7747 to 7427

Figured I'd better start a thread for Q&A on this swap.

The 7427 that I've bought came out of a '95 1/2 ton van with a 350 and automatic tranny.
The truck that it is going into is a '91 1/2 ton 2WD with currently a 305(not for long)and auto tranny.
I know already that the 4L60E shifting parameters are going to have to be 0ed out with the exception of the TCC lock.

Correct me if I'm wrong but doesn't the 7427 have the ESC built in?

How far downstream can I run a HEGO? Right now it can go in the exh. manifold but eventually it will be going into the exhaust possibly 36" from the collectors.
My plan for exhaust on this truck is 3" coming off the collectors with the left side crossing over under the tail housing of the tranny then going into a muffler with two 3" inlets and one 3" outlet then up over the rear end and out the right rear in the stock configuration. I would like to put the 02 in a crossover pipe right in front of the muffler,that way it reads both sides.

I read that you can hook a WB02 to the input for EGR position. Is that just for datalogging or can it be set up for BLM?

I was doing some research on the 7427 inputs and it has two for driveshaft speed. One is 2000PPM(DRAC) and the other is 40PPR(VSS). Do I need both?

WBO2 sensor has nothing to do with blm. It’s only purpose is for data logging and tuning.

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Originally Posted by TriumphR3

WBO2 sensor has nothing to do with blm. It’s only purpose is for data logging and tuning.

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Will it read in air/fuel or just the voltage it produced?

You only need a single 2 pulse per revolution VSS sensor connected to up to the Pin F13 on the ECU. Yes, the ESC is built into the 7427 ECI.

https://jagsthatrun.com/collections/...ce-holder-4pac

Howell also used to sell a 2pulse VSS, but I couldn't locate it via a Google search. Mine came from Howell.

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Originally Posted by scooterwrench

Will it read in air/fuel or just the voltage it produced?

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The ECU will require an OEM type narrow band O2 sensor to adjust fuel. Do yourself a favor and make sure to get the heated narrow band sensor. The wide band sensor is an additional separate sensor and control box that displays the AFR and outputs I believe a 0-10Volt signal to the 7427 ECU. This allows you to record your wideband O2 readings into your datalog.

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Originally Posted by tplasek

You only need a single 2 pulse per revolution VSS sensor connected to up to the Pin F13 on the ECU. Yes, the ESC is built into the 7427 ECI.

https://jagsthatrun.com/collections/...ce-holder-4pac

Howell also used to sell a 2pulse VSS, but I couldn't locate it via a Google search. Mine came from Howell.

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I've already got that covered.
When I bought ol Smoky the fuel and oil pressure gauges didn't work and new sensors didn't fix it. I had bought a set of Marshall instruments for a 98 S-10 that I was going to put my 355 in but lost interest in that POS so they went into Smoky. The original gauges were moonies with the VSSB/DRAC built into the gauge board that I wasn't going to be able to use so I bought a DRAC module,re-pinned it for my gear ratio and wired it in. The DRAC has four outputs. 40 ppr(tail shaft speed)for ECM,2000 ppm for speedo and ECM,4000ppm for cruise control and 128,000ppm for anti lock brakes. I used the 40ppr to run the speedo because it needed 4000-200,000ppm for it's input. The 2000ppm signal went to the ECM and the 4000ppm to the cruise control. I dropped kicked the RWAL brake module and valves into the garbage can,the dump valve was toast. So now I have the 2000ppm signal for pin F13 on the 7427 and the speedo has a 1:1 output that will pass the 40ppr signal to pin F12,,,,,,,,,if I need it! Do I need the 40ppr for correct TCC lock up on a 700R4?

WB02 signal is 0-5V off the controller.

The swap tutorial states that I should use pin E11 to drive the TCC but that is a pulse width modulated output. Pin E10 is the direct ground output for the TCC. Would using pin E11 allow the TCC to slip because it is not getting a direct ground signal?

Getting ready to swap the ECM's and got to thinking of how big a PITA it was going to be changing chips because of where the ECM is mounted. It's tucked up behind the glovebox on the extreme right hand side of the cab with not much wire to pull it out to change chips. I've made a remote mount chip socket mounted to the inside of the glovebox.
Y'all check this out.

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Originally Posted by scooterwrench

Getting ready to swap the ECM's and got to thinking of how big a PITA it was going to be changing chips because of where the ECM is mounted. It's tucked up behind the glovebox on the extreme right hand side of the cab with not much wire to pull it out to change chips. I've made a remote mount chip socket mounted to the inside of the glovebox.
Y'all check this out.

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That is a very clever solution. :thumbsup:

I'm wondering if there might be some signal loss or signal delay from the ZIF to the adapter board?

Possibly the ribbon cable will act like an antenna and pickup unwanted noise?

I've always let the PCM hang down from the connectors during the tuning process. (messy looking but convenient)

Attached are my notes for a 7747 to 7427 conversion.

