How To: Ditch EFI and keep TBI PCM for 4L60E Control.

[willie]

help. please.

i did exactly what you posted and still in limp mode. can you help me?

New Here, and just finished a TBI v6 to Carb 350 swap. Here is a how to on how to keep the 4L60E working.

Well, I finished swapping a Carb 350 into my truck, i am using the stock TBI PCM to control the 4L60E. and here is how!

DO NOT ATTEMPT THIS IF YOU HAVE EMISSIONS!

Transmission Control Via TBI PCM:

First off, Here is what the PCM needs to operate the 4L60E

-VSS
-CTS
-TPS
-A RPM Signal

Now i did the exact same thing 04SilveradoMykk did in his thread with his Vortec PCM, But my truck was stuck in limp home mode.

Mykk's Thread-> http://www.gmfullsize.com/forum/showthread.php?t=145089

I am running a Stock GM HEI distributor, and it is what i would recommend for a similar swap, I WOULD NOT keep the TBI Distributor, you have no clue as to what the PCM is gonna do without seeing fuel.

Now with a TBI engine, there is no crank sensor telling the PCM if its running.

It took me about a week to figure out what to do, but when i did its easy as 123.

1.Find the plug that used to plug into the Distributor and lead to the PCM.

2.Find the Purple/White wire

3. Take Wire and run it into the TACH position on your HEI Distributor.

4. Done!

Picture of wire with a quick disconnect.

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Here is a Picture of my TPS on my Speed Demon 650CFM

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Picture of Holley TPS Kit on a Holley 670CFM Street Avenger, Far better way to go.

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Picture of whole setup

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Here is a Video of me leaving my driveway, as you can see my tranny is functioning proper (I still manual shift it) if the purple/white wire wasn't hooked up, i wouldn't get 1st or OD.

http://s668.photobucket.com/albums/vv44/Low_Orange/?action=view&current=MOV01285.flv

as you can see in the video, my Speedo, Coolant temp and all other gauges work like factory (My Oil PSI gauge isn't working cause my Oil Sender is gone, Replaced with an Autometer unit)

So now that your 4L60E is working, lets carry onto Fuel.

Fuel:

I sent up my fuel system a little different then Mykk, Here is what i used.

-Stock TBI In-tank Pump
-Holley 12-803BP ByPass Regulator (http://www.summitracing.com/parts/HLY-12-803BP/)
-Marshall 0-15PSI Gauge, (Not shown)

It is VERY Important that if you are keeping the stock pump, you HAVE to have a return, i dont care what anyone else says, just capping off the return is gonna kill the pump, THE RETURN IS THERE TO COOL THE PUMP!.

Picture of my setup.

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Those are the stock TBI Fuel Lines, i just bent them a bit and cut off the fittings and installed some new ones.

I then ran a hose barb out the left side to the carb, shown here.

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at first it ran great, but i still wanted to check my PSI, so i added a gauge. using some fittings we had laying around, i dont have any pictures of it, sorry.

I found that my demon likes 6.5-7PSI. and the Holley Regulator is factory set at 5PSI.

After this, the engine ran very well, i would recommend this swap to anyone wanting a bit more out of their engine.

-Josh

 

[atlbigboipimpin]

I'm trying to duplicate this same build and I have a question pertaining to the shift linkage. My truck is a 1988 with the old linkage type hookup on the side of the tranny. But with the nuetral safety switch in the way it wont mount up correctly, so question is can I remove the safety switch and hook up linkage as it was on my old 700r4. Any help would be greatly appreciated and thanks in advance.

 

[MOBS]

Technically speaking, you can bypass the switch so long as the switch is in a position that it thinks tranny is in park or neutral. If not, it will stop the engine from cranking over. As far as deleting the switch, I'm not sure of the wiring scenario, so I can't help you there. Also, if the pcm reads off the nss, it might cause driveability issues, since it'll think it's in N or P.

 

[RyanR]

WOW! Great thread! Got my wheels turning!

I live in southern Arkansas where FI tuning is very limited, so I'm a carb lover and this really has me rethinking plans for my 96 Z. This is a great choice for stock and modified vortec's but my question is, why isn't anyone dropping a 5.3, 6.0, or 6.2 in? Carb it and let the stock black box pcm run the 4L60

 

[Horns]

WOW! Great thread! Got my wheels turning!

I live in southern Arkansas where FI tuning is very limited, so I'm a carb lover and this really has me rethinking plans for my 96 Z. This is a great choice for stock and modified vortec's but my question is, why isn't anyone dropping a 5.3, 6.0, or 6.2 in? Carb it and let the stock black box pcm run the 4L60

Because the tuning opportunities with the LS engines are pretty wild and with the ability of mail order tunes it's kind of goofy to take an engine like an LS and make it a carbed engine. It also has to do with the fact that most people who really like carbs, really like first generation small blocks too.

It's very possible to carb an LS engine though. GM even sells carbed LS crate engines.

 

[RyanR]

Because the tuning opportunities with the LS engines are pretty wild and with the ability of mail order tunes it's kind of goofy to take an engine like an LS and make it a carbed engine. It also has to do with the fact that most people who really like carbs, really like first generation small blocks too.

It's very possible to carb an LS engine though. GM even sells carbed LS crate engines.

Mail order tunes FTL! I'm a very big racing junkie, been in the Ford stuff the last several years and just recently got out... Try getting a fully built 700 rwhp Lightning tuned by mail tunes... complete nightmare! After that experience, if I can't have someone hands on with my rig or do it myself, I won't do it. I should of known better than building something so crazy around here in southern redneck central. So a carbed LS motor sounds like a win=win to me lol.

 

[Horns]

I'm talking mail order as in you run a data cable on your truck for a couple weeks and then send that information off to the tuner and they write the tune. There are many people who have done this with a company like black bear or MJ Engineering that are successful with it.

 

[RyanR]

I'm talking mail order as in you run a data cable on your truck for a couple weeks and then send that information off to the tuner and they write the tune. There are many people who have done this with a company like black bear or MJ Engineering that are successful with it.

Me too bro.... Was running SCT and used the 2 best tuners money could buy with absolutely no luck after countless datalogs, revised tunes, and emails... Never again! Which I'm sure a basic GM setup would be much easier to tune than my old Lightning obviously was. No more Fords and happy to back in the GM world again.

 

[fun4me]

Can't believe this thread is still around.

 

[FastOrange]

Can't believe this thread is still around.

Huh? Why?