Re: Tbi swap build thread
 

Yes, the 92 'may' have VATS anti-theft system. Check ECM I/O connector pin B6 which is input from VATS module. Two ways to get around it. First is to burn a new EPROM that disables this function. Requires some cash outlays for EPROM PCBA adapter, EPROM (or FLASH memory chip) and burning equipment or knowing someone to do it for you. Second approach is to build a 30 Hz pulse generator to provide 50% duty cycle pulse signal to pin B6. Once ECM sees this pulse signal during cranking it enables fuel injector driver circuits. Alternatively, find 1227747 ECM from 305 truck and use it as is - trucks did not have VATS system. The 7747 ECM will plug into Caprice harness and will work fine. I presume that you are going to omit AIR pump - it is only used during cold starts and later trucks did not have AIR system.

//RF

Re: Tbi swap build thread
 

Thanks. I better save myself some time/trouble and go ahead and obtain the 7747.

Re: Tbi swap build thread
 

Finally got mine running. cranked on the first try! Any way i i found a 4l60e how would i wire it to work with my comp? i dont have the number with me but i know it is from a 90 4.3 truck but my 350 runs fine with it stock.

Re: Tbi swap build thread
 

That '90 model tranny is a 700R4, the 4L60E didn't appear until 1993.
Kudos on getting it running!

Re: Tbi swap build thread
 

Are you running your 350 with a 4.3 ECM? If so it should be reprogrammed for the right injector size & engine displacement. It is probably dangerously lean as is.
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Re: Tbi swap build thread
 

well i havent had the exhaust done yet but it seams to run good. but who knows.

Re: Tbi swap build thread
 

Just post the contents of the part number label attached to ECM cover - this should tell us the ECM family and calibration type. If it is missing remove the EPROM cover held down with two screws and note the four letter code on EPROM chip.

//RF

Re: Tbi swap build thread
 

16144288 atkn

Re: Tbi swap build thread
 

BCC: ATKN
Year 1990
PROM Size 32724
ECM #16144288
Program ID: 160 ($A0)
Product Line: C1/K1/P1
Engine: LB4 4.3L
Transmission MD8 AUTO (700R4)

This ECM was specifically developed for V6 application. ECM will run V8, but limp mode will not work and calibration is off for a typical V8. However, you can modify VE and SA tables together with larger injectors. As is good enough to start your motor, but as for driving - very iffy.

//RF

Re: Tbi swap build thread
 

The 1227747 ECM's are so common you should be able to find a 5.7 OD auto version pretty easily and save yourself a bunch of time & effort.
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Re: Tbi swap build thread
 

Hey gand, great thread, really helps me in my journey. I am currently working on a TPI swap for my 86 C10.

I am fairly certain I have the VSS figured out. Could someone confirm or deny. I was feeling around on the back of the cluster and felt a square hole right behind the speedo, seems that is where the optical VSS sensor mounts. Would this be true?

If so, how do I remove the cluster without breaking it? That was my biggest fear, as I am well aware how fragile this old GM plastic is!

Re: Tbi swap build thread
 

That is where the optical VSS goes. The only sure way to not break off the left hand tab is to pull the dash pad. The rest of the cluster housing is pretty tough.
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Re: Tbi swap build thread
 

ok cool. I have already pulled the pad so I'll give it another try today

Re: Tbi swap build thread
 

You guys rock. Saved me $75 on a JTR sensor.

http://i272.photobucket.com/albums/j...y/102_0720.jpg

There it is, the speed sensor hole.

http://i272.photobucket.com/albums/j...y/102_0721.jpg

Installed an 80's Malibu VSS I had lying around. Perfect.

The four wires coming off the VSS, My guesses are:

Brown - 2k signal to ECU
Blk/wht - ground
Pink/blk - Hot in run/start
Yellow - 2k signal to cruise

Yes or no? There isn't much info on retrofitting an optical VSS.

Re: Tbi swap build thread
 

suscribe

Re: Tbi swap build thread
 

ok i decided on the nv3500. So my question is do i need a drac to make my vss work or can i wire the tailshaft mounted vss right to the ecm?

