Adam Mclaughlin

Hey Guys,

I am a new member to the group, this board was reffered to me by antoher web surfer at the pirate web site.

I have a 1993 LT-1 that came out of a Vette. It is set up for an automatic transmission, and california emissions.

I swapped the motor into a 1972 2wd blazer that I had, using a painless wiring harness and a 700R4 that is not computer controlled.

The truck starts and runs, but it has NO power. I tried a hypertech chip, no response. I tried replacing the computer and wiring harness, no better. Someone else replaced the computer and the wiring harness for me as well, no change.

I went to GM, and I ordered a stick shift computer module to take the automatic transmission part out of the picture. When I install this module, the engine starts, but will not run for more than 2 seconds.

What gives? Are the wiring harness so different that an automatic harness will not run in a stick shift computer? What changes are necessary to make all of this work and actually have some power?

Do I need to change the wiring harness? I tried to replace the computer module for a stick shift one because I wanted to take the automatic out of the equation, since the 700R4 behind the motor is not computer controlled.

Any suggestions?

Adam

Teal94Z

You apparently have some of the wiring wrong, just go back and trace over what you have done to double check it. Also, make sure the correct wires are on the plugs from the optispark, that will cause tons of problems if you have the plug wires crossed.

madwolf

Adam,
the 6 speed chip doesn't work because it has the Vehicle Anti Theft System enabled which is shutting your engine off.
What chip are you using currently? (the one that has no power)

PS. There were no computer controlled automatics on 93 LT1s. The only thing the computer controlled on that tranny is torque lockup and release. So technically the chip should work. It may set a code or two but it should work.

Adam Mclaughlin

WHo has a wiring diagram for me to check against? Painless doesn't give me squat.

The truck starts and runs OKAY witht the automatic chip, but starts and dies on the stick shift one with no other changes. How could the anti theft be jumping in here and causing me grief?

I really thought there would be a computer controlled 4L60E in there back in 1993, but I could be wrong. Huh.

There are six wires to the tranny hanging there in space, and I was wondering if that was the problem. That's why I tried to pull the automatic out of the equation.

The chip that has no power is the hypertech power one set up for an automatic.

How important is the VSS to the power curve? This guy does not have one set up correctly, or as far as I can tell accuarely. Does this make the machine a dog without it?

Again, who has a wiring diagram that they could shoot me?

Thanks for the quick replies, guys.

Adam

Prorac1

In 1993 Gm used the 4l60 (a upgraded? 700r4). It wasnt until 1994 that they started using computer controled trannys. (Hence the 4l60E). Also remember that your taking a motor that put a 3500 lbs F body or vette into the mid 14s and putting it into a 4500 lbs blazer. So all things considered (depending on how sluggish its acting) with stock manifolds etc. It probably wont be a rocket ship. Hope this helps. Prorac1

madwolf

No 4L60E on 93s. They put them in beginning 94.
Yes, the VATS is killing your engine with the other chip. I can disable all automatic tranny functions and VATS if that's what you need.

The lack of VSS *could* be the problem. The computer may be switching to limp mode and thus the power loss. Unfortunately, I don't have a 93 manual to verify that....

Adam Mclaughlin

Okay guys, Consider something like this.

When you goose the truck from a stop, it starts to launch like I think it should, then it slowly acclerates, and when it shifts gears it BOGS down. I didn't want to toss that up in the begining, because I have not gotten to verify it, but the owner complains of that.

I could work the VSS better. Does anyone know how many pulses per mile the 1993 LT-1 is looking for? That way I can get it and put together a VSS signal for it that would be acceptable for it's computer to handle.

It throws me NO codes no matter what, unless I disconnect a sensor or something.

Any more ideas pop up?

I am really liking how quickly you guys are getting back to me, This is very welcome and appreciated.

Adam

Adam Mclaughlin

Let me also say that I have connected up my Hewlett Packard 1740A scope on all of the sensors, injectors, modules, etc, and everything responds the way it should.

SO, I have checked out the easy stuff. I am leaning towards ordering a new VSS setup for the guy now. Could this be something worth looking into?

Adam

madwolf

I'm assuming you guys will be using a mechanical speedo, right? If so, the easiest way is to get a new chip or the stock chip reprogrammed to eliminate VSS. Much cheaper than ordering a VSS setup.
On 94-97 F-bodies, the Automatic VSS generated 40 pulses per second and the Manual VSS generates 17 pulses per second. I'm 95% sure the same applies to 93 F-bodies and Automatic Corvettes. Not sure about 6 speed vettes... I don't think it's a Borg Warner so it might have a different VSS too.

madwolf

Forgot to mention... you might want to try CorvetteForum. Check the C4 tech section or the C4 Scan and Tune....