I used the pin detect on my prom burner and a blank chip to test with and the first time it didn't pass. Broke out my ohm meter and discovered the small header connector didn't make a connection on pins 13,17 and 28. Pulled that one off,trimmed the cable back and pushed on another one and rechecked with the meter and then again with the burner,passed both tests that time. I read that the 7747 didn't play well with this setup and needed a signal amplifier but the 7427 didn't have that problem. That proto board was a little bit of a PITA. I had to solder in traces to make sure the ZIF socket got a good connection with the box header. That ribbon cable is only about 12" long so I'm hoping that will keep signal loss down to a minimum. If I do get noise I can shield the cable if need be.

I studied the tutorial on the site for the 7747 to 7427 swap and crossed referenced with the pinouts for the two and got a lot of notes written down.
I've pulled the .bin on the 7427 and read it. It's written for a 95 G series van with a 350 and I'm reading it with Fast 355's $OD 700R4 mask. It's going in a 91 C1500 with a 700R4 and 305. I haven't pulled the .bin on the 7747 yet.

Thanks for posting your pinout notes. It confirms that I need the 2000ppm VSS signal off my DRAC for pin F13 on the 7427. Pin F12 receives the 40ppr buffered signal from the DRAC which is now feeding my speedo. The speedo has an output to pass whatever signal it is receiving. If someday I ever decide to go with a 4L60-E or 4L80-E would I need that 40ppr hooked up to pin F12?

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Originally Posted by scooterwrench

Thanks for posting your pinout notes. It confirms that I need the 2000ppm VSS signal off my DRAC for pin F13 on the 7427. Pin F12 receives the 40ppr buffered signal from the DRAC which is now feeding my speedo. The speedo has an output to pass whatever signal it is receiving. If someday I ever decide to go with a 4L60-E or 4L80-E would I need that 40ppr hooked up to pin F12?

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1994 VSS
Attachment 19435

no TBI ecm/pcm requires a 40ppr signal directly. i believe either 2000 or 4000 ppm and can be selected in the calibration. you're VSSB is in the speedo housing IIRC.

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Originally Posted by tayto

no TBI ecm/pcm requires a 40ppr signal directly. i believe either 2000 or 4000 ppm and can be selected in the calibration. you're VSSB is in the speedo housing IIRC.

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Go back and read post #7

OK, I've made some changes to the 95 G series.bin mostly just changed the cyl. volume and injector specs for the 305,ran the speed limit up to 255,raised the rev limit up tp 5000 rpm,gave it a little more timing and raised the TCC to 35mph. On the 7747 it was going into third gear at the same the TC was locking(30mph)which made a harsh third gear shift at light throttle. I burned the chip with no issues save one. The original .bin in the 7427 was loaded at the bottom of the chip(as viewed on the buffer)and when I burned the new chip it burned it into the top. In the help section of TP it states to load the chip from 000000>00FFFF and that's where it put it but that's at the top of the chip. Is this going to create a problem or can the PCM find it in that region?

The 16197427 computer uses a 64K chip, hex addresses 000000 -> 00FFFF or 0000 -> FFFF

The 1227747 computer uses a 4K chip, hex addresses 000000 -> 000FFF or 000 -> FFF

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Originally Posted by dave w

The 16197427 computer uses a 64K chip, hex addresses 000000 -> 00FFFF or 0000 -> FFFF

The 1227747 computer uses a 4K chip, hex addresses 000000 -> 000FFF or 000 -> FFF

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I'm tuning for the 7427, SST 27SF512 EEPROM and I did use address 000000->00FFFF and you didn't answer my question. The original prom was loaded in the bottom and the prom I burned was loaded in the top,is this going to cause a problem?

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Originally Posted by scooterwrench

The original .bin in the 7427 was loaded at the bottom of the chip(as viewed on the buffer)and when I burned the new chip it burned it into the top. In the help section of TP it states to load the chip from 000000>00FFFF and that's where it put it but that's at the top of the chip. Is this going to create a problem or can the PCM find it in that region?

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As I said!

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Originally Posted by scooterwrench

As I said!

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The 27SF512 is a 64K chip, I think we can agree on that. :thumbsup:

The '7427 uses a 64K chip, I think we can agree on that. :thumbsup:

Chips like the 27SF512 can be used in the 1227747, which is a 4K chip, that requires an offset. The 4K offset is at the bottom 4K of the 27SF512 chip.

I simply don't understand the question, the 27SF512 is a 64K chip and the '7427 uses / requires a 64K chip.

Why the argument? If you know how big the BIN for your ECM is, and you know how big your chip is, why not just use TunerPro's built-in BIN Stacker? Just stack the BIN and you won't ever have to worry about entry vectors being wrong.

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Originally Posted by dave w

The 27SF512 is a 64K chip, I think we can agree on that. :thumbsup:

The '7427 uses a 64K chip, I think we can agree on that. :thumbsup:

Chips like the 27SF512 can be used in the 1227747, which is a 4K chip, that requires an offset. The 4K offset is at the bottom 4K of the 27SF512 chip.

I simply don't understand the question, the 27SF512 is a 64K chip and the '7427 uses / requires a 64K chip.

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OK Dave,
Let me see if I can explain this better;

First of all take the 7747 out of the equation,it's going on the shelf. I may read the PROM to compare the .bin but I am not going to use that ECM.

