brake light output etc., but I can't find a diagram online for the others.

[rfmaster]

I guess there I'll have to tackle this question.

The Master E2000 pump is a high pressure pump - used in 3 bar systems (45 PSI) - TPI for example. It is a bit on high side for TBI which really needs 30 PSI pump. The 95 PSI rating is a deadhead rating (0gph flow) as pump flow rate will vary vs. pressure. Long story short - it is OK, but there are better pumps out there for TBI application. So, at 15 PSI this pump will deliver around 43 GPH. Example of fuel flow rate chart




The 5/16" return line is a standard size line in OE TBI. Should work just fine. Use 3/8" or -6AN size for feed.

In the engine bay ECM harness does not include RWAL except for DRAC I/O. I would use ECM harness by itself which for the most part stays on passenger side of the engine bay. There are handful of wires that cross over toward driver side of the engine bay. The rest of it I would keep OE from '86. I do not know if that is the answer that's you were looking for.

//RF

[dropd80s]

RF,
Any advice on if I need the higher pressure rated hose for the return? I suppose I will as the pressure being bled off the regulator will be significant given the extra pressure my pump will generate. Thoughts?

Also, I managed to trace out the RWAL wires and remove them. The 86 I have came with no harness what so ever, so I had to swap the entire harness from the 90 burb. No major hassle. With the exception of the RWAL system I wanted to remove, which was no big deal, it was very easy. I think it was much more simple and much cleaner to swap the entire harness than to try and separate one harness and piggy back it onto another.

Thanks for your help. This thread has answered a lot of questions.

[rfmaster]

Originally Posted by dropd80s

RF,
Any advice on if I need the higher pressure rated hose for the return? I suppose I will as the pressure being bled off the regulator will be significant given the extra pressure my pump will generate. Thoughts?

Also, I managed to trace out the RWAL wires and remove them. The 86 I have came with no harness what so ever, so I had to swap the entire harness from the 90 burb. No major hassle. With the exception of the RWAL system I wanted to remove, which was no big deal, it was very easy. I think it was much more simple and much cleaner to swap the entire harness than to try and separate one harness and piggy back it onto another.

Thanks for your help. This thread has answered a lot of questions.

Return line is a low pressure unless there is a restriction that should not be there!. I use SAE30R7 (50 PSI rated fuel rated hose) in my return lines. For the most part you want use hardline (5/16 or 3/8" ID) for 90% of the run. Use rubber hose sparingly as it will age over time and will require eventual replacement.

Yes, harness dressing can be a load of fun!

Get it done.

//RF

[dropd80s]

Ok good to know. I am using what steel fuel line I can from the burb. I would say 80-85% of the lines will be OE steel. There will just be a short line from the burb lines to the pump and the pump to saddle tank. Thanks again for your help!

[BigBlocksRule]

Yet another newbie...
I have an '85 dually that I want to sell the engine and tranny out of and install a freshly rebuilt Gen 6 454 along with a 4L80E. I have a '95 that I'm using the cab and other parts for a different project, so I can strip the computer and harness out of it, this truck originally had a 350 and 4L80E. I have access to an '87 truck that I can snag a baffled TBI tank from and plan to install a transfer pump to move fuel from the unused tank into the one with the TBI fuel pump. I also have sourced a set of gauges from a '91 so I can use the electronic speedo.
What am I overlooking?