Re: Tbi swap build thread
 

I did a bit of search on this subject since I have never dealt with NV3500 trany. From what I could find the NV3500 employes a 40 pulse VSS (per shaft revolution), so that you'll have to sue a DRAC or Dakota digital buffer module to arrive to 2000 ppm signal that TBI ECM (aka 1227747) is expecting.

The Dokota Digital converter module is a Swiss army knife equivalent of GM DRAC minus the PITA. This module is pricy, but time and effort may justify the initial cost. Check their website SGI-5 Universal Signal Interface Unit.

//RF

Re: Tbi swap build thread
 

ok, also i have a question about dynamic efi. I have browzed there web site how hard is it to learn how to use.

Re: Tbi swap build thread
 

It is a lot easier than trying to burn own chips. There is a main thread (as well as several smaller threads) on thirdgen.org that deals with EBL user questions. Unless you have a fire breathing monster of a camshaft+engine EBL can handle.

I run EBL on all my conversions - see youtube videos. The key to TBI is selecting camshaft that provides about 14-16 in-Hg at idle and steady idle. After market camshaft with LSA of 112deg and higher with up to 214deg at 0.050 will do the trick. Tighter LSA (<112deg) results in lumpy idle which screws up MAP sensor readings and ECM will over fuel the engine. Long duration camshafts >220 deg also create havoc for O2 sensors at idle. Our trucks need low end torque, and high RPM HP is never really needed in a street truck. What we need is flat torque from 1500 to about 4500 RPM to get the weight going (and keep it going). A good RV cam will do this trick without creating problems for TBI system - for example CS1014R (flat tappet).

//RF

Re: Tbi swap build thread
 

Great thread guys! Looking to TBI my 85 here in the near future....

Re: Tbi swap build thread
 

looking to do a tbi swap to my 86 k30 dump. i got a 89 c2500 that used to be my dd. i plan on pulling the motor, wiring and all relays/sensors from under the hood, and computer soon. is there anything else that i will need from the donar truck. also am i gonna have to replace the 86 wiring under the dash or will i be able just to put power to the computer to run all engine componets.

Re: Tbi swap build thread
 

Im redoing my wiring on the 65 tbi, i would like some pictures of the swap done on 60-66 trucks please.

Re: Tbi swap build thread
 

One of the key components is VSS. Depending on the donor vehicle VSS can be PITA. Do you have donor identified? Also, you do not have to replace any of the under dash wiring - EFI is a standalone system and is adapted to your 86 harness - fuse box.

//RF

Re: Tbi swap build thread
 

A guy a few posts back asked about 700r4/4l60 integration. What's involved? I have an 87 sb, 350tbi/350 and of course I want the od. Any info on what might be involved? Really kinda thinking of getting a 94/95 computer and running tbi/4l60 like I had in my 95. Is this easy? A pipe dream? Anyone done it? I have 2 90 2wd burbs in a yard not far away that are still fairly complete with electronic speed outputs for the 700's. My 87 t350 is a cable. Will the tailshafts swap? Can I just put a later cluster in my truck? Sorry for all the questions, but I've been wondering. Thanks, Chip.

Re: Tbi swap build thread
 

Hey Chip
The 93-95 PCM's are (were for their day) advanced powertrain computers and much more powerful than C3 ECM found in 87-92 C/K's. The PCM can control TBI and 4L60E/80E as well as 700R4. It can also be used with manual gear boxes - all of this requires modifying EPROM. This is a long discussion (PCM mods) and better be done else where. There is a lot of information available - TGO, moates and elsewhere.
Regarding Spedo. This is where it gets a bit tricky since 93-95 used electronic speedometers. The VSS produces 40 pulse per shaft revolution which gets passed to DRAC module. DRAC module has three outputs which feed into anti lock brake system computer, cruise control and PCM.

To swap into 87 I would look into converting 4L60E VSS from electronic to mechanical drive with addition of inline VSS module to drive the PCM (assuming that there is no cruise control). This swap would require removal of reluctor ring pressed onto tail shaft and installation of drive gear to drive driven gear. You'll also need speedometer gear housing. For more info see link below.

http://www.transmissioncenter.net/sp...n_______va.htm

//RF