We know that the .bin doesn't fill the whole chip,there is a blank region,right!.

I will be running the 7427 ECM and have burned a 27SF512 chip to put in that 7427. When I read the original .bin(chip)out of the 7427 all the data was loaded in the bottom region of the chip(blank region at the top). When I burned the 27SF512 chip I used the instructions in the tunerpro help page and chose 000000->00FFFF as the address to burn the .bin in. When I loaded the buffer it put the .bin in the upper region of the chip(blank region at the bottom). Is this going to create an issue or will the processor still be able to read the .bin? Basically is it supposed to do that?

I'm not wanting a debate.

I think I'm beginning to understand the question, but my answer is a question.

Link to factory / original '7427 .bin: http://www.gearhead-efi.com/Fuel-Inj...Information-0D

Perhaps the original BCC is listed in the link to compare the .bin you're working with?

Sometimes when I read an original chip and compare the same BCC on the link above I get a few address that are different FF vs. 00. Maybe the difference I see when I read a chip vs. what .bin posted in the link is the tool / software I used to read the chip with?

I've used dozens of .bin files from the gearhead-efi library and they ALL worked, even when there are large regions of FF or 00 in the top / middle / bottom of the .bin file.

Possibly start with a known good .bin file from the gearhead-efi library and enjoy many many miles of smiles.:jfj:

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Originally Posted by scooterwrench

We know that the .bin doesn't fill the whole chip,there is a blank region,right!.

I will be running the 7427 ECM and have burned a 27SF512 chip to put in that 7427. When I read the original .bin(chip)out of the 7427 all the data was loaded in the bottom region of the chip(blank region at the top). When I burned the 27SF512 chip I used the instructions in the tunerpro help page and chose 000000->00FFFF as the address to burn the .bin in. When I loaded the buffer it put the .bin in the upper region of the chip(blank region at the bottom). Is this going to create an issue or will the processor still be able to read the .bin? Basically is it supposed to do that?

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Looking into the $OE definition, those BINs are 64KB. The 27SF512 is also a 64KB chip. This means you should not be modifying anything at all in TunerPro's settings for burning the BIN. The BIN's layout is already correct for the chip since both are the exact same size. The only time you would change the setting is if the BIN were smaller than the chip, and even then, rather than changing the address and praying I got it right I would just stack the BIN instead with the built-in BIN Stacker.

Hiya,
Well, it looks like he thinks the '7427 will run with his '7747 file, which it will not, stacked or otherwise. Good luck to him being insulting.

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Originally Posted by dave w

I'm not wanting a debate.

I think I'm beginning to understand the question, but my answer is a question.

Link to factory / original '7427 .bin: http://www.gearhead-efi.com/Fuel-Inj...Information-0D

Perhaps the original BCC is listed in the link to compare the .bin you're working with?

Sometimes when I read an original chip and compare the same BCC on the link above I get a few address that are different FF vs. 00. Maybe the difference I see when I read a chip vs. what .bin posted in the link is the tool / software I used to read the chip with?

I've used dozens of .bin files from the gearhead-efi library and they ALL worked, even when there are large regions of FF or 00 in the top / middle / bottom of the .bin file.

Possibly start with a known good .bin file from the gearhead-efi library and enjoy many many miles of smiles.:jfj:

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I'm with you dave,I don't want to debate it either. I thought I was asking a simple question apparently I have confused everyone.

BCC on the 7427 is BPSA and unless I missed it I didn't find it in the listing. I bought the thing off evilbay and the description was 95 van with 350 and auto tranny. No mention of series(G10,20,30)or which trans,60 or 80. Supposedly it came out of a running van so I would "think" the BIN is good.

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Originally Posted by scooterwrench

I'm with you dave,I don't want to debate it either. I thought I was asking a simple question apparently I have confused everyone.

BCC on the 7427 is BPSA and unless I missed it I didn't find it in the listing. I bought the thing off evilbay and the description was 95 van with 350 and auto tranny. No mention of series(G10,20,30)or which trans,60 or 80. Supposedly it came out of a running van so I would "think" the BIN is good.

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See attached for the information I have on BPSA

I seem to remember a gearhead-efi thread if BPSA is a V8 Manual Transmission $OD .bin file. Likely BPSA is an automatic 4L60E .bin file.

Also attached is a 4.3 manual trans .bin file.

BPSA 700R4 parameters

Attachment 19458

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Originally Posted by dave w

BPSA 700R4 parameters

Attachment 19458

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Thanks Dave,
Which definition file did you use?

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Originally Posted by scooterwrench

Thanks Dave,
Which definition file did you use?

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$OD

Link in post #24

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Originally Posted by dave w

$OD

Link in post #24

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Yeah,there's three.

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Originally Posted by scooterwrench

Yeah,there's three.

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Advanced $0D TP5 v251.xdf

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Originally Posted by dave w

Advanced $0D TP5 v251.xdf

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That one is pretty in-depth. I've been using that one and Fast 355's The advanced xdf kind of jumps around where 355's is a little more organized,at least for me.